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352 articles found

T0052 – Comparison of HPMC based polymers performance as carriers for manufacture of solid dispersions using the melt extruder

Preparation of amorphous solid dispersions using hot-melt extrusion process for poorly water soluble compounds which degrade on melting remains a challenge due to exposure to high temperatures. The aim of this study was to develop a physically and chemically stable amorphous solid dispersion of a poorly water-soluble compound, NVS981, which is highly thermal sensitive and degrades upon melting at 165 °C. Hydroxypropyl Methyl Cellulose (HPMC) based polymers; HPMC 3cps, HPMC phthalate (HPMCP) and HPMC acetyl succinate (HPMCAS) were selected as carriers to prepare solid dispersions using hot melt extrusion because of their relatively low glass transition temperatures. The solid dispersions were compared for their ease of manufacturing, physical stability such as recrystallization potential, phase separation, molecular mobility and enhancement of drug dissolution. Two different drug loads of 20 and 50% (w/w) were studied in each polymer system. It was interesting to note that solid dispersions with 50% (w/w) drug load were easier to process in the melt extruder compared to 20% (w/w) drug load in all three carriers, which was attributed to the plasticizing behavior of the drug substance. Upon storage at accelerated stability conditions, no phase separation was observed in HPMC 3cps and HPMCAS solid dispersions at the lower and higher drug load, whereas for HPMCP, phase separation was observed at higher drug load after 3 months. The pharmaceutical performance of these solid dispersions was evaluated by studying drug dissolution in pH 6.8 phosphate buffer. Drug release from solid dispersion prepared from polymers used for enteric coating, i.e. HPMCP and HPMCAS was faster compared with the water soluble polymer HPMC 3cps. In conclusion, of the 3 polymers studied for preparing solid dispersions of thermally sensitive compound using hot melt extrusion, HPMCAS was found to be the most promising as it was easily processible and provided stable solid dispersions with enhanced dissolution.
Indrajit Ghosh, Jennifer Snyder, Radha Vippagunta, Marilyn Alvine, Ronak Vakil, Wei-Qin (Tony) Tong, Sudha Vippagunta, International Journal of Pharmaceutics 419 (2011) 12– 19

T0047 – Thermal analysis of complex relaxation processes in poly(desaminotyrosyl-tyrosine arylates)

The goal of this study is to better understand the thermal characteristics and molecular behavior of two poly(desaminotyrosyl-tyrosine arylates). These two polymers were chosen from a combinatorial library of polymers developed by changing the type and size of the two substitutable chain locations. The objective of this work was to describe the origin of the complex relaxation processes that have been observed by thermal analysis methods. DSC, TMA and TSC studies were conducted on poly(desaminotyrosyl-tyrosine dodecyl dodecanedioate), poly(DT 12,10), and poly(desaminotyrosyl-tyrosine ethyl succinate), poly(DT 2,2), in film and fiber form. DSC experiments on poly(DT 2,2) show only a glass transition at about 80°C which is characteristic of an amorphous polymer. The DSC of poly(DT 12,10) shows multiple thermal events indicative of a more complex internal structure. The thermally stimulated current (TSC) analysis results for poly(DT 2,2) indicate a region of molecular mobility at about 80°C consistent with the Tg from DSC. For poly(DT 12,10) there is a dipole relaxation process observed at about 40°C. An additional region of mobility at 60°C for poly(DT 12,10) fibers is observed. The comparison of conventional TSC with a modified TSC procedure suggests that this process represents a spontaneous reorganization of the internal structure of the solid. The comparison of DSC and TSC results suggests that poly(DT 12,10) has two distinct modes of organization with a transition between these modes at about 60°C. Previously published results indicate that solid state structure formation is related to two different modes of hydrogen bonding in the internal structure of the solid.
G. Collins, S-U. Yoo, A. Recber, M. Jaffe, Polymer 48 (2007) 975-988

T0046 – Process-structure-property relationships of erodable polymeric biomaterials: II–long range order in poly(desaminotyrosyl arylates)

The long-range order of some bioerodable polyesteramides based on a desaminotyrosyl [Thermochim Acta 396 (2003) 141; Polym Adv Technol 13 (2002) 926; J Am Chem Soc 119 (1997) 4553] diol monomer has been investigated. The order is mesogenic, best described as a 'condis crystal' or smectic-like. In all cases where long-range order is present, ordered H bonds between amide groups are observed. The order stabilizes the polymer to dimensional change and mechanical relaxation under biorelevant conditions.
M. Jaffe, Z. Ophir, G. Collins, A. Recber, S-U. Yoo, J.J. Rafalko, Polymer 44 (2003) 6033-6042

T0045 – Characterisation of EVA encapsulant material by thermally stimulated current technique

The purpose of this investigation is to better define the thermal behaviour of EVA-based encapsulant during photovoltaic module encapsulation process and also in field exposure in desert climate using the thermally stimulated current (TSC) technique. TSC experiments were conducted on EVA in the temperature range from -150°C to 70°C, the measurements were carried out on uncured and cured specimens of EVA and on EVA samples especially prepared using the laminator equipment. When performing the measurements with the TSC instrument it was noted that the EVA exhibits two peaks assigned to dipole relaxation processes. The peak maximum current and the area under the TSC current peak were used for the determination of the glass transition temperature, activation energy and relaxation frequency. For original EVA, we found that glass transition temperature at constant polarisation voltage and under different polarisation temperatures remain unchanged and is located around -38°C. Also, the activation energy has been determined using initial rise method to be about 0.32 eV. At gel content of 70%, the cured EVA shows a reduced integrated area under the depolarisation peak, especially for the high temperature. The combined change in TSC peak parameters of EVA encapsulant is correlated with the degree of curing.
K. Agroui, G. Collins, Solar Energy Materials & Solar Cells 80 (2003) 33-45

T0040 – The thermal analysis of films in the 21st century: Relevance to cell culture, biochips and roll-to-roll circuits

Films may be considered as wide fibers, or as unique material geometry possessing two dimensional symmetry (X, Y, Z). Potentially different uniformity issues along the machine (long) and transverse directions of the film, characterization of Z-axis performance-especially as films become "thin" and the characterization/identification of surface modification, introduce the need for careful sampling strategies if the resulting thermal analysis data is to be reflective of either process history or end-use performance or both. Two dimensional imaging by a combination of techniques-i.e., DSC-WAXS-FTIR-AFM exploit the convenience of the sample geometry, while aiding in the definition of structural complexity. Molecular spectroscopy techniques (DMA, TSC) provide a sensitive and instructive tool for examining novel surface or interface chemistry. Characterization under biorelevant conditions (37°C, aqueous, standard saline, presence of adhesive and other proteins, presence of cells) is critical for the generation of meaningful data on films to be utilized biologically (cell culture, tissue engineering substrates, biochips). Of special interest are strategies for accelerated aging that allow prediction of biological or biorelevant performance.
M. Jaffe, G. Collins and J. Menczel, Thermochimica Acta 442 (226) 87-91

T0035 – Low frequency chain dynamic of cross-linked poly(acrylic acid)

Cross-linked poly(acrylic acid) (PAA) synthesized by radical polymerization in inverse suspension is a swelling gel. The physical structure of PAA has been analyzed using low frequency chain dynamic given by the analysis of thermo stimulated currents (TSC). The alpha primary dielectric relaxation mode observed around the glass transition temperature (Tg=+38°C) corresponds to the slowest dynamic. The relaxation times of the constituting processes show that it is due to a delocalized cooperative molecular mobility involving nanometric sequences of the hydrocarbon skeleton. The beta secondary dielectric relaxation mode observed at lower temperature (Tbeta=-35°C) corresponds to a higher frequency molecular mobility. It has been assigned to the cooperative mobility of hydrogen bonded COOH groups. In fact, the hydrogen bonded side chains behave as an hydrophilic matrix in which nanometric domains constituted by sequences of the main chain are embedded. Such a picture might explain the specific swelling properties of cross-linked PAA.
Ch. Mayoux, J. Dandurand and C. Lacabanne, Thermochimica Acta 421 (2004) 43-49.

T0034 – Analysis of Thermally Stimulated Current and effect of rubbery annealing around glass-rubber transition temperature in polyethylene terephtalate

Thermally stimulated currents (TSC) in amorphous polyethylene terephthalate films have been investigated in the temperature range of -180 to 140°C. This material shows a very weak intensity peak at approximately -95°C and another around 80°C originated from dipolar process (alpha-peak), as evidenced from the variation of polarizing conditions such as applied electric field and polarizing time. The effect of isochronal rubbery annealing starts to appear from a temperature of annealing of 90°C, it then appears in a TSC spectrum two components around 88 and 108°C allotted, respectively to the true and rigid amorphous phases. The first component tends to disappear in an irreversible way to the detriment of the second which implies the establishment of an order within material during annealing by the formation and growth of nodules. The thermostimulated currents technique allowed to calculate with good precision the activation parameters of each process as well as the evaluation of the crystallinity rate by an established empirical formula.
N. Benrekaa , A. Gourari, M. Bendaoud and K. Ait-hamouda, Thermochimica Acta 413 (2004) 39-46

T0033 – The use of thermal methods for predicting glass-former fragility

Glass-former fragility describes the changing dynamics of a supercooled liquid with temperature and so dictates the temperature of glass transition as well as the dynamics of the non-equilibrium glassy state. Fragility parameters can be calculated from either experimental relaxation time or viscosity data. Predictions of fragility can also be made using thermal methods. The objectives of this manuscript are to evaluate three thermal methods of fragility prediction and, using these methods, to predict the fragility of a number of pharmaceutical glass-formers. Using differential scanning calorimetry, fragility predictions were performed by extrapolating configurational entropy to zero and by calculating an activation enthalpy of structural relaxation at the glass transition (?ETg) from the scanning rate dependency of the glass transition temperature, and glass transition width. On comparison with experimental Vogel-Tammann-Fulcher (VTF) fragility parameters for four glass-formers, all thermal methods were found to have reasonable predictive ability. Characterisation of pharmaceutical glass-formers by all thermal methods yielded predicted VTF D parameters in the range of 7-15. Predictions for a further 10 pharmaceutical glass-formers using only the configurational entropy method were within this range suggesting that moderately 'fragile' behaviour may be a common feature of such materials.
K.J. Crowley and G.Zografi, Thermochimica Acta 380 (2001) 79-93

T0032 – Characterization of structural heterogeneity of polyurethane coatings

The thermal analysis techniques - Differential Scanning Calorimetry and ThermoStimulated Current - have been used to characterize a polyurethane high solid coating. The glass transition temperature, as determined by DSC, is 60°C. Below this glass transition temperature, an sub dielectric relaxation mode has been observed; it corresponds to cooperative movements precursor of the glass transition. The ss dielectric relaxation mode, located at Tg has been attributed to movements of soft sequences of the amorphous phase liberated at the glass transition temperature. The analysis of the fine structure shows that they are constituted of elementary processes characterized by relaxation times following a compensation law. Above Tg, the hs dielectric relaxation of hard sequences has been shown. It corresponds to hard sequences hydrogen bonded in polyurethane
P. Paolpi, C. Lacabanne, Journal of Applied Polymer Science 81 (2001) 2786 - 2790

T0031 – Study of molecular mobility at the secondary relaxations range in polyamide 66 and polyamide 66/EPR blends by thermally stimulatde creep and current

Thermally stimulated creep with fractional loading technique and thermally stimulated current have been used to investigate the relaxation processes of polyamide 66 and polyamide 66/EPR blends over temperature range covering y, beta and alpha-EPR. Absorbed water decreases the thermally stimulated creep and the thermally stimulated current height of y-relaxation. The thermally stimulated creep mechanical beta-relaxation in PA66 is characterized by a broad peak, while the thermally stimulated current dielectric one is composed of two separate processes beta1 and beta2 according to the maximum temperature decrease. The peak height of the beta1 component is increased by moisture while the beta2 component is not modified. According to the criteria of Starkweather for sample and complex relaxations, the y- and low temperature part of beta-relaxations have been assigned to localized non-cooperative motions. The high temperature part of beta-process and alpha-EPR-relaxation have positive activation entropies and result from high cooperative motions. These interpretations from thermal sampling analysis is in close aggrement with the predictions of Ngai's coupling model.
P. Demont, M. Diffalah, J.J. Martinez-Vega and C. Lacabanne, Journal of Non-Crystalline Solids 172-174 (1994) 978-984

T0030 – Ultra low frequency study of dielectric relaxation in ferroelectric Polyamide 11

C. Maraval, A. Bernés, D. Chatain, C.Lacabanne and J. I. Scheinbeim, Journal of Electrostatics 40-41 (1997) 331-336

T0029 – Thermal behavior of ferroelectric polyamide 11 in a relation to pyroelectric properties

The pyroelectric properties of oriented thin films of ferroelectric Polyamide 11 have been studied in the temperature range of -100°C up to +140°C. The temperature dependence of the experimental pyroelectric coefficient has been analyzed. Three changes of slope of the pyroelectric coefficient are observed at -20, +50, and +100°C. The origin of the lower temperature event has not yet been defined. The upper transition is attributed to chain movements in crystalline regions, and more precisely, to a crystalline phase transition. The intermediate event is close to the glass transition temperature Tg observed by DSC. It is attributed to the manifestation of the glass transition. Below Tg, the variations of the pyroelectric coefficient are very small. For higher temperatures, it increases rapidly, attesting to a major contribution of secondary pyroelectricity and dimensional effects above Tg. The breaking of hydrogen bonds occurring at the glass transition temperature observed on DSC thermograms does not affect pyroelectric properties. Pyroelectric properties are mildly reduced after annealing at temperatures up to +140°C. A comparative study of oriented ferroelectric films prepared by quenching from the melt and nonoriented slowly cooled samples has been carried out by means of DSC
L. Ibos, C. Maraval, A. Bernès, G. Teyssèdre, C. Lacabanne, S-L. Wu and J.I. Scheinbeim, Journal of Polymer Sciences 37 (1999) 715-723

T0027 – Relaxations in amorphous and semi-crystalline polyesters. A study by thermally stimulated depolarization currents

Thermally stimulated depolarization currents and differential scanning calorimetry are performed on thermoplastic polyesters to characterize both and relaxations. The influence on the different relaxations phenomena of the chemical structure (size of the naphthalene groups, presence of cyclohexane, length of the aliphatic group, ) as well as the influence of the crystallinity are discussed. The three phases model with a crystalline part, a rigid amorphous part unable to relax and an amorphous phase able to relax at various temperatures depending on the distribution of the relaxation times is used to explain the evolution of the main relaxation while the standard two-phases model is sufficient to explain the variations of the relaxation mode. Elementary analysis of both and relaxations show that the relaxation characterized by a continuous variation of activation energies as a function of temperature follows the activated state equation with a zero activation entropy while the cooperative a relaxation exhibits a prominent maximum of the activation energies at the glass transition temperature.
M. Kattan, E. Dargent, J. Grenet, Journal of Thermal Analysis and Calorimetry 76 (2004) 379-394

T0024 – Thermally-stimulated current and dielectric loss measurement of polypropylene and teflon-FEP films immersed in diarylethane

Some properties of oil/PP (biaxially stretched polypropylene) and oil/FEP (Teflon FEP) composite insulators have been investigated with TSC (thermally stimulated current) techniques. The oil/PP system showed three TSC peaks originating from carriers captured in the swollen surface region of the PP. The TSC spectra depended strongly on the polarity of the poling voltage and on the impregnating temperature. Their analysis yielded information on the carrier traps existing near the PP surface in the oil/PP interface region. On the other hand, the TSC spectrum of the oil/FEP system has a small impregnating temperature dependence and a small effect of the poling voltage polarity. The difference in TSC between oil/PP and oil/FEP systems is closely related to the difference in the oil-polymer interaction. The TSC is a useful method for investigating carrier traps in the surface region and their change due to the oil-polymer interaction. To investigate further the relation between the carrier traps and tan delta, collecting bias TSC was measured on a specimen to which an ac voltage was applied. The results indicate that the decrease in tan(delta) during the ac voltage application depends on the amount of trapped carriers near the polymer's surface or, the decrease in carriers in the oil
S. Ochiai, H. Iwasaki, M. Ieda and T. Mizutani, IEEE Transactions on Dielectrics and Electrical Insulation 1 (1994) 487-495

T0023 – Simulation of thermally stimulated curents in dielectric : effects of thermal expansion

The influence of thermal expansion on thermally stimulated currents has been studied by means of model calculations based on the bistable model of Fröhlich, considering especially the case of materials characterized by expansion coefficients markedly different above and below the relaxation range. A good qualitative and quantitative agreement has been obtained between theory and experiment in elastomeric materials (styrene-isoprene-styrene and isoprene-styrene-isoprene block copolymers) showing that thermal expansion is the main factor responsible for the appearance of current reversals in thermally stimulated polarization processes
J. Vanderschueren, M. Ladang, J. Niezette and M. Corapci, Journal of Applied Physics 58 (1985) 4654-4657

T0022 – Thermally Stimulated Currents from corona-charged polypropylene films : a thermal effect of vacuum deposition of metallic electrodes

It is demonstrated that the thermally stimulated currents (TSC) from positively or negatively corona-charged polypropylene strongly depend on the order of the following two processes: a process of vacuum deposition of Al electrodes on the sample polymer and a process of heat-treatment of the polymer. Observed results are explained by a thermal effect which is introduced during the vacuum deposition of metallic electrodes. This thermal effect of the vacuum deposition of metallic electrodes is the largest for Al and the smallest for Bi among Al, Au, Ag, and Bi. Observed TSC spectra have three peaks at about 68, 142, and above 147°C for positively charged samples and four peaks at about 48, 90, 142, and above 147°C for negatively charged samples, respectively. Origins of these TSC peaks are discussed in some detail.
A. Baba and K. Ikezaki, Journal of Applied Physics 57 (1985) 359-365

T0021 – Dielectric relaxation phenomena in PEEK

Molecular movements in poly(ether-ether-ketone) have been investigated by thermally stimulated currents (TSC). The TSC spectra have been analyzed as a function of crystallinity. Around -80°C, two sub-modes are observed: the lower temperature sub-mode has been attributed to localized cooperative movements in the crystallizable amorphous phase; and the upper temperature sub-mode has been located in the crystalline phase. The magnitude of the corresponding compensation line increases with the ratio of crystallinity. Around the glass transition temperature (145°C), the existence of two sub-modes has been shown: the lower temperature sub-mode has been attributed to the dielectric manifestation of the glass transition and the cooperative movements have been assigned to the "true amorphous region" of PEEK; the upper temperature sub-mode is dependant upon crystallinity. Regardless of the preceding sub-mode, the activation enthalpies of the constituting elementary processes are practically constant. This sub-mode has been attributed to the "rigid amorphous region", constrained by the crystallites.
M. Mourgues-Martin, A. Bernès and C. Lacabanne, Thermochimica Acta 226 (1993) 7-14

T0020 – Influence of the crystalline phase on the molecular mobility of PVDF

Thermostimulated current (TSC) spectroscopy was applied to the characterization of dielectric relaxations associated with the glass transition of a series of P(VDF/TrFE) copolymers. The maximum temperature of the -mode increases slightly as the TrFE unit content is increased, in the same manner as the glass transition temperature. By using the technique of fractional polarizations to the resolution of this relaxation mode, we have isolated, for all the polymers investigated, a series of elementary relaxation times that obey a compensation law. This behavior is characteristic of the free amorphous phase of polymers. The mean activation energy of this mode increases as the TrFE unit content is increased, due to a stiffening of molecular chains. Annealing of the copolymers above their ferroelectric-to-paraelectric transition induces a strong crystallinity increase of the materials. As a matter of fact, the amorphous phase is squeezed in to dimensions lower than the characteristic length scale associated with the glass transition
G. Teyssèdre, A. Bernes and C. Lacabanne, Journal of Polymer Science 31 (1993) 2027-2034

T0019 – Low-loss behavior of alpha-PVDF

The exact nature of the polarization processes in low-loss materials is not sufficiently understood and good experimental material is relatively scarce. Dielectric response of alpha-PVDF covering 8.5 decades of frequency between 10^(-2) and 3x10^6 Hz and a range of temperatures between 103 and 138 K were analyzed to reveal the nature of the dominant polarization process. Correcting for a series resistance and a Debye-like loss process at 50 kHz, the 'universal' fractional power law of dielectric response is well maintained, the residual tan delta falls between 0.002 and 0.02 depending on temperature and frequency, with the residual loss process presumed to be due to hopping charge carriers having an activation energy of 0.035 eV. The universal process itself has a relatively high loss but its amplitude is low and this accounts for the low tan delta
A.K. Jonscher and J.Menegotto, IEEE Transactions on Dielectrics and Electrical Insulation 7 (2000) 303-305

T0018 – Dielectric relaxation properties of filled ethylene propylene rubber

Thermally stimulated discharge currents and time domain dielectric spectroscopy were employed to characterize the behavior of clay-filled ethylene propylene rubber. Measurements were made on samples with different clay concentrations and particle sizes. The main effect of the clay filler on the electrical properties is on interfacial polarization which occurs at the clay polymer interface. The experimental results are sensitive to the shape of the clay particles. A few results indicate that other mechanisms also affect the electrical behavior of this material
A.M. Jeffery and D.H. Damon, IEEE Transactions on Dielectrics and Electrical Insulation 2 (1995) 394-408

T0017 – Origins of Thermally Stimulated Current in polyethersulfone

In order to understand the dominant carrier species in electrical conduction in polyethersulfone (PES), thermally stimulated current (TSC) measurements were carried out under various conditions. It was found that PES has two TSC peaks in the temperature range from 20 to 220°C, consisting of an alpha peak at ~210°C and a beta peak whose peak temperature moves towards a higher temperature with an increasing poling temperature. Even when the sample was not poled, PES shows a spontaneous current with its peak at ~210°C. Both the spontaneous current peak and the alpha peak were found to disappear when the sample had been heated to 230°C, keeping the external circuit closed. From such similarity of appearance and disappearance between the two peaks, it is concluded that they have the same origin. From the change in the spatial distribution of space charges inside the sample measured simultaneously with the TSC measurements, positive charges, probably due to K+ ions, existed nonuniformly in the sample from the beginning, and are thought to be responsible for the two peaks. From a similar study, the beta peak is considered to be due to polarization of ionic space charges during the poling process
E.J. Kim, T. Takeda and Y. Ohki, IEEE Transactions on Dielectrics and Electrical Insulation 3 (1996) 386-391

T0016 – Analysis of the experimental distribution of relaxation times around the liquid-glass transition of poly(vinylidene fluoride)

The dielectric relaxation mode associated with the liquid-glass transition of a semicrystalline polymer, polyvinylidene fluoride, has been analyzed by the technique of fractional polarizations. A discrete distribution of relaxation times following an Arrhenius law has been obtained experimentally. The activation energy of the "single'' relaxation processes are distributed according to a Gaussian function. Moreover, these relaxation times follow a compensation law. These results allowed us to introduce a continuous distribution of relaxation times whose parameters are temperature dependent. The validity of the method was verified for the thermally stimulated current spectra. Use is made of this distribution to compute the temperature and frequency dependence of the complex dielectric permittivity.
G. Teyssèdre, P. Demond and C. Lacabanne, Journal of Applied Physics 79 (1996) 9258-9267

T0013 – Study by thermostimulated currents of dielectric relaxations through the glass transition in an amorphous polymer : poly(n-butyl methacylate)

The study of poly(n-butyl methacrylate) (PnBMA) by thermostimulated currents has been performed in order to give a better definition of the molecular mobility when crossing the glass transition. It reveals the existence of two dipolar relaxation modes: alpha, ascribed to the glass-rubber relaxation, and alpha', which might be the dielectric manifestation of the liquid-liquid transition. The distribution of relaxation times and the evolution of the activation enthalpies when increasing the temperature have been studied by the fractional polarizations technique. It appears that the alpha and alpha' modes behave differently, showing the crossover from an Arrhenian to a Vogelian behavior. Furthermore, up to T, the cooperativity of molecular mobility is highlighted by the existence of a compensation law in agreement with Starkweather's criterion, and above T, results might be explained by the existence of an intermediate state neither glassy nor completely liquid.
E. Dudognon, A. Bernès and C. Lacabanne, Macromolecules 34 (2001) 3988-3992

T0008 – Comments on the compensation effect observed in thermally stimulated depolarization current analysis

Compensation has been reported for the relaxation parameters (the activation energy W and the pre-exponential factor t0) determined by using the thermal sampling (TS) technique. For the peaks obtained by the thermally stimulated depolarization current (TSDC) measurement, there is a relationship between W, t0 and the temperature of maximum intensity of the peak Tm that can be employed to deduce a general relationship between W, Tm, the compensation temperature Tc and the compensation time tc. This relationship can be used for a basic analysis of the compensation effect. By numerical simulations, and using parameters similar to those reported for concrete measurements, we show that it is possible to observe a compensation point only if the activation energy is a monotonically increasing power function of temperature of power coefficient between 1 and 2, more precisely, if Wincreases with temperature stronger than linearly but weaker than quadratically. The actual values of the compensation parameters are determined by the relationship between the activation energy and the temperature. The experimental uncertainties affecting the compensation temperature and the compensation time are significant, and consequently, it is not possible to have a precisely defined compensation point.
E.R. Neagu, R. Neagu, Thermochimica Acta 395 (2003) 183-189

T0007 – Coherent vibrations in “polar / non-polar”-like complex polymeric mixtures. A dielectric approach to percolation phenomena

The analysis of thermostimulated currents by the fractional polarization procedure has been used to establish the existence of a coherent vibration in Linseed oil/mastic varnish mixtures. This excitation is seen in the oil component when its proportion in the system is inferior to its percolation threshold. The observed phenomenon complies with compensation laws and is interpreted in the framework of the formalism developed by Fröhlich to understand collective phenomena in biological systems.
O. Pagès, A. Lamure, J. Dandurand, A. Zaoui and C. Lacabanne, Journal of Thermal Analysis and Calorimetry 57 (1999) 401-407

T0006 – Effect of water on thermally stimulated currents in oxidised low-density polyethylene

The electrical conduction properties of low-density polyethylene (LDPE) oxidised in an ozone atmosphere produced by an electrical discharge in air, particularly the current behaviour in a short-circuited state, have been investigated. An anomalous discharging current and a reverse TSC flowing in the same direction as the charging current were observed. It has been found that the cause of these unique phenomena exists not on the cathode side, but on the anode side and that the water absorbed in the oxidised LDPE plays an important part. It is suggested that these unique properties are due to protons (H+) injected at the anode, possibly associated with an anode oxidation reaction at the oxidised LDPE-electrode interface
M. Onoda, H. Nakayama, K. Amakawa, J. Phys. D. Appl. Phys. 23 (1990) 211-217

T0005 – Amorphous phase separation in polypropylene block copolymers as revealed by thermostimulated depolarization measurements. I.complex spectra study

The thermally stimulated depolarization (TSD) technique was used to observe the amorphous phase separation in polypropylene block copolymers and to attribute its various dielectric relaxations to precise mobile entities. The complex thermostimulated spectra of polypropylene block copolymers were compared to complex spectra of polymers of the same nature as those of its main components, i.e., isotactic polypropylene, high-density polyethylene, and propylene-ethylene rubber. With TSD we then studied a binary blend of polypropylene and high-density polyethylene and another blend of polypropylene and propylene-ethylene rubber and also the various parts of polypropylene block copolymer which were separated by a selective solvent extraction. From peak-position and intensity considerations we suggested the origin of the three relaxations appearing from 90 to 290 K in the TSD complex spectra of polypropylene block copolymer
D .Ronarc'h, P. Audren, J.L. Moura, Journal of Applied Physics 58 (1985) 466-473

T0004 – Thermally stimulated current observed in glass transition temperature

T. Hino, Y. Kitamura, Electrical Engineering in Japan 95 (1975) 24-30

T0003 – Open-circuit TSD method and anomalous air gap current in Teflon FEP

J.A. Giacometti, J.A. Malmonge, J.M.G.Neto, IEEE Transactions on Electrical Insulation EI-21 (1986) 383-387

L0185 – Preparation of a poly(methyl methacrylate)-reduced graphene oxide composite with enhanced properties by a solution blending method

Poly(methyl methacrylate) (PMMA)/graphene nanocomposites were prepared by a simple solution blending method. The glass transition temperature of the produced PMMA/graphene composite was increased by 37 °C with 1.0 wt.% RGO content, which is approximately 40% of improvement compared to that of pure PMMA. The thermal expansion coefficient (TEC) decreased by 68% with as low as 0.1 wt.% RGO loading. The electrical conductivity of the nanocomposites reached up to 0.037 S/m even with only 2.0 wt.% RGO, which increased by more than twelve orders of magnitude. The resulting nanocomposites showed that a stable colloidal suspension of graphene dispersion in organic solvent before blending with PMMA is necessary to fabricate the nanocomposites with enhanced properties.
Xiaopeng Zeng, Jingjing Yang, Wenxia Yuan, European Polymer Journal 48 (2012) 1674–1682

L0082 – Fabrication of gapless triangular micro-lens array

This study presents a new process to fabricate gapless triangular micro-lens array (GTMA) optical film. The process includes ultraviolet (UV) lithography, photoresist reflow process, Ni-Co electroplating and hot embossing technique. After photoresist triangular column array is defined by UV lithography, reflow technique is applied to melt photoresist triangular column array into the shape of triangular micro-lens array. With this reflowed triangular micro-lens array, metal Ni-Co is deposited and covered uniformly on the triangular micro-lens array using electroplating process. The growth rate of Ni-Co is controlled at 0.4-0.6 µm/min at electroplating current density of 1 A/dm2 (ampere square decimetre, ASD). After this electroplating process, a mold of GTMA is obtained, which is served as the primary mold. Next, with passivation technique applied on this primary mold's surface, a secondary mold is obtained by applying the electroplating process again. This secondary mold is served as master for the subsequent hot embossing process to replicate the GTMA pattern onto polymeric material of polymethyl methacrylate (PMMA) sheet. The Ni-Co mold with hardness over hardness of vicker (Hv) 650 is obtained. The stiffness and hardness of the mold play important roles in GTMA hot embossing process. In addition, this PMMA-based GTMA film used as optical film offers a 100% fill factor and high optical coupling efficiency to improve luminance. The optical measurement shows that this optical film with GTMA pattern increases 15.1% of luminance for backlight module (BLM) of liquid crystal display (LCD).
C.T. Pan, C.H. Su, Sensors and Actuators A Physical 134 (2007) 631-640

L0022 – Evolution of the coefficient of thermal expansion of a thermosetting polymer during cure reaction

The evolution of the coefficient of thermal expansion (CTE) of a thermosetting polymer during cure reaction is an important parameter for industrial applications such as composite processing since it influences the development of internal stresses in the material. The CTE being almost impossible to measure on a reacting thermoset, we propose to use an indirect method based on the modelling of ionic conductivity by a modified WLF equation, allowing to calculate the evolution of CTE from dielectric spectroscopy measurements. This method is applied to a dicyanate ester thermosetting polymer, leading to encouraging results both qualitatively and quantitatively.
E. Leroy, J. Dupuy, A. Maazouz, G. Seytre, Polymer 46 (2005) 9919-9927

E0207 – Synthesis and properties of biodegradable plastic films obtained by microwave-assisted cellulose acylation in homogeneous phase

Microwave-induced esterification of cellulose in homogeneous phase has been investigated. Cellulose was first solubilized in the solvent system LiCl/N,N-dimethylacetamide and then esterified by lauroyl chloride in the presence of N,N-dimethyl-4- aminopyridine. Microwave activation resulted in a drastic reduction of reaction time (1 min) compared to conventional heating. The mechanical and thermal properties of the plastic films obtained were established and a preliminary study of their biodegradability has been performed.
C. Satgé, R. Granet, B. Verneuil, P. Branland, P. Krausz, C. R. Chimie 7 (2004) 135-142

E0163 – Effect of acrylic polymer and nanocomposite with nano-SiO2 on thermal degradation and fire resistance of APP-DPER-MEL coating

Acrylic nanocomposite and flame retardant coatings with different acrylic polymers were prepared. The effect of molecular structure and molecular weight of acrylic resins and nanocomposite with nano-SiO2 on the interaction and char formation of ammonium polyphosphate- dipentaerythritol-melamine (APP-DPER-MEL) coating was investigated using differential thermal analysis (DTA), thermogravimetry (TG), Limiting Oxygen Index (LOI), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and fire protection test. The interaction of APP, DPER, MEL and 3F-1 acrylic resin led to the formation of intumescent coherent char at 300-450°C. Owing to low molecular weight and lack of benzene rings, F-963 acrylic resin decomposed at lower temperature than APP, and hence their endothermic interaction was destroyed. The well-distributed nano-SiO2 particles in acrylic nanocomposite could modify char formation and anti-oxidation of char structure at high temperature. It is noted that the fire protection properties of nanocoating with acrylic nanocomposite were better than those of flame retardant coatings with conventional acrylic resins.
Z. Wang, E. Han, W. Ke, Polymer Degradation and Stability 91 (2006) 1937-1947

B3361 – On the crystallization behavior of syndiotactic-b-atactic polystyrene stereodiblock copolymers, atactic/syndiotactic polystyrene blends, and aPS/sPS blends modified with sPS-b-aPS

Crystallization and morphological features of syndiotactic-b-atactic polystyrene stereodiblock copolymers (sPS-b-aPS), atactic/syndiotactic polystyrene blends (aPS/sPS), and aPS/sPS blends modified with sPS-b-aPS, with different compositions in aPS and sPS, have been investigated using differential scanning calorimetry (DSC), polarized light optical microscopy (POM) and wide angle X-ray diffraction (WAXRD) techniques. For comparative purposes, the properties of parent pristine sPS samples were also studied. WAXRD analyses revealed for all the samples, independently from their composition (aPS/sPS ratio) and structure (blends, block copolymers, blends modified with block copolymers), the same polymorphic ? form of sPS. The molecular weight of aPS and sPS showed opposite effects on the crystallization of 50:50 aPS/sPS blends: the lower the molecular weight of aPS, the slower the crystallization while the lower the molecular weight of sPS, the faster the crystallization. DSC studies performed under both isothermal and non-isothermal conditions, independently confirmed by POM studies, led to a clear trend for the crystallization rate at a given sPS/aPS ratio (ca. 50:50 and 20:80): sPS homopolymers > sPS-b-aPS block copolymers ?sPS/aPS blends modified with sPS-b-aPS copolymers > sPS/aPS blends. Interestingly, sPS-b-aPS block copolymers not only crystallized faster than blends, but also affected positively the crystallization behavior of blends. At 50:50 sPS/aPS ratio, blends (Blend-2), block copolymers (Cop-1) and blends modified with block copolymers (Blend-2-mod) crystallized via spherulitic crystalline growth controlled by an interfacial process. In all cases, an instantaneous nucleation was observed. The density of nuclei in block copolymers (160,000?190,000 nuclei mm?3) was always higher than that in blends and modified blends (30,000?60,000 nuclei mm?3), even for quite different sPS/aPS ratio. At 20:80 sPS/aPS ratio, the block copolymers (Cop-2) preserved the same crystallization mechanism than at 45:55 ratio (Cop-1). On the other hand, the 20:80 sPS/aPS blend (Blend-4) and blend modified with block copolymers (Blend-4-mod) showed a spinodal decomposition.
Liana Annunziata, Bernard Monasse, Paola Rizzo, Gaetano Guerra, Michel Duc, Jean-François Carpentier, Materials Chemistry and Physics 141 (2013) 891e902

B3343 – Development of thermoresponsive poly(propylene-g-N-isopropylacrylamide) non-woven 3D scaffold for smart cell culture using oxyfluorination-assisted graft polymerisation

Growing cells on 3D scaffolds is far superior to the conventional 2D monolayer culture method. In this study, a novel 3D thermoresponsive poly(propylene-g-N-isopropylacrylamide) (PP-g-PNIPAAm) non-woven fabric (gNWF) was developed for cell culture using oxyfluorination-assisted graft polymerisation (OAGP). New polar functional groups were detected on the oxyfluorinated NWF (oNWF), and PNIPAAm was confirmed in the gNWF by attentuated total-reflectance Fourier transform infrared (ATR-FTIR) and scanning X-ray photoelectron spectroscopy (S-XPS). Scanning electron microscopy (SEM) revealed a rough surface morphology and confinement of the PNIPAAm graft layer to the surface of the fibres in the gNWF. The OAGP method did not affect the crystalline phase of bulk PP, however, twin-melting thermal peaks were detected for the oNWF and gNWF indicating crystal defects. Contact angle studies showed that the surface of the gNWF exhibited a thermoresponsive behaviour. Hepatocyte cells attached onto gNWF disks in a bioreactor at 37 °C and remained viable for 10 days in culture. Upon cooling the cell culture media to 20 °C, cells were spontaneously released as 3D multi-cellular constructs without requiring destructive enzymes. The development of 3D thermoresponsive scaffolds capable of non-invasive 3D cell culture could provide a more reliable in vitro model for cells.
Avashnee S. Chetty, Viktoria Vargha, Arjun Maity, F. Sean Moolman, Claire Rossouw, Rajesh Anandjiwala, Lydia Boguslavsky, Dalu Mancama, Walter W. Focke, Colloids and Surfaces A: Physicochem. Eng. Aspects 419 (2013) 37– 45

B3341 – Saccharide effect on the LCST property of a polyether: Influence of structure and length

Saccharides and especially monosaccharides are well-known to affect the thermal transition of the LCST polymer solution. The studied LCST system is an aqueous polyetheramine solution under unprotected form. The role of saccharide has clearly been highlighted through thermal measurements (absorbance and ?DSC) and structural techniques (NMR). Moreover, the impact of the structure and the number of the saccharides unit have been disclosed on the cloud point temperature. The phase transition became lowered upon sugar addition.
Sabrina Belbekhouche, Virginie Dulong, Luc Picton, Didier Le Cerf, Colloids and Surfaces A: Physicochem. Eng. Aspects 428 (2013) 25– 31

B3338 – Thermosensitive hybrid hydrogels with silica nanoparticle-cross-linked polymer networks

A simple methodology for the preparation of thermosensitive organic-inorganic hybrid hydrogels using silica nanoparticle-mediated polymer networks is described. A thermosensitive copolymer poly[N-isopropylacrylamide-co-(3-methacryloxypropyltrimethoxysilane)], (pNS), with reactive side chains (Si-O-CH3) was first synthesized by free radical polymerization using N-isopropylacrylamide (NIPAAm) and 3-methacryloxypropyltrimethoxysilane (MAPTS). Then, simple mixing of the aqueous solution of this copolymer with silica nanoparticle (SiP) suspensions at room temperature led to the formation of thermosensitive hybrid hydrogels cross-linked with silica nanoparticles (SiP) which did not require any other processing like washing for the removal of unreacted monomers and initiators. The effects of SiP content on gelation abilities, temperature-responsive behaviors, swelling and deswelling kinetics, and mechanical properties of the hydrogels were investigated. The results showed that transparent hybrid hydrogels with adjustable network structures were obtained within a few minutes to a couple of hours depending on the concentration of the copolymers and the silica nanoparticles. The hybrid hydrogels exhibited a lower critical solution temperature (LCST) of around 33 °C with no significant deviation from conventional poly(N-isopropylacrylamide) hydrogels; the LCST was not significantly affected by the concentration of silica nanoparticles (which in these systems serve as the cross-linkers). In addition, the hydrogels showed significantly large equilibrium swelling ratios, improved mechanical strength, and suitable deswelling behavior, which can easily be tuned by varying the composition of the hybrid hydrogels.
Md. Ashraful Alam, Makoto Takafuji, Hirotaka Ihara, Journal of Colloid and Interface Science 405 (2013) 109–117

B3337 – Poly(N-isopropylacrylamide)-block-poly(vinyl pyrrolidone) block copolymer networks: Synthesis and rapid thermoresponse of hydrogels

In this work, we reported the synthesis of poly(N-isopropyl acrylamide)-block- poly(N-vinylpyrrolidone)-block-poly(N-isopropylacrylamide) triblock copolymer (PNIPAAm-b-PVPy-b-PNIPAAm) via reversible addition-fragmentation chain transfer polymerization/macromolecular design via the interchange of xanthate (RAFT/MADIX) process. This approach was further employed to prepare the PNIPAAm-b-PVPy block copolymer networks with N,N?-methylenebisacrylamide as the crosslinker. The results of small angle X-ray scattering (SAXS) indicate that the PNIPAAm-b-PVPy block copolymer networks were microphase-separated, in which PVPy was dispersed into PNIPAAm matrix as the microdomains. The architecture of block copolymer networks allows investigating the effect of the blocked permanently hydrophobic chains (viz. PVPy) on the deswelling and reswelling behavior of the PNIPAAm hydrogels. It was found that the diffusion of water molecules in PNIPAAm-b-PVPy block copolymer networks was in a non-Fickian and accelerating manner. The swelling ratios of the PNIPAAm-b-PVPy hydrogels were significantly higher than that of control PNIPAAm hydrogel. Compared to control PNIPAAm hydrogel, the PNIPAAm-b-PVPy hydrogels displayed an accelerated response to the external temperature changes in terms of deswelling and reswelling tests. The accelerated thermoresponsive properties is ascribed to the presence of the PVPy blocks in the PNIPAAm-b-PVPy block copolymer networks, which could act as the hydrophilic tunnels to facilitate the diffusion of water molecules in the PNIPAAm networks
Houluo Cong, Lei Li, Sixun Zheng, Polymer 54 (2013) 1370-1380

B3332 – Association states of multisensitive smart polysaccharide–block-polyetheramine copolymers

The water soluble properties of different copolymers based on pullulan-block-polyetheramine have been deeply studied. The polyetheramine group (PEA) corresponding to a propylene oxyde/ethylene oxyde ratio (PO/EO) of 29/6, is condensed, via amine link, to pullulans with various chain lengths. Different polysaccharide/PEA (PS/PEA) ratio copolymers have been investigated through macroscopic (cloud point, enthalpy) and mesoscopic scale approaches (critical aggregation concentration (CAC), mean number average hydrodynamic diameter (Dh) or aggregation number (Nag)). These systems are both pH and/or thermo-sensitive. Finally, it seems that three states can describe such systems (i) isolated copolymers (unimers) below the CAC, (ii) water soluble aggregates above the CAC and whatever the PS/PEA ratio is due to hydrophobic interactions and (iii) non-soluble aggregates (above the critical temperature) due to dehydration of polyetheramine groups but only if PS/PEA ratio is low enough.
Sabrina Belbekhouche, Jacques Desbrières, Thierry Hamaide, Didier Le Cerf, Luc Picton, Carbohydrate Polymers 95 (2013) 41– 49

B3301 – Films of dextran-graft-polybutylmethacrylate to enhance endothelialization of materials

We have synthesized new structures obtained from amphiphilic copolymers of dextran and polybutylmethacrylate with the aim of endothelialization of biomaterials. Grafting of butylmethacrylate onto dextran has been carried out using ceric ammonium nitrate as initiator. Three copolymers were obtained (11, 30 and 37 wt.% dextran) and homogeneous thin films were successfully prepared. In contrast to dextran, the resulting films were stable in water, and copolymers characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry and dynamic mechanical analysis showed evidence of hybrid properties between the parent homopolymers. Surfaces of films were smooth when analyzed by atomic force microscopy (roughness 2+/-1 nm) but greatly differed in their hydrophilicity by increasing the dextran content (water contact angle from 99 degrees to 57 degrees). In contrast to polybutylmethacrylate, where the proliferation of vascular smooth muscle cells (VSMCs) was excellent but that of endothelial cells was very low, the copolymer containing 11% of dextran was excellent for endothelial cells but very limited for VSMCs. An in vitro wound assay demonstrated that copolymer with 11% dextran is even more favorable for endothelial cell migration than tissue-culture polystyrene. Increasing the dextran content in the copolymers decreased the proliferation for both vascular cell types. Altogether, these results show that transparent and water-insoluble films made from copolymers of dextran and butylmethacrylate copolymers with an appropriate composition could enhance endothelial cell proliferation and migration. Therefore, a potential benefit of this approach is the availability of surfaces with tunable properties for the endothelialization of materials.
Sidi Mohamed Derkaoui, Amélie Labbé, Agung Purnama, Virginie Gueguen, Christel Barbaud, Thierry Avramoglou, Didier Letourneur, Acta Biomaterialia 6 (2010) 3506–3513

B3282 – Glass-Transition Temperatures in CO2 + Polymer Systems: Modeling and Experiment

We extend a previously published compressible lattice model to the prediction of glass-transition temperatures in CO2 + polymer systems. We have applied the model to published data as well as to new measurements of glass-transition temperatures in CO2 + poly(methyl methacrylate) (PMMA) and CO2 + poly(lactic acid) (PLA) systems. We demonstrate that the model is able to predict glass-transition temperatures in CO2 + polymer systems using a parameter that is obtained from sorption data and a second parameter that is obtained from FTIR measurements. The parameters are not dependent on temperature, pressure, or polymer molecular weight.
Anupama Kasturirangan, Carolyn A. Koh, Amyn S. Teja, Ind. Eng. Chem. Res. 2011, 50, 158–162

B3273 – Monitoring the aggregation behaviour of self-assembling polymers through high-resolution ultrasonic spectroscopy

Poloxamer 407 is a well-known self-assembling polymer with a wide range of temperature- and concentration-dependent phase behaviour, such as micellization and gelation. This work was carried out to demonstrate the potential of high-resolution ultrasonic spectroscopy in evaluating aggregation-deaggregation behaviour of self-assembling polymers. In order to achieve this objective, six different concentrations of Poloxamer 407 water dispersion were prepared and analysed between 5 and 35 degrees C using ultrasonic spectroscopy. For comparison, the same samples were also analysed by the DSC technique. The results showed that polymer aggregation process can be successfully monitored using both ultrasonic parameters of sound speed and attenuation. Furthermore, good agreement with DSC data was observed in terms of characteristic transition temperatures and also in terms of micellization kinetics and related parameters
Marco Cespi, Giulia Bonacucina, Giovanna Mencarelli, Stefania Pucciarelli, Gianfabio Giorgioni, Giovanni F. Palmieri, International Journal of Pharmaceutics 388 (2010) 274–279

B3239 – Influence of corona poling on the electrostrictive behavior of cellular polypropylene films

In this study, a quadratic electric field dependence of the strain on the ?30 kV corona-charged cellular polypropylene (PP) was observed, which was found to mainly originate from electrostriction after evaluation of Maxwell stress effect. The ?30 kV-charged sample presented a maximal strain twice as high as that of the non-charged sample for the same applied electric field. Both the dielectric constant and apparent electrostrictive coefficient of cellular PP were also seen to increase after corona poling treatment. We investigated such higher electrostrictive response from the behavior of surface potential decay, the TSC current and the thermal properties. From TSC current curves, it was found that a certain amount of charges became injected into the film. And then, the total charge within the PP was calculated by integrating the TSC current, which provided a convincing evidence for enhanced electrostriction of studied polymer. In addition, from DSC analysis, it was demonstrated that the corona treatment increased the crystallinity of the cellular PP, which was also highly desirable for enhancing the electrostrictive response. Increase in the permittivity and strain was explained experimentally and mathematically by using the space-charge theory and a simplified model.
J.W. Zhang, L. Lebrun, B. Guiffard, P.-J. Cottinet, R. Belouadah, D. Guyomar, L. Garbuio, Sensors and Actuators A 175 (2012) 87– 93

B3227 – Corona structure on demand: Tailor-made surface compartmentalization in worm-like micelles via random cocrystallization

We present a straightforward approach to well-defined 1D patchy particles utilizing crystallization-induced self-assembly. A polystyrene-block-polyethylene-block-poly(methyl methacrylate) (PS-b-PE-b-PMMA) triblock terpolymer is cocrystallized in a random fashion with a corresponding polystyrene-block-polyethylene-block-polystyrene (PS-b-PE-b-PS) triblock copolymer to yield worm-like crystalline-core micelles (wCCMs). Here, the corona composition (PMMA/PS fraction) can be easily adjusted via the amount of PS-b-PE-b-PMMA triblock terpolymer in the mixture and opens an easy access to wCCMs with tailor-made corona structures. Depending on the PMMA fraction, wCCMs with a mixed corona, spherical PMMA patches embedded in a continuous PS corona, as well as alternating PS and PMMA patches of almost equal size can be realized. Micelles prepared by cocrystallization show the same corona structure as those prepared from neat triblock terpolymers at identical corona composition. Thus, within a certain regime of desired corona compositions the laborious synthesis of new triblock terpolymers for every composition can be circumvented.
Joachim Schmelz, Holger Schmalz, Polymer 53 (2012) 4333-4337

B3160 – Study of the degradation mechanisms of polyethylene during reprocessing

The present work aims at evaluating the behaviour of various grades of high and low density polyethylene subjected to continuous injection moulding operations. It is based on a wide range of experimental techniques that allowed the establishment of relationships between the observed property changes and the structural modifications developed in the polymers. The study confirmed the coexistence of two distinct degradation mechanisms, crosslinking and chain scission, that occur due to thermo-oxidative reactions arising during the different injection moulding stages. The relative importance of these two mechanisms depends on the material structure and on the processing conditions used. It was also possible to confirm that the polyethylenes with lower molecular mass show low sensitivity to degradation during reprocessing. Furthermore, the more branched polymers (as is the case of LDPE) also proved to be less sensitive to thermo-degradation phenomena. Overall, it was concluded that the primary recycling of polyethylene, if performed under well controlled conditions, will lead to only minor material property losses.
A.A. Mendes, A.M. Cunha, C.A. Bernardo, Polymer Degradation and Stability 96 (2011) 1125-1133

B3159 – Investigations of a mechanically failed cable insulation used in indoor conditions

This paper presents the investigation work on different polymeric materials used as insulation materials of conductors in a multicore instrumentation cable. Among differently colored materials, only the white one presented cracks after a few years of use. Isothermal and non-isothermal DSC measurements were performed on initial (non-used) and aged (in service used or laboratory aged) materials as well as on raw materials in order to characterize their stability and the ageing state after storage, use in service or laboratory ageing. As shown by the oxidation induction time values, a pronounced antioxidant loss occurred for all materials during storage or service; plus a strong effect of the ambient light on stability was observed for the white insulation material. Around 3% of filler, consisting mainly of TiO2 particles (as revealed by SEM-XRF elemental analysis), was found in the white material. The higher degradability of the white material can be related to both the photocatalytic effect of the TiO2 particles and rapid loss of stabilizers.
S. Ilie, R. Setnescu, E.M. Lungulescu, V. Marinescu, D. Ilie, T. Setnescu, G. Mares, Polymer Testing 30 (2011) 173–182

B3158 – Permeation and sorption properties of poly(ether-block-amide) membranes filled by two types of zeolites

The experimental study of transport properties of mixed matrix membranes (MMMs) based on PEBA-4033 with two types of zeolites is reported. Gas (CO2, O2, N2) and vapor (benzene, toluene, methanol, water) permeation measurements were performed using the differential flow permeameter at temperature of 298.15 K and at atmospheric pressure. Gas/vapor permeation was monitored by measuring the changes of the thermal conductivity of carrier gas (H2). Sorption experiments were performed gravimetrically. Determined values of the transport parameters (permeability, diffusion and sorption coefficients) of all studied vapors revealed expected high-order permeability of PEBA based membranes for vapors in comparison with gases whereas increasing of zeolite-filler content up to 30 wt.% in polymer matrix led to higher values of permeability and gas/gas and vapor/gas selectivity in comparison with pure polymer.
Karel Friess, Vladimír Hynek, Milan Šípek, Wojciech M. Kujawski, Ondrej Vopicka, Miroslav Zgazar, Maciej W. Kujawski, Separation and Purification Technology 80 (2011) 418–427

B3151 – Antifouling performance of poly(acrylonitrile)-based membranes: From green synthesis to application

In order to develop clean ultrafiltration membranes able to prevent the fouling of biological compounds in filtration processes, poly(ethylene glycol) methyl ether acrylate (PEGA) was grafted to poly(acrylonitrile) (PAN) by free-radical polymerization in supercritical carbon dioxide (scCO2) and the grafted copolymer was blended with PAN to fabricate porous membranes using scCO2-induced phase inversion method. Fourier transform infrared (FT-IR) analysis, 1H nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC) confirmed that the poly(acrylonitrile)-graft-poly(ethylene oxide) (PAN-g-PEO) was successfully synthesized, for the first time, in scCO2. The effect of increasing PEGA content on the initial monomer feed mixture on graft polymer morphology and average molecular weight was studied. Blended membranes with different PEGA contents were investigated by scanning electron microscopy (SEM), mercury porosimetry and dynamical mechanical analysis (DMA) to characterize their morphological, physico-chemical and mechanical properties. Moreover, water contact angle measurements, pure water permeability and filtration experiments were performed to evaluate membrane hydrophilicity and fouling resistance properties. Permeation experiments of model foulants, bovine serum albumin (BSA) and starch solutions were used to investigate antifouling character of blend membranes at different pHs. PAN:PAN-g-PEO (70:30) showed to be the ultrafiltration membrane with best performance. Furthermore, comparing with conventional technologies blended membranes of PAN:PAN-g-PEO prepared by a scCO2-assisted process showed enhanced hydrophilicity, larger protein and starch solution permeabilities and good resistance to irreversible fouling, indicating that the technology is an efficient process to prepare fouling resistant membranes for biomacromolecule separations.
Telma Barroso, Márcio Temtem, Teresa Casimiro, Ana Aguiar-Ricardo, J. of Supercritical Fluids 56 (2011) 312–321

B3150 – Effects of copper filler sizes on the dielectric properties and the energy harvesting capability of nonpercolated polyurethane composites

Nonpercolated composites based on polyurethane (PU) filled with low concentrations copper (Cu) powders of varying sizes were studied as electrostrictive materials for mechanical energy harvesting. The dispersion of the fillers within the polymeric matrix was investigated by scanning electron microscopy, and results showed a relatively homogeneous dispersion for the microsized fillers and the existence of agglomerates for their nanosized counterparts. Differential scanning calorimetry measurements displayed that there occurred no interaction between the polymeric matrix and the microsized fillers whereas the nanosized fillers slightly enhanced the glass transition of the soft segments of PU and significantly affected the recrystallization temperature. The dependence of the dielectric properties of the composites as a function of the filler volume fraction and filler size was investigated over a broad range of frequencies, showing an increase in the permittivity when fillers were used. This increase was more pronounced for the composites containing nanosized fillers. The measurement of the harvested current and of the harvested power also demonstrated an enhancement of the energy harvesting capability when nanofillers were employed. From the experimental data, it appeared that the electrostrictive coefficient Q was not proportional to the inverse ratio of the permittivity and the Young modulus for the studied composites. Finally, analytical modeling of the harvested current and of the harvested energy offered an accurate description of the experimental data.
C. Putson, L. Lebrun, D. Guyomar, N. Muensit, P.-J. Cottinet, L. Seveyrat, B. Guiffard, J. Appl. Phys. 109, 024104 (2011)

B3091 – Microencapsulation of a cooling agent by interfacial polymerization: Influence of the parameters of encapsulation on poly(urethane–urea) microparticles characteristics

A series of polyurea-urethane microparticles containing xylitol were synthesized by interfacial polymerization from reaction between diphenyl methylene diisocyanate (MDI) and xylitol. This research was conducted to clarify the influence of different parameters on the encapsulation process, i.e. during the emulsion formation step and during the shell formation using contact angle measurement, Fourier-transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analyses. By carefully analyzing the influencing factors stirring rate and feeding weight ratio of core/shell monomers, the optimum synthetic conditions were found out. The results show that core/shell weight ratio influences not only the shell formation mechanism but also the mean diameter, microcapsule morphology, the encapsulation yield and the xylitol content. Thus, the choice of a core/shell weight ratio of 77.0-23.0 is the most suitable to obtain high encapsulation yield and xylitol loading content.
F. Salaün, G. Bedek, E. Devaux, D. Dupont, L. Gengembre, Journal of Membrane Science 370 (2011) 23–33

B3090 – Influence of the washings on the thermal properties of polyurea-urethane microcapsules containing xylitol to provide a cooling effect

In this report, the preparation and performance of microcapsules interacting with the absorbed water to promote a cooling effect were investigated. The microcapsules containing xylitol were prepared from xylitol and diphenyl methylene diisocyanate (MDI) by an interfacial polymerization process. The microencapsulated xylitol was characterized by scanning electron microscopy (SEM) to illustrate its porous surface structure and its morphology. The influence of the drying process after washing was analyzed by differential scanning calorimetry (DSC) prior to the determination of the heat of solution. The results show the perspectives of the usage of these microcapsules as a reversible cooling agent for moisture management.
F. Salaün, G. Bedek, E. Devaux, D. Dupont, Materials Letters 65 (2011) 381–384

B3059 – Differential scanning calorimeter and infrared imaging for electrocaloric characterization of poly(vinylidene fluoride-trifluoroethylenechlorofluoroethylene) terpolymer

Electrocaloric properties of poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) [P(VDF-TrFE-CFE)] terpolymer were determined by two methods. A modified differential scanning calorimeter measures the entropy variation when applying an electric field under isothermal conditions. Alternative technique consists of an infrared imaging camera that gives direct information on temperature variation in pseudo-adiabatic condition. Both techniques give similar results with a heat capacity of 1500 J/(kg K). For an electric field of 80V/lm, entropy variation was measured at 15.1 J/(kg K) and a temperature variation of 2.75K. High frequency measurement is possible using infrared imaging, and a strong frequency dependence of the electrocaloric effect was observed
Gael Sebald, Laurence Seveyrat, Jean-Fabien Capsal, Pierre-Jean Cottinet, Daniel Guyomar, Appl. Phys. Lett. 101, 022907 (2012)

B3050 – Manufacturing and characterization of water filled micro-composites

The goal of the present work was to manufacture water-filled micro-composites using a high pressure encapsulation process, PGSS (Particles from Gas Saturated Solutions), and to characterize the products by different analytical methods. As shell material a vegetable fat (hydrogenated Castor oil) is used. The obtained composites have tailor made properties like bulk density, particle size, morphology and water content. A special interest was laid on the distribution of water (core material) within the composites. Water distribution is studied using two different methods: H NMR and DSC. The analytical results suggest the presence of three different “types” of water: water between the particles, entrapped and bound water
L.G. Hanu, P. Alessi, A. Kilzer, S. Kareth, J. of Supercritical Fluids 66 (2012) 274– 281

B3009 – An in-situ simultaneous SAXS and WAXS survey of PEBAX nanocomposites reinforced with organoclay and POSS during uniaxial deformation

Poly(ether-block-amide) (PEBA), commercially known as PEBAX , nanocomposites filled with organically modified clay (Cloisite 30B) and trisilinolphenyl-polyhedral oligomeric silsesquioxane (tsp-POSS) were prepared by a melt mixing method, respectively. The structures of the nanocomposites were investigated using differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, and in-situ simultaneous small and wide angle X-ray scatterings (SAXS and WAXS) during uniaxial deformation. The FT-IR spectra showed the hydrogen bonding between the fillers and the PEBA which helped to disperse the fillers in the polymer matrix. The crystallinities and mechanical properties of the nanocomposites were improved compared to the neat polymer. Their origins were studied with an in-situ simultaneous SAXS and WAXS technique during the uniaxial deformation.
Tahseen Kamal, Soo-Young Park, Myong-Chan Choi, Young-Wook Chang, Wei-Tsung Chuang, U-Ser Jeng, Polymer 53 (2012) 3360-3367

B3008 – The effect of sulfonated graphene oxide on Sulfonated Poly (Ether Ether Ketone) membrane for direct methanol fuel cells

A novel composite membrane of sulfonated graphene oxide (s-GO) and SPEEK with various sulfonated graphene oxide contents was prepared and investigated. The sulfonation of graphene oxide and PEEK induces an increase in the number of sulfonic groups (SO3H), which significantly increases the proton conductivity of sulfonated graphene oxide/SPEEK membrane. The introduction of sulfonated graphene oxide in membranes not only improved proton conductivity, but also positively affected the mechanical properties and the blocking of methanol and water molecules passing through the membrane. Consequently, incorporation of sulfonated graphene oxide into SPEEK membrane has considerably increased the selectivity of the membrane. Therefore, this sulfonated graphene oxide/SPEEK membrane is a good candidate for usage in direct methanol fuel cells.
Yuseon Heo, Hyungu Im, Jooheon Kim, Journal of Membrane Science 425–426 (2013) 11–22

B3007 – Preparation of graphene nanoflakes/polymer composites and their performances for actuation and energy harvesting applications

Composites based on polyurethane (PU) or P(VDF-TrFE-CFE) terpolymer (T30) filled with various amounts of 60-nm thick graphene nanoflakes were prepared. The dielectric properties, including relative permittivity, loss tangent, and conductivity over a broad range of frequencies were presented and discussed according to the percolation theory. The percolation threshold was found to differ for the two systems, respectively, 7.2 and 3.0 vol. % for the PU and the T30 composites. Differential scanning calorimetry demonstrated that there was practically no interaction between the polymeric matrix and the fillers. The increase in permittivity could not be related to this very slight modification of the polymer but rather to the space charges induced by the graphene flakes. Moreover, measurements of the thickness strain under an applied electric field demonstrated a twofold increase of the actuation capability. The optimal value of the M33 electrostriction coefficient was for both systems obtained for a filler content somewhat lower than the percolation threshold. The PU-graphene composite exhibited better performances compared to its T30-graphene counterpart and this was attributed to the good ratio of relative permittivity to the Young modulus in addition to the specific morphology of the used polyurethane. The energy harvesting properties were investigated by monitoring the evolution of the current under a DC electric field and under AC mechanical strain. The T30-graphene composite was found to be the best material for energy harvesting as previously predicted based on its high permittivity
L. Seveyrat, A. Chalkha, D. Guyomar, L. Lebrun, J. Appl. Phys. 111, 104904 (2012)

B2975 – Investigating poly-(vinyl-chloride)-polyethylene blends by thermal methods

Poly-vinyl-chloride (PVC)-polyethylene (PE) alloys were prepared by melt blending using both low- and high-density polyethylene without applying a compatibilizer. The PVC and the PE are incompatible polymers; in spite of this fact stable microheterogeneous materials were obtained. Mechanical methods e.g. tensile tests generally (measured in the usual concentration range) do not support any compatibility. At higher concentrations, the incompatible parts mask the effect of molecular mixing, easily detected at low PE contents. Dynamic mechanical (DMA), differential scanning calorimetric tests were carried out. Glass transition temperatures were determined by both methods. DMA tests were made at four frequencies, and the energy of activation of PVC main transition was also calculated. The decrease of glass-transition temperatures and energy of activation show that there is a slight mixing of the polymers. Specimens were also investigated by infrared method. From the results of IR spectra, grafting reaction of PE can be assumed onto the PVC because of its dehydrochlorination.
Mariann Kollar, Gabriella Zsoldos, J Therm Anal Calorim (2012) 107, 645–650

B2903 – Study of dioxolane-dioxepane copolymers through IR and DSC

The composition of the copolymers of 1,3-dioxolane with 1,3-dioxepane was investigated using FT-IR and DSC. The first method produce accurate values for the overall composition, the later allows discriminating between the copolymer and the mixture of homopolymers
Dumitru-Mircea Vuluga, Magdalena Pantiru, Thierry Hamaide, Dan Sorin Vasilescu, Polymer Bulletin 52, 349–354 (2004)

B2902 – Degradation in Thermal Properties and Morphology of Polyetheretherketone-Alumina Composites Exposed to Gamma Radiation

Sheets of polyetheretherketone (PEEK) and PEEK-alumina composites with micron-sized alumina powder with 5, 10, 15, 20, and 25% by weight were fabricated, irradiated with gamma rays up to 10 MGy and the degradation in their thermal properties and morphology were evaluated. The radicals generated during irradiation get stabilized by chain scission and crosslinking. Chain scission is predominant on the surface and crosslinking is predominant in the bulk of the samples. Owing to radiation damage, the glass transition temperature, Tg increased for pure PEEK from 136 to 140.5 °C, whereas the shift in Tg for the composites decreased with increase in alumina content and for PEEK-25% alumina, the change in Tg was insignificant, as alumina acts as an excitation energy sink and reduces the crosslinking density, which in turn decreased the shift in Tg towards higher temperature. Similarly, the melting temperature, Tm and enthalpy of melting, ?Hm of PEEK and PEEK-alumina composites decreased on account of radiation owing to the restriction of chain mobility and disordering of structures caused by crosslinks. The decrease in Tm and ?Hm was more pronounced in pure PEEK and the extent of decrease in Tm and ?Hm was less for composites. SEM images revealed the formation of micro-cracks and micro-pores in PEEK due to radiation. The SEM image of irradiated PEEK-alumina (25%) composite showed negligible micro-cracks and micro-pores, because of the reinforcing effect of high alumina content in the PEEK matrix which helps in reducing the degradation in the properties of the polymer. Though alumina reduces the degradation of the polymer matrix during irradiation, an optimum level of ceramic fillers only have to be loaded to the polymer to avoid the reduction in toughness.
Falix Lawrence, Satyabrata Mishra, C. Mallika, U. Kamachi Mudali, R. Natarajan, D. Ponraju, S.K. Seshadri, T.S. Sampath Kumar, Journal of Materials Engineering and Performance, Volume 21(7) July 2012, 1266

B2888 – Thermal properties of polynorbornene (cis- and trans-) and hydrogenated polynorbornene

The thermal properties of trans-polynorbornene, cis-polynorbornene and hydrogenated polynorbornene were examined and its reversibility tested. Trans-polynorbornene samples, formed in various solvents, exhibit a softening range, from ambient temperature until 375°C. However, syndiotactic cis-polynorbornene samples show a narrower melting range (between 150 and 375°C). The fusion enthalpies of cispolynorbornene samples are around 300-400 J/g. The temperature of decomposition is ca. 456°C (minimum peak DSC) for trans-polynorbornene and ca. 466°C, 10°C higher, for cis-polynorbornene. The solvent used for the polymerization of norbornene has a negligible influence in the melting temperature range or in the decomposition temperature. The treatment with 2,6-di-tert-butyl-4-methyl-phenol during the isolation of polynorbornene leads to materials with different thermal properties. Transpolynorbornene isolated without 2,6-di-tert-butyl-4-methyl-phenol exhibited an exothermic peak accompanied by an slight increase in weight (1-2%), while samples treated with 2,6-di-tert-butyl-4-methyl-phenol do not show these features.
Miguel A. Esteruelas, Fernando González, Juana Herrero, Patricia Lucio, Montserrat Oliván, Begoña Ruiz-Labrador, Polymer Bulletin 58, 923–931 (2007)

B2845 – Rheological characterization of interfacial reaction in reactive polymer blends

An original method has been developped which allows to study the influence of chain diffusion on the reaction kinetics in reactive polymer blends. Blends with controlled multilayer morphologies were directly prepared in a rotational rheometer and timedependent dynamic mechanical measurements allowed to follow the progress of the reaction. Model miscible copolymers with different acrylic monomers were prepared for this study by controlling the composition, molecular weight and average number of reactive groups per chain. Reduced variables for the modulus and the reaction time were introduced to compare the results obtained for different concentrations of reactive groups. In comparison to homogeneous blends, the normalized results for the multilayered structures show that the extent of the reaction depends directly on the chain length and is thus controlled by chain diffusion.
Michel Bouquey, René Muller, Guy Schlatter, Christophe Serra, Polymer Bulletin 53, 377–386 (2005)

B2838 – A New Technique for Measuring Retrograde Vitrification in Polymer–Gas Systems and for Making Ultramicrocellular Foams from the Retrograde Phase

A stepwise temperature- and pressure-scanning thermal analysis method was developed to measure glass-transition temperature Tg in the two-phase polymer–gas systems as a function of gas pressure p, and was used to confirm recent theoretical predictions that certain polymer–gas systems exhibit retrograde vitrification, that is, they undergo rubber-to-glass transition on heating. A complete Tg-p profile delineating the glass–rubber phase envelope was established for the PMMA-CO2 system. The retrograde vitrification behavior observed, where at certain gas pressures the polymer exists in the rubbery state at low and high temperatures and in the glassy state at intermediate temperatures, was similar to that reported previously based on the creep-compliance measurements. The existence of the rubbery state at low temperatures was used to generate foams by saturating the polymer with CO2 at 34 atm and at temperatures in the range 20.2 to 24 °C followed by foaming at temperatures in the range 24 to 90 °C. Foams with very fine cell structure never reported before could be prepared by this technique. For example, PMMA foams with average cell size of 0.35 mm and cell density of 4.4 3 1013 cells/g were prepared by processing the low temperature rubbery phase
Y. Paul Handa, Zhiyi Zhang, Journal of Polymer Science, Part B, Polymer Physics, Vol. 38, 716–725 (2000)

B2837 – Effect of Compressed CO2 on Phase Transitions and Polymorphism in Syndiotactic Polystyrene

When treated with compressed CO2, syndiotactic polystyrene (sPS) undergoes a number of solid-solid transitions that do not occur on treatment with liquid solvents. For example, planar mesophase ? ?, ? ? ?, and ? ? ? transitions can be brought about under appropriate conditions of temperature and CO2 pressure. In addition, the transitions of glassy sPS to the planar mesomorphic and to the ? form, and the ? ? ? transition occur at temperatures lower than when the same transitions are effected under ambient pressure. The dissolved CO2 lowers the glass transition and the cold crystallization temperatures of sPS at the rate of -0.92 and -0.58 °C/atm, respectively. Crystallization kinetics from the sPS-CO2 solution follow the Avrami equation, but the value of the exponent n is lower than when crystallization is conducted under ambient pressure
Y. Paul Handa, Zhiyi Zhang, Betty Wong, Macromolecules 1997, 30, 8499-8504

B2836 – CO2-Assisted Melting of Semicrystalline Polymers

It is well-known by now that certain compressed gases above their critical temperatures can dissolve to considerable extents in polymers causing depression of glass transition, Tg, and crystallization, Tc, temperatures. Whereas there have been numerous investigations of CO2-induced depression in Tg of polymers, the corresponding investigations for Tc have been reported only for PPS7 and syndiotactic polystyrene (sPS). In the latter study, it was shown that Tc decreased linearly with an increase in CO2 pressure, in a fashion similar to the change in Tg with pressure. Furthermore, CO2 was also found to crystallize glassy sPS into its various crystalline forms and also to induce solid-solid transitions between the various crystalline forms. In particular, CO2 was found to transform ?-sPS into its ? form at a temperature at which the ? form was initially crystallized under ambient pressure. Such an apparent solid-solid transition below the melting temperature of the R form could be conjectured only if the ? crystals somehow underwent melting at a depressed temperature and then transformed to the ? form. This conjecture led us to undertake the present investigation on the effect of CO2 on the melting behavior of semicrystalline polymers.
Zhiyi Zhang, Y. Paul Handa, Macromolecules 1997, 30, 8505-8507

B2813 – Mixtures of a hydrophobic triblock copolymer (L121, PEO5PPO68PEO5) and a hydrophobic anionic surfactant (AOT, Sodium bis(2-ethylhexyl)sulfosuccinate), each alone forming turbid vesicular solutions in water, aggregate to produce a thermodynamically stable,

Mixtures of a hydrophobic triblock copolymer (L121, PEO5PPO68PEO5) and a hydrophobic anionic surfactant (AOT, Sodium bis(2-ethylhexyl)sulfosuccinate), each alone forming turbid vesicular solutions in water, aggregate to produce a thermodynamically stable, transparent, and isotropic solution. Mixed AOT/L121 aggregates could be confirmed by fluorescence, surface tension, differential scanning calorimetry (DSC), and isothermal titration calorimetry. In an isotropic region, where mixed aggregates are formed, there is a synergistic interaction between monomers of AOT and L121 in the mixture. In addition, small-angle neutron scattering experiments provided evidence that mixed aggregates have the shape of either spheres (with a certain polydispersity) or very short ellipsoids (axial ratio below 2), confirming a transition from giant multilamellar vesicles to small aggregates upon mixing the two hydrophobic amphiphiles. Upon dilution, the morphology changes to disk-like. From an examination of the results of all the methods the peculiar behavior of the mixed AOT/L121 system is explained.
Carlos Rodríguez-Abreu, Margarita Sanchez-Domínguez, Bojan Šarac, Marija Bešter Roga?, Rekha Goswami Shrestha, Lok Kumar Shrestha, Dharmesh Varade, Goutam Ghosh, Vinod K. Aswal, Colloid Polym Sci (2010) 288, 739–751

B2790 – Copolymers sensitive to temperature and pH in water and in water + oil mixtures: A DSC, ITC and volumetric study

Block copolymer micelles are receiving an increasing interest because of the variety of structures and the possibilities to tune them by changing external and internal parameters achieving the desired properties for a specific purpose. We have investigated the acid/base behavior, self-assembling and solubilization ability towards polar oils of star-like copolymers named Tetronics. They are composed of branched four-arms each one consisting of two blocks made of EO and PO units linked to the diethylenediamine group, which confers pH response ability. The copolymers T1107 and T90R4 were studied with a sequential and reverse architecture. The thermodynamics of the acid/base equilibrium was studied by ITC. The aggregation of T1107 in water was analyzed as functions of pH, composition and temperature. The enhanced oil solubilization in the aqueous T1107 aggregates was widely investigated highlighting the role of the oil structure, composition, temperature and pH. As a general result, the oil induces the copolymer aggregation and the solubilization power of micelles is tunable by changing the pH. Efforts have been devoted to model the calorimetric data in order to achieve the thermodynamic properties of the involved process. Finally, we showed that the Tetronic micelles are more promising than the conventional surfactants micelles because of the larger solubilization power and flexibility of the macromolecular system.
Rosario De Lisi, Gabriele Giammona, Giuseppe Lazzara, Stefana Milioto, Journal of Colloid and Interface Science 354 (2011) 749–757

B2786 – Crystallization-induced aggregation of block copolymer micelles: influence of crystallization kinetics on morphology

We present a systematic investigation of the crystallization and aggregation behavior of a poly(1,2-butadiene)-block-poly(ethylene oxide) diblock copolymer (PB-b-PEO) in n-heptane. n-Heptane is a poor solvent for PEO and at 70?C the block copolymer self-assembles into spherical micelles composed of a liquid PEO core and a soluble PB corona. Time- and temperature-dependent light scattering experiments revealed that when crystallization of the PEO cores is induced by cooling, the crystal morphology depends on the crystallization temperature (Tc): Below 30?C, the high nucleation rate of the PEO core dictates the growth of the crystals by a fast aggregation of the micelles into meander-like (branched) structures due to a depletion of the micelles at the growth front. Above 30?C the nucleation rate is diminished and a relatively small crystal growth rate leads to the formation of twisted lamellae as imaged by scanning force microscopy. All data demonstrate that the formation mechanism of the crystals through micellar aggregation is dictated by two competitive effects, namely, by the nucleation and growth of the PEO core.
Adriana M. Mihut, Jérôme J. Crassous, Holger Schmalz, Matthias Ballauff, Colloid Polym Sci (2010) 288, 573–578

B2784 – Do additives shift the LCST of poly (N-isopropylacrylamide) by solvent quality changes or by direct interactions?

The phase transition of thermoresponsive poly(N-isopropylacrylamide) is studied under the influence of additives considered as model substances for drugs. A series of aromatic compounds with similar structures, mainly benzaldehydes, is chosen. The lower critical solution temperature (LCST) is determined by differential scanning calorimetry and 1H-NMR. All additives cause a down shift of the LCST, which depends on additive molecular structure and concentration. Since the LCST shifts are not correlated to hydrophobicity or solubility of the additive, the detailed substitution pattern is discussed as the controlling factor. The question whether LCST shifts can be explained by either the additives affecting the solvent quality or by specific interactions of additives with the polymer is addressed by LCST determination in dependence on polymer concentration. Though both factors are relevant, specific additive-polymer interactions are shown to play a major role in controlling the LCST.
Christian Hofmann, Monika Schönhoff, Colloid Polym Sci (2009) 287,1369–1376

B2765 – Calorimetric Investigation of Chiral Recognition Processes in a Molecularly Imprinted Polymer

The molecular imprinting of polymers is a promising concept for designing highly selective receptor systems which is now fairly well understood froma structural point of view. However, only limited information is available on the thermodynamics of enantioselective recognition in imprints. In order to study this problem, the interactions of a pair of enantiomers (phenyl- ?-L- and phenyl-?-D-mannopyranoside) with a well-characterized imprinted polymer (D-enantiomer acted as template) have been investigated by means of isothermal batch and titration calorimetry. Batch calorimetric measurements with unstirred samples are affected by strong solvent–polymer interactions, such as swelling, causing large changes of the blank effects over long periods of time. Isothermal titration calorimetric measurements proved to be more efficient for studying imprinted polymers. The enthalpies of rebinding for both enantiomers strongly decrease with increasing degree of occupation of the available cavities. Only at low degrees of occupation (< 50%) was a significantly higher endothermic heat effect for the (D)-enantiomer (template) detected which indicates an enantioselective rebinding. The overall heats of rebinding were found to be endothermic and are composed of several different contributions that are discussed. In summary, the reported calorimetric results are generally in accordance with the proposed mechanism of chiral recognition in this type of molecular imprinted polymers.
Ralf Kirchner, Jurgen Seidel, Gert Wolf, Günter Wulff, Journal of Inclusion Phenomena and Macrocyclic Chemistry 43, 279–283 (2002)

B2749 – A new technique to characterize monomolecular micelles in random ethylene–propylene copolymers

A new technique to investigate the nano-structure of ethylene–propylene (EP) random copolymers has been developed. It consists in the measurement of the turbidity which develops at a lower critical solution temperature (LCST) in pentane solutions. The information on the solution comes from different types of turbidity obtained during a step-by-step temperature increase. The transient turbidity (hi) is associated with random coils (I) and structured coils (II) while the stable turbidity comes from aggregates (III). The proportion of (I), (II) and (III) depends on the solution history and on the solvent. The Mw distribution can be obtained from the set hi (Ti) of (I). Turbidity (II) has an unexpected gap in the hi (Ti) trace. The gap (10–20 K) is explained by the presence of two entities in solution. Their temperatures of phase separation permit their identification as monomolecular micelles, whose outer core is either E-rich or P-rich. This nano- structure is thought to exist in the solid and also in solution as a metastable state. The technique can differentiate between mobile chains in solutions (I, II) and attached chains in a network (III) through the sedimentation behaviour of the concentrated phase. Three samples with a similar (EP) content (0.75) made with different catalysts have been analysed by LCST and slow calorimetry.
Fabrice Gouanve, H. Phuong-Nguyen, Zohra Ferhat Hamida, Geneviève Delmas, Colloid Polym Sci (2005) 283, 994–1006

B2689 – Polymer–CO2 systems exhibiting retrograde behavior and formation of nanofoams

The sorption of compressed gases in polymers causing a reduction in the glass transition temperature (Tg) is well established. There is, however, limited information on polymer–gas systems with favorable interactions, producing a unique retrograde behavior. This paper reports on using a combination of established techniques of in situ gravimetric and stepwise heat capacity (Cp) measurements using high-pressure differential scanning calorimetry (DSC) to demonstrate the occurrence of this behavior in acrylonitrile–butadiene–styrene copolymer (ABS)–CO2 and syndiotactic poly(methyl methacrylate) (sPMMA)–CO2 systems. The solubility and diffusion coefficient of CO2 in the range 0 to 65?C and pressures up to 5.5MPa were determined, which resulted in a heat of sorption of ?15.5 and ?15 kJ mol?1, and an activation energy for diffusion of 28.3 and 32.1 kJmol?1 in the two systems, respectively. The fundamental kinetic data and the changes in Cp of the polymer–gas systems were used to determine the plasticization glass transition temperature profile, its relationship to the amount of gas dissolved in the polymer, and hence the formation of nano-morphologies
A Victoria Nawaby, Paul Handa, Xia Liao, Yamamoto Yoshitaka, Mizumoto Tomohiro, Polym Int 56, 67–73 (2007)

B2642 – Non-isothermal crystallization kinetic of poly(ethylene terephthalate)/fumed silica (PET/SiO2) prepared by in situ polymerization

A number of poly(ethylene terephthalate) (PET) nanocomposites were prepared by in situ polymerization using different amounts (0.5, 1, 2, 3 and 4 wt%) of fumed silica (SiO2). The polymerization of PET was carried out by the two-stage melt polycondensation method. From DSC studies it was found that the melting point of the nanocomposites was shifted slightly to higher temperatures by the addition of SiO2 till 3 wt% while for PET–4 wt% SiO2 nanocomposite the melting point was reduced. As the amount of SiO2 was increased the crystallization became faster, and there was, also, a shifting of the temperature of the crystallization peak to higher values, this being evidence that SiO2 can act as nucleating agent. At higher content (3 and 4 wt%) the temperature of the crystallization peak is lower than that of PET–2 wt% SiO2 due to the formation of crosslinked macromolecules. The activation energy is calculated with the Friedman's method. PET/SiO2 samples present lower activation energy compared to that of neat PET, except those of PET–4% SiO2, in which the activation energy have a maximum value for ? = 0.8 probably due to the second crystallization peak. Extensive crystallization studies by using Avrami, Ozawa and Malek methods verified that PET and its nanocomposites must be crystallized by two mechanisms with different activation energies taking place in different degrees of crystallization.
G. Antoniadis, K.M. Paraskevopoulos, D. Bikiaris, K. Chrissafis, Thermochimica Acta, 510 (2010) 103–112

B2641 – Kinetics study of cold-crystallization of poly(ethylene terephthalate) nanocomposites with multi-walled carbon nanotubes

A series of PET/MWCNTs nanocomposites were prepared by in situ polymerization using different amounts of multi-walled carbon nanotubes (MWCNTs). The polymerization of poly(ethylene terephthalate) (PET) was prepared by the two-stage melt polycondensation method. The values of the activation energy of the nanocomposites, as calculated with the Kissinger's and Ozawa–Flynn–Wall (OFW) methods, are larger than the ones of pristine PET. These values are 107.9 kJ/mol for PET-0% MWCNTs and 154.0 kJ/mol for PET-1% MWCNTs which is the larger value among all. Avrami plots present a linear portion, almost parallel to each other, which is followed by a deviation at larger temperatures. Straight lines are obtained from Ozawa plots only for PET-0.25% MWCNTs at least for three different heating rates. The dependence of the activation energy on the degree of conversion, from the Avrami, Malek and Ozawa plots, gives indications that for the kinetic description of the cold-crystallization of PET/MWCNTs cannot be used only one crystallization mechanism which obeys to Avrami equation. Only for the PET-0.25 one crystallization mechanism can be used at least for the major part of the crystallization conversion. So, in order to describe their crystallization mechanisms at least two mechanisms with different activation energies must be used. These two mechanisms maybe are taking part in different degree of crystallization conversions for every nanocomposite.
G. Antoniadis, K.M. Paraskevopoulos, D. Bikiaris, K. Chrissafis, Thermochimica Acta,493 (2009) 68–75

B2593 – Simultaneous determination of sorption, heat of sorption, diffusion coefficient and glass transition depression in polymer–CO2 systems

Polymer–CO2 interactions dictate the evolution of various phenomena such as sorption of CO2, polymer swelling, and polymer plasticization. The knowledge of key quantities and parameters such as the amount of absorbed gas, the heat of sorption, or the diffusion coefficient is of great importance for a rational design of related processes. We have designed and constructed an apparatus based on the combination of Calvet calorimetry and pressure drop method. This combination allows for the determination of the amount of absorbed CO2, the heat of sorption, the diffusion coefficient of CO2 in the polymer and, finally, the concentration of CO2 that causes plasticization of the polymer at a specific temperature (below the atmospheric glass transition temperature). We describe and propose a methodology for the simultaneous measurement of the four, above mentioned, parameters. The glass transition depression is determined by a novel approach which, in addition, allows for information about the kinetics of plasticization to be derived. New results at 54.3 °C and at various pressures are presented for the PMMA–CO2 system, and wherever possible, compared with literature data and modeled with the NRHB (Non Random Hydrogen Bonding) model and the dual sorption model.
Costas Tsioptsias, Costas Panayiotou, Thermochimica Acta, 521 (2011) 98–106

B2541 – Aggregation in aqueous media of tri-block copolymers tuned by the molecular selectivity of cyclodextrins

The water cyclodextrin poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) mixtures have been investigated to explore the temperature effect on the aggregation of the copolymer in the presence of cyclodextrins (CDs). The CDs with different cavity sizes were chosen because they may include either the hydrophilic poly(ethylene oxides) block or both kinds of blocks. The differential scanning calorimetry and viscosity experiments straightforwardly evidenced that the critical micellar temperature is shifted to larger values by adding a CD which is able to include the middle poly(propylene oxide) block while it is not influenced by the presence of CD which is selective to the poly(ethylene oxide) block. The enthalpy of aggregation decreases upon the CD addition for all the investigated systems.
Rosario De Lisi, Giuseppe Lazzara, J Therm Anal Calorim (2009) 97, 797–803

B2500 – Calorimetry in Nonstandard Conditions: The Noncrystalline Phases of Linear Polyethylene

A linear Union Carbide PE (UC) has been analyzed by nonstandard calorimetry with a common DSC calorimeter and a Setaram C80 calorimeter. Nonstandard calorimetry entails using a low rate of heating (0.5–1 K/min), a small mass (0.5–1.5 mg), and an open cell (O-cell) instead of the standard C-cell. Events in Ocells overlap less and occur with a faster kinetics than in C-cells. PE crystals are nascent, solution-grown (S-grown), press-grown (P-grown), and strained by extrusion. In Part A, the traces show that the phase-changes in the melt, previously observed in a C80 calorimeter (slow T-ramp) and characterized by ?Hnetwork, can be observed with a common DSC in nonstandard conditions. In Part B, the difference between the Cand O-cells and the changes in the main peak enthalpy (?Hortho) are of interest. The main result is that, in O-cells, the value of ?Hortho around Tortho, exceeds unambiguously in certain conditions ?Hortho found for perfect orthorhombic crystals. The main endotherm contains then another contribution, namely ?Hnetwork. Crystal reorganization during the slow T-ramp is followed in the C- and O-cells on S-grown crystals. In O-cells, lamellar thickening observed in the slow-ramp is more extensive. The ease of phase-change depends on the sample history. It is as follows: strained-part extruded > nascent > S-grown > P-grown. Co-operative chain motions are more hindered in the standard C-cells than in the O-cells. In Part C, lower values of m succeed in bringing phase-changes in P-grown (O-cells) samples. The origin of the events is discussed: three processes are thought to contribute to the phase-changes namely, melting of strained short-range order, activation of vibrations in the CH2 groups, and fast decay of chain orientation which occurs simultaneously with melting
Ilyes Jedidi, Zohra Ferhat-Hamida, Genevieve Delmas, Journal of Polymer Science: Part B: Polymer Physics, Vol. 45, 1932–1949 (2007)

B2424 – Fireproofing of polyurethane by organophosphonates. Study of degradation by simultaneously TG/DSC

In this work, we have studied the degradation processes of polyurethane containing phosphonate groups used as a fireproofing agent. These studies are undertaken by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC) measurements. It is found that fireproofing agents with phosphonate react with oxygen in the air and prevent the complete combustion of the material. It is also found that the energy released during combustion is low when comparison is performed with other fireproofing materials.
B. Youssef, B. Mortaigne, M. Soulard, J. M. Saiter, Journal of Thermal Analysis and Calorimetry, Vol. 90 (2007) 2, 489–494

B2391 – An in situ study of plasticization of polymers by high pressure gases

A high pressure differential scanning calorimetry technique is described for studying polymer plasticization by compressed gases at pressures to 100 atm. The in situ meaurements avoid problems due to gas desorption encountered with conventional DSC's thus providing an accurate way to detremine the change in glass transitions temperature Tg with pressure p. The entire Tg-p curve can be established in less than 2 days.
Zhiyi Zhang, Paul Handa, Journal of Polymer Science, Part B, Polymer Physics, Vol. 36, 977-982, 1988

B2284 – Titanium ketimide complexes as a-olefin homo- and copolymerisation catalysts. X-ray diffraction structures of [TiCp'(N=CtBu2)Cl2] (Cp’ = Ind, Cp*)

The synthesis of [TiInd(N=CtBu2)Cl2] and the applications of [TiCp'(N=CtBu2)Cl2] (Cp' =Ind, Cp*, Cp) as ethylene and propylene homopolymerisation catalysts, as well as its behaviour as catalysts of ethylene and 10-undecen-1-ol copolymerisation are described. The optimisation of the catalytic reactions showed that all compounds are very active homopolymerisation catalysts, particularly [TiInd(N=CtBu2)Cl2] that gives 123.37 x 10^(6) g/(molTi [E] h) and 50.77 x 10^(6) g/(molTi [P] h) of linear polyethylene and atatic polypropylene, respectively. The less active homopolymerisation catalyst, [TiCp(N=CtBu2)Cl2], is the most effective ethylene/ 10-undecen-1-ol copolymerisation catalyst, leading to the highest degree of polar monomer incorporation. The polymers obtained were characterised by NMR and DSC. The molecular structures of [TiCp'(N=CtBu2)Cl2] (Cp' =Ind, Cp*) were determined by Xray diffraction studies.
A.R. Dias, M.T. Duarte, A.C. Fernandes, S. Fernandes, M.M. Marques, A.M. Martins, J.F. da Silva, S.S. Rodrigues, Journal of Organometallic Chemistry 689 (2004) 203-213

B2277 – An analysis on changes in structure, tensile properties of polytetrafluoroethylene film induced by protons

Effect of 100 keV proton radiation on the structure and tensile properties of PTFE film was investigated. The change in structure before and after proton radiation was mainly evaluated by means of differential scanning calorimetry. The experimental results show that under radiation of 100 keV protons for the fluence less than 7 x 10^(15) p/cm2, the DSC characteristics including the phase enthalpy of transformations at room temperature ?Hrt1 and ?Hrt2; the melting enthalpy ?Hm1 and ?Hm2; the crystallization exothermal enthalpy ?Hc; and Tg II were decreased, while the melting temperature was increased a little with the fluence increase. The change in crystallization enthalpy ?Hc indicated the increase of molecular weight of the PTFE film, but for 150 keV when the fluence exceeded the fluence of 10^(16)/cm2, the molecular weight decreased gradually. With increasing proton fluence, the thermal gravity loss was decreased, while the initial decomposition temperature increased, demonstrating that crosslinking of molecular chains occurred. With the increase of the proton fluence, for proton with energy less than 150 keV, the tensile fracture strength increased at first, but when the fluence exceeded 10^(16)/cm2, the tensile fracture strength showed a decreasing trend. While for the proton of 170 keV, the tensile fracture strength ?f increased abruptly at the fluence of 2 x 10^(13)/cm2, with the fluence increasing further, the tensile fracture strength ?f decreased gradually. The change of tensile properties could be related with the competition of branching crosslinking and the scission degradation.
G. Peng, H. Geng, D. Yang, S. He, Radiation Physics and Chemistry 69 (2004) 163-169

B2276 – Rheometers in scanning mode by changing the rates of linear temperature programming for the cure of rubbers

Using moving die rheometers under isothermal conditions, as usual, for determining the kinetic parameters of the cure of rubbers leads to two types of drawback. The first, because of the three experiments at least which are necessary at temperatures selected within a narrow temperature window; the second because it takes some time for thermal equilibrium to be established after the sample, initially at room temperature, has been introduced into the dies of the apparatus kept at the fixed temperature. A new way of running the rheometers with temperature programming with a constant rate of increase has been presented, which eliminates the above drawbacks. Nevertheless, another disadvantage of this new technique arises, as the rate of temperature programming is the same during the whole process of heating and cure. Thus, in order to reduce the length of time the experiments take, an improvement is described based on the fact that the rate of temperature increase is very high at the beginning of the heating stage up to the temperature at which the reaction of cure starts, followed by a lower heating rate within the temperature range where the reaction develops. The theoretical study of this new method is made enabling the evaluation of the torque-temperature curves. From these torque-temperature curves, a method has been elaborated for evaluating the kinetic parameters such as the activation energy and the pre-exponential factor, as well as the overall order of the reaction, which are thus obtained from only one experiment. The value of the heating rate should be between 2 and 10 K/min over the stage of cure and could be of the order of 50 K/min during the heating stage. The profiles of temperatures developed through the thickness of the sample during the whole process are flatter than those obtained with the isothermal rheometer, leading subsequently to more uniform profiles of the state of cure as they are obtained by calculation. Moreover, shorter experiment times are obtained over the method based on the linear programming temperature system.
I.D. Rosca, J.M. Vergnaud, Polymer Testing 23 (2004) 59-67

B2258 – Provision of thermodynamic properties of polymer systems for industrial applications

The provision of thermodynamic properties is essential for the design of optimal processes in industry. In this manuscript, five examples from the thermophysical-property group of Bayer Technology Services (BTS) illustrate the provision of thermodynamic properties of polymer systems in industry: (1) Experimental determination of high-pressure VLLE for the separation of solvent from polymer after solution polymerisation without the necessity of evaporation. (2) Basics of an apparatus and technique for the determination of VLE and diffusion coefficients in polymers according to a pressure decay method. (3) Usage of inverse gas chromatography (IGC) for the determination of VLE and diffusion coefficients in polymers. (4) Correction of data from a calorimeter according to a thermodynamic model in order to obtain heat capacities, cP , of pure solvents and polymer + solvent mixtures. (5) Usage of statistical associating fluid theory (SAFT) in order to model a polymer + solvent system with strong specific interactions including self-association and cross-association.
O. Pfohl, R. Dohrn, O. Pfohl, R. Dohrn, Fluid Phase Equilibria 217 (2004) 189-199

B2240 – Cellulose nanocrystals reinforced poly(oxyethylene)

Nanocomposite materials were prepared from poly(oxyethylene) (POE) as the matrix and a stable aqueous suspension of cellulose nanocrystals extracted from tunicate as the reinforcing phase. After dissolving POE in water and mixing with the cellulose nanocrystals suspension, solid films were obtained by casting and evaporating the preparations. Resulting films were characterized using scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis and dynamic mechanical analysis. Favorable interactions between cellulose and POE were evidenced and assumed to be partially responsible for a decrease of the crystallinity of the matrix. A thermal stabilization of the nanocomposites for temperatures higher than the melting temperature of POE was reported and ascribed to the formation of a rigid cellulosic network within the matrix assumed to be governed by a percolation effect. The formation of this percolating network was not altered by the matrix crystallization process and filler/POE interactions.
M.A.S.A. Samir, F. Alloin, J-Y. Sanchez, A. Dufresne, Polymer 45 (2004) 4149-4157

B2229 – Experimental thermochemical study of two 2-alkylbenzimidazole isomers (alkyl=propyl and isopropyl)

This paper reports the values of the standard (p° = 0.1 MPa) molar enthalpy of formation in the condensed, at T = 298.15 K, for 2-R-benzimidazoles (R=propyl, isopropyl), derived from, the respective enthalpies of combustion in oxygen, measured by static bomb combustion calorimetry and the standard molar enthalpies of sublimation, at T = 298.15 K, obtained using Calvet microcalorimetry in the case of 2-isopropylbenzimidazole and, by the variation of vapour pressures, determined by the Knudsen effusion technique, with temperatures between (344 and 365) K for 2-propylbenzimidazole. Heat capacities, in the temperature ranges from T = 268 K to near their respective melting temperatures, T = 421 K for 2-propylbenzimidazole and T = 464 K for 2-isopropylbenzimidazole, were measured with a differential scanning calorimeter. These values were used to derive the standard molar enthalpies of formation, of the two 2-benzimidazole derivatives, in gaseous phase.
M.A.V. Ribeiro da Silva, M.D.M.C. Ribeiro da Silva, L.M.P.F. Amaral, P. Jiménez, M.V. Roux, J.Z. Davalos, M. Temprado, P. Cabildo, R.M. Claramunt, J. Elguero, O. Mo, M. Yanez, J. Chem. Thermodynamics 36 (2004) 533-539

B2228 – Standard molar enthalpies of formation of three N-benzoylthiocarbamic-O-alkylesters

The standard (p° = 0.1 MPa) molar enthalpies of combustion in oxygen of three crystalline N-benzoylthiocarbamic-O-alkylesters, PhCONHCSOR, R=Et (Hbtcee), n-Bu (Hbtcbe), n-Hex (Hbtche), were measured at T = 298.15 K by rotating bomb calorimetry. The standard molar enthalpies of sublimation of the three compounds were measured using Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the compounds in their crystalline and gaseous phases, respectively.
M.A.V. Ribeiro da Silva, L.M.N.B.F. Santos, B. Schröder, F. Dietze, L. Beyer, J. Chem. Thermodynamics 36 (2004) 491-495

B2227 – Thermochemistry of benzoquinones

A thermochemical study of the p-benzoquinone and the duroquinone has been performed by different calorimetric techniques. Applying heat flux calorimetry and differential scanning calorimetry, the enthalpies of fusion for each substance were measured. Enthalpies of combustion in condensed phase were determined by static bomb combustion calorimetry hence the enthalpies of formation in solid phase were derived. Data of enthalpy of sublimation of both compounds were obtained by d.s.c. and independently by using a quartz crystal microbalance, and then applied to derive the enthalpy of formation in gas phase of these benzoquinones. From this set of experimental data, resonance, isodesmic, and homodesmotic stabilization energies were computed. Results made it possible to elucidate that the p-benzoquinone is antiaromatic while the duroquinone is an aromatic compound.
A. Rojas-Aguilar, Honorio Flores-Lara, Melchor Martinez-Herrera, Francisco Ginez-Carbajal, J. Chem. Thermodynamics 36 (2004) 453-463

B2214 – Influence of Sb2O3 particles as filler on the thermal stability and flammability properties of poly(methyl methacrylate) (PMMA)

The thermal stability behaviour and the flammability properties of poly(methyl methacrylate) (PMMA) filled with antimony oxide (Sb2O3), at different Sb2O3 amounts: 5, 10 and 20 wt%, were studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), cone calorimetry and limiting oxygen index (LOI) measurements. Samples were prepared using a twinscrew machine and subsequently injection molded. The experimental results obtained show that Sb2O3 particles retard the degradation and flammability of PMMA. The LOI increases to 24 for PMMA/Sb2O3 with just 20 wt% Sb2O3. An increase of the thermal stability between about 25 and 40°C for 5-20 wt% of Sb2O3 was demonstrated by TGA in air. Cone calorimeter measurements showed that the heat release rate (HRR) significantly decreased in the presence of Sb2O3. Epiradiateur tests showed an increase of the ignition time between 10 and 20%. In a tentative way to establish how Sb2O3 acts as a flame retardant for PMMA, the activation energy of the thermal degradation was determined by the model-free isoconversional method of Vyazovkin.
A. Laachachi, M. Cochez, M. Ferriol, E. Leroy, J.M. Lopez Cuesta, N. Oget, Polymer Degradation and Stability 85 (2004) 641-646

B2199 – Micro Raman and atomic force microscopy analysis of naturally aged polyethylene

The deterioration of naturally aged low-density polyethylene (LDPE) film was observed by elongation properties, DSC melting enthalpies and surface geometric characteristics by use of atomic force microscopy (AFM). The decrease of elongation at break under the influence of ageing was in good accordance with the increase of melting enthalpies and both phenomena could be explained by the gradual decrease of molecular mass of the polymer. On the wavy surface with a wavelength range of 10-15 mm, valleys with amplitudes from 160 to 600 nm could be observed by AFM depending on the time of ageing. The increase of deepness of valleys was explained not by the gradual erosion of the degraded surface but by the gradual increase of crystallinity, consequently the gradual shrinking on the surface of the polymer film. The gradual increase of crystallinity in the surface region of the film could be demonstrated by confocal Raman microscopy.
A. Szép, P. Anna, I. Csontos, Gy. Marosi, Sz. Matko, Gy. Bertalan, Polymer Degradation and Stability 85 (2004) 1023-1027

B2196 – Probing relaxation of chain segments of polytert-butylacrylate film by force distance curve of atomic force microscopy

The force distance (F-D) curves of polytert-butyl acrylate (PtBuA) films have been studied by atomic force microscopy with various probing frequencies from 20 to 70°C. The adhesion force is found to increase as the temperature increasing, which is corresponding to the glass-to-rubber transition of the polymer film. The F-D curve shows a typical shape in the case of about 2.5 nN applied force, but a break-free tail occurs in the case of about 24 nN applied force when the probing frequency is within an appropriate ranges, in which the polymer film transfers from the glass state to the glassy-rubbery state. We attribute the break-free tail to that the segments of PtBuA chains can be resonantly adhered to and released from the tip. Our observation indicates that the polymer segments adhered to the tip can be enhanced by their relaxation during the glassy-rubbery transition, and the average activation energy of the relaxation is estimated as about 2.1 eV.
X. Wang, Q. Shi, H. Hu, K. Zhang, European Polymer Journal 40 (2004) 2179-2183

B2193 – Analytical expressions of specific heat capacities for aqueous solutions of CMC and CPE

As previously reported, the influence of temperature and mass concentration on the specific heat capacity of two highly viscous solutions has been measured using adiabatic calorimetry. The absolute measurements were automated to operate steadily over the temperature range 290-360K with an average heating rate of 8 x 10^(-4) Ks-1. For both solutions of carboxy-methyl-cellulose (CMC) and carboxy-poly-ethylene (CPE), the evolution of specific heat capacities with temperature is compared with that of pure water. With CPE solutions, the increase of the temperature translated into an evolution of the Cp is comparable to the pure water with a value that varies with concentration. For CMC solutions, we observe the same temperature behaviour for a concentration of 83 g l-1. For weaker concentrations, the influence of the temperature is different. To account for the influence of temperature and concentration parameters, we propose a correlation that facilitates the utilisation of these results corresponding to a relative error inferior to 2%.
N. Semmar, J.L. Tanguier, M.O. Rigo, Thermochimica Acta 419 (2004) 51-58

B2182 – Mechanical durability of a polymer concrete: a Vickers indentation study of the strength degradation process

In order to evaluate the mechanical durability of some classes of Polymer Concrete a strength degradation process, as consequence of Vickers indentations at various loads, has been studied for different materials. After optical microscopy, SEM investigations and flexural tests, it has been possible to determine the Vickers hardness, the fracture toughness and the Gc of different Polymer Concrete and, for comparison, of a traditional ceramic material and of some natural stones of different origin.
G.D. Soraru', P. Tassone, Construction and Building Materials 18 (2004) 561-566

B2181 – Synthesis and characterization of bismaleimide-polyetherimide-titania hybrid

Ternary hybrids of bismaleimide-polyetherimide-titania were synthesized by sol-gel reaction and characterized by Scanning Electron Microscope, Energy Dispersive X-ray Analysis, Thermogravimetric Analysis and Differential Scanning Calorimeter. Moreover, their mechanical properties were also measured. The results indicated that titania could be introduced into the blends of bismaleimide-polyetherimide(BMI/PEI) by sol-gel reaction. Although, the titania content in BMI-rich phase was higher than that in PEI-rich phase, the titania particles dispersed in the hybrids were almost uniform. The introduction of titania actually changed the ultimate phase structure of the PEI modified BMI system because of the chelate complex formation between o,o'-diallyl bisphenol A and dibutoxy bis(acetylacetonato) titanium (IV), which was proved by their ultraviolet spectra. If the content of titania was increased under a specific PEI content, the morphology of the bismaleimide-polyetherimide- titania hybrids remained unaffected apparently, while its mechanical properties were obviously improved.
L. Zhao, L. Li, J. Tian, J. Zhuang, S. Li, Composites: Part A 35 (2004) 1217-1224

B2180 – Thermal and crystalline behaviour of silk fiborin/nylon 66 blend films

A series of blend films of silk fibroin (SF) with nylon 66 were prepared by the common solution cast method. DSC analysis of every blend sample showed a large and broad endothermic peak around 150°C. For SF/nylon 66 samples containing 10 and 30 wt% SF, large spherulites were observed and their melting processes were recorded using a polarizing microscope with hot-stage. Furthermore, a detailed study on 30 wt% SF sample indicated a distribution of two distinct spherulites: large spherulites in part A and much smaller ones in part B. In WAXD pattern, the large spherulites presented new peaks different from nylon 66 or silk's characteristic peaks that were ever reported, while the small ones assumed triclinic form of normal nylon 66. SEM showed that the SF and nylon 66 were nearly miscible in all ratios except that of 50 wt% SF.
Y. Liu, Z. Shao, P. Zhou, X. Chen, Polymer 45 (2004) 7705-7710

B2176 – Load dependence and scanning size effect on friction of Polytert-butylacrylate film

The friction of Polytert-butylacrylate (PtBuA) film was measured at different temperatures by the friction force microscopy (FFM). The load dependence and the scanning size effect on the friction of the film were investigated. It was found that, because the Young modulus of polymer decreased drastically with the temperature, the friction showed almost linear feature with the external load at temperatures below the glass-to-rubber transition temperature (Tg) of the polymer but sub-linear feature at temperatures above Tg. The friction was also observed to increase with the scanning size from 30 to 300 nm but saturate for the larger scanning size. As a comparison, the silicon oxidation films were scanned respectively with a clean tip as well as a polymer coated tip. The results indicated that the behaviour of the scanning size effect on the friction was contributed to the stretch and the fracture of molecular chains as the tip scanning on the polymer film surface.
X. Wang, Q. Shi, H. Hu, Thin Solid Films 466 (2004) 183-188

B2137 – A novel liquid-crystalline phase in dilute aqueous solutions of methylcellulose

The existence of liquid-crystalline (LC) phases in dilute methylcellulose solutions is demonstrated by exothermic peaks in differential scanning calorimetry (DSC) curves upon heating and is evidenced by a discontinuity of the dynamic storage modulus when the concentration of methylcellulose increases. This crystalline phenomenon is further confirmed by polarized light microscopy and optical rotatory dispersion measurements. It is found that the appearance of the LC formation is related to the temperature, concentration, and molecular weight of methylcellulose.
Y. Yin, K. Nishinari, H. Zhang, T. Funami, Macromolecular Rapid Communications 27 (2006) 971-975

B2136 – Voltammetric characterization on the hydrophobic interaction in polysaccharide hydrogels

Cyclic voltammetric (CV) investigations on the properties of microdomains in polysaccharide hydrogels, methyl cellulose (MC) and kappa-carrageenan (CAR), coated on glassy carbon electrodes were reported in which methylene blue (MB), tris(1,10-phenanthroline)cobalt(III) ((Co(phen)3)3+/2+) cations, and ferricyanide/ferrocyanide ((Fe(CN)6)3-/4-) anions were used as electroactive probes. Information on the patterns and strength of intermolecular interactions in these polysaccharide hydrogels can be inferred from the net shift of normal potentials (E°'), the change of peak currents (ip), the ratio of binding constants (Kred/Kox) for reduced and oxidized forms of bound species, and the apparent diffusion coefficients (Dapp) of probe in hydrogels. The transition of hydrophobic interaction in MC hydrogel with temperature was manifested by the CV method, which is in agreement with the evolution of the storage modulus (G') during gelation. It was also found that, in addition to inducing the change of E°' and ip of these probes used, the hydrophobic-hydrophilic nature of the microenvironment in hydrogels coated on the substrate electrodes greatly influenced the peak-peak separation (?Ep) of MB and the redox reversibility of (Fe(CN)6)3-/4- via modulation of both the heterogeneous electron-transfer process at the gel-substrate interface and the charge-transfer process in hydrogels. The results imply that the CV method is of significant benefit to the understanding of the gelation driving forces in the polysaccharide hydrogels at a molecular level.
Y. Yin, H. Zhang, and K. Nishinari, J. Phys. Chem. B 111 (2007) 1590-1596

B2130 – Structure and photoluminescent features of di-amide cross-linked alkylene-siloxane hybrids

Novel amide cross-linked alkylene-siloxane hybrid materials (di-amidosils) synthesized by the sol-gel process have been investigated. Two samples identified by the notation d-A(x) with x = 4 and 8 (where x is the number of methylene groups of the alkylene chain) have been produced as transparent, amorphous, rigid monoliths. The d-A(8) material is thermally stable up to approximately 245°C. In this hybrid the siliceous framework is mainly composed of [-(CH2)Si(OSi)3)] and [-(CH2)Si(OSi)2(OH)] substructures. Structural unit distances of 4.1 and 4.2 Å and average interparticle distances of 12 and 17 Å have been determined for d-A(4) and d-A(8), respectively. In these compounds the alkylene chains are disordered and adopt gauche conformations. While a negligible proportion of the amide linkages remain non-bonded, the great majority of these groups belong to highly disordered strong hydrogen-bonded amide-amide associations. The hybrids introduced are room temperature white light emitters, presenting an intense, broad emission band in the blue/purplish-blue spectral region. The origin of such a band has been ascribed to the convolution of donor-acceptor pair (D-A) recombinations that occur in the NH groups of the amide linkages and in the siliceous nanodomains. The maximum quantum yield value of the d-A(8) di-amidosil is 5.4%.
S.C. Nunes, V. de Zea Bermudez, J. Cybinska, R.A. Sa Ferreira, J. Legendziewicz, L.D. Carlos, M.M. Silva, M.J. Smith, D. Ostrovskii and J. Rocha, J. Mater. Chem. 15 (2005) 3876-3886

B2116 – Thermo-oxidative dehydrochlorination of rigid and plasticised poly(vinyl chloride)/poly(methyl methacrylate) blends

The aim of this work was to study the thermo-oxidative dehydrochlorination of rigid and plasticised poly(vinyl chloride)/poly(methyl methacrylate) blends. For that purpose, blends of variable compositions from 0 to 100 wt% were prepared in the presence (15, 30 and 50 wt%) and in the absence of diethyl-2-hexyl phthalate as plasticiser. Their miscibility was investigated by using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Their thermo-oxidative degradation at 180 ± 1°C was studied and the amount of HCl released from PVC was measured by a continuous potentiometric method. Degraded samples were characterised, after purification, by FTIR spectroscopy and UV-visible spectroscopy. The results showed that the two polymers are miscible up to 60 wt% of poly(methyl methacrylate) (PMMA). This miscibility is due to a specific interaction of hydrogen bonding type between carbonyl groups (C=O) of PMMA and hydrogen (CHCl) groups of PVC as shown by FTIR analysis. On the other hand, PMMA exerted a stabilizing effect on the thermal degradation of PVC by reducing the zip dehydrochlorination, leading to the formation of shorter polyenes.
K. Aouachria, N. Belhaneche-Bensemra, Polymer Degradation and Stability 91 (2006) 504-511

B2111 – Study of free-radical copolymerization of itaconic acid/2-acrylamido-2-methyl-1-propanesulfonic acid and their metal chelates

The monomer reactivity ratios for itaconic acid (IA)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in N,Ndimethylformamide solution using the benzoyl peroxide (Bz2O2) as an initiator with different monomer-to-monomer ratios in the feed were investigated by studying the resulting copolymer composition via elemental analysis. Composition results were summarized and various methods were employed to estimate the monomer reactivity ratios including the use of the Error-in Variables-Model method using a computer program, RREVM. The estimates of the reactivity ratios from the EVM method are found to be rIA = 0.4636 and rAMPS = 0.0357. These values suggest that IA is more reactive than AMPS and the copolymer will be richer in IA units. Cu(II) and Ni(II) chelates of the copolymers were prepared and the formation constants of each complex were determined by the mole-ratio method using the UV-vis spectroscopy. UV-vis studies showed that the complex formation tendency increased in the followed order: Cu(II) > Ni(II). The copolymers and their metal chelates were characterized by FT-IR spectra and SEM analysis. Also, thermal stabilities of the copolymers and their metal chelates were investigated using TGA and DSC analysis.
R. Coskun, C. Soykan, A. Delibas, European Polymer Journal 42 (2006) 625-637

B2096 – Improvement of mechanical properties of poly(DL-lactide) films by blending of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(DL-lactide) (PDLLA) were blended at different ratios in an attempt to form a biomaterial with suitable properties for nerve regeneration. FT-IR and X-ray analysis showed that the blending of the PDLLA component did not alter the helical structure of PHBHHx, but did lead to a reduction of crystallinity. Differential scanning calorimetry (DSC) analysis indicated that the two polymers were immiscible in the melted state. The mechanical properties of certain composite films were more desirable than those of unblended PDLLA films. Blends consisting of PDLLA and PHBHHx at ratios of 2:1 and 1:2 exhibited a lower elastic modulus and a higher elongation at break compared to unblended PDLLA. ELISA results indicated that the amount of fibronectin adsorbed on composite films was much higher than the amount adsorbed on PDLLA film. The results of this study demonstrate the feasibility of using PDLLA/PHBHHx blended materials for biomedical applications.
Y. Gao, L. Kong, L. Zhang, Y. Gong, G. Chen, N. Zhao, X. Zhang, European Polymer Journal 42 (2006) 764-775

B2082 – Electrosynthesis and characterization of a poly(paraphenylene) deriving from p-fluoroanisole

The electrochemical oxidation of p-fluoroanisole (p-FA) in the solvent acetonitrile leads to oligomers and polymers of poly(paraphenylene) type. The electropolymerization process involves coupling reactions of the cation radicals intermediates. The obtained polymers are separated according to their chain length by selective precipitation in cyclohexane and ether. The corresponding structures are characterized by NMR, MS, FTIR, UV and XR diffraction. A preliminary physical study shows that the polymers are photoluminescent with a maximum emission in the near infrared.
S. Bergaoui, A. Haj Saîd, S. Roudesli, F. Matoussi, Electrochimica Acta 51 (2006) 4309-4315

B2077 – Thermal stability and flammability of silicone polymer composites

Silicone polymer composites filled with mica, glass frit, ferric oxide and/or a combination of these were developed as part of a ceramifiable polymer range for electrical power cables and other high temperature applications. This paper reports on the thermal stability of polymer composites as determined by thermogravimetric techniques, thermal conductivity and heat release rate as measured by cone calorimetry. The effects of fillers on thermal stability and flammability of silicone polymer are investigated. Of the fillers studied, mica and ferric oxide were found to have a stabilising effect on the thermal stability of silicone polymer. Additionally, mica and ferric oxide were found to lower heat release rates during combustion, but only mica was found to increase time to ignition.
L.G. Hanu, G.P. Simon, Y-B. Cheng, Polymer Degradation and Stability 91 (2006) 1373-1379

B2065 – Proton exchange membranes based on poly(vinylidene fluoride) and sulfonated poly(ether ether ketone)

Blend membranes were obtained by solution casting from poly(vinylidene fluoride) (PVDF) and sulfonated poly(ether ether ketone) (SPEEK) in N,N-dimethylacetamide (DMAc). DSC and XRD were used to characterize the structure of the blend membranes. The effect of PVDF content on the membrane properties was investigated. The methanol permeability, water uptake and the swelling ratio of blend membranes decreased with the increase of PVDF content. Though the proton conductivity decreased upon the addition of PVDF, they were still comparable to that of Nafion® 117 membrane. Higher selectivities were also found for most blend membranes in comparison with Nafion® 117 membrane. The effect of methanol concentration on solution uptake, swelling ratio and methanol permeability of the blend membranes was also studied.
S. Xue, G. Yin, Polymer 47 (2006) 5044-5049

B2037 – Nanocomposites of isotactic polypropylene reinforced with rod-like cellulose whiskers

Nanocomposite films of isotactic polypropylene reinforced with cellulose whiskers highly dispersed with surfactant were prepared for the first time and compared with either bare or grafted aggregated whiskers. Films obtained by solvent casting from toluene were investigated by means of X-ray diffraction, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Evaluation of the crystallization behavior showed that the aggregated or surfactant-modified whiskers induced two crystalline forms (alpha and beta) in the nanocomposites and also acted as nucleating agents for isotactic polypropylene. The linear mechanical properties above the glass-rubber transition were found to be drastically enhanced for all three of the nanocomposites as compared to the neat polypropylene matrix, and these effects were attributed to a mechanical coupling between the polypropylene crystallites and filler/filler interactions. For the mechanical experiments at large deformations, the quality of the whisker dispersion was found to play a major role. The nanocomposites obtained with the surfactant-modified whiskers exhibited enhanced ultimate properties when compared to the neat matrix or to the composites containing the other filler types.
N. Ljungberg, J-Y. Cavaillé, L. Heux, Polymer 47 (2006) 6285-6292

B2028 – Microstructural investigation of dense membranes in relation to their gas transport properties

The morphology together with the gas permeation properties of crosslinked membranes prepared from different amounts of a polyorganophosphazene -(-NP(R1)0.18(R2)0.76(R3)1.06-)n- where R1 = 2-allylphenoxy, R2 = 4-isobutylphenoxy and R3 = 4-methoxyphenoxy ( Mw = 1, 350, 000 g/mol) and a hydride terminated polydimethylsiloxane Mn = 14, 400 g/mol were investigated. The microstructure of some resulting films was first examined by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The transport properties of the films were second examined with respect to their permeability to light gases such as He, H2, O2, N2 and CO2, and selectivity ratios were established. Different theoretical copolymer permeability models were tested as a function of the chemical composition to investigate the relationship between morphology and permeation properties and to give a complete insight into the copolymer morphology. Selectivity ratios are discussed as a function of the penetrant nature and of the copolymer structure.
A. Bac, C. Damas, C. Guizard, Journal of Membrane Science 281 (2006) 548-559

B2018 – Compatibilisation of polyethylene/ground tyre rubber blends by gamma irradiation

In the present work, gamma irradiation is used for the in situ compatibilisation of blends of recycled high density polyethylene (rHDPE) and ground tyre rubber (GTR) powder. The expected compatibilisation mechanism involves the formation of free radicals, leading to chain scission within rubber particles, crosslinking of polyethylene matrix and co-crosslinking between the two blend components at the interface. While uncompatibilised rHDPE/GTR blends show poor mechanical properties, especially for elongation at break and Charpy impact strength, irradiation leads to a significant increase of these mechanical performances. Such behaviour is attributed to the development of an adhesion between GTR particles and the surrounding thermoplastic matrix. This conclusion is supported by in situ scanning electron microscopy observations during microtensile tests, showing strong elongation of GTR particles upon deformation of irradiated blends.
R. Sonnier, E. Leroy, L. Clerc, A. Bergeret, J.M. Lopez-Cuesta, Polymer Degradation and Stability 91 (2006) 2375-2379

B1972 – Cold drawing of polymers: Plasticity and aging

Physical aging and mechanical deformation on polyisobutylmethacrylate (PIBMA) and polymethylmethacrylate (PMMA) have been investigated below but close to the glass transition temperature using calorimetry and elastic neutron scattering. We have studied the effect of physical aging before, during and after the deformation on the mechanical, thermal responses combined to a structural analysis ranging from the radius of gyration to the monomeric scales. On one hand we report that, as expected, plastic strains rejuvenate glassy polymer aged before drawing, and also that no aging effect occurs during the plastic deformation. Moreover, the enthalpic relaxation functions as measured by calorimetry on aged samples, before and after stretching, remain quite similar. On the other hand, we find that stretching a glassy chain induces a strong anisotropy at large scale, around the radius of gyration. This anisotropy disappears gradually at smaller scale down to the monomer structure. However, while the anisotropy is lost at the local scale, the static structure factor is still altered by the plastic strain. Theses changes at the monomer scale may be responsible of the complete loss of thermal history operated before stretching. The cold-drawn sample posses a slightly modified structure leading to a distinct glassy state which enthalpic relaxation remains unaltered. So plastic deformations do not simply rejuvenate a glassy polymer, it induces a 'metamorphosis'.
F. Casas, C. Alba-Simionesco, F. Lequeux, H. Montès, Journal of Non-Crystalline Solids 352 (2006) 5076-5080

B1949 – Miscibility of PVC/PMMA blends by vicat softening temperature, viscometry, DSC and FTIR analysis

This paper deals with the miscibility of polyvinyl chloride (PVC) with polymethyl methacrylate (PMMA). Blends of variable compositions from 0 to 100wt% were prepared in the presence (15, 30 and 50 wt%) and in the absence of di ethyl- 2 hexyl phtalate as plasticizer. Their miscibility was investigated by using various analytical methods: determination of the Vicat softening temperature, a viscometry method based on the alpha criterion of polymer-polymer miscibility, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The results show that the plot of Vicat temperature against composition is a continuous curve, indicating the miscibility of the blend. The viscometry method and DSC find that the two polymers are miscible up to about 60wt% of PMMA. This miscibility is due to a specific interaction of hydrogen bonding type between carbonyl groups (C = O) of PMMA and hydrogen from (CHCl) groups of PVC, as evidenced by FTIR spectroscopy. The two-band deconvolution shows an increase in associated groups percentage in the domain of miscibility.
K. Aouachria, N. Belhaneche-Bensemra, Polymer Testing 25 (2006) 1101-1108

B1937 – Polyethylene/ground tyre rubber blends: Influence of particle morphology and oxidation on mechanical properties

Results concerning the influence of the modification of morphological and chemical characteristics of ground tyre rubber (GTR) powders on the mechanical properties of polyethylene (HDPE or LDPE)/GTR blends are given. In order to improve the interfacial adhesion between rubber particles and matrix, two oxidation treatments of the GTR powder by potassium permanganate (in solution) and g-irradiation (in air) were performed. Then, the powder was incorporated in a HDPE matrix containing a small amount of maleic anhydride grafted polyethylene (MAgPE). The effect on the mechanical properties of the blends was studied. Since none of them was really effective, we conclude that oxidation cannot compensate for the lack of chemical reactivity of GTR powders.
R. Sonnier, E. Leroy, L. Clerc, A. Bergeret, J.M. Lopez-Cuesta, Polymer Testing 26 (2007) 274-281

B1922 – Synthesis, characterization and thermal degradation mechanism of three poly(alkylene adipate)s: Comparative study

Three high molecular weight aliphatic polyesters derived from adipic acid and the appropriate diol e poly(ethylene adipate) (PEAd), poly(propylene adipate) (PPAd) and poly(butylene adipate) (PBAd) e were prepared by two-stage melt polycondensation method (esterification and polycondensation) in a glass batch reactor. Intrinsic viscosities, GPC, DSC, NMR and carboxylic end-group measurements were used for their characterization. Mechanical properties of the prepared polyesters showed that PPAd has similar tensile strength to low-density polyethylene while PEAd and PBAd are much higher. From TGA analysis it was found that PEAd and PPAd have lower thermal stability than poly(- butylene adipate) (PBAd). The decomposition kinetic parameters of all polyesters were calculated while the activation energies were estimated using the Ozawa, Flynn and Wall (OFW) and Friedman methods. Thermal degradation of PEAd was found to be satisfactorily described by one mechanism, with activation energy 153 kJ/mol, while that of PPAd and PBAd by two mechanisms having different activation energies: the first corresponding to a small mass loss with activation energies 121 and 185 kJ/mol for PPAd and PBAd, respectively, while the second is attributed to the main decomposition mechanism, where substantial mass loss takes place, with activation energies 157 and 217 kJ/mol, respectively.
T. Zorba, K. Chrissafis, K.M. Paraskevopoulos, D.N. Bikiaris, Polymer Degradation and Stability 92 (2007) 222-230

B1894 – Thermotropic phase behavior of triple-chained catanionic surfactants with varying headgroup chemistry

Catanionic surfactants result from the pairing of oppositely charged amphiphilic molecules, forming a new class of surfactant molecules with various interesting lyotropic and thermotropic properties. With the aim of probing the role of both headgroup chemical nature/structure and molecular shape, a series of catanionic surfactants were synthesized. The cationic portion of the molecule is kept constant, being the dioctadecyldimethylammonium double chain. Different single-chained surfactants with varying headgroups and chain lengths are used as the anionic pair. The thermotropic behavior has been studied by DSC and the mesophase structural investigated by polarized light microscopy. The results indicate that, for a given chain length, parameters such as headgroup polarity and charge density, as well as volume, influence the catanionic surfactant behavior. The thermodynamic parameters are qualitatively evaluated, considering the headgroup chemical nature and the overall molecular structure.
E.F. Marques, R.O. Brito, Y. Wang, B.F.B. Silva, Journal of Colloid and Interface Science 294 (2006) 240-247

B1889 – Thermo-mechanical properties of LLDPE/SiO2 nanocomposites

Two series of linear low density polyethylene (LLDPE)/SiO2 nanocomposites were prepared. They were based on two types of commercial LLDPE, one prepared by metallocene (mLLDPE) and the other by traditional Ziegler-Natta (zLLDPE) catalysts, and silica nanoparticles surface treated with dimethyldichlorosilane. The silica nanonparticles used have an average diameter of 16 nm, and their weight fraction varied from 2 up to 10%. The structure and thermal-mechanical features of the nanocomposites were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), dynamic mechanical spectroscopy (DMA) as well as tensile tests. The effect of nanoparticles on crystallinity, and hence to the morphology of the materials was studied. The secondary transitions were also affected by the filler presence, while the tensile properties were reinforced with varying the nanoparticle weight fraction. The addition of the nanofillers brought up an increase in the elastic modulus and the tensile strength of mLLDPE accompanied by an unusual dramatic increase in the elongation at break. The same trend, although to a lesser extent, was observed for the zLLDPE/SiO2 composites. The increment of the elastic modulus of the composites with increasing filler content was simulated with three micromechanical models developed in previous works. The model which assumes an effective interface between the matrix and the nanoparticles provided the best fitting with the experimental data of mLLDPE/SiO2.
E. Kontou, M. Niaounakis, Polymer 47 (2006) 1267-1280

B1872 – Analysis of the chemical composition distribution of ethylene/alpha-olefin copolymers by solution differential scanning calorimetry: an alternative technique to Crystaf

A series of ethylene/1-hexene copolymers synthesized with a metallocene catalyst with varying comonomer contents but constant molecular weights were analyzed with crystallization analysis fractionation (Crystaf), solid state differential scanning calorimetry (solid state DSC) and solution differential scanning calorimetry (solution DSC). Experimental solution DSC exotherms were compared to Crystaf profiles obtained under similar crystallization conditions. At the same cooling rates (0.1°C/min), considerable differences were found for samples with low levels of short chain branching although the discrepancy became less significant with increasing branching. Very good agreement was found between the Crystaf profiles of metallocene copolymers obtained at a cooling rate of 0.1°C/min and solution DSC exotherms of samples crystallized at the rate of 0.01°C/min. Good agreement was also observed between the Crystaf and solution DSC profiles of a Ziegler-Natta linear low-density polyethylene (LLDPE) sample when crystallized at the same cooling rate of 0.2°C/min. In conclusion, solution DSC is a useful technique for simulating profiles obtained by Crystaf analysis, although very slow analysis times must be used for samples with less than 4 mol% comonomer.
D.M. Sarzotti, J.B.P. Soares, L.C. Simon, L.J.D. Britto, Polymer 45 (2004) 4787-4799

B1871 – Influence of TiO2 and Fe2O3 fillers on the thermal properties of poly(methyl methacrylate) (PMMA)

The thermal properties of pure poly(methyl methacrylate) (PMMA) and PMMA filled with 5%, 10%, 15% and 20% of nanometric particles of titanium oxide (TiO2) and ferric oxide (Fe2O3) were investigated under air atmosphere by DSC, TGA and LOI measurements on samples prepared by solvent casting method. In the presence of the filler, the thermal stability of the polymer appeared to be significantly improved. A linear relationship between LOI and glass transition temperature (Tg) suggests that the restriction of mobility of the polymer chains is directly linked to the increase of stability.
A. Laachachi, M. Cochez, M. Ferriol, J.M. Lopez-Cuesta, E. Leroy, Materials Letters 59 (2005) 36-39

B1849 – Silicone-polyacrylate composite latex particles. Particles formation and film properties

Composite latex particles with a polydimethylsiloxane PDMS core and a poly(methyl methacrylate-co-n-butyl acrylate) P(MMA-BA) copolymer shell were synthesized by seeded emulsion polymerization using the PDMS latex as the seed. The compatibility between the two polymer phases was changed by introducing vinyl groups in the latex core. Monomer conversions and particle size evolution were monitored to see the influence of the nature of the core functionality on the polymerization kinetics and on the extent of secondary nucleation. Particle morphology was characterized by cryo-transmission electron microscopy. The P(MMA-BA) copolymer formed a regular shell around the PDMS seed, whereas nonuniform coatings were formed when vinyl functionalities were introduced into the seed. Films were produced from the latexes, and their surface property was analyzed by X-ray photoelectron spectroscopy and contact angle measurements. It was shown that the PDMS component segregated to the polymer/air interface and that the extent of segregation depended on the original particles structure. Because PDMS has a very low glass transition temperature, it can easily diffuse throughout the film material. However, protected by an acrylic shell, polymer diffusion is significantly hindered and the film then displays all the characteristic properties of the acrylic copolymer. The surface composition of the films formed by the structured particles which PDMS core was not totally covered by the polyacrylate, was found to be intermediate between the composition of the films issued from the core-shell latexes and that of the films produced from blends of pure polyacrylate and PDMS latexes.
M. Lin, F. Chu, A. Guyot, J-L. Putaux, E. Bourgeat-Lami, Polymer 46 (2005) 1331-1337

B1848 – High solids content emulsion polymerisation without intermediate seeds. Part III. Reproducibility and influence of process conditions

The reproducibility and robustness of a unseeded process for the production of high solid content, low viscosity latex are examined. A series of runs showed that the experiments are very reproducible both in terms of the particle size distribution and the shear viscosity of the final latex. It is also shown that it is the surfactant concentration and feed profiles that are the most sensitive issues in maintaining product specifications since they control the rate of generation of small particles.
S. Boutti, C. Graillat, T.F. McKenna, Polymer 46 (2005) 1223-1234

B1847 – Titanium and zirconium ketimide complexes: synthesis and ethylene polymerisation catalysis

The syntheses of ketimide titanium complexes of the type Ti(N=CtBu2)3X (X = Cl, Cp, Ind), Ti(N=CtBu2)4 and the zirconium complex CpZr(N=CtBu2)2Cl are described. When activated by MAO, all compounds are ethylene polymerisation catalysts. In the conditions studied, the most active catalyst is CpZr(N=CtBu2)2Cl, with an activity of 2.7 . 105 kg/(molZr [E] h). Titanium complexes are less active by about two orders of magnitude. The polyethylene produced is linear, as determined by NMR spectroscopy. Molecular structures of Ti(N=CtBu2)3X (X = Cl, Cp, Ind) and Ti(N=CtBu2)4 were determined by X-ray single crystal diffraction.
A.M. Martins, M.M. Marques, J.R. Ascenso, A.R. Dias, M.T. Duarte, A.C. Fernandes, S. Fernandes, M.J. Ferreira, I. Matos, M.C. Oliveira, S.S. Rodrigues, C. Wilson, Journal of Organometallic Chemistry 690 (2005) 874-884

B1838 – Highly active new alpha-diimine nickel catalyst for the polymerization of alpha-olefins

A new silylated alpha-diimine ligand, bis[N,N0-(4-tert-butyl-diphenylsilyl-2,6-diisopropylphenyl)imino]acenaphthene 3, and its corresponding Ni(II) complex, {bis[N,N0-(4-tert-butyl-diphenylsilyl-2,6-diisopropylphenyl)imino]acenaphthene}dibromonickel 4, have been synthesized and characterized. The crystal structures of 3 and 4 were determined by X-ray crystallography. In the solid state, complex 4 is a dimer with two bridging Br ligands linking the two nickel centers, which have square pyramidal geometries. Complex 4, activated either by diethylaluminum chloride (DEAC) or methylaluminoxane (MAO) produces very active catalyst systems for the polymerization of ethylene and moderately active for the polymerization of propylene. The activity values are in the order of magnitude of 107 g PE (mol Ni [E] h) 1 for the polymerization of ethylene and of 105 g PP (mol Ni [P] h) 1 for the polymerization of propylene. NMR analysis shows that branched polyethylenes (PE) are obtained at room or higher temperatures and almost linear PE is obtained at 0 C with 4/DEAC.
H-R. Liu, P.T. Gomes, S.I. Costa, M.T. Duarte, R. Branquinho, A.C. Fernandes, J.C.W. Chien, R.P. Singh, M.M. Marques, Journal of Organometallic Chemistry 690 (2005) 1314-1323

B1828 – Propofol induced micelle formation in aqueous block copolymer solutions

The effect of propofol (2,6-diisopropylphenol) on the aqueous solution behaviour of three non-ionic block copolymers (F127, F87, and F68) has been investigated using differential scanning calorimetry (DSC), dynamic light scattering (DLS), and osmolality measurements. The DSC data showed that Tonset for the micellisation transitions of each block copolymer moved to lower temperature and that the corresponding micellisation enthalpy ( Hmic) decreased with increasing propofol concentration. DLS measurements showed that the addition of propofol to aqueous solutions of the block copolymers induced the formation of micelles at temperatures well below the critical micellisation temperature (CMT) of the pure copolymer and that at low temperatures large sized aggregates of monomeric copolymer and propofol are formed. The size of the aggregates formed depends both on the temperature and the propofol concentration. Osmolality measurements showed that the number of osmotically active particles detected in a 10% (w/w) F127 solution decreased with increasing propofol concentration. The data suggests that propofol induces micelle formation and that propofol is likely solubilised within the core of the block copolymer aggregates.
C. Dwyer, C. Viebke, J. Meadows, Colloids and Surfaces A: Physicochem. Eng. Aspects 254 (2005) 23-30

B1824 – Thermal stabilisation of poly(vinyl chloride) by organotin compounds

The effect of LSN 117 (dioctyl tin bis isooctyl thioglycollate, an organotin compound) on the heat stability of plasticised PVC was investigated in this study. The organotin stabiliser had carbonyl and carboxylate groups and PVC contained traces of Fe, Zn, Ca, Cu and Sn. The heat stability of the films were tested at 140°C and 160°C or 180°C by heating in an air circulation oven up to 2 h and by measuring HCl evolved using a Metrohm 763 PVC thermomat and by thermogravimetric analysis. The onset of HCl evolution was at 14.3 and 2.5 h at 140°C and 160°C, respectively, for PVC film without LSN117. On the other hand, the film with LSN117 did not evolve HCl in 30.3 h at 140°C. HCl started to evolve from the films with LSN 117 in 14.3 h at 160°C. The TGA curve also indicated PVC film with LSN 117 degraded at higher temperatures than control films. LSN 117 was found to be a good heat stabiliser for plasticised PVC and it did not have any detrimental effect on mechanical properties.
E. Ark?s, D. Balköse, Polymer Degradation and Stability 88 (2005) 46-51

B1808 – Ordering in surfactant mixtures induced by polymers

We studied ternary mixtures of nonionic surfactant (C12E6, n-dodecyl hexaoxyethylene glycol monoether), polymer (PEG, polyethylene glycol), and water. A small amount of PEG induces demixing into the polymerrich and surfactant-rich phases in the ternary PEG/C12E6/water mixture. Above a certain concentration and/or molecular weight of PEG, the surfactant-rich phase orders, even in a solution consisting of a few percent of surfactant. The phase boundary acts as a semipermeable membrane, and the equilibrium is determined by the chemical potential of water in two phases. The explicit expression for the amount of PEG needed to order C12E6 water solution is given and verified experimentally. The analysis of the coexistence conditions leads to the conjecture that only two oxygen atoms in the outward part of the hydrophilic surfactant head strongly affect the chemical potential of water. Our methodology is generic, i.e., on the same basis one can design a similar experiment for any surfactant/polymer/water system and find the right proportions of polymer that induce order in a surfactant-rich phase.
R. Holyst, K. Staniszewski, and I. Demyanchuk, J. Phys. Chem. B 109 (2005) 4881-4886

B1794 – Radiation polymerization of diethyl fumarate

Diethyl fumarate (DEF) has been polymerized by gamma irradiation using doses in the range 50-300 kGy, and in this dose range the polymerization yield increased almost linearly. The polymer has a glass transition temperature of about 20°C, softening point about 15°C, and decomposition temperature 300°C.
H. Alkassiri, Radiation Physics and Chemistry 73 (2005) 61-63

B1783 – Kinetics of scrap tyre pyrolysis under fast heating conditions

The kinetics of scrap tyre pyrolysis has been studied by means of thermogravimetry (runs at constant temperature and following temperature ramps) and using a fast heating microreactor. The advantages of the microreactor for obtaining kinetic data at higher temperatures (in the 773-973 K range) than those corresponding to thermogravimetry and under conditions similar to those of continuous large-scale reactor are clearly shown. The validity of the kinetic parameters determined (E = 98.6 kJ mol 1 and k0 = 7.35 104 s 1) will only be restricted by unavoidable heat and mass transfer limitations, which have been minimized by using a particle size smaller than 0.2 mm. The kinetic results are evidence, on the one hand, of the limitations of these laboratory techniques for the kinetic study and, on the other, of the inherent heat and mass limitations of this material. Through monitoring by gas chromatography, the kinetics of formation of hydrocarbon products has been determined. These products are interesting as raw materials for petrochemistrical industry (mainly light olefins and aromatics) and for the synthesis of basic materials in tyre manufacturing (isoprene and 1,3-butadiene).
R. Aguado, M. Olazar, D. Vélez, M. Arabiourrutia, J. Bilbao, J. Anal. Appl. Pyrolysis 73 (2005) 290-298

B1781 – Mechanism of butane skeletal isomerization on sulfated zirconia

A kinetic model of the skeletal isomerization of n-butane and isobutane on sulfated zirconia in the absence of Pt is presented. The skeletal isomerization of butane on sulfated zirconia has been shown to be initiated by oxidative dehydrogenation of the alkane. This is followed by the formation of alkoxy groups/carbenium ions at the surface, induced by strong Bronsted acid sites. The isomerization of the secbutyl carbenium ion occurs mono-molecularly, as suggested by the 100% selectivity for isomerization extrapolated to zero conversion. With increasing conversion, the selectivity decreased linearly, leading to propane and pentanes up to 40% of conversion. The lower selectivity for isomerization is qualitatively explained by reactions of isobutene present in small concentrations in the reactor at higher conversions. Transient experiments show conclusively that the isomerization of the carbenium ion and not the hydride transfer from the alkane to the carbenium ion is the rate-determining step.
X. Li, K. Nagaoka, L.J. Simon, R. Olindo, J.A. Lercher, Journal of Catalysis 232 (2005) 456-466

B1779 – Effects of epoxy treatment of organoclay on structure, thermo-mechanical and transport properties of poly(ethylene terephthalate-co-ethylene naphthalate)/organoclay nanocomposites

Poly(ethylene terephthalate-co-ethylene naphthalate) (PETN) nanocomposites containing two different organoclays, Cloisite 20A and 30B, were prepared by melt intercalation using an extruder. The organoclays was treated with epoxy monomer to further improve the polar interactions with PETN matrix. The morphological, thermal-mechanical, mechanical and gas barrier characteristics of the nanocomposites were evaluated using several characterization tools. It is found that the Cloisite 30B had better interactions with PETN and was more uniformly dispersed within PETN than Cloisite 20A. Epoxy treatment of Cloisite 30B organoclay resulted in improvements in d-spacing between silicate layers, thermo-mechanical and tensile properties, as well as thermal stability, processing and gas barrier characteristics of the PETN/30B nanocomposites. These results suggest that the epoxy acted as the compatibilizer as well as the chain extender, improving the chemical interactions between PETN and organoclay, while discouraging the macromolecular mobility of polymer chains in the vicinity clay particles. The implications and the mechanisms behind these observations are discussed.
M. Lai, J-K. Kim, Polymer 46 (2005) 4722-4734

B1777 – Toward an understanding of thermoresponsive transition behavior of hydrophobically modified N-isopropylacrylamide copolymer solution

Poly(N-isopropylacrylamide-co-vinyl laurate)(PNIPAAm-co-VL) copolymers were prepared at various feed ratios via conventional radical random copolymerization. The formation, composition ratios and molecular weight of copolymers were examined. The thermoresponsive behaviors of PNIPAAm and PNIPAAm-co-VL solutions at low and high concentrations were intensively investigated by turbidity measurement, Micro-DSC, temperature-variable state fluorescence, 1H NMR and dynamic light scattering (DLS). Several important results were obtained that (1) incorporation of PVL results in much lower and broader LCST regions of the copolymer solutions, and facilitates the formation of hydrophobic microdomains far below LCST, causing a pronounced aggregation in solutions (2) temperaturevariable 1H NMR spectra shows that during the phase transition, the 'penetration' of PNIPAAm into the hydrophobic core is a process accompanied with a transition of isopropyl from hydration to dehydration as well as a self-aggregation of hydrophobic chains at different temperature stages (3) according to the 1H NMR spectra of polymer solutions obtained at varied temperatures, the microdomains from hydrophobic VL moieties have a different accessibility for isopropyl groups and the entire chains during phase transition (4) temperaturevariable DLS demonstrates that the temperature-induced transition behavior of copolymers is supposedly divided into three stages: pre- LCST aggregation (<20°C), coil-globule transition at LCST (20-25°C) and post-LCST aggregation (>25°C).
Z. Cao, W. Liu, P. Gao, K. Yao, H. Li, G. Wang, Polymer 46 (2005) 5268-5277

B1745 – Synthesis of highly cross-linked poly(diethylene glycol dimethacrylate) microparticles in supercritical carbon dioxide

Herein we report the synthesis of poly(diethylene glycol dimethacrylate), poly(DEGDMA), by free-radical heterogeneous polymerization in supercritical carbon dioxide (scCO2), using a commercially available carboxylic acid endcapped perfluoropolyether oil (Krytox 157FSL) as stabiliser. The effect of initial concentration of stabiliser, monomer and initiator on the yield and morphology of the resulting polymer has been investigated. Krytox worked effectively as a stabiliser and discrete poly(DEGDMA) particles with diameters ranging from 1.28 to 2.08 lm and narrow particle size distribution were produced in supercritical carbon dioxide, in high yield and in short reaction times, without making use of harmful organic solvents.
T. Casimiro, A.M. Banet-Osuna, A.M. Ramos, M. Nunes da Ponte, A. Aguiar-Ricardo, European Polymer Journal 41 (2005) 1947-1953

B1722 – Linear and crosslinked copolymers of p-tert-butylcalix[4]arene derivatives and styrene: New synthetic approaches to polymer-bound calix[4]arenes

As an extension of our previous studies concerning the free radical copolymerisation of 25,26,27-tripropoxy-28-(4- vinyl-benzyloxy)-p-tert-butylcalix[4]arene (3) with styrylic monomers, we report herein on the synthesis and characterisation of new terpolymers derived from 3, styrene and divinylbenzene, having nominal crosslinking degrees ranging from 4% to 40% wt. The terpolymers exhibited good thermal stabilities (DSC) and were prepared in good yields. Depending on the reaction conditions (dilution degree and aqueous phase to porogen ratio), materials with identical nominal crosslinking but otherwise differentiated morphologies and swelling abilities were obtained. In a related study, the radical polymerisation of styrene was carried out in the presence of a novel calix[4]arene derivative 4, bearing two distal benzyl-vinyl groups in the lower rim. It is shown that, albeit the presence of two phenolic groups within the calixarene moiety which could have functioned as inhibitors of the free radical polymerisation, the macrocycle was able to take part in the copolymerisation reaction, yielding new soluble and crosslinked polymers. In both cases, no pendant vinyl groups were found in the polymeric materials. The probable mechanisms underlying their formation are discussed.
A.R. Mendes, C.C. Gregorio, P.D. Barata, A.I. Costa, J.V. Prata, Reactive & Functional Polymers 65 (2005) 9-21

B1718 – Temperature induced phase transition of interpenetrating polymer networks composed of poly(vinyl alcohol) and copolymers of N-isopropylacrylamide with acrylamide or 2-acrylamido-2-methylpropyl-sulfonic acid

Interpenetrating polymer networks (IPNs) composed of poly(vinyl alcohol) (PVA) and poly(N-isopropylacrylamide-co-X) (PNIPAAmco- X) were prepared by using a two-step method. Hydrophilicity of PNIPAAm chains was increased by adding acrylamide (AAm; hydrophilic neutral monomer) or 2-acrylamido-2-methylpropylsulfonic acid (AMPS; anionic charged monomer). The effect of the incorporation of chemically crosslinked PVA into the temperature induced phase transition as well as swelling behavior of the responsive hydrogels were studied. The volume phase transition (VPT) of IPNs was investigated by cloud point measurement and differential scanning calorimetry. Significant differences in volume phase transition enthalpies of PNIPAAm (DHVPT) and volume phase transition temperatures (TVPT) were found. The DHVPT decreases with increasing co-monomer concentration. In several cases the phase transition was not followed by macroscopic shrinking of IPNs. Thus this property is advantageous for several technical applications.
A. Szilagyi, M. Zrinyi, Polymer 46 (2005) 10011-10016

B1711 – TG and DSC studies of naturaland artificial aging of polypropylene

We study the evolution of thermal degradation of samples of polypropylene (PP), during their aging for two periods of 60 and 80 days. The study, using thermogravimetric analysis (TG) and differential scanning calorimetric (DSC) analyses, focused on two types of aging: the naturalone under the impact of the solar environment and the artificialone which was carried out by exposing the sample to radiations of a 100W commercial lamp. The comparative study of these two types of aging shows that the thermaldegradation of the PP increases as a function of time of aging. Indeed, for a same duration, this thermal degradation is more important in the artificialaging case than it is in the naturalone and is an increasing function of aging. The prolonged and continuous thermal effect produced by the lamp, in the case of the artificial aging, weakened the polymer and implies very important acceleration of the process of degradation. The results obtained during heating and cooling of the samples, using the DSC, show an evolution of the phase transition temperatures and the corresponding enthalpies of melting and crystallization.
M. Rjeb, A. Labzour, A. Rjeb, , S. Sayouri, Y. Claire, A. Périchaud, Physica A 358 (2005) 212-217

B1705 – Application of an extended Tool-Narayanaswamy-Moynihan model. Part 2. Frequency and cooling rate dependence of glass transition from temperature modulated DSC

In the first part of this paper a Tool-Narayanaswamy-Moynihan-model (TNM) extended by non-Arrhenius temperature dependence of the relaxation time was applied to describe results from temperature modulated DSC (TMDSC). The model is capable to describe the
S. Weyer, H. Huth, C. Schick, Polymer 46 (2005) 12240-12246

B1704 – Synthesis and swelling behaviour of hydrophobically modified responsive polymers in dilute aqueous solutions

New series of associating polymers were synthesised in order to investigate opposite behaviours of hydrophobically modified water-soluble polymers and thermoresponsive water-soluble polymers carrying LCST stickers. On the basis of a poly(acrylic acid) bac
N. Padmanabha Iyer, D. Hourdet, M.V. Badiger, C. Chassenieux, P. Perrin, P.P. Wadgaonkar, Polymer 46 (2005) 12190-12199

B1688 – Thermogravimetric investigations of carbonaceous materials-Syndiotactic polystyrene systems

A system of a syndiotactic polystyrene (s-PS)-carbonaceous material, obtained as a result of syndiotactic polymerisation of styrene in the presence of carbonaceous materials of organic origin of different degree of coalification before and after their ammoxidation, was studied. The initial materials were plum stone waste, brown coal and hard coal. The interactions between the system components were studied by the method of differential scanning calorimetry (DSC). It has been found that the type of the carbonaceous material used determines the thermal effects of the phase transitions in s-PS (detected on thermograms) and the melting point of s-PS. It has been shown that on melting of the syndiotactic polystyrene in the presence of the carbonaceous materials containing a relatively large number of oxide groups, the polymer oxidation reactions occur. This effect does not occur when carbonaceous materials with preliminary ammoxidation are applied.
L. Wachowski, W. Skupinski and M. Hofman, Thermochimica Acta 44 (2006) 7-11

B1643 – Hybrid thickeners in aqueous media

Responsive thickeners have been obtained by grafting onto poly(sodium acrylate) [PAA] macromolecular stickers characterized by a lower critical solution temperature (LCST) in water: poly(N-isopropylacrylamide) [PNIPA] or poly(ethylene oxide-co-propylene oxide) [PPO]. As these LCST polymeric side chains are able to interact specifically with silica surfaces, while the macromolecular backbone does not, the aim of the present work was to study the formation of hybrid self-assemblies in aqueous solutions between inorganic nano-particles and copolymers. Despite very strong electrostatic repulsions taking place between silica beads and PAA chains at pH 8, specific interactions were clearly evidenced for all organic/inorganic mixtures and their properties were studied by rheology and calorimetry. At low temperature, PNIPA side-chains strongly adsorb on silica surfaces and promote the formation of hybrid networks with viscoelastic properties close to chemical gels. The 3D structure is very stable, even in the presence of salt ([NaCl] = 0.1 mol/l), and thermothickening properties are observed above the LCST of PNIPA due to self-assembling of non-adsorbed stickers. PAAgPPO solutions display a similar behaviour with thermothickening properties in the presence of added nanoparticles. Nevertheless the association between PPO and silica are weaker and the hybrid network is no longer stable at high ionic strength.
D. Portehault, L. Petit, N. Pantoustier, G. Ducouret, F. Lafuma and D. Hourdet, Colloids and Surfaces A: Physicochem.Eng.Aspects 278 (2006) 26-32

B1642 – Thermoreversible behavior of associating polymer solutions: Thermothinning versus Thermothickening

Self-assembling properties of poly(sodium acrylate) grafted with dodecyl [C12], PAAgC12, or poly(N-isopropylacrylamide) [PNIPA] side chains, PAAgPNIPA, were studied in unentangled semidilute aqueous solution. While PAAgC12 self-associates through hydrophobic interactions, the gelation of PAAgPNIPA is triggered by heating in response to the lower critical solution temperature of PNIPA (LCST ~ 32°C). The local structure of the physical networks was investigated by small-angle neutron scattering, and the scattering patterns were described using a polydisperse sphere model taking into account hard-sphere interactions. This model allow us to draw a realistic picture of physical gels with quantitative information concerning the size of hydrophobic cores, the volume fraction of stickers in the aggregates, the fraction of stickers which take part in the aggregation process, the range of repulsive interactions, and the structural modifications induced by temperature. The description of the network is in good agreement with complementary data obtained from DSC and 13C NMR. In the present work, a special emphasis has been given to the important relationship existing between the viscoelastic properties of associating polymer solutions and the binding energy of stickers leaving temporarily the micellar junction. Depending on the endothermic or exothermic nature of the disengagement process of the sticker (heat of demicellization), the relaxation time of the network and the viscoelastic properties will either decrease or increase with the temperature. The consequence is that aqueous solutions of PAAgC12 and PAAgPNIPA exhibit opposite rheological properties with the temperature, namely thermothinning and thermothickening. By mixing these two copolymers, we show that intermediate properties can be obtained but in that case a microphase-separated network is obtained as a result of copolymer segregation.
D. Hourdet, J. Gadgil, K. Podhajecka, M.V. Badiger, A. Brûlet and P.P. Wadgaonkar, Macromolecules 38 (2005) 8512-8521

B1597 – Determinazione della concentrazione della frazione organica di pitture in emulsione mediante il calore di combustione

C. Pagella, P. Silvestri, F. Raffaghello, D.M. De Faveri, La rivista dei combustibili 50 (1996) 219-227

B1583 – High-sensitivity isothermal and scanning microcalorimetry in PNIPA : Hydrogels around the volume phase transition

Mechanical and dynamic light scattering measurements show that at 20°C poly(N-isopropylacrylamide) (PNIPA) hydrogels are in good solvent conditions. At this temperature, the average value of the collective diffusion coefficient is D = 4 x 10^(-7) cm2/s. The value of the enthalpy found by isothermal microcalorimetry is roughly twice that reported in the literature. Even at extremely low scanning rates (0.02°C/min), full thermal equilibrium was not achieved in DSC. Small-angle X-ray scattering measurements confirmed that the gel collapse involves two stages. The first is prompt microphase separation in which the polymer chains form clusters of size approximately 10 nm, separated by distances of several hundred nanometers. The second stage involves slow relaxation and expulsion of solvent, with an estimated diffusion coefficient at 40°C equal to about 10^(-17) cm2/s. The slow relaxation of the frozen network is responsible for the hysteresis in the DSC measurements and can explain the discrepancies in the reported values of the enthalpy.
K. Laszlo, K. Kosik, E. Geissler, Macromolecules 37 (2004) 10067-10072

B1487 – Plasticization of polystyrene by high pressure gases : a calorimetric study

M.L. O'Neill, Y.P. Handa, Assignment of the Glass Transition, ASTM STP 1249 (1994) 165-173

B1459 – Enthalpic and volumetric studies of the interactions of propionamide in aqueous carboxylic acid solutions at 298.15K

The enthalpies of solution and the molar volumes have been determined for propionamide in aqueous ethanoic acid and propionic acid solutions using a C-80 microcalorimeter and a DMA60/602 densimeter. The enthalpic and volumetric interaction coefficients of propionamide with the two carboxylic acids have been evaluated. Combining the previous studies for butyramide, the pair interaction coefficients are discussed from the point of view of dipole-dipole and structural interactions and the triplet interaction coefficients are interpreted by using the solvent separated association pattern.
Y. Lu, Y. Han, M. Liu, Q. Cheng, X. Lou, J. Lu, Thermochimica Acta 416 (2004) 65-70

B1454 – Thermoreversible polymers adsorbed to colloidal silica : A 1H NMR and DSC study of the phase transition in confined geometry

The phase transition of the thermoreversible polymer PNIPAM, which shows a coil-to-globule transition due to the lower critical solution temperature (LCST) behavior in aqueous solution, is investigated in the restricted geometry of an adsorption layer. Furthermore, a charged copolymer is studied to investigate the influence of charges on the phase transition. Both polymers are adsorbed to colloidal silica and studied by 1H NMR and differential scanning calorimetric (DSC) experiments. In solid state 1H NMR relaxation experiments the signals of solid spins in trains and of liquid spins in tails and loops can be identified. 1H liquid state spectra detect the phase transition of the loops and tails into immobile segments with increasing temperature. The transition is broadened as compared to the polymer in solution, especially at low surface coverage. For the copolymer, the transition is incomplete, since mobile segments remain even at high temperature. They are attributed to electrostatic repulsion from the surface, leading to a mobile arrangement of the copolymer layer. Micro-DSC experiments confirm the finding of an increased width of the transition at the interface, which depends on the surface coverage. Furthermore, an increase of the transition temperature with decreasing polymer amount is observed, which is most pronounced for the copolymer, and is a further indication of an electrostatically hindered phase transition. In conclusion, despite a negligible influence of a low fraction of charges on the phase transition in solution, the phase transition in adsorption layers is very sensitive to charged segments. Combining NMR and DSC methods, local information on the transition behavior of different polymer segments at the interface, such as loops and tails, or charged monomers, can be obtained.
M. Schönhoff, A. Larsson,P. Welzel, D. Kuckling, J. Phys. Chem. B 106 (2002) 7800-7808

B1442 – Hydrolysis of waste polyethylene terephthalate and characterization of products by differential scanning calorimetry

Neutral hydrolysis of waste polyethylene terephthalate (PET) has been carried out with different amounts of water and different catalysts, in the presence of xylene. The organic solvent made it possible to employ very little amounts of water, lower temperatures and pressures and providing concentrated ethylene glycol (EG) solutions in contrast with previous methods, yielding intermediates suitable for PET preparation. These intermediates were characterized by FTIR spectroscopy, acid value (AV), hydroxyl value (HV), viscosity average molecular weight () determinations as well as by DSC. Multiple heating/cooling runs in DSC apparatus were carried out and a deconvolution procedure was applied using Haarhoff-Van der Linde (HVL) function to verify the presence of the same components and also to compare polymerization tendency of these various hydrolysis products.
G. Güçlü, T. Yalçinyuva, S. Özgümüs, M. Orbay, Thermochimica Acta 404 ( 2003) 193-205

B1427 – Thermodynamics of hydrogen bonding in polycomplexes of poly(4-vinylpyridine) with maleic acid-alt-ethylene copolymer

Hydrogen bonding formation in a polymer complex between poly(4-vinylpyridine) (P4VPy) and maleic acid-alt-ethylene (MA-alt-E) copolymer has been studied. Fourier transform infrared spectroscopic (FT-IR) studies have evidenced that the carboxylic groups of MA-alt-E interact with the pyridine ring of P4VPy. The existence of hydrogen bonding interactions in these systems is shown by the appearance of new bands at 1640 and 1503 cm-1 and a broadening of the -C=C- band of the pyridinic ring. The thermodynamic analysis of the hydrogen bonding was performed through the estimation of the enthalpy of mixing in the polycomplex formation process. ?HM was determined by means of an association model developed by Painter and co-workers and by flow calorimetric direct measurements. These results showed a high negative value for the enthalpy of mixing, which is consistent with the blend miscibility given that ?HM is the main contribution to the change of the free energy of mixing, ?GM
V. Villar, L. Irustra, M.J. Fernandez-Berridi, J.J. Iruin, M. Iriarte, L. Gargallo, D. Radic, Thermochimica Acta 402 (2003) 209-218

B1402 – Blend formation between homo- and co-polymers at 298.15 K PMMA-SAN blends

Solution heats in chloroform at 25°C have been measured experimentally for poly(methylmethacrylate) (PMMA), samples of poly(styrene-co-acrylonitrile) (SAN) containing from 5 to 37 mass% of acrylonitrile, and some PMMA-SAN blends prepared inside the miscibility range. From these data the mixing enthalpies for blend formation were obtained. Use of the mixing heats values in the framework of the Prigogine-Flory-Patterson theory allowed to calculate values of the exchange energy parameters between the components of the blends much more negative than existing literature data. Calculation of binary interaction energy parameters between the single repeat units of the copolymer from the above data, and from model compounds, clearly indicates a strong increase of the intramolecular repulsive energy between nitrile and styrene units of SAN, as compared with the interaction between the corresponding free model molecules.
C. Cardelli, G. Conti, P. Gianni, R. Porta, Journal of Thermal Analysis and Calorimetry 71 (2003) 353-365

B1294 – Thermodynamics of polymers mixtures:study on the mixing process of the poly(styrene)/poly(vinylmethylether) system

The miscibility of poly(styrene) and poly(vinylmethylether) is studied both by measuring the glass transition temperatures of the mixture and with the application of the Flory-Prigogine theory in the approximated form due to Patterson. For these calculations, the enthalpy of mixing of the two polymers is evaluated by measuring the enthalpies of solution of the pure polymers and of the mixture. The trend of the interaction parameters with the temperature for two samples of poly(styrene) of different molecular weight is discussed.
P. Casarino, S. Vicini, E. Pedemonte, Thermochimica Acta 372 (2001) 59-66

B1268 – Compatibility range in polymer mixtures : an approach using analogue calorimetry and group contribution procedures

The mixing enthalpies of blends of polymethylmethacrylate (PMMA) with poly(styrene-co-acrylonitrile) (SAN) were investigated by analogue calorimetry through the determination of the excess enthalpies of pseudobinary model mixtures corresponding to the addition of methyl-i-butyrate to a binary mixture of acetonitrile or propionitrile plus toluene or ethylbenzene. A group contribution procedure, based on UNIQUAC equation, was also devised and the polymeric mixing enthalpies were calculated from properly defined group contributions. Enthalpies for polymeric interactions were introduced into the Flory-Huggins equation and the miscibility window of PMMA-SAN mixtures was calculated. The results show a qualitative agreement with the experimental miscibility data and indicate that both the analogue calorimetry and the group contribution procedures yield correct results when acetonitrile, and not propionitrile, is chosen as the model for the polyacrylonitrile repeat unit of the copolymer.
C. Cardelli, G. Conti, P. Gianni and R. Porta, Journal of Thermal Analysis and Calorimetry 62 (2000) 135-151

B1223 – An approximative method for the evaluation of the partial heats of fusion of the once folded and extended modification of poly(ethylene oxide) 6000

PEG 6000 can exist in an once folded and in an extended modification. The small difference in the melting temperatures of the two forms results in a significant overlap of the corresponding melting peaks. After completion of the phase transition the shape of a melting peak (second branch) registered by DSC is determined by the relaxation of the measuring system only. Therefore it is possible to separate overlapping melting peaks by means of the standardised relaxation function of the DSC system. This approach was used to separate the overlapping melting peaks of the two PEG modifications. The partial heats of fusion as well as the peak maxima characterising the individual melting processes were determined from the separated peaks. Furthermore, this technique enables an observation of changes in the modifications of PEG and could possibly be a useful tool for investigations of other polymers which show similar characteristics.
T. Hantke, I. Zimmermann, Thermochimica Acta 345 (2000) 67-72

B1211 – In-Situ measurements of the plasticization of polymers by gases using a high-pressure DSC.

Z. Zhang and Y.P. Handa, ANTEC '97, 806 (1997) 2051-2053

B1198 – Effect of milling on the thermal behaviour of poly(ethylene terephthalate).

The solid state amorphization of poly(ethylene terephthalate), applying mechanical milling, is described. Their effect on samples quenched or slowly cooled after the melt as well as in samples with different crystallinity degrees, attained from annealing treatments, is characterized using differential scanning calorimetry and X-ray diffraction at room temperature. In previously annealed poly(ethylene terephthalate) at several temperatures some differences appear in the amorphization after milling. However, effects other than the crystallinity degree have to be taken into account to explain them.
J. Font, J. Muntasell, E. Cesari, Thermochimica Acta 333 (1999) 169-172

B1173 – Transition-temperature differences on cooling for a monotropic liquid-crystal polyester observed in DSCs of different design

Most commercial differential scanning calorimeters (DSC) belong to two types of design, namely the power-compensation DSC and the heat-flux DSC. There have been some reports in the literature indicating differences in response between these two types of instrument. Most of these differences have been observed on heating, and it is often assumed that the response on cooling is symmetrical. In this work, we report on differences observed on cooling a monotropic liquid-crystal polyester in several DSCs of the two designs. The monotropic liquid-crystal polyester used here had two exothermic transitions under moderate cooling rates. It was found that the heat-flux instruments tended to give overlapping exothermic peaks, suggesting that the second transition started before the first was complete. The power-compensation instruments, on the other hand, showed completely separated peaks at the same cooling rates. A monotropic liquid-crystal polymer with appropriate crystallisation kinetics may be a good material to evaluate the DSC response on cooling.
Z. Bashir, N. Khan, D.M. Price, Thermochimica Acta 319 (1998) p 47-53

B1171 – Réticulation sous hautes fréquences (27.12 MHz) des matériaux composites à matrice polymère thermodurcissable et à renforts variés

P. Alazard et A. Gourdenne

B1138 – Coupling microcalorimeter with electrochemical instruments for thermoelectrochemical research.

A measurement system that couples a commercial microcalorimeter with usual electrochemical instruments was established for electrochemical calorimetry of electrode reactions. Apparent enthalpy change of anodic oxidation of ferrocyanide ion to ferricyanide ion and apparent enthalpy change of cathodic reduction of hydrogen ion to hydrogen gas were determined with this system. The difference between the apparent enthalpy change and the value calculated with conventional thermodynamic data of aqueous ions was found to be a constant at a given temperature. This system can further be used to determine unknown standard enthalpy changes of electrode reactions.
H. Zhang, P. Zhang, Z. Fang, Thermochimica Acta 303 (1997) 11-15

B1133 – Phase angle correction for TMDSC in the glass-transition region.

Temperature-modulated DSC (TMDSC) allows the determination of frequency (time) dependent heat capacities. If heat capacity is frequency dependent, for example, in the glass-transition region, one get a phase angle between heating rate and heat-flow rate which is related to material intrinsic properties. Because heat does not propagate but flows, the time-consuming heat transfer into the sample yields an additional phase angle. This phase angle has to be taken into account if one wants to calculate the imaginary part of the complex heat capacity of the sample from the measured phase angle. The heat transfer related phase angle depends on frequency, heat capacity and heat conductance. In the case of glass-transition, heat capacity and heat conductance may change in the respective temperature interval. A correction for the corresponding phase angle is suggested. 0
S. Weyer, A. Hensel, C. Schick, Thermochimica Acta 304/305 (1997) 267-275

B1131 – Broad band heat capacity spectroscopy in the glass-transition region of polystyrene.

The combination of results from temperature modulated DSC (TMDSC) and 3w-method (HCS) in the glass-transition region allows broad band heat capacity spectroscopy in a frequency range of seven orders of magnitude. In an Arrhenius diagram, the curve for calorimetrie data is close to that of dielectric data, except from some remaining problems of temperature calibration. The dynamic glass-transition temperature and the width of the transition interval are determined in the frequency range 10P4 < v < 103 Hz and compared with DSC measurements on linear cooling (vitrification). The dynamic calorimetrie data are obtained in the liquid equilibrium state, where the dispersion of the glass-transition interval is related to the mean temperature fluctuation of cooperatively rearranging regions (CRR). As expected from the fluctuation approach to glass transition, this temperature fluctuation increases with increasing temperature. This indicates decreasing size of CRRs with increasing temperature. The a = qlST*w parameter is obtained as a = 6~t2 from a comparison of thermal and dynamic glass transition.
S. Weyer, A. Hensel, J. Korus, E. Donth, C. Schick, Thermochimica Acta 304/305 (1997) 251-255

B1109 – Etudes comparatives et identification des polyethylenes par analyses thermique, différentielle et de diffraction des rayons X

In thermal analysis polyethylenes can be characterized by their melting temperature. With the polyethylene mixtures studied, we obtained the best results during solidification. Crystallization temperature decreased in the order: high density PE, low density PE linear, radical low density PE. Calorimetric measurement of crystallization enthalpies allowed the determination of the composition of each of the polyethylenes, in regenerated and recycled mixtures in relation with the frame of the plastic waste valorisation process. The rate of crystallization obtained from X-ray diffraction spectra of these polymers is function of their volumic mass. A good agreement has been observed between these two techniques.
Y. Claire, J. Kaloustian, O. Cerclier, C. Baudrion, A. Périchaud, Journal of Thermal Analysis 48 (1997) p 233-245

B1097 – Analysis of physical and chemical networks by slow DSC and turbidimetry

Semicrystalline polymers are made of a crystalline phase and of an amorphous phase. Recently, NMR, Raman and FTIR experiments have identified a third phase comprised of defects such as tie-molecules, in the organization of chains. Our investigation of physical gels has led us to believe that by following the heat flow in a very slow temperature ramp (0.05 K min-1), phasechanges, unnoticed in the usual fast ramp, could be detected. These are associated to a physical network strained in the temperature ramp. In order to obtain more information on the network phase, the polymer has been crosslinked The characteristics obtained by slow calorimetry and turbidimetry of the original and modified materials are compared.
P. Bernazzani, G. Delmas, Journal of Thermal Analysis 49 (1997) 449-454

B1095 – Thermoanalytical study of nucleating effects in polypropylene composites. 3. Intumescent flame retardant containing polypropylene

Engineering application of polypropylene requires the employment of flame retardants. Reactive compounding of ammonium-polyphosphate and synergist additives with polypropylene is an effective way for forming flame retardant polypropylene. Both the ammonium-polyphosphate and the additives used for improving its performance effect the crystallization and melting behavior of polypropylene. Encapsulation of flame retardant additives with appropriate elastomer, in order to improve their water resistancy, causes further changes in degree of crystallinity and consequently in the mechanical properties.
Gy. Marosi, P. anna, I. Balogh, Gy, Bertalan, A. Tohl, M.A. Maatoug, Journal of Thermal Analysis 48 (1997) 717-726

B1093 – Heat of mixing in polymer blends based on poly(vinyl acetate).

Knowledge of the heat of mixing is very important in order to evaluate the interaction parameter, according to the Patterson theory. In this work we illustrate the results regarding some polymer blends, based on poly(vinyl acetate) and some polyacrylates with different substituent groups. In this way it is possible to understand the effect of the lateral group hindrance, as it will be illustrated in the paper.
P. Casarino, P. Lavaggi, E. Pedemonte, Journal of Thermal Analysis 47 (1996) 165-170

B1086 – Slow calorimetry and heat of fusion of poly(4-methyl pentene-1).

The heat of fusion of nascent poly(4-methyl pentene-1)(P4MP) has been measured with a slow temperature-ramp. Two melting ranges have been observed. A broad endotherm is found mostly below the equilibrium melting temperature,T m,o. The total heat of fusion H total is the sum of H dsc, the melting enthalpy found by rapid heating and a second endotherm, H network, a contribution associated with the heat of disordering of a physical network. Similar reported analysis have been presented before on polyethylene and isotactic polypropylene. The H total for P4MP is found to be 100±10 J g-1, in the upper range of the expected values of H o, the heat of fusion of perfect crystals. The value of H total constitutes a lower limit of H o in cases like that of P4MP where other methods lead to ambiguous results. The comparison ofT m andT d, the melting and dissolution temperatures, and other results support the hypothesis that the equilibrium phase at the melting of P4MP is partially rigid while it is a liquid (or a mixture of a glass and a liquid) at the dissolution.
H. Phuong-Nguyen, G. Charlet, G. Delmas, Journal of Thermal Analysis 46 (1996) 809-832

B1084 – Thermal analysis of fibre forming polymers. Multiphase systems.

Different levels of fibre technologies and application, from synthesis to degradation has been studied using the methods of thermal analysis. Recent results of these studies on synthetic and natural fibres are summarized. The effect of chemical and physical modification of polyolefin fibres as well as the synthesis of polymer emulsion used as additive in fibre technologies could be followed by DSC, DMA, TG methods.
Gy. Marosi, P. Anna, Gy. Bertalan, A. Tohl, R. Lagner, I. Balogh, I. Papp, Journal of Thermal Analysis 47 (1996) 463-473

B1082 – Thermoanalytical study of nucleating effects in polypropylene composites. 1. Liquid crystal polymer containing polypropylene

Nucleating and transcrystallization behaviour of additives in engineering PP composites and the effect of modified interfacial structure is the subject of this series of papers. The first part concentrates on polypropylene/liquid crystalline polyester blends. Increased crystallisation temperature and degree of crystallinity of polypropylene is characteristic to the blends containing different amount of LCP additive. Transcrystallization process governs the formation of crystalline structure in these systems in course of isothermal crystallisation at 132C. The nucleating effect of LCP gives rise to more uniform crystalline structure in the polypropylene phase.
Gy. Marosi, Gy. Bertalan, P. Anna, A. Tohl, R. Lagner, I. Balogh, P.F. La Mantia, Journal of Thermal Analysis 47 (1996) 1155-1161

B1081 – Thermoanalytical study of nucleating effects in polypropylene composites. 2. Filler and elastomer containing polypropylene

Interfacial structure plays an important role in the performance of polypropylene composites. Transcrystalline interfacial layer were determined in talc filled polypropylene. The crystallization and melting behaviour of talc and CaCC3 filled polypropylene could be modified with smaller amount of additives like elastomer and surfactants. Through the effect of these additives the structure of interface and the degree of crystallinity could be controlled in filled polypropylene.
Gy. Marosi, R. Lagner, Gy. Bertalan, P. Anna, A. Tohl, Journal of Thermal Analysis 47 (1996) 1163-1170

B1076 – Mesure de la composition phasique de polymères par calorimétrie.

M. Paillard, G.D. Patterson, Univ. du Quebec à Montréal, Rapport d'activité

B1074 – Photo-polymerization analysis with DSC.

J.M. Pickard, Thermal Trends 3 (1996) 4-8

B1073 – Mechanism of the pet and aramide yarn-to-rubber adhesion.

H.C. Zegers

B1063 – Testing the kinetic and thermal parameters for the cure of an unsaturated polyester.

The cure of an unsaturated polyester was studied by using experiments and a model of the process. Two kinds of experiment were conducted, one with the calorimetry in scanning mode for determining the kinetics of curve, the other with a rather large cylinder. The numerical model was constructed by taking into account the heat transferred by conduction through the resin, and convection at the surface, as well as the kinetics of heat generated by the cure reactions. The temperature-time histories in the middle of the cylinder obtained either from experiments or by calculation were compared, and found in good agreement, providing the accuracy of the values of the kinetic and thermal parameters.
A. Sahli, R. Granger, J.M. Vergnaud, Thermochimica Acta 285 (1996) 277-288

B1043 – Analyse thermique différentielle et de diffraction des rayons X de mélanges de polyéthylènes.

Y. Claire, J. Kaloustian, O. Cerclier, C. Baudrion, A. Périchaud, JEEP (1996) 89-92

B1021 – Information given by slow calorimetry on the phase composition of polyolefins.

H. Phuong Nguyen, G. Charlet, G. Delmas, 24th NATAS Conférence (1995) 530-535

B1002 – Utilisation de l’analyse thermique à l’identification des polyéthylènes

Y. Claire, Y. Le Ny, C. Baudrion, J. Kaloustian, A. Périchaud, JCAT (1995) 52-57

B1001 – Application de la calorimétrie différentielle à la caractérisation thermique des polymères

S. Tarifa P. Alazard, JCAT (1995) 58-63

B0968 – The crystallization and melting region

V.B.F. Mathot, Calorimetry and Thermal Analysis of Polymers, chapter 9, 251-286

B0967 – Thermal transitions and gelation in polymer solutions

H. Berghmans, Calorimetry and Thermal Analysis of Polymers, chapter 8, 215-230

B0964 – The malek method in the kinetic study of polymerization by differential scanning calorimetry

A comparative kinetic study of polymerization by differential scanning calorimetry (DSC) has been carried out by use of calculations based on the Freeman-Carroll, Ellerstein, Achar-Brindley-Sharp, multiple linear regression and Malek methods. With the estak-Berggren model of a modified Malek method, we have extracted kinetic information from curves showing a presence of more than one component using criteria based on the minimization of the difference between experimental and calculated thermograms.
N. Sbirrazzuoli, Y. Girault, L. Elégant, Thermochimica Acta 249 (1995) 179-187

B0938 – Natural and artificial ageing of an alkyd based wood finish. Calorimetric investigations

Wood protection in exterior use is generally achieved with a stain. This protective product is often obtained from an alkyd resin. A natural and artificial ageing have been studied by measuring the glass transition temperature (Tg) of the finish variations in terms of time. In both ageings, the Tg variations are the same; there is an increase in Tg during the first steps of ageing and then a stabilization. A behaviour equation is proposed and is perfectly suitable to both ageings. Time constants are calculated. This equation shows that the artificial ageing machine chosen is a good means of artificial ageing. It allows the reproduction and the acceleration by 10 times of phenomena which are observed during the natural ageing.
L. Podgorski, A. Merlin, J.M. Saiter, Journal of Thermal Analysis 41 (1994) 1319-1324

B0935 – The effect of thermal parameters on the cure of a bulk moulding composite with polyester

Because composites made of polyester are transformed into three dimensional solid materials during the irreversible cure reaction, a good knowledge of this process is advantageous. The effect of the thermal parameters such as the thermal conductivity and heat capacity of the resin on the process are of great interest. Heat capacity plays an important role because it influences both the heat transferred by conduction and the heat evolved by the cure reaction. Thermal conductivity influences heat conduction alone, and thus is less important. The kinetics of the heat generated by the cure reaction were determined by calorimetry in scanning mode. The study was carried out using a thin sheet of composite heated into the slabs of a mould, with a one-dimensional heat transfer. A numerical model that had been previously tested, provided the precise effect of each parameter on the process.
V. Plesu, J.M. Vergnaud, Thermochimica Acta 228 (1993) 83-93

B0930 – Evaluation of the Flory-Huggins interaction parameter for poly(styrene-co-acrylonitrile) and poly(methyl-methacrylate) blend from enthalpy of mixing measurements

A direct determination of enthalpy of mixing (?Hmix) is of interest in predicting miscibility in polymer - polymer systems. Such measurements present, however, working difficulties, so a reliable indirect approach has been attempted. The enthalpy of mixing ?Hm is obtained by application of Hess law to heat of solution measurement for blends and their components in a common solvent. For SAN/PMMA blend, corresponding to the weight ratio 50:50, the experiments were performed by the Hess law approach at 29.4 and 49.3°C on dilute polymer solutions, for various concentrations, getting very good correlation data. This leads to a negative value of the interaction parameter FHx(1,2) and by ?Gmix diagram it is possible to make a comparison for each temperature in accordance with the LCST behaviour of these mixtures.
D. Frezzotti, G.P. Ravanetti, Journal of Thermal Analysis 41 (1994) 1237-1243

B0923 – The investigation of solution-crystallized polyethylene by slow calorimetry

Single crystals of low molar mass polyethylene (PE) have been grown and dissolved in decalin. A C8O calorimeter was used to follow the heat flow during dissolution and crystallization. The aim of this study was to determine if new information on this well investigated subject could be obtained using exactly controlled conditions for the phase change. These conditions were: leaving the crystals in their mother solution for analysis, recording the dissolution traces in an unusually slow temperature ramp (0.2-12 K h-1), following the growth of the crystals continuously during the whole crystallization process and obtaining very accurate enthalpies for the phase change. Three new results have been found: a high-temperature phase change occurs in the solution on cooling and on heating, with a corresponding change in enthalpy of 40-50 J g-1 which gives new information on the phase composition of low molar mass PE and on the interlamellar phase; the change of growth rate during crystallization is found to be linear with time; and for crystals grown at high Tc, two kinetics of dissolution/crystallization are observed. The first result is attributed to strain in chains, and the third to the dissolution/crystallization of the (100) face in larger crystals which have a truncated lozenge shape.
H. Phuong-Nguyen and G. Delmas, Thermochimica Acta 238 (1994) 257-275

B0918 – Melting and crystallization of tetrafluoroethylene-ethylene copolymers

The melting and crystallization of copolymers of tetrafluoroethylene with ethylene, synthesized in bulk and in suspension by semi-flow method, were studied by DSC. X-ray diffractions and infrared spectra of the copolymers were measured and new crystalline reflections, different from those of the homopolymers were observed. The melting temperature of the copolymers synthesized in bulk depends strongly on.the composition and exhibits several maxima. A certain small decrease in the melting temperature within the range of the alternating composition is observed. For alternating copolymers synthesized in suspension, the peaks are monomodal indicating a higher structural and chemical homogeneity of the copolymer. The nonisothermal crystallization kinetics in the temperature interval from 260 to 255°C of the alternating copolymer prepared in suspension can be described by a modified Avrami equation. The mechanism of nucleation and nuclei growth during the nonisothermal crystallization of the tetrafluoroethylene-ethylene copolymer is close to that of polyethylene.
G. Kostov, B. Bogdanov, Al. Nikolov, Journal of Thermal Analysis 41 (1994) 925-934

B0910 – Charakterisierung von organokieselsäurepolymeren durch thermoanalytische untersuchungen

Four organosilicate polymers synthesized by addition of vinyl- and H-substituted double four-ring silicic acid derivatives were characterized using DSC and simultaneous TG-DTA measurements. Thermooxidative decomposition proceeds in several steps: Oxidation of (Si-H) groups, oxidation of (Si-CH2-CH2-Si) bridges, and oxidation of (Si-CH3) groups, with formation of new (Si-O-Si) bonds. 29Si-NMR-spectroscopic measurements confirm this interpretation. Thermoanalytical methods of investigation proved useful to characterize these organosilicate polymers.
P. Kölsch, I. Pitsch, D. Schultze, D. Heidemann, D. Hoebbel, Journal of Thermal Analysis 41 (1994) 789-806

B0907 – Deconvolution of the thermal effects of the heat of conduction and heat of cure reaction for an unsaturated polyester

Bulk moulding compound (BMC) composites have been cured in heated moulds, following an irreversible reaction which transforms the polymer into a three-dimensional network. The process is very complex because conduction heat transfer is associated with the heat evolved from the cure reaction. Modelling of this process is necessary, enabling simulation of the process and thus providing more information than experiments. The deconvolution of the two phenomena, heat transfer and chemical reaction, allows one to understand better the evolution of the process and to optimize the operational conditions. The contributions to the rise in temperature from heat conduction and chemical reaction have different histories in different parts of the composite, and can explain the temperature-, state-of-cure-, or heat-flux-time histories. The reaction-rate-time history is very sensitive in the earlier stages of curing, and supplements information obtained from the state-of-cure histories. The study was made on a thin sheet of composite in a metallic mould heated by oil, with one-dimensional heat transfer. The analysis was made using a numerical method that has been previously described and tested.
V. Plesu, R. Granger, J. Bouzon, J.M. Vergnaud, Thermochimica Acta 241 (1994) 67-85

B0899 – Compressed-gas-induced plasticization of polymers

The glass transition in polystyrene-ethylene at pressures up to 78 atm has been studied using a Tian-Calvet heat-flow calorimeter. The glass transition temperature Tg decreases with an increase in ethylene pressure, the largest depression being 67°C at 78
Y.P. Handa, S. Capowski and M.O'Neill, Thermochimica Acta 226 (1993) 177-185

B0893 – A study on polymer-polymer interactions through mixing calorimetry

The aim of this work is to describe the most recent achievements in the field of the physical chemistry of mixing. The systems studied have been classified according to the amount of thermic effect due to the blending and its interpretation. When polystyr
A. Brunacci, J. Yin, E. Pedemonte and A. Turturro, Thermochimica Acta 227 (1993) 117-124

B0863 – Evaluation of the Flory-Huggins interaction parameter for poly(styrene-co-acrylonitrile) and poly(methyl-methacrylate) blend from enthalpy of mixing measurements

D. Frezotti, G.P. Ravanetti, JCAT (1993) 135-138

B0855 – Thermal stability of barium-doped iron oxides with spinel structure

Previous experiments have demonstrated the influence of the size and surface area of particles of iron oxides with spinel structure on the oxidation (Fe3O4 => y-Fe2O3 and transformation (y-Fe2O3 => alpha-Fe2O3) enthalpies and temperatures. In the present paper,
Ch. Sarda and A. Rousset, Thermochimica Acta 222 (1993) 21-31

B0828 – Kinetic study of solid-plastic transitions. Part 2. Influence of experimental conditions

The aim of this study is to incorporate the influence of different experimental conditions on the thermodynamic and kinetic parameters of the solid-plastic transition of pentaerythritol. The results show the importance of sublimation effects occurring with such phase change materials, which present a high vapour pressure and a low thermal conductivity. The influence on kinetic parameters and thermogram shapes is also discussed, and finally, a solution is proposed to overcome errors linked to the differential scanning calorimetry characterization of transformation of energetic materials, by proceeding to this analysis by means of a thermocouple located in the sample.
N. Sbirrazzuoli, Y. Girault and L. Elegant, Thermochimica Acta 210 (1992) 223-231

B0817 – Heat and stored energy of plastic deformation of solid polymers and heterogeneous blends

Measurements of the mechanical work (A), the heat of deformation (Q) and differences between these quantities, i.e. the internal energy (AU) stored in samples were performed under the unidirectional compression loading conditions by using constant temperature deformation calorimetry. It is shown for several glassy (PS, PC, PI-BD, PET, epoxy-amine network, ABS) semi crystalline (PBT, PET) polymers and blends (PC: ABS, PC: PBT), that 45-85% of the mechanical work of deformation is converted to internal energy stored in deformed samples AU is quite high as compared with metals.
O.B. Salamatina, S.N. Rudnev, V.V. Voenniy and E.F. Oleynik, Journal of Thermal Analysis 38 (1992) 1271-1281

B0806 – Kinetic study of solid-plastic transitions. Part 1 Comparison of methods describing the transition by differential scanning calorimetry

Following our research on organic phase-change materials, we tested the different kinetic methods, described in previously established software, on the solid-plastic transition of pentaerythritol using criteria based on the minimization, of the difference between experimental and calculated thermograms obtained by differential scanning calorimetry. The good modelling of the Achar-Brindley-Sharp method, which does not require long calculation times, led to its selection from other differential methods. The Freeman-Carroll and Ellerstein methods are not appropriate for modelling the transition.
N. Sbirrazzuoli, Y. Girault and L. Elegant, Thermochimica Acta 202 (1992) 233-239

B0802 – La modélisation de la vulcanisation

x
J.M. Vergnaud, J. Bouzon, Caoutchoucs & Plastiques 718 (1992) 49-53

B0799 – Supercritical-gas induced changes in the morphology and glass transition of polymers

S. Capowski, P. Handa, M. O'Neill, Congrès NATAS (1992) 157-163

B0782 – Measurement of heat of adsorption of polyethylene oxide on dolomite, silica and alumina by microcalorimetry

Direct measurements of the heat of adsorption of a 5 million molecular weight polyethylene oxide polymer on dolomite, quartz, and alumina were made using a microcalorimeter. Heat of adsorption was measured as a function of polymer dosage and temperature. The adsorption process was determined to be endothermic. It was observed that ?H is a strong function of temperature and is affected also by polymer preparation time.
B.M. Moudgil, S. Behl and N.S. Kulkarni, Journal of Colloid and Interface Science 148 (1992) 337-342

B0776 – Moisture sorption by a saturated polyester (P.E.T) calorimetric study

D. Langevin, J.M. Saiter, J. Grenet, JCAT (1992) 257-263

B0684 – Pair interaction parameter for compatible poly(styrene)-poly(a-methylstyrene) mixtures

Heats of solution measurements have been performed on sharp fractions of poly(styrene), poly(alpha-methylstyrene) and their blends to study their compatibility and to quantify the interaction parameter of this system. The results show that the heat of mixing of the two polymers is negative and independent of the temperature at which blends are prepared; this leads to a negative value of the interaction parameter, in keeping with the general behaviour of these mixtures. The effects of the molecular weights is also discussed.
E. Pedemonte and L. Lanzavecchia, Thermochimica Acta 162 (1990) 223-227

B0683 – Evaluation of the interaction parameter for poly(styrene)-poly(a-methylstyrene) mixtures from heat of solution measurements

Heats of solution measurements have been performed on poly(styrene), poly(alpha-methylstyrene) and their blends to study their compatibility and quantify the interaction parameter of this system. The results show that the heat of mixing of the two polymers is negative and independent of the temperature at which blends have been prepared; this leads to a negative value of the interaction parameter in keeping with the general behaviour of these mixtures.
L. Lanzavecchia and E. Pedemonte, Thermochimica Acta 137 (1988) 123-128

B0660 – Analyse de modèles d’étude cinétique de la transition solide-plastique par DSC.

F. Wilmet, N. Sbirrazzuoli, Y. Girault, L. Elégant, AFCAT (1990) 251-256

B0623 – The measurement of heats of mixing of polymer alloys by a heat of solution method

Direct measurement of the heat of mixing (interaction) of polymers is not feasible due to their high viscosity. The indirect approach described here is a heat of solution method, in which a Hess's Law cycle is used to determine the heat of mixing from the individual heats of solution of the alloy and its constituent polymers in a common solvent. The main limitation of this approach lies in obtaining adequate precision on the experimentally determined heats of solution, as these are large compared to the calculated heat of mixing. With this method the heat of mixing of a 75/25 (%by wt) poly(dimethyl) phenylene oxide/polystyrene alloy has been determined by Setaram C-80 microcalorimeter as 4.9 + 0.2 jg-1. The precision of the method shows an improvement compared with published data.
P.N. Aukett and C.S. Brown, Journal of Thermal Analysis 33 (1988) 1079-1084

B0622 – Free energy of mixing of polymer blends by heat of solution measurements: atactic-PS/PPO and isotactic-PS/PPO blends

L.F. Whiting, S.S. Eadie, NATAS (1988) 836-841

B0592 – Crystallization of systems of water and polyoxyethylene

The thermal behaviour of systems of water and polyoxyethylenes (POE) of different molecular weights was investigated by differential scanning calorimetry at a cooling rate of 5 deg/min-1 In the narrow concentration range 55-60 wt% POE, the systems showed a reduced crystallization ability or no crystallization at all. The tendency to supercooling in the water/POE systems is highest at eutectic and slightly higher POE concentrations, and rises with increasing POE molecular weight.
B. Bogdanov and M. Mihailov, Journal of Thermal Analysis 30 (1985) 1027-1033

B0590 – Quantitative thermal characterization of carbon-epoxy composites using differential scanning calorimetry and thermogravimetric analysis

A differential scanning calorimetry (DSC) method has been developed to characterize carbon-epoxy prepregs. DSC was done with nitrogen as the atmosphere in order to avoid the oxidation reactions which degrade the epoxy resin during heating. Since the resin distribution in a given batch of prepreg is not entirely uniform, and since the sample used for DSC is relatively small, the percentage of resin may vary significantly from sample to sample, even though they are taken from the same sheet of prepreg. Hence, the exact resin content must be determined for each sample in order to obtain reproducible values for the curing enthalpy. A thermogravimetric (TG) method using an oxidizing atmosphere has been developed for this purpose. After the DSC experiment, a TG analysis is done on the same sample. The exact mass of resin is found on the TG curve at the inflexion point corresponding to the end of oxidation of the epoxy resin and to the beginning of oxidation of the carbon fibres. For Narmco 5208/WC3000 prepreg, this inflexion point occurs at about 580°C. This procedure gives enthalpy values with a relative standard deviation smaller than 1%. The aging of the prepreg when exposed for 66 days at room temperature and 50% relative humidity was also studied using these thermal methods.
D. Noël, J-J. Hechler, K.C. Cole, A. Chouliotis and K.C. Overbury, Thermochimica Acta 125 (1988) 191-208

B0587 – Simultaneous TG/DSC and TG/MS analyses of polymeric and energetic materials

B. Whitaker, C.R. Brown, C. Chang, J.A. Daniels and T.L. Shell - Monsanto -Ohio USA

B0585 – Comparative study of a reaction of low enthalpy (rubber cure) by DC and DSC

The two techniques of calorimetry, the first using isothermal conditions (DC) and the second using a scanning mode (DSC) are compared by considering a reaction of low enthalpy (5 cal g-1) (rubber cure). It is necessary to use a large sample (150 mg), because of the difficulty of dispersing the ingredients in the rubber. The model used takes into account not only the kinetics of reaction of the cure, but also the heat transferred by conduction through the rubber. The kinetics of the heat evolved from the cure reactions is determined by DSC using a low heating rate when the effect of heat transfer may be considered negligible. Significant disadvantages of the DC technique are discussed. Because of the time required for the calorimeter to establish thermal equilibrium, the first part of the reaction with the induction period has not been studied and a considerable part of the heat of reaction of the cure is lost. Also very high gradations of temperature occur through the sample, causing the development of an inhomogeneous process. These disadvantages are shown to be less important in the DSC technique.
J.Y. Armand and J.M. Vergnaud, Thermochimica Acta 116 (1987) 111-124

B0551 – Effect of heating rate and sample size on heat transfer through the sample in DSC

As it is very often the first step of the process, heat transfer plays an important role, especially for systems heated in scanning mode. The problem is studied in the simple case when no reaction occurs. In the present case, heat is transferred through the cross-section of a cylinder heated on faces with a constant heating rate. The gradients of temperature through the sample when they are established are proportional to the heating rate on faces and to the square of the diameter of the cylinder. The shape of the gradients of temperature are obtained at different times when these gradients are not established and when they are constant. The heat flux emitted through the face-calorimeter interface are also determined. The value of heat flux is certainly the best parameter for testing the validity of the model.
J.Y. Armand, R. Gonnet, R. Jones, J. Bouzon, M. Touchard and J.M. Vergnaud, Thermochimica Acta 103 (1986) 341-351

B0534 – Calorimetric studies of high molecular polyethylene oxide films isothermally uniaxially stretched at room temperature

The melting behaviour of oriented polyethylene oxide (PEO) films when the film samples were heated in the free state and in the isometric state were investigated by use of DSC. It was shown that in the first case the endotherms of melting have multiple peaks, while in the other case they have one peak. Non-linear dependences of the melting temperature and enthalpy of oriented films on the pressing temperature of the initial PEO isotropic film samples were determined
B. Bogdanov and M. Michailov, Journal of Thermal Analysis 30 (1985) 551-556

B0522 – DSC indagini di polimeri epossidici di interesse elettrotecnico

P. Tomi, L. Elégant, G. Augier, G. Pecqueux, AICAT, Ferrara, (1986) 204-208

B0517 – Study of heat flux and profiles of temperature and state of cure obtained in an isothermal calorimeter with rubber cure of low enthalpy

Although the cure of rubber is not very exothermic (10 cal g-1), important temperature gradients are developed through the sample when it is submitted to heat inside the calorimeter. Calorimetry studies have been conducted under isothermal conditions with a cylindrical sample of between 100 and 200 mg. The profiles of temperature and state of cure developed through the cross-section of the sample have been calculated, as well as the heat flux obtained through the sample-calorimeter interface. The heat flux-time curves calculated are in agreement with the experimental ones. Data concerned with the kinetics of heat evolved by the overall reaction and heat transfer by conduction are used for these calculations. Calculations have been done with the help of an explicit numerical method with finite differences. The method described here enables one to collect simultaneously some complementary information on heat flux (the rate of reaction) along with profiles of temperature and state of cure.
A. Khouider, J.B. Rochette and J.M. Vergnaud, Thermochimica Acta 89 (1985) 81-92

B0516 – Mesure de la vulcanisation du caoutchouc et autres matériaux par calorimétrie

Méthode permettant de déterminer la cinétique de la chaleur dégagée par la réaction globale. Il est alors possible d'intégrer dans des modèles mathématiques construits à partir de méthodes explicites d'analyse numérique, les transferts thermiques et l'acte réactionnel
J.M. Vergnaud, Spectra, n° 113, vol 14 (1986) 25-29

B0489 – Compatible polymer mixtures. Evaluation of the interaction parameter from heat of solution measurements

E. Pedemonte, L. Lanzavecchia, AICAT, Ferrara, (1986) 519-521

B0480 – DSC study of the bulk polymerisation of N-vinylsuccinimide

The kinetics of the bulk polymerization of N-vinylsuccinimide were studied by differential scanning calorimetry. The polymerization process was found to be second-order, with respect to the monomer, with a polymerization enthalpy ranging from -55 to -60 kJ mol-1.
M. Morcellet, Thermochimica Acta 80 (1984) 361-365

B0479 – Effect of variation in the values of the thermal properties of rubber on the vulcanization of thin and thick sheets

The effect of a 30% variation around a mean value of thermal property values on the vulcanization of 1 and 2 cm thick rubber sheets is studied, by using a molding process at 40°C for the initial rubber and 120°C for the injected rubber. The thermal properties chosen are the diffusivity and the product of density and heat capacity. This variation in thermal properties has a slight effect on sheets =< 1 cm thick, but becomes significant when the thickness is >= 2 cm. This must be taken into account when calculating the time necessary for the state-of-cure to reach 90% at the midplane of the sheets.
M. Abdul, B. Rochette, A. Sadr and J.M. Vergnaud, Thermochimica Acta 80 (1984) 287-296

B0477 – Effect of variation in the kinetic parameters on the vulcanization of rubber sheet

The purpose of this work is to show that a slight variation in the kinetic parameters of vulcanization (rate constant, activation energy) has a very pronounced effect on the vulcanization of rubber sheet. Experiments were performed using microcalorimetry and a heated mold pressing a 2 cm thick rubber sheet. The resulting variations in the temperature profile through the rubber and the profile of the state of cure were considered. The variations in the kinetic parameters were due either to a slight change in the rubber composition or to experimental errors in calorimetry.
Ch. Ferradou and J-M. Vergnaud, Thermochimica Acta 68 (1983) 283-290

B0394 – Détermination des paramètres cinétiques de la vulcanisation du caoutchouc

J.M. Vergnaud et al., AFCAT, La Gaillarde (1983) 67

B0384 – Kinetics study of theoverall reaction of rubber vulcanization by differential calorimetry.

J.M. Vergnaud et al., Eurocaoutchouc, Paris (1982)

B0372 – Kinetic parameters of the overall reaction of scrap rubber vulcanization by 2% sulfur

The purpose of this work was to show that the temperature gradients developed in the rubber mass during vulcanization could be predicted if the kinetics of reaction and the physical properties of the rubber were known. Experiments were performed using differential calorimetry, and a mold pressing a 1 cm thick rubber sheet. The overall reaction was found to be first order with an activation energy of about 25 kcal mole-1, when the sulfur percentage was 2.
A. Accetta, J. M. Vergnaud, P. Le Parlouer, Thermochimica Acta 59 (1982) 149-156

A2333 – Preparation and biological characterization of cellulose graft copolymers

Acrylic acid (AA) and acrylonitrile (AN) were graft polymerized onto cellulose fluff pulp using ceric ammonium nitrate as initiator. The resulting copolymers were saponified with dilute sodium hydroxide and characterized by FT-IR, SEM and TGA. The potential value of the modified cellulose was assessed through measurements of absorbency properties. A fibre-hydrogel was prepared by an addition of a bifunctional monomer, ethyleneglycol dimethacrylate (EDMA) used for grafting. In second approach, biocide cellulose carbamate was prepared by impregnating the fibres in aqueous thiourea solution and subsequent grafting with acrylonitrile. Antimicrobial activity of the treated cellulose sample was studied against Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis according to AATCC test method 100–1999. The results show that the treated fibre gives higher antimicrobial activity. The strong antimicrobial functions achieved on modified fibres, proved that the synthesized biomaterial was effective, very simple and practical to the textile finishing industry.
Wassila Dahou, Djamila Ghemati, Atika Oudia, Djamel Aliouche, Biochemical Engineering Journal 48 (2010) 187–194

A2315 – Novel polymer anchored Cr(III) Schiff base complexes: Synthesis, characterization and antimicrobial properties

New polymer-bound Schiff bases and Cr(III) complexes have been synthesized by the reaction of 4-benzyloxybenzaldehyde, polymer-bound with 2-aminophenol, 2-amino-4-chlorophenol and 2-amino-4-methylphenol. The structure of polymeric-Schiff bases and their Cr(III) complexes have been characterized by elemental analyses, magnetic measurements, IR, UV–Vis, TG-DTA and 1H-NMR. All these compounds have also been investigated for antibacterial activity by the well-diffusion method against Staphylococcus aureus (RSKK-07035), Shigella dysenteria type 10 (RSKK 1036), Listeria monocytogenes 4b(ATCC 19115, Escherichia coli (ATCC 1230), Salmonella typhi H (NCTC 901.8394), Staphylococcus epidermis (ATCC 12228), Brucella abortus (RSKK-03026), Micrococcs luteus (ATCC 93419, Bacillus cereus sp., Pseudomonas putida sp. and for antifungal activity against Candida albicans (Y-1200-NIH).
Canan Selvi, Dilek Nartop, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 95 (2012) 165–171

A2301 – Investigation of electrokinetic and electrorheological properties of polyindole prepared in the presence of a surfactant

In this study, synthesis of polyindole (PIN) was carried out without and with the presence of a sodium dodecyl sulfate (SDS) surfactant (SPIN), using FeCl3 as an oxidizing agent. The synthesized materials were subjected to various characterizations techniques namely: particle size, magnetic susceptibility, elemental analysis, density, conductivity, dielectric constant, FTIR, 1H NMR, TGA, XRD, and SEM. Characterization results revealed the successful preparation of the homopolymers of PIN and SPIN. Zeta (?)-potentials of the samples were measured in aqueous and non-aqueous (silicone oil, SO) media. Electrokinetic properties of PIN and SPIN in aqueous media were determined by ?-potential measurements in the presence of various electrolytes (NaCl, BaCl2, AlCl3, Na2SO4) and surfactants (cetyltrimethyl ammonium bromide, SDS, and Triton X-100). Besides, the effect of pH onto ?-potentials of the materials was also examined. The suspensions prepared in SO were subjected to external electric field strength and their electrorheological (ER) properties were investigated. Then the effects of shear rate, frequency, and temperature onto ER activities of the suspensions were examined. Further, creep and creep–recovery tests were applied to the PIN/SO and SPIN/SO suspension systems and reversible non-linear viscoelastic deformations observed under applied electric field.
H. Ibrahim Unal, Bekir Sahan, Ozlem Erol, Materials Chemistry and Physics 134 (2012) 382– 391

A2296 – Effect of corona discharge treatment on mechanical and thermal properties of composites based on miscanthus fibres and polylactic acid or polypropylene matrix

In this study, we investigated the mechanical and thermal properties of composites based on miscanthus fibres and poly lactic acid or polypropylene matrices. The treatment of fibres by corona discharge which results in a surface oxidation and an etching effect as shown by X-ray photoelectron spectroscopy and scanning electron microscopy, leads to an improvement of the interfacial compatibility between matrix and fillers. Hence the homogeneity of materials (checked by X-ray tomography and fractographic evaluation) is better, the mechanical properties measured by classical tensile tests are improved (Young moduli increase around 10–20%). Dynamic mechanical analysis performed on samples leads to similar conclusions (higher modules and slight increase of glass transition temperature hence restricted molecular movement). The thermal stability of composites was investigated by thermogravimetric analysis. While the incorporation of raw fibres leads to a slight decrease of decomposition temperature, it is systematically increased as soon as fillers have been treated.
M. Ragoubi, B. George, S. Molina, D. Bienaimé, A. Merlin, J.-M. Hiver, A. Dahoun, Composites: Part A 43 (2012) 675–685

A2260 – Electrical transport, optical and thermal properties of polyaniline–pumice composites

In this study, electrical conductivity, photoconductivity, absorbance and thermal properties of polyaniline (PANI) and polyaniline–pumice composites were investigated. Temperature dependent conductivity and photoconductivity measurements were carried out in the temperature range of 80–400 K. The measurements revealed that the dominant conduction mechanisms in polyaniline and 15% pumice doped composite were hopping conduction. The low activation energies calculated for 36% pumice doped composite indicated that this sample has highly defective and degenerate structure due to the high pumice content. Polyaniline and pumice doped composites showed semiconductor behavior with the exponential variation of inverse temperature dependence of electrical conductivity. Photoconductivities of the PANI and PANI–pumice composites under various illumination intensities were studied and it was found for all samples that the conductivity increased with increasing temperature and light intensity, but decreased with increasing pumice content in the structure. Absorbance spectrum has been determined in the wavelength range of 300–700 nm and it was found that the band gap values decreased as the pumice content was increased. Thermogravimetric analysis have shown for all samples that the mass loss has started above around 300 K due to the loss of moisture from the structures. As a result of this work, it was found that polyaniline and polyaniline–pumice composites had low resistivity and high band gaps and could be used as a window layer semiconductor in heterojunction solar cell applications.
K. Y?lmaz, A. Akgoz, M. Cabuk, H. Karaagac, O. Karabulut, M. Yavuz, Materials Chemistry and Physics 130 (2011) 956– 961

A2235 – Distillation of granulated scrap tires in a pilot plant

This paper reports the pyrolytic treatment of granulated scrap tires (GST) in a pilot distillation unit at moderate temperature (550 °C) and atmospheric pressure, to produce oil, char and gas products. Tire-derived oil is a complex mixture of organic C5–C24 compounds, including a very large proportion of aromatic compounds. This oil has a high gross calorific value (?43 MJ kg?1) and N and S contents of 0.4% and 0.6%, respectively, falling within the specifications of certain heating fuels. The distillation gas is composed of hydrocarbons; methane and n-butane are the most abundant, investing the distillation gas with a very high gross calorific value (?68 MJ N m?3). This gas is transformed into electric power by a co-generation turbine. The distillation char is mostly made of carbon but with significant inorganic impurities (?12 wt%). The quality of the solid residue of the process is comparable to that of some commercial chars. The quantity of residual solids, and the qualities of the gas, liquid and solid fractions, are similar to those obtained by conventional pyrolytic treatments of waste tires. However, the simplicity of the proposed technology and its low investment costs make it a very attractive alternative.
Félix A. López, Teresa A. Centeno, Francisco José Alguacil, Belén Lobato, Journal of Hazardous Materials 190 (2011) 285–292

A2221 – Studies on PEM fuel cell noble metal catalyst dissolution

A combination of electrochemical, spectroscopic and gravimetric methods was carried out on Proton Exchange Membrane (PEM) fuel cell electrodes with the focus on platinum and ruthenium catalysts dissolution, and the membrane degradation. In cyclic voltammetry (CV) experiments, the noble metals were found to dissolve in 1 M sulfuric acid solution and the dissolution increased exponentially with the upper potential limit (UPL) between 0.6 and 1.6 vs. RHE. 2–20% of the Pt (depending on the catalyst type) was found to be dissolved during the experiments. Under the same conditions, 30–100% of the Ru (depending on the catalyst type) was found to be dissolved. The faster dissolution of ruthenium compared to platinum in the alloy type catalysts was also confirmed by X-ray diffraction measurements. The dissolution of the carbon supported catalyst was found one order of magnitude higher than the unsupported catalyst. Other factors like medium acidity, chloride content and oxygen partial pressure all turned out to influence the noble metal dissolution. The degradation of the polyfluorinated sulfonic acid membrane electrolyte was also found to be an important source of increased acidity in the Three-Phase-Boundary (TPB), and consequently the dissolution of the noble metal catalysts.
Shuang Ma Andersen, Laila Grahl-Madsen, Eivind M. Skou, Solid State Ionics 192 (2011) 602–606

A2218 – Synthesis and characterization of novel room temperature vulcanized (RTV) silicone rubbers using octa[(trimethoxysilyl)ethyl]-POSS as cross-linker

A novel cross-linker octa[(trimethoxysilyl)ethyl]-POSS (OPS) based on a Vinyl-POSS derivative was firstly prepared via hydrosilylation chemistry. The novel POSS cross-linker was applied to hydroxyl terminated polydimethylsiloxane (HPDMS) matrix to prepare a series of novel RTV silicone rubbers. The chemical incorporation of novel POSS cross-linker into PDMS by hydrolytic condensation reaction was verified by attenuated total reflection (ATR) infrared spectroscopy. Morphology, thermal properties and mechanical properties of these novel RTV silicone rubbers have been studied by means of scanning electron microscope (SEM), thermal gravimetric analysis, universal tensile testing machine and dynamic mechanical analysis, respectively. The results displayed a pronounced enhancement effect of the novel cross-linker OPS on thermal stabilities and mechanical properties of RTV silicone rubbers as compared with the PDMS polymers prepared with tetramethoxysilane (TMOS), tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMOS) cross-linkers. Subsequently, the thermal decomposition of representative novel RTV silicone rubber in nitrogen was monitored by TGA coupled with real-time IR, and the degradation residues were also characterized by FTIR. It was found that the POSS cages were beneficial to increasing the degradation residues. The striking enhancements in thermal properties and improvements on mechanical properties could be attributable to the synergistic effect of the increasing dimensionality of cross-linking networks resulting from three-dimensional structure of OPS cross-linker, the plasticization of self-cross-linked OPS cross-linker and uniform distribution of POSS-rich domains.
Dongzhi Chen, Shengping Yi, Pengfei Fang, Yalan Zhong, Chi Huang, Xiaojun Wu, Reactive & Functional Polymers 71 (2011) 502–511

A2212 – Influence of rheological additives on char formation and fire resistance of intumescent coatings

Styrene–butyl acrylate copolymer based fire retardant coatings were prepared using intumescent flame-retardant additives and mineral clay type rheological additives. Three different widely used nanoclays, organic-modified montmorillonite, palygorskite and sepiolite were applied in order to determine their effect on the flame retardancy. Significant differences were found when their heat-shielding activities were evaluated. It was observed that the addition of different clay particles in amount of 0.25 w% changes the char formation process; the height, the morphology, the structure and also the mechanical resistance of the protecting shield. The different geometry and composition of the additives induced different changes in fire performance. In case of palygorskite the catalytic effect of Fe accelerated mainly the thermal decomposition, therefore the fire resistance decreased. The plate-like montmorillonite reduced the extent of the intumescent char, whereas also improved the mechanical and sustained heat resistance of the fire protecting shield. The fibrous sepiolite of low Fe content assisted the development of efficient protecting shield, which exhibited optimal cell structure, suitable thickness, and thus ensured better heat-insulating performance. Consequently, fire retardant effect of sepiolite was found to be better than the other studied clay types.
B. Bodzay, K. Bocz, Zs. Bárkai, Gy. Marosi, Polymer Degradation and Stability 96 (2011) 355e362

A2209 – Poly(sodium styrene sulfonate)-b-poly(methyl methacrylate) diblock copolymers through direct atom transfer radical polymerization: Influence of hydrophilic–hydrophobic balance on self-organization in aqueous solution

A series of poly(sodium styrene sulfonate)-b-poly(methyl methacrylate), PSSNa-b-PMMA, amphiphilic diblock copolymers have been synthesized through atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in N,N-dimethylformamide/water mixtures, starting from a PSSNa macroinitiator. The kinetics of the polymerization was followed by 1H NMR, while the chemical composition of the copolymers was verified by a variety of techniques, such as 1H NMR, FTIR and TGA. The MMA content of the copolymers ranges from 0 up to 60 mol%, while the number–average molecular weight of the PSSNa macroinitiator was 9000 g/mol. The self-association of the diblock copolymers in aqueous solution was compared to the respective behavior of similar random P(SSNa-co-MMA) copolymers through optical density measurements, pyrene fluorescence probing, dynamic light scattering and surface tension measurements. It is shown that the diblock copolymers form micellar structures in water, characterized by an increasing hydrophobic character and a decreasing size as the length of the PMMA block increases. These micelle-like structures turn from surface inactive to surface active as the length of the PMMA block increases. Moreover, contrary to the MMA-rich random copolymers, the respective diblock copolymers form water insoluble polymer/surfactant complexes with cationic surfactants such as hexadecyltrimethyl ammonium bromide (HTAB), leading to materials with antimicrobial activity
Evdokia K. Oikonomou, Aikaterini Bethani, Georgios Bokias, Joannis K. Kallitsis, European Polymer Journal 47 (2011) 752–761

A2192 – Promotion of organotin modified SBA-15 in the selective carboxylation of BPA with DMC

Two-methylcarbonate-ended-BPA (DmC(1)) was selectively synthesized from dimethyl carbonate (DMC) and bisphenol A (BPA) over organotin modified SBA-15. Organotin modified samples were characterized by XRD, FT-IR, BET and TG, and the relations between catalytic performance and catalyst properties were discussed. When heterogeneous SBA-15(CH2)3SnOC4H9 was used as catalyst, DmC(1) achieved better yield and higher selectivity than that obtained over homogeneous (C4H9)2SnO. The confined region effect of SBA-15(CH2)3SnOC4H9 was the main reason to promote the reaction between one-methylcarbonate-ended-BPA (MmC(1)) and DMC
Zhenhuan Li, Kunmei Su, Bowen Cheng, Jun Ming, Lei Zhang, Yongchao Xu, Catalysis Communications 12 (2011) 932–935

A2143 – Nanopore generation in hybrid polycyanurate/poly(e-caprolactone) thermostable networks

Novel nanoporous thermosetting films were obtained from thermostable polycyanurate (PCN)-based hybrid networks synthesized by polycyclotrimerization of cyanate ester of bisphenol E in the presence of a modifier reactive toward cyanate groups, i.e. dihydroxytelechelic polycaprolactone (PCL). The nanoporous structure was generated in PCN/PCL hybrid networks after extraction of unreacted free PCL sub-chains which were not chemically incorporated into the PCN cross-linked framework. Structure–property relationships for precursory and porous PCN/PCL hybrid networks were investigated using a large array of physico-chemical techniques. The porosity associated with the networks after extraction was more particularly evaluated by SEM and DSC-based thermoporometry: pore sizes around 10–90 nm were determined along with pore volumes as high as about 0.3 cm3 g 1. Density and dielectric measurements strongly suggested the occurrence of closed pore structures. Due to their high thermal stability as investigated by TGA, nanoporous PCN/PCL hybrid cross-linked films could be considered as promising materials for potential applications as thermostable membranes.
Olga Grigoryeva, Kristina Gusakova, Alexander Fainleib, Daniel Grande, European Polymer Journal 47 (2011) 1736–1745

A2106 – Sorption of phenol from aqueous solution by novel magnetic polysulfone microcapsules containing Cyanex 923

This paper describes the sorption of phenol from aqueous solution by using novel magnetic polysulfone (PSF) microcapsules containing Fe3O4 nanoparticles and mixture of trialkyl-phosphine oxides (Cyanex 923) (Cyanex 923/Fe3O4@PSF microcapsules). The preparation of the Cyanex 923/Fe3O4@PSF microcapsules was based on the phase-inversion technique. The prepared microcapsules were characterized by using Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and Vibrating Sample Magnetometer (VSM). Fe3O4 nanoparticles in the microcapsules provided easier separation via application of external magnetic field. The experiments indicated that phenol could be removed from aqueous solution at a pH range between 3 and 9. The Cyanex 923/Fe3O4@PSF microcapsules prepared with dispersed phase containing 3.35% of Cyanex 923 (by wt.) provided the highest removal. The sorption reached an equilibrium in 120 min and it obeyed the pseudo-second order kinetic model. The non-linear Chi-square (?2) statistical test showed that Langmuir isotherm model better represented the sorption data in comparison to Freundlich and Redlich–Peterson models. The Langmuir sorption capacity (Qo) and sorption constant (b) were 0.664 mmol/g and 0.855 L/mmol, respectively. The regenerated microcapsules could be used five times with no change in their sorption capacity and magnetic separability.
Senar Ozcan, Ali Tor, Mehmet Emin Aydin, Fatma Beduk, Ilker Akin, Reactive & Functional Polymers 72 (2012) 451–457

A2105 – The effect of ultra-thin graphite on the morphology and physical properties of thermoplastic polyurethane elastomer composites

Composites of thermoplastic polyurethane (TPU) and ultra-thin graphite (UTG) with concentrations ranging from 0.5 wt.% to 3 wt.% were prepared using a solution compounding strategy. Substantial reinforcing effects with increased loadings are achieved. Compared to neat TPU, values for storage modulus and shear viscosity are enhanced by 300% and 150%, respectively, for UTG concentrations of 3 wt.%. Additionally, an enhancement of thermal properties is accomplished. The crystallization temperature and thermal stability increased by 30 °C and 10 °C, respectively, compared to neat TPU. Furthermore, the use of oxidized UTG (UTGO) with its added functional oxygen groups suggests the presence of chemical interactions between UTG and TPU, which additionally impact on the thermal properties of the corresponding composites. Controlling the oxidation degree, thus offers further possibilities to obtain composites with tailored properties. The presented approach is straightforward, leads to homogeneous TPU-UTG composites with improved materials properties and is especially suitable for commercial UTG materials and further up-scaled production.
Olivia Menes, Manuela Cano, Adolfo Benedito, Enrique Giménez, Pere Castell, Wolfgang K. Maser, Ana M. Benito, Composites Science and Technology 72 (2012) 1595–1601

A2059 – Synthesis and characterization of low content of different SiO2 materials composite poly (vinylidene fluoride) ultrafiltration membranes

A comparison of the morphology and performance of virgin poly (vinylidene fluoride) (PVDF) ultrafiltration (UF) membrane, and PVDF-composite membranes with low content of two different SiO2 (N-SiO2 and M-SiO2 particles) was carried out. Cross-sectional area and surface morphology of the membranes were observed by scanning electron microscopy and atomic force microscopy. Surface hydrophilicity of the porous membranes was determined through the measurement of a contact angle. Performance tests were conducted on the composite membranes through water flux and bovine serum albumin (BSA) retention. Average pore size and surface porosity were calculated based on the permeate flux. Thermal stability and mechanical stability were determined by thermogravimetric analysis and tensile stress tests. The results indicate that N-SiO2/PVDF (P-N) membranes possessed larger average pore size and porosity, which led to higher water flux and a slight decline in BSA retention. On the other hand, M-SiO2/PVDF (P-M) membranes had better mechanical stability and anti-fouling performance with enhanced membrane hydrophilicity and decreased membrane surface roughness. Both of the P-N and P-M membranes exhibited typical asymmetric morphology and improved thermal stability.
Chanjuan Liao, Jianquan Zhao, Ping Yu, Hua Tong, Yunbai Luo, Desalination 285 (2012) 117–122

A2056 – Porosity control of cold consolidated geomaterial foam: Temperature effect

Porous K-geopolymers with mutli-scale porosity were synthetized, based on the production of molecular hydrogen due to the oxidation of free silicon associated with polycondensation reactions. The various drying steps at low temperatures influencing the foams morphology were evaluated in function of parameters like mass effect, mold dimensions and drying cycles. The results obtained evidenced the possibility to perform reproducible foams with a control of their porosity. These foams are in agreement with the environmental demand with their recycling properties and their low cost of production due to the cheap materials used and the low temperature of synthesis. Some other advantages like their fire resistance, acid/base resistance, their good mechanical properties and their good thermal conductivity is a good point for future applications. As an example a homogeneous foam with a pore size of 1.5 mm at 50 °C (9 days for an achieved drying but consolidated before) can be prepared. Moreover the porosity can be controlled with various temperature cycles decreasing the time of synthesis. From the cycles tested (70–55 °C and 70–23 °C), some homogeneous samples were obtained with pores sizes varying from 0.5 to 1.5 mm. Then the work was extended to larger surfaces exchange, what evidences the importance of drying and mass effects upon the porosity as well as the mechanical properties of the mold used during synthesis.
Joseph Henon, Arnaud Alzina, Joseph Absi, David Stanley Smith, Sylvie Rossignol, Ceramics International 38 (2012) 77–84

A2055 – Preparation and characterization of silica/fluorinated acrylate copolymers hybrid films and the investigation of their icephobicity

Inexpensive hydrophobic and icephobic coatings and films were obtained by a simple method. These coatings were prepared by mixing silica sol and fluorinated acrylate copolymers. There was a phase separation process in the film-forming which can provide the excellent performance. Small amount (about 2 wt.%) of fluorinated (methyl) acrylate was used in all of these coatings. The coatings were eco-friendly by using ethanol as the solvent system. Scanning electron microscopy, atomic force microscope, energy dispersive X-ray fluorescence spectrometer, water contact angle, thermal gravimetric analysis and tests of adhesion and hardness had been performed to characterize the morphological feature, chemical composition, hydrophobicity and icephobicity of the surface, thermal stability and mechanical properties of the coatings. The results showed that the films had good hydrophobicity, high thermal stability and excellent mechanical properties of adhesion strength and pencil hardness. Furthermore, by testing their properties of delaying water droplet from icing, it was found that ice formation was delayed for 90 min compared with the glass surface at ? 5.6 °C. The hybrid coatings may be suitable for large-scale and practical application owing to its flexibility and simplicity.
Yanfen Huang, Mingjie Hu, Shengping Yi, Xinghai Liu, Houbin Li, Chi Huang, Yunbai Luo, Yan Li, Thin Solid Films 520 (2012) 5644–5651

A2006 – Synergistic effect between POSS and fumed silica on thermal stabilities and mechanical properties of room temperature vulcanized (RTV) silicone rubbers

In this paper, both divinyl-hexa[(trimethoxysilyl)ethyl]-POSS (DVPS) and fumed silica were firstly introduced into polydimethylsiloxane (PDMS) system using as the cross-linker and the reinforcing filler respectively. And a series of novel RTV silicone rubbers synergistically enhanced by DVPS and fumed silica were prepared. The cross-linked networks in the novel RTV silicone rubbers have been studied by attenuated total reflection infrared spectroscopy, and the dispersions of POSS and fumed silica in these novel RTV silicone rubbers have been observed by means of scanning electron microscope (SEM). And thermal stabilities, thermo-oxidative stabilities and mechanical properties of these novel RTV silicone rubbers were studied by means of thermal gravimetric analysis and universal tensile testing machine, respectively. From the obtained results, it was found that synergistic effect between POSS-rich areas and fumed silica on thermal stability and mechanical property of RTV silicone rubber indeed existed. And the experimental results also exhibited that the thermal stabilities and mechanical properties of the novel RTV silicone rubbers were far better than those of the reference materials (DVPR and MTFR). The striking enhancements in thermal properties and improvements on mechanical properties of novel RTV silicone rubbers were likely attributed to the synergistic effect between POSS-rich domains and fumed silica. Meanwhile, it was found that the mechanical properties of RTV silicone rubbers prepared with a given amount of POSS cross-linker were enhanced with the increment of the loading amount of fumed silica.
Dongzhi Chen, Yan Liu, Chi Huang, Polymer Degradation and Stability 97 (2012) 308-315

A1922 – Preparation and characterization of Polyvinylbutyral/Graphene Nanocomposite

Poly (vinylbutyral) (PVB) was synthesized by condensation of poly (vinylalcohol) (PVA) with butyraldehyde. Nanocomposites of PVB with graphene (0.1 to 0.6 wt%) were prepared via solution blending. The structure and properties of prepared compounds were characterized by FT-IR, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile strength tester (TST). The prepared nanocomposites showed considerable thermal and mechanical properties than PVB and showed good toughness and flexibility.
Mortaza Hajian, Mohammad Reza Reisi, Gholam Ali Koohmareh, Ali Reza Zanjani Jam, J Polym Res (2012) 19, 9966

A1921 – Preparation of a poly(methyl methacrylate)-reduced graphene oxide composite with enhanced properties by a solution blending method

Poly(methyl methacrylate) (PMMA)/graphene nanocomposites were prepared by a simple solution blending method. The glass transition temperature of the produced PMMA/graphene composite was increased by 37 C with 1.0 wt.% RGO content, which is approximately 40% of improvement compared to that of pure PMMA. The thermal expansion coefficient (TEC) decreased by 68% with as low as 0.1 wt.% RGO loading. The electrical conductivity of the nanocomposites reached up to 0.037 S/m even with only 2.0 wt.% RGO, which increased by more than twelve orders of magnitude. The resulting nanocomposites showed that a stable colloidal suspension of graphene dispersion in organic solvent before blending with PMMA is necessary to fabricate the nanocomposites with enhanced properties
Xiaopeng Zeng, Jingjing Yang, Wenxia Yuan, European Polymer Journal 48 (2012) 1674–1682

A1917 – Chemically modified graphene oxide/polybenzimidazobenzophenanthroline nanocomposites with improved electrical conductivity

Graphene/polybenzimidazobenzophenanthroline nanocomposites were prepared through the liquid phase exfoliation of graphene oxide (GO) and reduced graphene oxide (rGO) in methanesulfonic acid with subsequent solution mixing. Various chemical and combined chemical-thermal methods were examined to be effective for producing rGO with highly graphitic structure and excellent electrical conductivity. Raman and X-ray photoelectron spectroscopy showed higher degree of reduction of the GO with the combined chemical-thermal method compared to other chemical reduction processes. Structural characterization of the nanocomposites by X-ray diffraction, scanning electron microscopy and transmission electron microscopy showed good exfoliation and dispersion of both GO and rGO fillers in the polymer matrix. The thermogravimetric analysis found that the nanocomposites with rGO have higher onset and maximum weight loss temperatures than those with GO. Compared with the pure polymer, the electrical conductivity of the nanocomposites containing 10 wt% GO and GO reduced by the combined chemical-thermal treatment showed a remarkable increase by four and seven orders of magnitude, respectively. Long-term in-situ thermal reduction was performed to further improve the conductivities of the nanocomposites.
Jeong-Hyun Park, Arup Choudhury, B.L. Farmer, T.D. Dang, Soo-Young Park, Polymer 53 (2012) 3937-3945

A1911 – TG–DSC–FTIR–MS study of gaseous compounds evolved during thermal decomposition of styrene-butadiene rubber

The thermal decomposition behavior of styrene-butadiene rubber was studied using a system equipped with thermogravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, and mass spectroscopy. Two different experiments were conducted. From these experiments, thermogravimetric analysis results indicated a mass loss of 58 % in the temperature range of ~ 290–480 °C and a mass loss of 39 % in the temperature range beyond 600 °C. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirmed the presence of oxides, even at 1,000 °C, accounting for the Zn, Mg, Al, Si, and Ca in the original sample.
Antonyraj Arockiasamy, Hossein Toghiani, David Oglesby, M. F. Horstemeyer, J. L. Bouvard, Roger L. King, J Therm Anal Calorim, 2012

A1871 – Entrapment of Organic Molecules within Metals. 2. Polymers in Silver

We describe a new type of composite material: polymers entrapped within a metal. Polystyrene-sulfonic acid and poly(vinyl alcohol) were entrapped within silver. Detailed procedures for the entrapment are provided, and it is shown that this entrapment is a distinctly different process from polymer adsorption on the metal surface. Characterization of these new composites includes XRD measurements, SEM with EDAX, surface area, porosity, and density measurements, and full oxidative degradation analysis by thermogravimetry (TGA/DTA/DTG) coupled to mass spectrometry. A pronounced effect of the metal caging on the thermal degradation of the two entrapped polymers was observed. On the basis of all experimental observations a proposition is made as to the molecular level picture of the entrapment.
Hanna Behar-Levy, Gennady E. Shter, Gideon S. Grader, David Avnir, Chem. Mater. 2004, 16, 3197-3202

A1868 – New Poly(Methacrylate)s Containing Benzylpiperazine and Methylpiperidine Moieties

The synthes?s of two new methacrylate esters containing 2-(4-benzyl piperazin-1-yl)-2-oksoethyl and 2-(4-methylpiperidin-1-yl)-2-oksoethyl group are described. The monomers produced from the reaction of corresponding 4-methylpiperidinechloroacetamide and 1-benzylpiperazinechloroacetamide with sodium methacrylate were polymerized in DMSO solution at 65°C using AIBN as an initiator. The monomers and their polymers were characterized by IR, 1H- and 13C-NMR spectroscopy. The glass transition temperature of the polymers were investigated by DSC and the apparent thermal decomposition activation energies (E d ) were calculated by Ozawa method using the SETARAM Labsys TGA thermobalance. By using gel permeation chromatography, weight average ( Mw ) and number average ( Mn ) molecular weights and polidispersity, indices of the polymers were determined
Cengiz Soykan, ?brahim Erol, Hasan Türkmen, Yunus Akçamur, Journal of Polymer Research , September 2004, Volume 11, Issue 3, pp 181-187

A1851 – Thermal Stability of Polymer Compositions with Modified Alumina

Organic fillers are used to enhance the performance of polymer composite materials by inducing various interactions on the polymer–filler interface, that affect the mechanic, physicochemical, thermooxidative inclusive, properties of the composite materials. In modifying the properties of polymer materials one should take account of the chemical composition of the filler and its specific surface area. Recently nanoparticles of various chemical nature have come into use as functional additives to polymers. Possessing a large specific surface area, such particles enter chemical bonding with the polymer, which restricts mobility of its fragments. Of particular interest is chemical modification of fillers, thereby considerably extending their functions in composite materials. When choosing way to modifying fillers, one should put emphasis on uniformity of distribution of functional additives over the surface, strength of their bonding with the surface, and possibility for transformation into complex structures. Forming on the filler surface of groups inhibiting thermooxidative processes favors greater stability of the composite material [2, 5]. Furthermore, chemical modification should not affect dispersity of filler, in particular, cause nanoparticle agglomeration. One of the most promising present techniques for chemical modification of the surface of solid materials is molecular layering (ML). This technique provides a uniform coating of the activated surface by nanoparticles, their strong bonding with the surface, and an exact composition at the molecular level. Here we present the results of research on the thermooxidative destruction and combustibility of polymer composite materials: PEN-I foam plastic on the basis of an epoxide–novolak block copolymer and poly(methyl methacrylate), filled with alumina and products of its surface modification with organoelement groups.
S. A. Trifonov, A. A. Malygin, A. K. Dyakova, J.-M. Lopez-Cuesta, N. Cinausero, Russian Journal of General Chemistry, 2008, Vol. 78, No. 11, pp. 2214–2219

A1813 – PMMA/Zn2SiO4:Eu3+(Mn2+) Composites: Preparation, Optical, and Thermal Properties

Luminescent composites of poly(methylmethacrylate) (PMMA) and nanophosphors (Zn2SiO4:Mn2+, Zn2SiO4:Eu3+) were prepared by dispersion casting method. It was found that nanoparticles embedded in PMMA matrix preserve their typical phosphorescence emission. The influence of Zn2SiO4 nanofillers on thermal properties of PMMA was also investigated. A shift towards higher glass transition temperatures and slight improvements in thermal stability of the nanocomposites compared to pure PMMA were observed and are discussed herein.
Ljubica Ðacanin, Svetlana R. Lukic, Dragoslav M. Petrovic, Zeljka Antic, Radenka Krsmanovic, Milena Marinovic -Cincovic, Miroslav D. Dramicanin, Journal of Materials Engineering and Performance, Volume 21(7) July 2012—1509

A1752 – Comparative investigation on the thermal degradation and stabilization of carbon fiber precursors

Thermal degradation and stabilization of two kinds of polyacrylonitrile (PAN) fibers have been investigated by a combination of FT-IR, differential scanning calorimetry (DSC), modulated DSC, thermogravimetry (TG), thermal shrinkage behavior, in situ mass spectrometry (MS), and tensile property examinations. The two types of precursor fibers exhibit distinct properties after oxidative stabilization, but they can both make carbon fibers with equivalent mechanical properties. Compared with PAN/itaconic acid precursor fibers, the fibers containing acrylamide comonomers show a doublet appearance, broader exothermic peak, lower threshold degradation temperature, and more amount of heat evolved in DSC thermogram, which is favorable to obtain uniform microstructures in oxidative stabilization process. The two types of samples produce different ring structures in the thermal degradation and stabilization process, as evidenced by results from tensile test, TG–MS and thermal shrinkage behavior analyses. In addition, the molecular rearrangement or melting of ordered structures accompanying with nitrile polymerization was also detected from modulated DSC.
Gang-Ping Wu, Chun-Xiang Lu, Li-Cheng Ling, Yong-Gen Lu, Polym. Bull. (2009) 62, 667–678

A1691 – Effect of crystalline structure of polypropylene random copolymers on mechanical properties and thermal degradation kinetics

Polypropylene random copolymers are a relatively new type of polypropylene (PP) modified plastics, which were introduced over the last years on the market. The comonomer which is most commonly used is ethylene at random concentrations for the improvement of mechanical and thermal properties of the final material. For the present work, we characterized and compared the mechanical properties and the thermal degradation kinetics results of polypropylene random copolymer (PPR) with 7% ethylene content and polypropylene random copolymer/enhanced crystalline structure/improved temperature resistance (PPRCT), which is formed by using a special ?-nucleation process, which leads to a homogenous dispersion of equal sized ?-crystals. The tensile strength properties of PPRCT are improved due to the presence of both ?- and ?- crystals, making the final product more ductile than neat PP or its random copolymer (PPR), which both consist exclusively of ?- crystals (monoclinic system). Characterization with XRD and DSC confirmed the two crystalline phases of PPRCT. Thermogravimetric (TG) studies of PPRCT showed that the new material exhibits better thermal stability than neat PPR, since 1% mass loss of PPRCT appeared at temperatures 10 ?C higher than neat PPR. The activation energy of degradation of PPRCT and PPR was calculated using the Kissinger, Akahira and Sunose (KAS) method. Degradation took place into two stages; the first stage which corresponded to an initial small mass loss was simulated with an nth order model (Fn), while the second stage was attributed to the main degradation mechanism of the material and was simulated with an nth order model with autocatalysis (Cn). When the calculated activation energies with isoconversional and modelfitting methods are compared, PPRCT has much higher activation energy than PPR, a fact which indicates the higher thermal stability of PPRCT.
Dimitrios G. Papageorgiou, Dimitrios N. Bikiaris, Konstantinos Chrissafis, Thermochimica Acta 543 (2012) 288– 294

A1682 – Synthesis, Characterization, and Thermal Degradation Mechanism of Fast Biodegradable PPSu/PCL Copolymers

Poly(propylene succinate)/poly(e-caprolactone) (PPSu/PCL) 25/75, 50/50, and 75/25 w/w copolymers were prepared using a combination of polycondensation and ring opening polymerization. The randomness of copolymers was characterized using 1H NMR and 13C NMR spectroscopy. From molecular weights and DSC measurements it was observed that the molecular weight decreased with increasing the wt % content of PPSu, while the copolymers containing 50 and 75 wt % PPSu were completely amorphous. Enzymatic hydrolysis revealed that biodegradation rate was much enhanced compared with that of neat PCL and increased by increasing the PPSu content. From TGA analysis it was also found that the PPSu/PCL copolymers had similar thermal decomposition behaviour with the pure polyesters and exhibited their maximum decomposition rates at temperatures 400–420 8C. Two different mechanisms, which follow each other, were used to adequately describe their decomposition kinetics. The first one corresponded to the first stage taking place at 280–365 8C, where small mass loss was recorded and activation energies ranged between 94 and 156 kJ/mol. The second one took place at 370–460 8C and corresponded to the stage where the main polyester mass was decomposed. The activation energies for this stage ranged between 200 and 240 kJ/mol.
S. Papadimitriou, N. Bikiaris, K. Chrissafis, K. M. Paraskevopoulos, S. Mourtas, Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 45, 5076–5090 (2007)

A1637 – Sulfonated derivatives of polyparaphenylene as proton conducting membranes for direct methanol fuel cell application

Proton conducting polymers derived from polybenzoyl-1,4-phenylene (PBP) and poly-p-phenoxybenzoyl-1,4-phenylene (PPBP) were synthesized by the ‘Colon synthesis technique’. The sulfonation of these proton conducting polymers was carried out using either sulphuric acid or tetramethylsiliylchlorosulfonate (TMSCl) as sulfonating agent, and their thermal properties were evaluated. Both sulfonated PBP and PPBP are thermally stable up to at least 215 °C. The sulfonated sPPBP exhibited good conductivity as proton conducting membranes at room temperature and were tested as electrolyte membranes for a single direct methanol fuel cell (DMFC) in terms of water absorption, methanol permeability and electrical performance. The water uptake of the sPPBP was found to be larger than that of the sPBP, i.e., 65 and 43 mol%, respectively. The permeability to methanol was found to be 10 times lower than sPPBP and sPBP compared to a NafionÒ membrane. In spite of this, performance in a single DMFC was found to be twice inferior to that with NafionÒ 117. Optimisation of the sulfonation level and of the electrode-membrane interfaces was lead to better results.
C. Le Ninivin, A. Balland-Longeau, D. Demattei, C. Coutanceau, C. Lamy, J.M. Léger, Journal of Applied Electrochemistry 34: 1159–1170, 2004.

A1636 – Ac-conductivity and dielectric relaxations above glass transition temperature for parylene-C thin films

45% semi-crystalline parylene-C (–H2C–C6H3Cl–CH2–)n thin films (5.8 ?m) polymers have been investigated by broadband dielectric spectroscopy for temperatures above the glass transition (Tg = 90°C). Good insulating properties of parylene-C were obtained until operating temperatures as high as 200°C. Thus, low-frequency conductivities from 10?15 to 10?12 S/cm were obtained for temperatures varying from 90 to 185°C, respectively. This conductivity is at the origin of a significant increase in the dielectric constant at low frequency and at high temperature. As a consequence, Maxwell–Wagner–Sillars (MWS) polarization at the amorphous/crystalline interfaces is put in evidence with activation energy of 1.5 eV. Coupled TGA (Thermogravimetric analysis) and DTA (differential thermal analysis) revealed that the material is stable up to 400°C. This is particularly interesting to integrate this material for new applications as organic field effect transistors (OFETs).
A. Kahouli, A. Sylvestre, F. Jomni, B. Yangui, J. Legrand, Appl Phys A (2012) 106, 909–913

A1611 – Copolymerization of 2-(4-tert-butylphenoxy)-2-oxo-ethyl Methacrylate with Methyl Methacrylate and Styrene: Synthesis, Characterization, and Monomer Reactivity Ratios

A tertierbutylphenoxy group containing methacrylate based monomer 2-(4-tert-butylphenoxy)-2-oxo-ethyl methacrylate (TBPOEMA) was synthesized by reacting 4-tertierbutylphenyl chloroacetate (TBPClAcO) with sodium methacrylate in acetonitrile. TBPClAcO was prepared by reacting tertierbutylphenol dissolved in benzene with chloroacetylchloride. The free-radical-initiated copolymerization of TBPOEMA, with methyl methacrylate (MMA) and styrene (ST) was carried out in dimethylsulphoxide (DMSO) solution at 65[`(M)]overline M
Cengiz Soykan, Ibrahim Erol, Journal of Polymer Research, 02/2004, 11(1) 53-63.

A1604 – Nafionbased composite electrolytes for proton exchange membrane fuel cells operating above 120 ?C with titania nanoparticles and nanotubes as fillers

Nafion/titania based fillers composites are prepared by casting and tested in proton exchange membrane fuel cells (PEMFCs) operating at elevated temperatures (130 ?C). Three types of titania based fillers are studied: nanoparticles with nearly spherical shape, mesoporous particles with high surface area, and hydrogen titanate nanotubes. Properties of composites related to PEMFC operation, such as water absorption/retention and proton conductivity, are determined and correlated with microstructural data obtained by small angle Xray scattering. The addition of titanate nanotubes changes more markedly the physical properties of the composite electrolytes as compared to titanium oxide nanoparticles with different surface area, a feature probably related to the intrinsic hydration and proton conductivity of the nanotubes. Polarization curves of H2/O2 PEMFCs using composite electrolytes indicate that composite electrolytes contribute to a significant boost of H2/O2 PEMFC performance at 130 ?C.
B.R. Matos, E.I. Santiago, J.F.Q. Rey, A.S. Ferlauto, E. Traversad, M. Linardi, F.C. Fonseca, Journal of Power Sources 196 (2011) 1061–1068

A1597 – Separation and purification of aloe polysaccharides by a combination of membrane ultrafiltration and aqueous two-phase extraction

A two-step process was developed for the purification of polysaccharides from the pulp of Aloe varavia using aqueous two-phase system (ATPS) extraction and a novel copolymer ultrafiltration membrane. The first step was ATPS under optimal separations conditions using a total composition of 18% PEG2000, 25% ammonium sulfate, pH 3.0, and 0.3 M NaCl. To form the copolymer membrane, poly(acrylonitrile-acrylamide-styrene) was prepared by solution polycondensation using azoisobutyronitrile as initiator. Then, membranes were formed from the dissolved copolymer by the phase inversion method. Copolymer structure was investigated by infrared spectrum and thermogravimetric analysis (TGA). The copolymer membrane surface and cross section were observed by scanning electron microscopy. The water flux of this membrane was 26.33 mL/(cm2 h), and retention was 96% for bovine serum albumin and 34% for dextran T40000. The separation and purification of aloe polysaccharide were carried using this copolymer membrane following ATPS. The TGA of aloe polysaccharide demonstrated a high purity of the polysaccharide. By gas chromatographic analysis, it was shown that mannose is the main monosaccharide in the aloe polysaccharide, and only a few glucose residues are present.
Jian-min Xing, Fen-fang Li, Appl Biochem Biotechnol (2009) 158, 11–19

A1594 – Synthesis and characterization of novel optically active and photoactive aromatic polyesters containing 1,8-naphthalimidyl pendant group by step-growth polymerization

Novel optically active polyesters (PE)s by step-growth polymerization of a chiral diacid containing naphthalimidyl and flexible chiral groups with different diols via direct polyesterification reaction with tosyl chloride/pyridine/dimethyl-formamide system as condensing agent were prepared. The resulting PEs were characterized using FT-IR, 1H NMR, UV–vis spectroscopy, fluorimetry, and elemental analysis. Fluorescence properties of the PE3h as a representative one were examined in several polar aprotic solvents which reveal that this polymer has photoactive properties. Furthermore, thermal properties of these polymers were investigated using thermogravimetric and differential thermogravimetric analyses. The glass-transition temperatures of PE3b and PE3f were recorded between 264 and 220 °C by differential scanning calorimetry, and the 10% weight loss temperatures were ranging from 350 °C under nitrogen. The obtained macromolecules are readily soluble in many organic solvents.
Shadpour Mallakpour, Elaheh Hashemi, Polym. Bull. (2010) 65, 551–563

A1590 – Microwave irradiation as a versatile tool for increasing reaction rates and yields in synthesis of optically active polyamides containing flexible L-leucine amino acid

In this investigation, a series of thermally stable and optically active polyamides (PA)s containing bulky pendant chiral functionality from polymerization of a diacid monomer containing rigid phthalimide and flexible L-leucine groups, (2S)-5-[4-(4-methyl-2-phthalimidylpentanoylamino)benzoylamino]isophthalic acid with several aromatic and aliphatic diisocyanates such as 4,40-methyl-enebis(phenyl isocyanate), toluylene-2,4-diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate under gradual heating method were prepared and compared with microwave-assisted polycondensation method. The polymerization reactions occurred rapidly under microwave irradiation and produced a series of PAs with good yields and moderate inherent viscosities of 0.26–0.68 dL/g. All of the new PAs showed good solubility and were readily dissolved in aprotic organic solvents. The resulting polymers were characterized by FT-IR, 1H NMR spectroscopy, and elemental analysis technique. Thermal stability and thermal properties of PAs were evaluated by thermogravimetric analysis and differential scanning calorimetry. The interpretation of kinetic parameters (E, ?H, ?S, and ?G) of thermal decomposition stages have been evaluated using Coats–Redfern equations.
Shadpour Mallakpour, Amin Zadehnazari, Amino Acids (2010) 38, 1369–1376

A1589 – Synthesis and properties of new highly soluble poly(amide-ester-imide)s containing poly(ethylene glycol) as a soft segment

In this study, a new class of highly soluble poly(amide-ester-imide)s (PAEI)s contains poly(ethyleneglycol) (PEG) as hydrophilic and soft segment were prepared. Poly(ethylene glycol)-bis-(N-trimellitylimido-4-phenyl carboxylic acid) (3) as a novel diacid monomer was synthesized via two step. The reaction of poly(ethylene glycol) (PEG 6000) with trimellitic anhydride chloride yield poly(ethylene glycol)-bis-trimellitic anhydride (1). The reaction of dianhydride 1 with p-aminobenzoic acid (2) produces novel diacid monomer 3. The direct polycondensation technique of the diacid 1 with several aromatic diamines was carried out in pyridine/N-methyl-2-pyrrolidone/triphenylphosphite/CaCl2 as condensing agent. The resulting novel PAEIs with inherent viscosities ranging between 0.21 and 0.42 dl g-1, were obtained in good yield. This group of polymers exhibit excellent solubility in a variety of organic solvents and water. All of these polymers were characterized with FT-IR spectroscopy. Thermal properties, 1H-NMR and XRD study of these PAEIs were also reported. The results demonstrate that this polymers show crystalline structure as well as high thermal stability. In addition the effect of PEG length on solubility and thermal properties of the polymers were also studied.
Majid Kolahdoozan, Razieh Mirsafaei, Shadpour Mallakpour, Polym. Bull. (2012) 68, 1239–1254

A1588 – Poly(4-vinylpyridine)/SBA-15 (P4VP/SBA-15) composites with various amounts of SBA-15 were prepared and characterized. The physical and chemical properties of P4VP/SBA-15 were investigated by XRD, BET, FT-IR, TGA, and SEM techniques. The catalytic performa

Poly(4-vinylpyridine)/SBA-15 (P4VP/SBA-15) composites with various amounts of SBA-15 were prepared and characterized. The physical and chemical properties of P4VP/SBA-15 were investigated by XRD, BET, FT-IR, TGA, and SEM techniques. The catalytic performance of each material was determined for the Knoevenagel condensation reaction between carbonyl compounds and ethyl cyanoacetate in the presence of water as a solvent. The effects of reaction temperature, the amount of catalyst, amount of support, solvent, and the amount of benzoyl peroxide during the synthesis of P4VP/SBA-15 were investigated, as well as the recyclability of the heterogeneous composite. The catalyst used for this synthetically useful transformation showed a considerable level of reusability as well as very good activity. This reaction occurred rapidly when water was used as a solvent, so we assume it to be a green reaction.
Majid Kolahdoozan, Roozbeh Javad Kalbasi, Zohreh S. Shahzeidi, Monatsh Chem (2012) 143, 325–334

A1496 – In situ prepared PBSu/SiO2 nanocomposites. Study of thermal degradation mechanism

A series of nanocomposites consisted of poly(butylene succinate) (PBSu) and fumed silica nanoparticles (SiO2) were prepared using the in situ polymerization technique. The amount of SiO2 used directly affected the final molecular weight of the prepared polyesters. At a low SiO2 content (0.5 wt.%) the molecular weight obtained was higher compared to neat PBSu, however at higher concentrations this was gradually reduced. The melting point of the matrix remained unaffected by the addition of the nanoparticles, in contrast to the crystallinity, which was dramatically reduced at higher SiO2 contents. This was mainly due to the extended branching and cross-linking reactions that took place between the carboxylic end groups of PBSu and the surface silanols of the nanoparticles. Thermal degradation of the PBSu/SiO2 nanocomposites was studied by determining theirs mass loss during heating. From the variations of the activation energies, calculated from the thermogravimetric curves, it was clear that nanocomposites containing 1 wt.% SiO2 content had a higher activation energy compared to pure PBSu, indicating that the addition of the nanoparticles could slightly increase the thermal stability of the matrix. However, in PBSu/SiO2 nanocomposite containing 5 wt.% SiO2 the activation energy was smaller. This phenomenon should be attributed to the existence of extended branched and cross-linked macromolecules, which reduce the thermal stability of PBSu, rather than to the addition of fumed silica nanoparticles.
A.A. Vassiliou, K. Chrissafis, D.N. Bikiaris, Thermochimica Acta, 495 (2009) 120–128

A1488 – In situ prepared PET nanocomposites: Effect of organically modified montmorillonite and fumed silica nanoparticles on PET physical properties and thermal degradation kinetics

In the present study a series of PET nanocomposites were prepared by in situ polymerization using different amounts of organically modified montmorillonite (OMMT) with a triphenylphosphine compound and fumed silica nanoparticles (SiO2). As verified by TEM micrographs, the dispersion of both nanoparticles into the PET matrix was homogeneous while montmorillonite was dispersed in the exfoliated form. The intrinsic viscosities of the prepared nanocomposites were affected by the addition of the nanoparticles and in both cases a slight increase was observed. Tensile strength was also increased by increasing nanoparticles content while both types of nanoparticles act as nucleating agents, enhancing the crystallization rates of PET. From the thermogravimetric curves it was concluded that PET and the samples with different nanoparticles presented good thermostability, since no remarkable mass loss occurred up to 320 °C (<0.5%). The activation energy (E) of degradation of the studied samples was estimated using the Ozawa, Flynn and Wall (OFW) method. Pure PET had an E = 223.5 kJ/mol while the activation energy of PET/SiO2 2 wt.% nanocomposites was almost identical (222.1 kJ/mol). However, PET/OMMT 2 wt.% nanocomposites exhibited a higher activation energy (228.3 kJ/mol), indicating that OMMT incurred a stabilizing effect upon the decomposition of the matrix. The form of the conversion function for all the studied samples obtained by fitting was the mechanism of nth-order auto-catalysis.
A.A. Vassiliou, K. Chrissafis, D.N. Bikiaris, Thermochimica Acta, 500 (2010) 21–29

A1446 – Kinetics of thermal degradation of polymers. Complementary use of isoconversional and model-fitting methods

The thermal degradation of polymers has been studied quite extensively using thermogravimetric measurements. For the kinetic description, most of the times single rate heating data and model-fitting methods have been used. Since the thermal degradation of the polymers is a very complex reaction, the choice of a reliable model or a combination of kinetic models is very important. The advantages or the disadvantages of using a single heating rate or multiple heating rates data for the determination of the kinetic triplet have been investigated. Also, the activation energy has been calculated with the isoconversional and model-fitting methods. The reaction model was determined with the model-fitting method. The limits of all these procedures were investigated with experimental data of the thermal degradation of the poly(ethylene adipate) (PEAd).
K. Chrissafis, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 1, 273–283

A1427 – Thermal properties of Nafion–TiO2 composite electrolytes for PEM fuel cell

Thermal analysis has been used to evaluate the stability, glass transition, and water retention of Nafion based polymer–ceramic electrolytes. These electrolytes are envisioned as promising replacement of Nafion in fuel cells operating above 100 °C. The polymeric matrix prepared by casting exhibits lower crystallinity than the extruded Nafion, a feature that affects the water absorption properties. The addition of titania-based nanotubes and nanoparticles to the polymer has enhanced the water retention at high temperatures (*130 °C) and the glass transition temperature, respectively. Such results are important for the design of composite electrolytes for the operation of fuel cells at high temperatures.
B. R. Matos, E. M. Arico, M. Linardi, A. S. Ferlauto, E. I. Santiago, F. C. Fonseca, J Therm Anal Calorim (2009) 97:591–594

A1406 – Thermal behaviour of hydroxymethyl compounds as models for adhesive resins

Urea–formaldehyde (UF) and phenol–formaldehyde (PF) resins are the most widely used wood adhesives. The first stage in resin manufacturing is the formation of methylol derivatives which polycondensation leads to building the tridimensional network. Understanding the behaviour of methylol compounds in curing provides useful information for developing appropriate resin structures. Thermal behaviour of N,N0-dihydroxymethylurea, 2- and 4-hydroxymethylphenols, urea and phenol as model compounds for UF, PF and phenol–urea–formaldehyde (PUF) resins was followed by TG-DTA method. The measurements were carried out by the labsys instrument Setaram at 30–450 °C in nitrogen flow. The characteristic signals for model compounds and for some reaction mixtures were measured by high resolution 13C NMR spectroscopy.
K. Siimer, P. Christjanson, T. Kaljuvee, T. Pehk, I. Saks, J Therm Anal Calorim (2009) 97,459–466

A1405 – TG-DTA study of melamine-urea-formaldehyde resins

The thermal behaviour of MUF resins from different suppliers with different content of melamine was studied, along with the 13C NMR spectroscopic analysis of resin structure and the testing of particleboards in current production at Estonian PB factory P¬rnu Plaaditehas AS. The chemical structure of resins from DMSO-d6 solutions was analysed by 13C NMR spectroscopy on a Bruker AMX500 NMR spectrometer. The melamine level in different MUF resins is compared by the ratios of carbonyl carbon of urea and triazine carbon of melamine in 13C NMR spectra. Curing behaviour of MUF resins was studied by simultaneous TG-DTA techniques on the Labsysä instrument Setaram. The shape of DTA curves characterisises the resin synthesis procedure by the extent of polymerisation of UF and MF components and is in accordance with structural data.
K. Siimer, P. Christjanson, T. Kaljuvee, T. Pehk, I. Lasn, I. Saks, Journal of Thermal Analysis and Calorimetry, Vol. 92 (2008) 1, 19–27

A1404 – Thermal behaviour of melamine-modified urea–formaldehyde resins

Thermal behaviour of industrial UF resins modified by low level of melamine was followed by TG-DTA technique on the labsysTM instrument Setaram together with the 13C NMR analysis of resin structure and testing boards in current production at Estonian particleboard factory Pa¨rnu Plaaditehas AS. DTA curve of UF resin which has been cocondensed during synthesis with even low level of melamine shows the shift of condensation exotherm and water evaporation endotherm to considerable higher temperatures. The effect of melamine monomer introduced to UF resin just before curing was compared. The effect of addition of urea as formaldehyde scavenger was studied.
Kadri Siimer, Tiit Kaljuvee, Tönis Pehk, Ilmar Lasn, J Therm Anal Calorim (2010) 99, 755–762

A1403 – Thermal stability of new complexes bearing both acrylate and aliphatic amine as ligands

This paper reports the investigation of the thermal stability of a series of new complexes with mixed ligands of the type [M(en)(C3H3O2)2]×nH2O ((1) M=Ni, n=2; (2) M=Cu, n=0; (3) M=Zn, n=2; en=ethylenediamine and (C3H3O2)=acrylate anion). The thermal behaviour steps were investigated in a nitrogen flow. The thermal transformations are complex processes according to TG and DTA curves including dehydration, ethylenediamine elimination as well as acrylate thermolysis. The final products of decomposition are the most stable metal oxides except for complex (2) that generates metallic copper.
Mihaela Badea, Rodica Olar, Dana Marinescu, Gina Vasile, Journal of Thermal Analysis and Calorimetry, Vol. 92 (2008) 1, 205–208

A1361 – A kinetic analysis of thermal decomposition of polyaniline/ZrO2 composite

Synthesis, characterization and thermal analysis of polyaniline (PANI)/ZrO2 composite and PANI was reported in our early work. In this present, the kinetic analysis of decomposition process for these two materials was performed under non-isothermal conditions. The activation energies were calculated through Friedman and Ozawa–Flynn–Wall methods, and the possible kinetic model functions have been estimated through the multiple linear regression method. The results show that the kinetic models for the decomposition process of PANI/ZrO2 composite and PANI are all D3, and the corresponding function is f(?)=1.5(1–?)2/3[1–(1–?)1/3]–1. The correlated kinetic parameters are Ea=112.7±9.2 kJ mol–1, lnA=13.9 and Ea=81.8±5.6 kJ mol–1, lnA=8.8 for PANI/ZrO2 composite and PANI, respectively.
S.-X. Wang, Z.-C. Tan, Y.-S. Li, L.-X. Sun, Y. Li, Journal of Thermal Analysis and Calorimetry, Vol. 92 (2008) 2, 483–487

A1358 – TG-DTA study of melamine-urea-formaldehyde resins

The thermal behaviour of MUF resins from different suppliers with different content of melamine was studied, along with the 13C NMR spectroscopic analysis of resin structure and the testing of particleboards in current production at Estonian PB factory P¬rnu Plaaditehas AS. The chemical structure of resins from DMSO-d6 solutions was analysed by 13C NMR spectroscopy on a Bruker AMX500 NMR spectrometer. The melamine level in different MUF resins is compared by the ratios of carbonyl carbon of urea and triazine carbon of melamine in 13C NMR spectra. Curing behaviour of MUF resins was studied by simultaneous TG-DTA techniques on the Labsysä instrument Setaram. The shape of DTA curves characterisises the resin synthesis procedure by the extent of polymerisation of UF and MF components and is in accordance with structural data.
K. Siimer, P. Christjanson, T. Kaljuvee, T. Pehk, I. Lasn and I. Saks, Journal of Thermal Analysis and Calorimetry, Vol. 92 (2008) 1, 19–27

A1357 – Effect of alkylresorcinols on curing behaviour of phenol-formaldehyde resol resin

Thermal behaviour of cure-accelerated phenol-formaldehyde (PF) resins was studied using the addition of commercial mixture of water soluble oil shale alkylresorcinols (AR) to PF resin, 5-MR being as model compound. The acceleration effect of AR is based on the promotion of condensation of resin methylol groups and subsequent reaction of released formaldehyde with AR. Commercial PF resins SF -3013VL and SF -3014 from the Estonian factory VKG Resins have been used. The chemical structure of resins was characterised by 13C NMR spectroscopy. TG-DTA analysis was carried out using labsysTM instrument Setaram. By TG-DTA measurements, the shift of exothermic and endothermic peaks and the changes of mass loss rate in the ranges of 1.5–10 g AR/100 g PF resin were studied. The effect of AR on the curing behaviour of PF resins was also followed by gel time. Testing of the plywood when using PF resin with 5 mass% of AR shows that the press time could be reduced by about 15%.
K. Siimer, T. Kaljuvee, P. Christjanson, T. Pehk and I. Saks, Journal of Thermal Analysis and Calorimetry, Vol. 91 (2008) 2, 365–373

A1348 – Vinyl acetate/butyl acrylate copolymers-part 1: mechanism of degradation

This work deals with the mechanism of degradation of vinyl acetate/butyl acrylate (VA/BA) copolymers varying the VA/BA ratio. It is shown that for higher VA contents, the degradation starts at comparatively lower temperature but a more thermally stable material is formed. The mechanism of degradation of VA/BA copolymers is then compared with PVA and PBA homopolymers. It appears that the fractions of degradation (gases, high boiling products and residue) for VA/BA copolymer is a combination of those of polyvinyl acetate (PVA) and polybutyl acrylate (PBA). However, a slight stabilisation occurs when VA/BA are co-polymerised together compared with a VA and BA combination. Moreover, the comparison of the thermo-oxidative degradation with the pyrolysis demonstrates that the mechanisms are similar at least up to 450°C.
S. Duquesne, J. Lefebvre, R. Delobel, G. Camino, M. LeBras, G. Seeley, Polymer Degradation and Stability 83 (2004) 19-28

A1316 – 1,4-Di(1,2,3,4-tetrazol-2-yl)butane as a precursor of new 2D and 3D coordination polymers of Cu(II)

A series of new coordination polymers of Cu(II) have been prepared in a reaction between copper(II) perchlorate or tetrafluoroborate salt and a novel ligand 1,4-di(1,2,3,4-tetrazol-2-yl)butane (bbtz). The compounds were characterised by an elemental analysis, TG measurements, IR, EPR and UV-Vis spectroscopy. Crystal structures of bbtz and five complexes of Cu(II) were determined by a single crystal X-ray diffraction measurement performed at 100 K. The composition and architecture of the obtained complexes strongly depend on the reaction conditions especially on the kind of solvent. Investigated complexes are composed of polymeric macrocations and non-coordinated anions. In all cases the bbtz molecules act as the bidentate ligand coordinated to metal(II) ions via N4, N4' nitrogen atoms from tetrazole rings. The complexes {[Cu(bbtz)2(MeOH)2]X2} (X=ClO4- , BF4- ) crystallise from methanol as 2D coordination polymers. In these compounds central metal ions are coplanar linked by molecules of bbtz and a coordination sphere is completed by axially coordinated solvent molecules. The complexes {[Cu(bbtz)3]X2} (X=ClO4- , BF4- ) were synthesised in EtOH/H2O solvent system and posses a common network topology. In this group of complexes each central atom is linked by ligand molecules to six other in plane arranged central atoms resulting in 2D networks. Reactions between Cu(II) salts and bbtz performed in absolute ethanol resulted in the formation of the next type of product. In {[Cu(bbtz)3](ClO4)2 . 2EtOH} neighboured copper(II) ions are linked by ligand molecules in the three directions what leads to the formation of 3D net. A crystal of this complex is composed of two mutually interpenetrated 3D networks.
R. Bronisz, Inorganica Chimica Acta 357 (2004) 396-404

A1314 – Complex formation and degradation in poly(acrylonitrile-co-vinyl acetate) containing metal nitrates

Polymers containing metal-nitrates have been proposed as advantageous precursors for high temperature superconductors such as yttriumbarium- copper-oxide (YBCO). The advantage lies in using conventional polymer processing such as fiber spinning or microlithography before pyrolysis. This research investigated complex formation and degradation in poly(acrylonitrile-co-vinyl acetate) (P(AN-VA)) containing either yttrium nitrate (YN) or barium nitrate (BaN) and follows a similar investigation for copper nitrate. Complex formation was observed in P(AN-VA)/YN but not in P(AN-VA)/BaN. The exothermic nitrate degradation below the P(AN-VA)) cyclization temperature involved the release of NO3, a reaction with the nitrile group that disrupted cyclization, and, for BaN, P(AN-VA) degradation. For a P(ANVA)/ nitrate ratio of 2/1 there was no cyclization and the degradation temperature was reduced by about 200°C. The pyrolysis of P(ANVA)/ BaN yielded largely BaCO3, which is likely to impede the formation of YBCO.
M.S. Silverstein, Y. Najary, Y. Lumelsky, I. von Lampe, G.S. Grader, G.E. Shter, Polymer 45 (2004) 937-947

A1300 – Intumescent paints: fire protective coatings for metallic substrates

This study investigates the role of the binder in an intumescent paint. In fact, it is generally known that acid source, carbon source and blowing agent are the main ingredients of such a paint. However, since the binder may react with these ingredients, it is also a very important component of an intumescent paint. To begin with, the effect of the nature of the monomers composing the polymeric binder, on the chemical reactivity between the binder and the intumescent additives is investigated using thermogravimetric analysis, solid state NMR and FTIR analysis. It is found that the thermal stability increases when the copolymer is based on substituted styrene. Subsequently, the efficiency of protective behaviour of the intumescent coatings is evaluated varying the nature of the binder resin. It is found that the thermal insulation is greatly improved when using a mixture of a linear copolymer presenting a good reactivity with the acid source and a cross-linked copolymer as binder in the intumescent paint.
S. Duquesne, S. Magnet, C. Jama, R. Delobel, Surface and Coatings Technology 180-181 (2004) 302-307

A1299 – Effect of different thermal treatments on the self-assembled nanostructures of a styrene-butadiene-styrene star block copolymer

Time evolution of the lamellar self-assembling behaviour of a commercial styrene-butadiene-styrene (SBS) star block copolymer, submitted to two different thermal treatments under thermooxidative degradation conditions, is reported. A microphase separation process, leading to partially oxidized butadiene and polystyrene-rich copolymer, occurs in the block copolymer exposed at 150°C in air. The timing of the microphase separation depends upon previous thermal treatment, however, when the microphase separation takes place, the same evolution can be observed independently of the thermal treatment. The evolution of the morphologies has been observed by Tapping Mode Atomic Force Microscopy (TM-AFM). The evolution of the oxidation reactions and their influence on the molecular mass has been followed by thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). Fourier transform infrared (FTIR) spectroscopy has been used to analyse the chemical changes involved in the nano/microphase separation process.
E. Serrano, A. Zubeldia, M. Larranaga, P. Remiro, I. Mondragon, Polymer Degradation and Stability 83 (2004) 495-507

A1297 – In situ polymerization of interleaved monomers: a comparative study between hydrotalcite and hydrocalumite host structures

Vinyl benzene sulfonate (styrene sulfonate, VBS) and polystyrene sulfonate (PSS) were incorporated into Layered Double Hydroxides (LDH) by templating reaction. The two host structures investigated are Zn2Al(OH)6Cl. nH2O of hydrotalcite-type and Ca2Al(OH)6Cl.nH2O of hydrocalumite-type. The electrostatic binding between sulfonate groups of VBS and the inner-surface of LDH host structure evaluated by 13C CP-MAS NMR spectroscopy causes some shifts in the resonance lines. In situ polymerization of VBS molecules between LDH sheets is reached after soft heat treatment. Its completion requires a good matching between the layer charge density and the projected surface area of the guest molecule achieved by a ratio M2+ to M3+ of 2. For the pristine material, the change from Oh to Td aluminum site appears to be a collective process for the hydrocalumite, whereas it is more progressive for the hydrotalcite-type material. For the corresponding organoceramics, the site conversion before the breakdown of the lamellar structure is substantially reduced, and especially for PSS/LDH nanocomposite obtained by in situ polymerization. CaAl-VBS intercalate crystallizes in C2/c space group inducing a bilayer arrangement of VBS anions in the interlamellar space. Furthermore, distances between anionic sites allow an in situ zig-zag polymerization of syndiotactic type along the a axis. For hydrotalcite, the short Al3+-Al3+ distance at a?3 prevents also the formation of PSS other than syndiotactic. The thermal stability of the nanocomposites depends on the host structure but also on the synthesis pathway.
L. Vieille, E.M. Moujahid, C. Taviot-Guého, J. Cellier, J-P. Besse, F. Leroux, Journal of Physics and Chemistry of Solids 65 (2004) 385-393

A1291 – The effects of humidity on gas transport properties of sulfonated copolyimides

Hydrogen, oxygen and carbon dioxide transport properties are studied at various hydration rates for a large series of sulfonated copolyimides synthesized with a naphthalenic dianhydride, a sulfonated diamine and various non-sulfonated diamines. For all copolymers, the gas permeability coefficient decreases when the relative humidity increases in the range 0-70% and an increase of gas flux is observed at high hydration. The magnitude of the permeability coefficient variation depends on the gas polarity and on the copolymer composition. A detailed analysis of the gas transport properties at anhydrous state and of the water sorption mechanism as a function of the copolymers composition allows to explain all the gas permeability variations as a function of hydration.
F. Piroux, E. Espuche, R. Mercier, Journal of Membrane Science 232 (2004) 115-122

A1245 – Thermogravimetric kinetic model of the pyrolysis and combustion of an ethylene-vinyl acetate copolymer refuse

A kinetic study of the pyrolysis as well as the combustion of EVA copolymer refuse originating from the footwear industry was carried out by thermogravimetric analysis. Different runs were performed at heating rates between 5-20°C min-1 and atmospheres with different percentages of oxygen: 0, 10 and 20% (v/v). Pyrolysis and combustion processes can be simulated by two series reactions. The results obtained indicate that the second reaction begins when the first one is almost finished which implies that a good correlation is also obtained by simulation of the thermal decomposition of two independent fractions.
A.N. Garcia, R. Font, Fuel 83 (2004) 1165-1173

A1241 – Interaction between chitosan and alkyl beta-D-glucopyranoside and its effect on their antimicrobial activity

The interactions between chitosan and nonionic surfactant-alkyl beta-D-glucopyranoside (AG) in solid state and aqueous solution have been investigated by using FT-IR spectroscopy, thermal analysis, powder X-ray diffraction, viscometry and gel permeation chromatography (GPC). The FT-IR spectra demonstrated that interaction between -NH3+ and -OH groups of chitosan and -OH groups of AG occurred by electrostatic force or hydrogen bonding. Results of thermal analysis and X-ray diffraction indicated that higher orders of structure such as aggregation chain conformation etc and crystallinity of chitosan seemed changed by addition of AG. Results of viscometry and GPC showed that, in aqueous solution, AG most likely made the chitosan chains extend and disaggregate. Interestingly, antimicrobial activity of the dynamic association (mixed solution of chitosan and AG) was much higher than that of chitosan and AG separately. Minimum inhibition concentration (MIC) of dynamic association was 2-8 times lower than that of chitosan alone, and it could kill more microorganisms in a shorter time. The reasons for the enhanced antimicrobial activity of the dynamic association mixture are carefully discussed in terms of the interaction between chitosan and AG.
H. Liu, Y. Du, X. Wang, Y. Hu, J.F. Kennedy, Carbohydrate Polymers 56 (2004) 243-250

A1240 – Biocomposites based on plasticized starch: thermal and mechanical behaviours

The paper is focusses on the study of the thermal and mechanical behaviour of reinforced agro-materials. Various formulations based on plasticized starch matrix have been carried out, varying matrix formulation, filler content, fibres length and nature. Cellulose and lignocellulose fibres, which show unequal surface tensions, have been tested. After extrusion and injection moulding, the properties of these wheat starch-based biocomposites are analysed. Mechanical properties (tensile tests), thermo-mechanical properties (DMTA) and thermal degradation (TGA) are analysed. DMTA analysis shows important variations of main relaxation temperature, which can be linked both, to interactions resulting in a decrease of starch chain mobility and to a regular reinforcing effect. These results are consistent with the static mechanical behaviour, which vary according to the filler content (up to 30 wt%), fibre nature (cellulose vs. lignocellulose) and fibre length (from 60 µm to 1 mm). Besides, we have shown that the addition of cellulose fillers improves the thermal resistance of these biocomposites. Finally, we have tested the impact of the addition of biodegradable polyesters into these composites without significant effect on the postprocessing stability.
L. Averous, N. Boquillon, Carbohydrate Polymers 56 (2004) 111-122

A1237 – One-pot synthesis of dimethyl carbonate and glycols from supercritical CO2, ethylene oxide or propylene oxide, and methanol

Direct syntheses of dimethyl carbonate (DMC) and glycols (GCs) from supercritical (SC) CO2, epoxides (propylene oxide or ethylene oxide), and methanol were carried out using different solid catalysts prepared in this work. The effects of various conditions, such as reaction temperature, pressure, reaction time, molar ratio of the reactants, and the properties of the supports of the catalysts, on the conversion and yields were investigated. KI supported on ZnO (KI/ZnO) and KI/ZnO with K2CO3 (K2CO3-KI/ZnO) were very active and selective for the reaction after calcinations. At 423 K, all epoxides were reacted in 4 h; the yields of DMC and GC exceeded 57% when ethylene oxide was used, and the amount of the by-products was very small (0.2%). The K2CO3-KI/ZnO could be reused four times, and the yield and selectivity remained unchanged. No leaching of the active catalyst components was detectable at the experimental conditions, probably because the reaction was conducted in homogenous supercritical conditions, where non-corrosive CO2 was the main component in the reaction mixture. A mechanism of the reaction was proposed on the basis of the experimental results. This route may be an effective way to produce DMC and glycols in large-scale because it is simple, the raw materials are cheap, and the amount of by-products is very small.
Y. Chang, T. Jiang, B. Han, Z. Liu, W. Wu, L. Gao, J. Li, H. Gao, G. Zhao, J. Huang, Applied Catalysis A: General 263 (2004) 179-186

A1219 – Development of EVOH-kaolinite nanocomposites

This paper reports on a novel route to develop EVOH-kaolinite nanocomposites by a melt intercalation process and on some relevant nanocomposite properties as a function of composition. The kaolinite clay used is a very cheap raw material of the tile industry and as such needed to be refined and chemically modified prior to the melt intercalation step. The modification was carried out with dimethyl-sulfoxide, methanol and octadecylamine in order to increase the basal plane distance of the original clay by a factor of more than three. Melt blended nanocomposites were characterized by WAXS, TEM, DSC, TGA and oxygen transmission rate. From the early results, partial exfoliation and intercalation of the clay platelets was the dominant morphology attained. An increase in thermal resistance, glass transition temperature, crystallinity and barrier properties to oxygen were also observed for mass clay loadings below 8%.
L. Cabedo, E. Giménez, J.M. Lagaron, R. Gavara, J.J. Saura, Polymer 45 (2004) 5233-5238

A1206 – Vinyl acetate/butyl acrylate copolymers Part 2: Fire retardancy using phosphorus-containing additives and monomers

This study deals with the fire retardant performance of vinyl acetate (VA)/butyl acrylate (BA) copolymers using phosphorus compounds as additive or as co-monomer. First, VA/BA copolymer has been mixed with phosphorus additives from various sources: red phosphorus, organo-phosphates, organo-phosphonate, inorganic phosphate and an intumescent system (ammonium polyphosphate and pentaerythritol). The incorporation of 5 wt.-% phosphorus leads to VA/BA copolymers with improved fire properties whatever the source of phosphorus used. The best performance is achieved with the intumescent system. Second, VA and BA monomers have been copolymerised with phosphorus monomers (phosphate and phosphonate). Both systems present fire retardancy of interest. The better performance is achieved using phosphonate. Both systems are assumed to work in the condensed phase.
S. Duquesne, J. Lefebvre, G. Seeley, G. Camino, R. Delobel, M. Le Bras, Polymer Degradation and Stability 85 (2004) 883-892

A1203 – Mechanism of co-pyrolysis of coal-tar pitch with polyvinylpyridine

Co-pyrolysis of coal-tar pitch and poly(4-vinylpyridine) cross-linked with 25 wt.% of divinylbenzene (PVP) or the oxidized form of the co-polymer (PVPox) was studied as a possible way of manufacturing of carbonaceous materials enriched in nitrogen. Interactions of pitch with polymers were evaluated using thermogravimetry, elemental analysis, infrared spectroscopy in the DRIFT mode, X-ray photoelectron spectroscopy and optical microscopy. The tendency to depolymerization of PVP on heat treatment results in a little effect of the polymer on the thermal behaviour of the blend. PVPox is a stronger modifier of pitch carbonization behaviour and much more efficient source of nitrogen in the co-pyrolysis. The principal chemical interaction between pitch and PVPox is the dehydrogenative polymerization of pitch constituents induced by polymer oxygen groups. The oxidation of PVP does not affect the nitrogen functionalities transformation on pyrolysis.
B. Grzyb, J. Machnikowski, J.V. Weber, J. Anal. Appl. Pyrolysis 72 (2004) 121-130

A1200 – Bioengineering polyfunctional copolymers. VII. Synthesis and characterization of copolymers of p-vinylphenyl boronic acid with maleic and citraconic anhydrides and their self-assembled macrobranched supramolecular architectures

New boron-containing anion active functional copolymers are synthesized by complex-radical copolymerization of 4-vinylphenyl boronic acid and maleic or citraconic anhydrides with 2,2'-azobisisobutyronitrile as an initiator in DMF at 70°C under nitrogen atmosphere. Macrobranched derivatives of these copolymers are synthesized by the partial grafting with alpha-hydroxy,omega-methoxy-poly(ethylene oxide) and incorporation with poly(ethylene imine). Effect of H-bonding on the formation of self-assembled supramolecular macrocomplexes with higher crystallinity and thermal stability was observed and confirmed by FTIR, and 1H(13C DEPT-135( NMR spectroscopy, X-ray diffraction, DSC and TGA analyses of monomer, homopolymer, copolymer and grafted copolymer systems. Observed water solubility, biocompatibility and high density of acid groups in macromolecules allow these anion active B-containing copolymer systems for the developing new generation of effective antitumor agents, polymeric carriers for enzymes, gene delivery and boron neutron capture therapy.
G. Kahraman, O. Beskardes, Z.M.O. Rzaev, E. Piskin, Polymer 45 (2004) 5813-5828

A1193 – Adsorption of concanavalin A on the well-characterized macroporous chitosan and chitin membranes

Macroporous chitosan membranes were prepared by solvent evaporation method in the presence of silica particles which were used as a porogen. These membranes were cross-linked under alkaline conditions, using epichlorohydrin as the cross-linking agent. The macroporous chitin membranes were obtained by acetylating the chitosan membranes with acetic anhydride in methanol. SEM photographs showed a homogeneous pore distribution throughout the membranes with 16.1-17.9 µm average pore sizes. The adsorption and desorption properties of concanavalin A (Con A) on the membranes were investigated by fluorescence spectroscopy. The equilibrium adsorption time was found to be 2 h during the static adsorption experiments. The calculated adsorption rates for chitosan and chitin membranes were rad = 0.613 and 0.541 mg Con A/g dry membrane-minute, respectively at the initial protein concentration of 1.0 mg ml-1. The adsorption isotherms represented a monolayer of Con A at 0.5-2.0 mg ml-1 concentration range. The adsorption studies which were carried out at flow rate of 2 ml min-1 showed that adsorbed quantities of Con A decreased markedly in the presence of flow, and they were similar ( 14-15 mg Con A/g dry membrane) for both chitosan and chitin membranes. The fluorescence studies verified the absence of denaturation in the recovered Con A.
M. Gümüsderelioglu, P. Agi, Reactive & Functional Polymers 61 (2004) 211-220

A1140 – Semivolatile and volatile compounds in combustion of polyethylene

The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that alpha,omega-olefins, alpha-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
R. Font, I. Aracil, A. Fullana, J.A. Conesa, Chemosphere 57 (2004) 615-627

A1135 – Catalytic degradation of expandable polystyrene waste (EPSW) over mordenite and modified mordenites

The performance of the several different modified mordenite zeolites in the degradation of expandable polystyrene waste (EPSW) was investigated in this study. The composition of the degradation products, especially the liquid fraction was compared to understand the role of H-mordenite and the effect of its modification through framework dealumination and metal impregnation. The degradation was carried out in a batch reactor at 360 and 400°C. The dealuminated mordenite with SiO2/Al2O3 ratio of 86 showed enhanced styrene/styrene dimer and styrene/ethylbenzene molar ratios at lower (360°C) and higher (400°C) temperature, respectively. This was attributed to the intermediate acid strength distribution generated on removal of framework aluminum by acid leaching. Modification of H-mordenite by metal impregnation substantially changed the acidic and catalytic properties in polystyrene degradation. The 0.64 wt.% phosphorous loading on H-mordenite showed improved EPSW conversion, styrene yield and SM/EB molar ratio at 400°C. The 0.32 wt.% phosphorous loading facilitated the improvement in SM/EB molar ratio with higher styrene selectivity than thermal degradation at 360°C.
V.R. Chumbhale, J-S. Kim, S-B. Lee, M-J. Choi, Journal of Molecular Catalysis A: Chemical 222 (2004) 133-141

A1133 – Thermal evolution and crystal structure of a polymeric complex: Pb3(3,5-dicarboxylatopyrazole)2(NO3)2.4H2O

Pb3(pdc)2(NO3)2.4H2O (pdcZdeprotonated 3,5-pyrazole-dicarboxylic acid) has been prepared and is stable up to 100°C. Above this temperature the hydration water loss is noted before 200°C. Until 360°C the material becomes amorphous during the decomposition of the organic ligand; at 365°C crystallization occurs and can be formulated as a mixture of PbO and lead oxynitrates, which subsequently recombines between 395 and 445°C into Pb6O5(NO3)2 over 570°C, the residue is essentially red PbO. Pb3(pdc)2(NO3)2.4H2O crystallizes in the monoclinic system, a=20.3688(7), b=6.4232(4), and c=18.1059(7) Å , beta=118.44(1)°, space group C2/c, Z=4. The structure displays an original polymeric coordination complex where the lead(II) is found in two different environments: (-Pb2-pdc-)N chains are identified along the [001] direction, while inter chains Pb2-pdc and Pb1-pdc links are bridging these chains in a layer like tridimensionnal structure, where pdc is acting as an hexadentate ligand.
F. Bentiss, P. Roussel, M. Drache, P. Conflant, M. Lagrenée, J.P. Wignacourt, Journal of Molecular Structure 707 (2004) 63-68

A1131 – Gas transport properties of starch based films

This paper deals with gas transport properties of starch based films. Oxygen permeability of plasticised starch, octanoated starch, starch- EVOH blend, and PE-starch multilayer was first studied. The best gas barrier properties of starch based films are generally obtained for low water and plasticiser contents. It was then shown that the interesting low permeability of these systems is due to the low solubility of gases. These results broaden the scope of starch gas transport properties, which are generally discussed in terms of mobility (i.e. gas diffusivity).
P. Dole, C. Joly, E. Espuche, I. Alric, N. Gontard, Carbohydrate Polymers 58 (2004) 335-343

A1127 – Preparation of an anionicazo pigment-pillared layered double hydroxide and the thermo- and photostability of the resulting intercalated material

A large anionic pigment has been intercalated into a layered double hydroxide (LDH) host by ion-exchange of an Mg/Al LDHnitrate precursor with a solution of C.I. Pigment Red 48:2 (the calcium salt of 4-((5-chloro-4-methyl-2-sulfophenyl)azo)-3-hydroxy- 2-naphthalene-carboxylic acid), in ethane-1,2-diol. After intercalation of the pigment, the interlayer distance in the LDH increases from 0.86 to 1.72 nm. Infrared spectra and TG-DTA curves reveal the presence of a complex system of supramolecular host-guest interactions. The UV-visible diffuse reflectance spectra of C.I. Pigment Red 48:2 show marked changes after heating at 200°C and above, whereas there are no significant changes in the spectra of the intercalated pigment after heating at temperatures up to 300°C, showing that the thermostability is markedly enhanced by intercalation in the LDH host. The pigment-intercalated LDHs exhibits much higher photostability to UV light than the pristine pigment, in the case of both the pure solids and their composites with polypropylene, as shown by measurement of CIE 1976 L*a*b* color difference (?E) values.
S. Guo, D. Li, W. Zhang, M. Pu, D.G. Evans, X. Duan, Journal of Solid State Chemistry 177 (2004) 4597-4604

A1113 – Influence of preparation conditions on thermal properties of lanthanide benzenepolycarboxylates

Properties of lanthanide 1,2,4-benzenetricarboxylates and lanthanide 1,2,4,5-benzenetetracarboxylates obtained by a classical synthesis method and under hydrothermal conditions were compared. Solid 1,2,4-benzenetricarboxylates and 1,2,4,5-benzenetetracarboxylates of cerium, neodymium and erbium were prepared by a classical precipitation method. The same lanthanide compounds were obtained also from hydrothermal reaction. All obtained products were examined by elemental analysis. General formulae of complexes were: Ln(1,2,4-btc).xH2O and Ln4(1,2,4,5-btec)3.yH2O. The thermal analysis shows that hydrothermal conditions cause the coordination of less number of water molecules to complex molecule. Because lanthanide ions exhibit the most often the coordination number equal 8 or 9 one can conclude that the coordination ability of carboxylic groups under hydrothermal conditions is different from that under mild ones. Probably, in hydrothermal conditions the carboxylic groups of 1,2,4-benzenetricarboxylate ions are able to form more coordination bonds with lanthanide ions than under normal pressure.
M. Iwan, R. Lyszczek, A. Ostasz and Z. Rzaczynska, Journal of Thermal Analysis and Calorimetry 88 (2007) 157-162

A1107 – Role of montmorillonite in flame retardancy of ethylene-vinyl acetate copolymer

The effects of non-treated (MMT), organophilic (OMM), and olefin/silicone polymer intercalated (IMM) montmorillonites on the thermal stability of ethylene-vinyl acetate copolymer (EVA) and on the flammability of magnesium hydroxide filled EVA were studied. The influence of various treatments on the delamination of montmorillonites in EVA was detected by rheological measurements and by Raman microscopy. The latter was a unique method for rapid detection of the dispersion also in highly filled EVA. Enhancement of thermo-oxidative stability of EVA and flame-retarded EVA could be observed by thermal analysis in the presence of variously treated montmorillonites. The flame-retardant ef- ficiency of magnesium hydroxide was improved by simultaneous application of MMT and IMM. The increased performance of magnesium hydroxide was explained by the rheological effect of the IMM, catalytic effect of MMT and chemical interactions of montmorillonites with the metal hydroxide.
A. Szép, A. Szabo, N. Toth, P. Anna, G. Marosi, Polymer Degradation and Stability 91 (2006) 593-599

A1106 – Synthesis of phosphorus-based flame retardant systems and their use in an epoxy resin

Methods are proposed to synthesize efficient organophosphorous compounds and combine them with montmorillonite nanoparticles. The chemical-physical structure and mechanism of action of the new systems were studied in epoxy resin. Best results were achieved using the fully phosphorylated calixresorcinarene derivative: the heat release rate peak could be decreased by 61% and the LOI value was increased from 21 to 28. The salt form of additives in case of phosphorylated phloroglucine derivatives was not advantageous in epoxy resin, because the additives could not participate in the crosslinking process effectively due to their inhomogenous distribution in the matrix. The incorporation of the nanoparticles did not create the desired flame retardant effect which can be explained by the increased heat conductivity and lower mobility of the nanoparticles due to the crosslinked structure.
A. Toldy, N. Toth, P. Anna, G. Marosi, Polymer Degradation and Stability 91 (2006) 585-592

A1104 – Soluble PPVs with few structural defects: Synthesis and characterization

A series of 2,5-dialkoxy poly(1,4-phenylenevinylene) derivatives with different alkoxy side-chain lengths were synthesized via a modified Gilch polymerization. Prolonged reaction and additional base treatment at elevated temperature lead to PPVs with very low chlorine content and few structural defects. The polymers were synthesized in satisfactory yields (45-65%) and had number-average molecular weights of 10,000- 14,000. Structural characterization was accomplished by FT-IR, 1H-NMR, 13C-NMR spectroscopy and by elemental analysis. All polymers are amorphous, stable up to 300°C and soluble in both chloroform and tetrahydrofuran. The UV-Vis absorption and emission in the solid state are in the range 496-507 nm and 578-629 nm, respectively. Band gaps calculated from the UV-Vis spectra edge are in the range 2.06-2.11 eV. Lightemitting diodes (LEDs) based on these polymers were fabricated and characterized by current-voltage measurements.
H. Trad, M. Majdoub, J. Davenas, Materials Science and Engineering C 26 (2006) 334 - 339

A1102 – Synthesis and characterization of copolymers based on styrene and partially fluorinated acrylates

Copolymers of styrene and fluorinated acrylate monomers with F-octylalkyl, F(CF2)8(CH2)n' side groups were prepared by free radical polymerization. Thermal behaviour of the resulting polymers was investigated by DSC and TGA. Even if at the macroscopic scale the polymers surfaces are homogeneous and clear, the analysis indicates that all samples exhibit two glass transitions temperatures. This discontinuity may be regarded as an indication for microphase separation of fluorine-rich and polystyrene-rich microphases. Water and hexadecane contact angles measurements show that these polymers are quite surface active in the solid state. Surface and bulk organizations were investigated by XPS analysis. A strong correlation between bulk organization and surface properties of the polymers could be established. Preferential adsorption of fluorinated segments at the material surface were more pronounced than expected in the bulk.
S. Saïdi, F. Guittard, C. Guimon, S. Géribaldi, European Polymer Journal 42 (2006) 702-710

A1101 – Study of free-radical copolymerization of itaconic acid/2-acrylamido-2-methyl-1-propanesulfonic acid and their metal chelates

The monomer reactivity ratios for itaconic acid (IA)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in N,Ndimethylformamide solution using the benzoyl peroxide (Bz2O2) as an initiator with different monomer-to-monomer ratios in the feed were investigated by studying the resulting copolymer composition via elemental analysis. Composition results were summarized and various methods were employed to estimate the monomer reactivity ratios including the use of the Error-in Variables-Model method using a computer program, RREVM. The estimates of the reactivity ratios from the EVM method are found to be rIA = 0.4636 and rAMPS = 0.0357. These values suggest that IA is more reactive than AMPS and the copolymer will be richer in IA units. Cu(II) and Ni(II) chelates of the copolymers were prepared and the formation constants of each complex were determined by the mole-ratio method using the UV-vis spectroscopy. UV-vis studies showed that the complex formation tendency increased in the followed order: Cu(II) > Ni(II). The copolymers and their metal chelates were characterized by FT-IR spectra and SEM analysis. Also, thermal stabilities of the copolymers and their metal chelates were investigated using TGA and DSC analysis.
R. Coskun, C. Soykan, A. Delibas, European Polymer Journal 42 (2006) 625-637

A1074 – Improvement of mechanical properties of poly(DL-lactide) films by blending of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(DL-lactide) (PDLLA) were blended at different ratios in an attempt to form a biomaterial with suitable properties for nerve regeneration. FT-IR and X-ray analysis showed that the blending of the PDLLA component did not alter the helical structure of PHBHHx, but did lead to a reduction of crystallinity. Differential scanning calorimetry (DSC) analysis indicated that the two polymers were immiscible in the melted state. The mechanical properties of certain composite films were more desirable than those of unblended PDLLA films. Blends consisting of PDLLA and PHBHHx at ratios of 2:1 and 1:2 exhibited a lower elastic modulus and a higher elongation at break compared to unblended PDLLA. ELISA results indicated that the amount of fibronectin adsorbed on composite films was much higher than the amount adsorbed on PDLLA film. The results of this study demonstrate the feasibility of using PDLLA/PHBHHx blended materials for biomedical applications.
Y. Gao, L. Kong, L. Zhang, Y. Gong, G. Chen, N. Zhao, X. Zhang, European Polymer Journal 42 (2006) 764-775

A1069 – Adsorption of copper(II), nickel(II) and cobalt(II) ions from aqueous solution by methacrylic acid/acrylamide monomer mixture grafted poly(ethylene terephthalate) fiber

A reactively fibrous adsorbent was prepared by graft copolymerization of methacrylic acid (MAA)/acrylamide (AAm) monomer mixture onto poly(ethylene terephthalate) (PET) fiber and characterized by Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The adsorption of Cu(II), Ni(II) and Co(II) ions from aqueous solution by the reactive fiber was examined by batch equilibration technique. The effects of graft yield, pH, adsorption time, initial ion concentrations and adsorption temperature on the adsorption amount of ions were investigated. The reusability and selectivity of the reactive fiber were also investigated. The results showed that the adsorption of the metal ions followed the following order Cu(II) > Ni(II) > Co(II). The adsorption amounts of ions increased with the increase of grafting yield, shaking time, and pH of the medium. The adsorption amounts of Ni(II) and Co(II) ions increased but Cu(II) ions were not affected with increasing adsorption temperature. It was found that the adsorption isotherm of the ions fitted Langmuir-type isotherms. From the Langmuir equation the adsorption capacity was found as 31.25 mg/g fiber for Cu(II), 43.48 mg/g fiber for Ni(II), and 27.17 mg/g fiber for Co(II), respectively. The competitive adsorption tests verified that this reactive fiber possessed good adsorption selectivity for Cu(II) with the coexistence of Co(II) and Ni(II). It can be regenerated by 1M HNO3 without losing their activity.
R. Coskun, C. Soykan, M. Saçak, Separation and Purification Technology 49 (2006) 107-114

A1065 – The influence of water on the intercalation of epoxy monomers in Na-montmorillonite

The intercalation of a typical UV-curable epoxy monomer (CE) in unmodified montmorillonite and the effect of hydration on the intercalation reaction are studied. Montmorillonite in the sodium form was submitted to a controlled hydration/dehydration cycle and the water content was checked by TGA/XRD analyses. The structure of the hydrated Na+-montmorillonite was determined from the values of the basal spacings and from the water content of the hydrated form: a coordination of four water molecules per Na ion was found, corresponding to a minimum of energy calculated by molecular dynamics simulation. When dispersing the clay in the CE monomer, the anhydrous Na+-montmorillonite did not show any intercalation; on the contrary the hydrated form showed an increase of the basal spacing. A possible mechanism to explain the intercalation of the CE monomers is proposed.
R. Bongiovanni, D. Mazza, S. Ronchetti, E.A. Turcato, Journal of Colloid and Interface Science 296 (2006) 515-519

A1047 – Mechanical properties of short flax fibre bundle/poly(epsilon-caprolactone) composites: Influence of matrix modification and fibre content

Composites were prepared by mixing biodegradable poly(epsilon-caprolactone) thermoplastic (PCL) with short flax fibre bundles. In order to improve fibre/matrix adhesion, poly(epsilon-caprolactone)-g-maleic anhydride copolymer (PCL-g-MA) compatibilizer was prepared in an internal mixer. The grafting reaction of maleic anhydride (MA) onto PCL polymer was carried out in presence of dicumyl peroxide as initiator. Mechanical properties were analysed as a function of compatibilizer concentration and fibre amount. In addition, thermal properties of flax/PCL and flax/PCL-g-MA composites were also examined by thermogravimetric (TG) analysis. Composites fabricated with flax fibre bundles and PCL-g-MA matrix showed the highest tensile and flexural strength. Scanning electron microscopy (SEM) of fractured surfaces confirmed the adhesion improvement between flax fibre bundles and PCL-g-MA matrix. Results obtained by thermogravimetric analysis showed that fibre addition and matrix modification slightly reduced the thermal stability of composites. The correlation between the experimental mechanical properties of short flax fibre bundle reinforced PCL composites with values calculated by various empirical models has also been analysed. For composites based on PCL-g-MA matrix, a good agreement was found between empirical model and experimental values for all fibre contents. However, for composites based on PCL matrix a good agreement only existed until 20 wt% flax fibre content, and beyond this value, experimental strength felt well below predictions.
A. Arbelaiz, B. Fernandez, A. Valea, I. Mondragon, Carbohydrate Polymers 64 (2006) 224-232

A1038 – Removal of some heavy metal ions from aqueous solution by adsorption using poly(ethylene terephthalate)-g-itaconic acid/acrylamide fiber

In this study, a new fibrous adsorbent was prepared by grafting itaconic acid/acrylamide (IA/AAm) comonomers onto poly(ethylene terephthalate) (PET) fibers for removal of Cu(II), Ni(II) and Co(II) metal ions from aqueous solution by using batch adsorption method. Effects of various parameters such as grafting yield, pH, shaking time, initial ion concentration and reaction temperature on the adsorption amount of ions onto reactive fibers were investigated. Moreover, the recyclability and selectivity of the reactive fibers were studied. The results show that the adsorption rate of metal ions followed as given in the order Ni(II) > Co(II) > Cu(II). The adsorption amount of ions increased with grafting yield, shaking time, adsorption temperature and pH of the medium. The maximum adsorption capacities of the reactive fiber for Cu(II), Ni(II) and Co(II) are 7.73, 13.79 and 14.81 mg/g, respectively. It was found that the adsorption isotherm of the ions fitted Langmuir-type isotherm. The activation energies of ions for adsorption were calculated as 17.32, 12.83 and 6.98 kJ/mol for Cu(II), Ni(II) and Co(II) ions, respectively. It was observed that the grafted fibers are stable and regenerable by acid without losing their activity and it is more selective for Cu(II) ions in the mixed solution of Cu-Ni, Cu-Co, and Cu-Ni-Co at pH 4. The grafted fibers and the metal loaded fibers were characterized by FTIR, TGA and SEM.
R. Coskun, C. Soykan, M. Saçak, Reactive & Functional Polymers 66 (2006) 599-608

A0998 – Structure of zinc hydroxy-terephthalate: Zn3(OH)4(C8H4O4)

The new lamellar hydroxide teraphthalate Zn3(OH)4(C8H4O4) was synthesised by the hydrothermal method and was characterized by single crystal X-ray diffraction, IR and UV spectroscopy and thermogravimetric analysis. The compound crystallises in the monoclinic space group C2/c with: a = 28.1000(5) Å, b = 6.3101(1) Å, c = 14.8359(3) Å, beta = 121.564(1)°, V = 2241.43 Å3, Dx = 2.538 g/cm3 and Z = 4. The zinc(II) atoms present four, five and six fold O-coordination. Due to the peculiar coordination of the zinc atoms, the inorganic layers form stairways running along [001]. These stairways-like layers are bridged by terephthalate (tp) groups leading to a 3D framework.
A. Carton, S. Abdelouhab, G. Renaudin, P. Rabu, M. François, Solid State Sciences 8 (2006) 958-963

A0997 – Resistance of polyimide/silica hybrid films to atomic oxygen attack

Polyimide/silica (PI/SiO2) hybrid films were prepared by the sol-gel process to improve the erosion resistance of polyimide materials in atomic oxygen (AO) environments. The p-aminophenyltrimethoxysilane (APTMOS) was used as a coupling agent to enhance the compatibility between the PI and SiO2. The effects of the APTMOS addition on the morphology and property of the PI/SiO2 hybrids were investigated using UV-Vis spectrophotometer, FTIR spectroscopy and SEM. The thermal properties and AO resistance of the PI/SiO2 hybrids were investigated by TGA and in the AO simulator, respectively. The results showed that the addition of APTMOS remarkably reduced the size of the silica particles, the PI/SiO2 hybrid films became transparent, and the compatibility between the PI and SiO2 and the thermal stability of the hybrids were significantly improved. During AO exposure, a passive inorganic SiO2 layer was formed on the PI/SiO2 hybrid films, causing the hybrid films to possess excellent AO resistance. The optical properties of the PI/SiO2 hybrid films were not altered after AO exposure.
S. Duo, M. Li, M. Zhu, Y. Zhou, Surface & Coatings Technology 200 (2006) 6671-6677

A0982 – Isoconversional kinetic analysis of stoichiometric and off-stoichiometric epoxy-amine cures

The curing reaction of stoichiometric and off-stoichiometric diglycidyl ether of bisphenol A (DGEBA) and 1,3-phenylene diamine (m-PDA) mixtures was studied by differential scanning calorimetry, thermogravimetric analysis and rheological measurements. In order to highlight the side reactions such as etherification and homopolymerization, the neat DGEBA and DGEBA/DMBA (N,N-dimethylbenzylamine) mixture were examined. The classical model-fitting and the advanced isoconversional methods were used to determine the activation energy of the different reactions. The advanced isoconversional method leads to a good agreement between isothermal, nonisothermal and rheological results. The effective activation energies of primary amine epoxy reaction, etherification and homopolymerization were estimated to about 55-60, 104 and 170 kJ mol-1, respectively.
N. Sbirrazzuoli, A. Mititelu-Mija, L. Vincent, C. Alzina, Thermochimica Acta 447 (2006) 167-177

A0939 – Effect of organic acids and nano-sized ceramic doping on PEO-based solid polymer electrolytes

Composite solid polymer electrolytes (CSPEs) consisting of polyethyleneoxide (PEO), LiClO4, organic acids (malonic, maleic, and carboxylic acids), and/or Al2O3 were prepared in acetonitrile. CSPEs were characterized by Brewster Angle Microscopy (BAM), thermal analysis, ac impedance, cyclic voltammetry, and tested for charge-discharge capacity with the Li or LiNi0.5Co0.5O2 electrodes coated on stainless steel (SS). The morphologies of the CSPE films were homogeneous and porous. The differential scanning calorimetric (DSC) results suggested that performance of the CSPE film was highly enhanced by the acid and inorganic additives. The composite membrane doped with organic acids and ceramic showed good conductivity and thermal stability. The ac impedance data, processed by non-linear least square (NLLS) fitting, showed good conducting properties of the composite films. The ionic conductivity of the film consisting of (PEO)8LiClO4:citric acid (99.95:0.05, w/w%) was 3.25x10^(-4) S cm-1 and 1.81x10^(-4) S cm-1 at 30°C. The conductivity has further improved to 3.81x10^(-4) S cm-1 at 20°C by adding 20 w/w% Al2O3 filler to the (PEO)8LiClO4 + 0.05% carboxylic acid composite. The experimental data for the full cell showed an upper limit voltage window of 4.7V versus Li/Li+ for CSPE at room temperature.
J.W. Park, E.D. Jeong, M-S. Won, Y-B. Shim, Journal of Power Sources 160 (2006) 674-680

A0902 – Conversion of crystal structure of the chitin to facilitate preparation of a 6-carboxychitin with moisture absorption-retention abilities

Chitin has been subjected to regiospecific oxidation at C-6 with NaOCl in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and NaBr at room temperature in aqueous solution to yield fully soluble 6-carboxychitin. Several physical and chemical pretreatments of the original chitin changed its crystal structure from alpha to beta. After this pretreatment of the chitin the oxidation was easier to effect and the yield was greatly increased from 36% to 97% and the molecular weight was about 4 x 10^4 which was ca. 8 times that from the unpretreated chitin. Infrared spectroscopy (IR), X-ray diffraction, 13C NMR and solid-state NMR measurements, and thermal analysis techniques were used to characterize their molecular structures. The moisture absorption and retention abilities of these types of compounds were compared with those of sodium hyaluronan and carboxymethyl chitosan (CMCS) and were found to be superior. They therefore have the potential to substitute for hyaluronan for use in cosmetics and clinical medicine fields.
L. Sun, Y. Du, J. Yang, X. Shi, J. Li, X. Wang, J.F. Kennedy, Carbohydrate Polymers 66 (2006) 168-175

A0867 – Interactions between chlorinated paraffins and melamine in intumescent paint – investing a way to suppress chlorinated paraffins from the formulations

It is known that acid source, carbon source and blowing agent are the main ingredients of an intumescent paint. Melamine and halogenated additives, such as polychlorinated alkanes (PCAs) are used as blowing agents, however, the legislation tends to prohibit the use of halogenated coumpounds for environmental reasons. The aim of our study is to investigate the mode of action of melamine and PCAs in an intumescent formulation. Their interactions are also studied. It is found that the combination of PCAs and melamine leads to more efficient systems. Spectroscopic analyses (FTIR and solid state 13C NMR) led us to conclude that when the intumescent paint was heated melamine condensed to create melem via Diels-Alder-type reaction. Melem could then react with PCAs leading to the stabilisation of the PCA-melamine mixture. The proposed mechanism of action led us to propose a method for the substitution of PCAs.
P. Ducrocq, S. Duquesne, S. Magnet, S. Bourbigot, R. Delobel, Progress in Organic Coatings 57 (2006) 430-438

A0855 – Synthesis, characterization and hydrolysis of an aliphatic polycarbonate by terpolymerization of carbon dioxide, propylene oxide and maleic anhydride

Terpolymerization of propylene oxide (PO), carbon dioxide (CO2) and maleic anhydride (MA) was carried out by using a polymer-supported bimetallic complex (PBM) as a catalyst. A degradable aliphatic poly(propylene carbonate maleate) (PPCM) was synthesized, and determined by FT-IR, 1H NMR, 13C NMR, DSC, TGA and WAXD measurements. The influences of various reaction conditions such as molar ratio of the monomers, reaction time and reaction temperature on the terpolymerization progress were investigated. The results showed that MAwas inserted into the backbone of CO2-PO successfully. The viscosity, glass transition temperature and decomposition temperature of the terpolymers were much higher than those of poly(propylene carbonate) (PPC). Because of the existence of the MA ester unit, PPCM had stronger degradability than PPC in a pH 7.4 phosphate-buffered solution. MA offered an ester structural unit that gave the terpolymers remarkable degradability. And the degradation rate of the backbone increased with the insertion of MA into the terpolymers.
Y. Liu, K. Huang, D. Peng, H. Wu, Polymer 47 (2006) 8453-8461

A0851 – Comparative study of the effect of different nanoparticles on the mechanical properties and thermal degradation mechanism of in situ prepared poly(e-caprolactone) nanocomposites

Various poly(e-caprolactone) nanocomposites were prepared in situ by the ring-opening polymerization of e-caprolactone. Four different nanoparticles were used. Two layered silicates, such as montmorillonite (Cloisite Na+ and Cloisite 20A), one in the form of spherical nanoparticles (fumed silica SiO2) and multi-walled carbon nanotubes (MWNT). Thermal degradation under dynamic conditions as well as mechanical properties under tension of the prepared materials were comparatively examined. All nanoparticles, despite resulting in a small molecular weight (Mv) decrease, induced a substantial enhancement of Young's modulus and tensile strength compared to neat PCL. From TGA analysis it was concluded that modified montmorillonite and fumed silica accelerate the decomposition of PCL due to respective aminolysis and hydrolytic reactions that the reactive groups on the surface of these materials can induce. On the other hand, carbon nanotubes and unmodified montmorillonite can decelerate the thermal degradation of PCL due to a shielding effect. The activation energies of all the prepared samples were estimated using the Ozawa, Flynn and Wall (OFW) and Friedman methods. Thermal degradation of PCL and its nanocomposites was found to be satisfactorily represented by two mechanisms having different activation energies. The first corresponds to a small mass loss, while the second, attributed to the main decomposition mechanism, corresponds to the substantial mass loss that takes place. The nanoparticles do not affect the decomposition mechanism but only the activation energies.
K. Chrissafis, G. Antoniadis, K.M. Paraskevopoulos, A. Vassiliou, D.N. Bikiaris, Composites Science and Technology 67 (2007) 2165-2174

A0839 – Highly carbonized polyaniline micro- and nanotubes

We have obtained unique highly carbonized polyaniline micro- and nanotubes as a new, thermally stable nanomaterial for nanosensors and nanodevices with a wide range of possible applications, comparable to carbon nanotubes. Polyaniline nanostructures are easy to prepare and handle in wet conditions, including controlled growth. Temperature-induced transformations of polyaniline micro- and nanotubes into highly carbonized analogues have been observed at and above 800°C, while the temperature was elevated slowly from 20°C up to 1100°C. Carbonized products have the same morphology (micro- and nanotubes), but a lower spin density than the starting material (e.g. 10^14 g-1 for the sample heated at and above 800°C, and 10^19 g-1 before heating). Simultaneously, the electrical conductivity changes from 7.4 x 10^(-5) S/cm for the starting material to 4.8 x 10^(-9) S/cm, 1.3 x 10^(-11) S/cm and finally 2.4 x 10^(-6) S/cm for samples obtained at room temperature, 250°C, 500°C and 800°C, respectively. Chemical transformations and unique molecular structures formed are discussed. Applications in nanotechnology, including sensors and electronic nanodevices, are expected in the light of experiments already performed.
J.J. Langer, S. Golczak, Polymer Degradation and Stability 92 (2007) 330-334

A0826 – Radiation-induced grafting of acrylamide onto guar gum in aqueous medium: Synthesis and characterization of grafted polymer guar-g-acrylamide

Mutual radiation grafting technique has been applied to carry out grafting of acrylamide (AAm) onto guar gum (GG) using highenergy Co60 gamma radiation to enhance its flocculating properties for industrial effluents. The grafted product was characterized using analytical probes like elemental analysis, thermal analysis, Fourier transformed infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The grafting extent was observed to decrease with the dose rate and increase with the concentration of AAm. Thermo gravimetric analysis (TGA) of grafted and ungrafted samples indicated better stability of grafted product. gamma and microwave radiation effect on grafted and virgin GG has also been reported.
J. Biswal, V. Kumar, Y.K. Bhardwaj , N.K. Goel, K.A. Dubey, C.V. Chaudhari, S. Sabharwal, Radiation Physics and Chemistry 76 (2007) 1624-1630

A0823 – Synthesis, characterization and thermal degradation mechanism of three poly(alkylene adipate)s: Comparative study

Three high molecular weight aliphatic polyesters derived from adipic acid and the appropriate diol e poly(ethylene adipate) (PEAd), poly(propylene adipate) (PPAd) and poly(butylene adipate) (PBAd) e were prepared by two-stage melt polycondensation method (esterification and polycondensation) in a glass batch reactor. Intrinsic viscosities, GPC, DSC, NMR and carboxylic end-group measurements were used for their characterization. Mechanical properties of the prepared polyesters showed that PPAd has similar tensile strength to low-density polyethylene while PEAd and PBAd are much higher. From TGA analysis it was found that PEAd and PPAd have lower thermal stability than poly(- butylene adipate) (PBAd). The decomposition kinetic parameters of all polyesters were calculated while the activation energies were estimated using the Ozawa, Flynn and Wall (OFW) and Friedman methods. Thermal degradation of PEAd was found to be satisfactorily described by one mechanism, with activation energy 153 kJ/mol, while that of PPAd and PBAd by two mechanisms having different activation energies: the first corresponding to a small mass loss with activation energies 121 and 185 kJ/mol for PPAd and PBAd, respectively, while the second is attributed to the main decomposition mechanism, where substantial mass loss takes place, with activation energies 157 and 217 kJ/mol, respectively.
T. Zorba, K. Chrissafis, K.M. Paraskevopoulos, D.N. Bikiaris, Polymer Degradation and Stability 92 (2007) 222-230

A0806 – Polyhedral oligomeric silsesquioxanes (POSS) thermal degradation

The mechanism of thermal degradation of several substituted polyhedral oligomeric silsesquioxanes (POSS) cages is studied in this work. Hydrogen POSS and methyl POSS shows incomplete sublimation on heating, both in inert atmosphere and in air. Isobutyl and octyl substituted POSS undergo an almost complete evaporation when heated in inert atmosphere. In air, oxidation competes with volatilization, producing a considerable amount of silica-like residue on heating up to 800°C. Phenyl POSS shows a higher thermal stability than saturated aliphatic POSS and limited volatility, producing a ceramic residue at high yield on heating in nitrogen, composed of a silica containing a considerable amount of free-carbon. A lower amount of residue is shown after heating in air, corresponding to the POSS Si-O fraction. A vinyl POSS cage/network resin is also studied, in comparison to above materials, showing the highest ceramic yield.
A. Fina, D. Tabuani, F. Carniato, A. Frache, E. Boccaleri, G. Camin, Thermochimica Acta 440 (2006) 36-42

A0800 – Thermal degradation kinetics of the biodegradable aliphatic polyester, poly(propylene succinate)

The preparation of the biodegradable aliphatic polyester poly(propylene succinate) (PPSu) using 1,3-propanediol and succinic acid is presented. Its synthesis was performed by two-stage melt polycondensation in a glass batch reactor. The polyester was characterized by gel permeation chromatography, 1H NMR spectroscopy and differential scanning calorimetry (DSC). It has a number average molecular weight 6880 g/mol, peak temperature of melting at 44°C for heating rate 20°C/min and glass transition temperature at 36°C. After melt quenching it can be made completely amorphous due to its low crystallization rate. According to thermogravimetric measurements, PPSu shows a very high thermal stability as its major decomposition rate is at 404°C (heating rate 10°C/min). This is very high compared with aliphatic polyesters and can be compared to the decomposition temperature of aromatic polyesters. TG and Differential TG (DTG) thermograms revealed that PPSu degradation takes place in two stages, the first being at low temperatures that corresponds to a very small mass loss of about 7%, the second at elevated temperatures being the main degradation stage. Both stages are attributed to different decomposition mechanisms as is verified from activation energy determined with isoconversional methods of Ozawa, Flyn, Wall and Friedman. The first mechanism that takes place at low temperatures is auto-catalysis with activation energy EZ157 kJ/mol while the second mechanism is a first-order reaction with EZ221 kJ/mol, as calculated by the fitting of experimental measurements.
K. Chrissafis, K.M. Paraskevopoulos, D.N. Bikiaris, Polymer Degradation and Stability 91 (2006) 60-68

A0748 – Study on the pyrolysis of wood-derived rayon fiber by thermogravimetry-mass spectrometry

The thermal pyrolysis of wood-derived rayon fiber has been studied from ambient temperature up to 800°C by thermogravimetry-mass spectrometry (TG-MS) analysis in an inert environment. Following an initial plateau region, the wood-derived rayon fiber rapidly decomposes in a narrow temperature range of 300-350°C. After this sharp weight loss, there is a gradual but constant weight loss up to 800°C. The values of kinetic parameters have been determined by using two dynamic thermogravimetric curves (TG and DTG). The data show that kinetics of wood-derived rayon fiber is similar to that of other cellulosic materials thermal degradation. Gases and tarry volatile products formed from the pyrolysis of wood-derived rayon fiber are monitored by MS. Water (m/z 18) is the predominant ion observed, followed by CO (m/z 28), CO2 (m/z 44) and CH4 (m/z 16). The MS signals show that the tarry volatiles are composed of varieties of compounds. The formation reactions of primary products from the pyrolysis are discussed in detail in the present paper.
Q. Liu, C. Lv, Y. Yang, F. He, L. Ling, Journal of Molecular Structure 733 (2005) 193-202

A0696 – A new chemical polymerization process for substituted anilines. Application to the synthesis of poly(N-alkylanilines) and poly(o-alkylanilines) and comparison of their respective properties

A new chemical polymerization process has been developed for the synthesis of polyaniline derivatives. Various poly(N-alkylanilines) and poly(o-alkylanilines) bearing different alkyl chain lengths (3-18 carbons) can be prepared by oxidation with ammonium persulfate in a mixture comprising methanesulfonic acid, water, hexane and a cosolvent (THF). Using this general process and further purification procedures, we found that numerous polymers can be produced in their dedoped forms with very high purity and reproducibility. The physical, spectral and thermal properties of poly(N-alkylanilines) and poly(o-alkylanilines) were studied and compared. As expected, the solubility of these substituted polyanilines in their dedoped form increased with alkyl chain length, and doped polymers containing long alkyl chains were also totally soluble in the usual organic solvents.
A. Falcou, A. Duchêne, P. Hourquebie, D. Marsacq, A. Balland-Longeau, Synthetic Metals 149 (2005) 115-122

A0692 – Flame retardancy of biodegradable polymers and biocomposites

The efficiency of ammonium polyphosphate in different biocomposites was compared. For the comparison flame retarded lignocellulosic filler reinforced biocomposites were prepared using polypropylene (PP), polyurethane (PUR) and fully biodegradable starch matrices. The compatibility of wood flake with PP was improved by application of an alkoxy silane based reactive surfactant. The silylation improved not only the compatibility but also the thermal stability of the wood flake according to TG measurements. Raman spectroscopic analysis of the silylated product showed that the improved thermal stability is the result of reduced ratio of the amorphous phase of cellulose. The phosphorus additives in flame retarded PUR biocomposites, comprising waste bio fillers and recycled polyol, proved to be very effective because both the matrix and the filler components participate in mechanism of flame retardancy. Plasticised thermoplastic starch could be flame retarded efficiently by as little as 10% ammonium polyphosphate. After their service life the biocomposites can be utilised as chemical fertilizer.
Sz. Matko, A. Toldy, S. Keszei, P. Anna, Gy. Bertalan, Gy. Marosi, Polymer Degradation and Stability 88 (2005) 138-145

A0690 – Thermal and fire behaviour of ammonium polyphosphate/acrylic coated cotton/PESFR fabric

The influence of an intumescent back coating, applied to a cotton/PESFR (Trevira CS ) fabric, on thermal and fire behaviour system is investigated. The intumescent system is made of an acrylic binder resin and ammonium polyphosphate (APP). Thermal and fire behaviours are analysed. The pure acrylic binder resin coated on fabric leads to a decrease in the thermal and fire properties of the virgin materials. When APP is added to the binder resin, the decrease in the properties due to the handling treatment is limited.
C. Drevelle, J. Lefebvre, S. Duquesne, M. Le Bras, F. Poutch, M. Vouters, C. Magniez, Polymer Degradation and Stability 88 (2005) 130-137

A0687 – Kinetic analysis of pyrolysis of cross-linked polymers

Decomposition of crossed-linked polymers in an inert atmosphere occurs in such a way that they tend to conserve the structure of their matrix. Bond breaking inside the polymer matrix requires a large amount of energy. That is why decomposition of crossedlinked polymers preferentially takes place via a chemical conversion of side chains. Probably, to a first approximation, the side chains can be considered as being almost independent during the decomposition. In other words, the overall decomposition can be described as a set of parallel processes. In such a case, the final residue of the polymer after decomposition can be described as a substance with certain properties independent of the way of obtaining this residue. The accuracy of approximation of kinetic information by using such assumptions is exemplified in four-stage decomposition of cross-linked (rigid) polyurethane in nitrogen. As shown, the set of four activation energies, obtained as a result of the approximation, can be used for sufficiently accurate prediction of the decomposition under arbitrary thermal conditions.
J. Lefebvre, V. Mamleev, M. Le Bras, S. Bourbigot, Polymer Degradation and Stability 88 (2005) 85-91

A0686 – Intumescent polypropylene/flax blends: a preliminary study

This study deals with the effect resulting from the association of pentaerythritol with flax fibres in an intumescent PP/Fibre/ ammonium polyphosphate/pentaerythritol/melamine system. This consists only in a preliminary to prove the efficiency of intumescent additives systems in polyolefin/flax composites considering the fire behaviour and the thermal stability of the material. The study confirms the Fire Retardance performances of a PP/flax/ammonium polyphosphate composite considering cone calorimeter data. Moreover, it shows that charring of the flax fibers in this composite does not give an interesting material in term of dynamic property. Using an intumescent model additive, we show that association of charring of the cellulosic material and of the intumescent system allows to obtain an optimized FR formulation.
M. Le Bras, S. Duquesne, M. Fois, M. Grisel, F. Poutch, Polymer Degradation and Stability 88 (2005) 80-84

A0685 – Thermoplastic resins for thin film intumescent coatings – towards a better understanding of their effect on intumescence efficiency

This study investigates the role of the binder in the efficiency of intumescent coatings. It is generally known that an acid source, a carbon source and a blowing agent are the main ingredients of such paints. However, since the binder may react with these ingredients, it may significantly affect the intumescence process. To begin with, the effect of the nature of the monomers, which compose the binder, on the chemical reactivity between the binder and the intumescent additives is investigated using thermogravimetric analysis. It is found that the thermal stability is enhanced when the copolymer is prepared with substituted styrene. Subsequently, the effect of the binder is investigated from a physical aspect. Special attention is devoted to the expansion rate and the dynamic viscosity. Finally, the efficiency of protective behaviour of the intumescent coatings prepared with the copolymers is evaluated. It is found that the thermal insulation is greatly improved when using a mixture of linear and crosslinked copolymers as the binder in intumescent coatings particularly when these copolymers are prepared from monomers showing good reactivity with ammonium polyphosphate.
S. Duquesne, S. Magnet, C. Jama, R. Delobel, Polymer Degradation and Stability 88 (2005) 63-69

A0684 – Polypropylene as a reductive agent for dehalogenation of brominated organic compounds

A new method for debromination of organics by a reductive medium like polypropylene is investigated. The reaction is carried out in inert atmosphere to avoid rapid oxidation of the polymer. Through this detoxification procedure, hydrogen bromide and small brominated alkanes are formed. Experiments in closed ampoules are carried out with tetrabromobisphenol A, dibromophenol, pentabromodiphenyl ether, dichlorophenol and an oil formed by pyrolysis of printed circuit boards in the Haloclean process. The reaction is examined under isothermal conditions in a temperature range between 300 and 400 (C and a residence time between 10 and 30 min. Optimal conditions were found at 350 (C and at a residence time of 20 min. As chlorinated phenols are not destroyed under these conditions, the process may be a valuable procedure to gain hydrogen bromide out of mixtures of halogenated feed materials. Also, under atmospheric pressure, a reaction between polypropylene and brominated compounds takes place as could be proved by thermogravimetric analysis. Bromobenzene has an accelerating effect on the rate of weight loss of the polymer, but at higher concentrations, it can also be slowed down.
A. Hornung, S. Donner, A. Balabanovich, H. Seifert, Journal of Cleaner Production 13 (2005) 525-530

A0645 – Homopolymerization of 5-alkyl-2-norbornenes and their copolymerization with norbornene over novel Pd(acac)2/PPh3/BF3OEt2 catalyst system

The homopolymerization of 5-alkyl-2-norbornenes and their copolymerization with norbornene have been successfully carried out employing Pd(acac)2/PPh3/BF3OEt2 catalyst system. The activity of the catalyst system is comparable to that of most active late-transition metal catalysts described in the literature. The molecular weight distributions of homo- and copolymers indicate a single-site, highly homogeneous character of the active catalyst species. The incorporation of flexible alkyl groups onto the main chain of norbornene as well as copolymerization of 5-alkyl-2-norbornenes with norbornene represent useful methods for lowering the glass transition temperature (Tg), i.e. improving the processability. The simplicity of catalytic system composition might be of industrial importance.
G. Myagmarsuren, K-S. Lee, O-Y. Jeong, S-K. Ihm, Polymer 46 (2005) 3685-3692

A0644 – Characterization and photooxidative behaviour of nanocomposites formed with polystyrene and LDHs organo-modified by monomer surfactant

Layered double hydroxide (LDH) organo-modified by a surface-active monomer, 3-sulfopropyl methacrylate (SPMA) was used as filler for polystyrene (PS). Different nanocomposites SPMA/LDH:PS were prepared by bulk polymerization process using low amount of initiator. The two components, filler and polymer, as well as the degree dispersion of the reactive filler as a function of its loading in PS were characterized by a combination of several techniques: X-ray diffraction, high resolution 13C CP-MAS NMR, FTIR, UV-visible, thermal analysis, SEC and MET. The nanocomposites were submitted to UV-light exposures in the presence of oxygen. The oxidation photoproducts and the rates of oxidation were compared for the various samples. It was shown that the filler was not modifying the oxidation mechanism of the polymer, but had a slight effect on the oxidation rate.
F. Leroux, L. Meddar, B. Mailhot, S. Morlat-Thérias, J-L. Gardette, Polymer 46 (2005) 3571-3578

A0638 – Intermolecular interaction and properties of cross-linked materials from poly(ester-urethane) and nitrochitosan

Two series of semi-interpenetrating polymer network (semi-IPN) films, coded as PUNT and PUN, have been prepared from amorphous nitrochitosan (NCH) and semicrystalline poly(ester-urethane) (PU) cross-linked to the hydroxy groups of tris(hydroxymethyl)propane (TMP) and NCO groups of PU prepolymer, respectively, by a casting method. The effects of different cross-linking methods and NCH content on the crystallization and hydrogen bonding strengths of the films were studied by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) with the curve fitting method and wide angle X-ray diffraction (WAXD). The miscibility and mechanical properties of the films were measured by dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), density measurement, thermogravimetric analysis (TGA), tensile testing and solvent swelling testing. The results revealed that the degree of crystalline for the semi-IPN films was lower than that of PU, because of the addition of amorphous NCH to destroy the original ordered structure in the PU film. Moreover, the crystal domain formation for the PUNT films cross-linked with TMP can be more easily interrupted than to other selfcrosslinked PUN films without TMP, resulting in a new disordered hydrogen bonded band in ATR-FTIR spectra. The PUNT films exhibited better miscibility as well as higher density, thermal stability, tensile strength and water resistance than the PUN films, suggesting an effective interpenetration and dense network structure. The differences between the two series of the films can be attributed to a relatively dense crosslinking network and strong intermolecular hydrogen bonding occurred between NCH and PU in the PUNT films as a result of the reaction cross-linked with TMP. It is noted that with an increase of NCH from 5 to 30% w/w, the thermal stability, tensile strength and water resistance of the PUNT films increased.
M. Zeng, L. Zhang, J.F. Kennedy, Carbohydrate Polymers 60 (2005) 399-409

A0612 – Stability of poly(3-dodecylthiophene) upon doping and thermal de-doping

Poly(3-dodecylthiophene) (p3ddt) was prepared by oxidative polymerisation, doped with iodine, and characterised by surface resistivity, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), to study its stability and structural changes upon repeated doping and de-doping. The surface resistivity of p3ddt was greatly affected by the thermal de-doping temperature; at lower de-doping temperatures (<200°C), its conductivity gradually recovered with doping time; it would partially or completely lose conductivity above the de-doping temperature at 200°C. Both the pristine and doped p3ddt decomposed at around 350°C; the iodine uptake ability decreased while re-doping with the increase in heating temperature. XPS results revealed that doping and heating was accompanied by oxidation with the participation of oxygen. These structural distortions and chemical transformations may contribute to the increase in surface resistivity upon heating.
Jinwei Wang, Polymer Degradation and Stability 89 (2005) 15e20

A0611 – Synthesis, characterization and photocross-linking of copolymers of furan and aliphatic hydroxyethylesters prepared by transesterification

Mild experimental conditions were applied to the synthesis of furan-aliphatic photoreactive copolymers by bulk transesterification, which called upon potassium carbonate as the catalyst, reaction times of about 30 h and temperatures ranging from 95 to 120°C. The ensuing copolymers contained 3-10% of furan photoreactive monomer units, which absorbed at 308 nm, and had molecular weights of about 8000. They were semi-crystalline materials with glass transition temperatures of K51 to K62°Cand were stable up to 225°C. The irradiation in the near-UV of concentrated solutions or thin films of these copolymers resulted in their cross-linking and suggested their possible use as photoresists, particularly in offset printing plates.
E. Lasseuguette, A. Gandini, M.N. Belgacem, H-J. Timpe, Polymer 46 (2005) 5476-5483

A0609 – Organosilane-modified maghemite nanoparticles and their use as co-initiator in the ring-opening polymerization of -caprolactone

Hydroxyl and amino groups were introduced on maghemite nanoparticles surface by grafting of (3-glycidoxypropyl)trimethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxy silane, in several solvents including water, toluene and N,N-dimethylformamide. Coating of maghemite particles by a biocompatible and biodegradable polyester, namely the poly( -caprolactone) was then achieved, by an aluminum isopropoxide-catalyzed ring-opening polymerization of -caprolactone initiated 'from' the maghemite particles surface. Silane and polymer coating were characterized by TGA and DRIFT spectroscopy. In this manner, nanocomposites containing up to 0.43 g of polymer per gram of maghemite were obtained.
C. Flesch, M. Joubert, E. Bourgeat-Lami, S. Mornet, E. Duguet, C. Delaite, P. Dumas, Colloids and Surfaces A: Physicochem. Eng. Aspects 262 (2005) 150-157

A0601 – Kinetic study of the pyrolysis of neoprene

Kinetics of neoprene thermal decomposition has been performed under dynamic conditions at different heating rates, between 5 and 80°C/ min in a TG apparatus. The same kinetic model has been applied simultaneously to runs performed at different heating rates and different atmospheres allowing a good correlation of the weight loss data. A mechanism based on three independent reactions has been used to model the thermal decomposition. The first reaction is of an order close to two, and the other two reactions are of order below one, similar to other plastic materials. Different alternatives for the mathematical treatment for fitting TG data were considered. The accuracy of the calculated kinetic parameters was studied by means of a sensibility analysis.
J.A. Caballero, J.A. Conesa, I. Martin-Gullon, R. Font, J. Anal. Appl. Pyrolysis 74 (2005) 231-237

A0600 – Thermo-oxidative decomposition of polyvinyl chloride

Pyrolysis and combustion of polyvinyl chloride resin have been studied by thermogravimetric analysis. Nine different runs with about 5 mg sample mass have been carried out in three different atmospheres (He; He:O2 9:1; and He:O2 4:1) and heating rates (5, 10 and 20°C/ min). Adequate kinetic simplified models have been proposed and all heating rates have been simultaneously correlated with the same set of kinetic constants, obtaining good results. The pyrolysis model consists of one first reaction producing gases and solid residue followed by two parallel reactions of previous solid, whereas the combustion model adds a third parallel reaction with oxygen and three new combustion reactions to burn char formed in the three previous reactions. Different considerations have been taken into account during the optimization to achieve the best results. Parameters obtained have been discussed and also compared with others from literature.
I. Aracil, R. Font, J.A. Conesa, J. Anal. Appl. Pyrolysis 74 (2005) 215-223

A0581 – Study of hygrothermal ageing of glass fibre reinforced PET composites

Hygrothermal ageing has been investigated on glass fibre reinforced polyethylene terephthalate (PET) composites using complementary techniques and a multiscale approach in order to identify the different steps of the material's degradation. For early ageing times (t!6 h), DMTA tests give evidence of the plasticisation of the PET matrix. GPC measurements and acid end group titration show that the chemical degradation step of the composites occurs immediately and that the main degradation mechanism is random chain scission. The changes in morphology resulting from hydrolysis, investigated through DSC and SAXS experiments, reveal a decrease in the long period that may result from the diffusion of oligomers out of the spherulites. The water uptake for long ageing times is attributed to an interfacial debonding which induces an osmotic pressure in this area. Photomechanical measurements highlight the development of microcracks within the aged material that induced an increase in the variation of material volume.
M.P. Foulc, A. Bergeret, L. Ferry, P. Ienny, A. Crespy, Polymer Degradation and Stability 89 (2005) 461-470

A0545 – Kinetic parameters of a cyanate ester resin catalyzed with different proportions of nonylphenol and cobalt acetylacetonate catalyst

The isothermal cure of a dicyanate ester monomer has been investigated by differential scanning calorimetry (DSC) in the presence of different quantities of a catalyst system formed by nonylphenol (NP) and cobalt (II) acetylacetonate (Co(AcAc)2). Two sets of experiences were studied. Firstly, the NP composition was varied from 0 to 10 per hundred resin (phr) and secondly, the Co(AcAc)2 loadings were changed at 2 phr of NP. It has been observed that the cyanate conversion increases significantly after the first addition of the metal catalyst and, also, at the same time the thermal stability improves. Moreover, the kinetic data have been fitted with a second-order equation respect to the cyanate conversion in the kinetically conversion regime. Also, both the activation energies and the kinetic order respect to the NP and the Co(AcAc)2 have been determined.
C.M. Gomez, I.B. Recalde, I. Mondragon, European Polymer Journal 41 (2005) 2734-2741

A0544 – Mechanical properties and microstructure of high strength concrete containing polypropylene fibres exposed to temperatures up to 200°C

High strength concrete has been used in situations where it may be exposed to elevated temperatures. Numerous authors have shown the significant contribution of polypropylene fibre to the spalling resistance of high strength concrete. This investigation develops some important data on the mechanical properties and microstructure of high strength concrete incorporating polypropylene fibre exposed to elevated temperature up to 200°C. When polypropylene fibre high strength concrete is heated up to 170°C, fibres readily melt and volatilise, creating additional porosity and small channels in the concrete. DSC and TG analysis showed the temperature ranges of the decomposition reactions in the high strength concrete. SEM analysis showed supplementary pores and small channels created in the concrete due to fibre melting. Mechanical tests showed small changes in compressive strength, modulus of elasticity and splitting tensile strength that could be due to polypropylene fibre melting.
A. Noumowe, Cement and Concrete Research 35 (2005) 2192 - 2198

A0541 – Rheological and mechanical comparative study of in situ polymerized and melt-blended nylon 6 nanocomposites

The rheological and mechanical properties of commercial neat nylon 6 and nylon 6 nanocomposites containing organically-modified montmorillonite (organoclays) produced by either in situ polymerization or melt-blending were investigated. The dynamic and steady shear, capillary and extensional viscosity of the neat nylon 6 and nylon 6 nanocomposite melts were studied, as well as the tensile properties of the solid material. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the organoclays were largely very well exfoliated, although the lateral size scale of the platelets was different for each material. The in situ polymerized nanocomposite exhibited higher melt viscosity and higher tensile ductility than the melt-blended nanocomposite which was related to improved dispersion and polymer-silicate interactions for this material. Scanning electron microscopy confirmed that the nanocomposite failure surfaces showed more evidence of brittle behavior than the failure surfaces of neat nylon 6, and also that agglomerates of organoclay could be seen easily in the fracture surface of the melt-blended nanocomposite, but not to the same degree as in the in situ polymerized nanocomposite. This is in addition to very fine, individually-dispersed silicate laminates that form in each case.
J. Tung, R.K. Gupta, G.P. Simon, G.H. Edward, S.N. Bhattacharya, Polymer 46 (2005) 10405-10418

A0536 – Polystyrenes with macro-intercalated organoclay. Part I. Compounding and characterization

Nanocomposites of polystyrene (PS) were prepared using a melt compounding or co-solvent method. Two commercial PS were used, and two organoclays-one prepared in this laboratory (COPS), and the other commercial Cloisitew 10A (C10A). The COPS is a product of clay intercalation with a copolymer of styrene and vinyl benzyl tri-methyl ammonium chloride. According to the XRD diffraction data, the clay platelets in COPS and its PNC with PS were relatively well dispersed, i.e. with the interlayer spacings of d001Z7-8 nm. By contrast, d001 in PNC prepared with C10A was only 4 nm. However, the number of clay platelets per stack in PS/COPS was found to be significantly larger than that in PS/C10A, viz. mZ3-12, compared to mZ2-6. The scanning and transmission electron microscopy indicated that in the PS matrix COPS existed in form of large, immiscible domains.
M. Sepehr, L.A. Utracki, X. Zheng, C.A. Wilkie, Polymer 46 (2005) 11557-11568

A0533 – TG and DSC studies of naturaland artificial aging of polypropylene

We study the evolution of thermal degradation of samples of polypropylene (PP), during their aging for two periods of 60 and 80 days. The study, using thermogravimetric analysis (TG) and differential scanning calorimetric (DSC) analyses, focused on two types of aging: the naturalone under the impact of the solar environment and the artificialone which was carried out by exposing the sample to radiations of a 100W commercial lamp. The comparative study of these two types of aging shows that the thermaldegradation of the PP increases as a function of time of aging. Indeed, for a same duration, this thermal degradation is more important in the artificialaging case than it is in the naturalone and is an increasing function of aging. The prolonged and continuous thermal effect produced by the lamp, in the case of the artificial aging, weakened the polymer and implies very important acceleration of the process of degradation. The results obtained during heating and cooling of the samples, using the DSC, show an evolution of the phase transition temperatures and the corresponding enthalpies of melting and crystallization.
M. Rjeb, A. Labzour, A. Rjeb, , S. Sayouri, Y. Claire, A. Périchaud, Physica A 358 (2005) 212-217

A0504 – Effect of molecular weight on thermal degradation mechanism of the biodegradable polyester poly(ethylene succinate)

A series of aliphatic polyesters, in particular poly(ethylene succinate), having different molecular weights, were synthesized from succinic acid and ethylene glycol, following the melt polycondensation process. Intrinsic viscosities (IV), GPC, DSC, 1H NMR and carboxylic end group measurements were used for their characterisation. From thermogravimetric analysis, it was concluded that the molecular weight of polyesters achieved during polycondensation are strongly related to thermal stabilities of initial oligomers. In order to synthesise high molecular weight polyesters, the number average molecular weight of oligomers must not be lower than 2300-3000 g/mol, since thermal decomposition begins at temperatures lower than 200°C. However, even in that case, polycondensation temperatures must not exceed 230-240°C. From TGA studies, it was found that sample having different molecular weights could be divided into two groups characterized by different thermal stability. In the first group, belong samples with intrinsic viscosity of IV = 0.08 dL/g and in the second one all the other samples (IV > 15 dL/g). From kinetic analysis of thermal degradation, it was found that degradation of all polyesters takes place in three stages, its one corresponding to a different mechanisms. Degradation of samples with low molecular weight is more complex that that of polyesters having high molecular weights. The values of the activation energy and the exponent n for the two groups of samples-with different molecular weight-are similar, regarding the first two mechanisms, while there is an alteration in the case of the third mechanism.
K. Chrissafis, K.M. Paraskevopoulos and D.N. Bikiaris, Thermochimica Acta 440 (2006) 166-175

A0503 – Thermal and crystallization studies of short flax fibre reinforced polypropylene matrix composites: Effect of treatments

The effect of fibre treatments on thermal stability of flax fibre and crystallization of flax fibre/polypropylene composites was investigated. For thermal stability study, flax fibres have been treated using maleic anhydride, maleic anhydride polypropylene copolymer, vinyltrimethoxy silane and alkalization. In order to compare thermal stability of flax fibres thermogravimetry (TG) analysis has been used. Kinetic parameters have been determined by Kissinger method. Results showed that all treatments improved thermal stability of flax fibres. For crystallinity analysis, three different techniques have been used, differential scanning calorimetry analysis (DSC), pressure-volume-temperature (PVT) measurements for analysis of volume shrinkage and polarized optical microscopy (POM). All techniques results showed that addition of flax fibre increased crystallization rate. Besides, depending on fibre surface treatment and crystallization temperature, flax fibre/PP composites can show transcrystallinity.
A. Arbelaiz, B. Fernandez, J.A. Ramos and I. Mondragon, Thermochimica Acta 440 (2006) 111-121

A0483 – Thermal degradation of poly(acrylic acid) containing copper nitrate

A high temperature superconductor (HTSC) precursor containing a polymer and metal nitrates may be processed with relative ease before pyrolysis. This article focuses on the thermal decomposition of poly(acrylic acid) (PAAc) containing copper nitrate (Cu-N) as a first step in the study of an HTSC precursor containing copper, barium and yttrium nitrates. The degradation of PAAc/Cu-N was found to be a complex multi-stage process that was not always directly related to the degradation of the individual components. Adding Cu-N to PAAc causes a dramatic decrease in thermal stability. While the degradation of PAAc in argon yields a carbonaceous residue, no such residue was found for the degradation of PAAc/Cu-N in air. The rate of PAAc/Cu-N degradation is significantly higher in air than in argon. The decomposition mechanisms include polymer chain scission catalysed by copper ions and the formation of terminal macroradicals that generate low molecular weight organic compounds.
S. Dubinsky, G.S. Grader, G.E. Shter, M.S. Silverstein, Polymer degradation and stability 86 (2004) 171-178

A0479 – Thermal degradation mechanism of ploy(ethylene succinate) and poly(butylene succinate): comparative study

Two aliphatic polyesters that consisted from succinic acid, ethylene glycol and butylene glycol, -poly(ethylene succinate) (PESu) and poly(butylene succinate) (PBSu)-, were prepared by melt polycondensation process in a glass batch reactor. These polyesters were characterized by DSC, 1H NMR and molecular weight distribution. Their number average molecular weight is almost identical in both polyesters, close to 7000 g/mol, as well as their carboxyl end groups (80 eq/106 g). From TG and Differential TG (DTG) thermograms it was found that the decomposition step appears at a temperature 399°C for PBSu and 413°C for PESu. This is an indication that PESu is more stable than PBSu and that chemical structure plays an important role in the thermal decomposition process. In both polyesters degradation takes place in two stages, the first that corresponds to a very small mass loss, and the second at elevated temperatures being the main degradation stage. The two stages are attributed to different decomposition mechanisms as is verified from the values of activation energy determined with iso-conversional methods of Ozawa, Flyn, Wall and Friedman. The first mechanism that takes place at low temperatures, is auto-catalysis with activation energy E = 128 and E = 182 kJ/mol and reaction order n = 0.75 and 1.84 for PBSu and PESu, respectively. The second mechanism is nth-order reaction with E = 189 and 256 kJ/mol and reaction order n = 0.68 and 0.96 for PBSu and PESu, respectively, as they were calculated from the fitting of experimental results.
K. Chrissafis, K.M. Paraskevopoulos, D.N. Bikiaris, Thermochimica Acta 435 (2005) 142-150

A0436 – Thermal behaviour of urea-formaldehyde resins during curing

Urea-formaldehyde (UF) resins are the most widely used polycondensation resins today in manufacturing particleboards. The performance of UF resins in their processing is greatly influenced by curing characteristics. The cure process has been monitored by TG-DTA technique on a Setaram labsys instrument in dynamic heating conditions at different heating rates. Commercial UF resins from different suppliers used in Estonian particleboard factories were selected for TG-DTA measurements. Experiments were carried out without and with catalysts. Ammonium chloride and ammonium sulphate were used. Curing characteristics were evaluated both for fresh and aged resins.
K. Siimer, T. Kaljuwee, P.Christjanson, Journal of Thermal Analysis and Calorimetry 72 (2003) 607-617

A0435 – Poly(urethane methacrylate) thermosetting resins studied by thermogravimetry and thermomechanical analysis

Two different poly(urethane acrylate) resins (one with a trimer: PUA1, the second with a dimer: PUA2) prepared [1] by photo curing reaction are investigated by means of thermogravimetry and thermomechanical measurements. The lack of mass loss found up to 300°C for both systems shows their good thermal stability. Beyond this temperature, two mass losses occur consecutively. This mass loss already studied by TG-FTIR coupled measurements for PUA1 resin has been attributed to the degradation of carbonyl groups [1]. The extension to PUA2 and the comparison between the mass loss magnitude and the relative contain in acrylate of the resins leads to attribute the first degradation to the degradation of the acrylate fraction. The degradation of dimer based resin occurs earlier and with a faster kinetic than the trimer based resin. The variations of linear expansion and penetration coefficients measured by thermomechanical analysis (penetration probe) in the glassy state and in the glass transition temperature domain (the onset glass transition temperatures measured by DSC at 20°C min-1 are respectively equal to 111 and 107°C for PUA1 and PUA2, the transitions, not well defined, extending over 30°C), show that despite of a weaker compactness, the trimer based resin is more rigid than the dimer one.
J. Ledru, B. Youssef, J.M. Saiter and J. Grenet, Journal of Thermal Analysis and Calorimetry 68 (2002) 767-774

A0406 – FTIR study of the thermal degradation of poly(vinyl alcohol)

The degradation of poly(vinyl alcohol) was investigated using TG analysis and Fourier transform infrared spectroscopy to determine the effect of atmosphere on the process of degradation. In the spectra, four vibrational modes were identified that characterised the major steps of the degradation process. These were the O-H, C-H, C=O and C=C stretching modes. The mechanism observed for degradation in an inert atmosphere was in accordance with the accepted mechanism of elimination followed by pyrolisation. Evidence of conjugated polyenes, however, was not observed. For the air atmosphere, oxidation in both steps of the degradation process was observed.
P.S. Thomas, J.P. Guerbois, G.F. Russell, B.J. Briscoe, Journal of Thermal Analysis and Calorimetry 64 (2001) 501-508

A0383 – FTIR study of the thermal degradation of poly(vinyl alcohol)

The degradation of poly(vinyl alcohol) was investigated using TG analysis and Fourier transform infrared spectroscopy to determine the effect of atmosphere on the process of degradation. In the spectra, four vibrational modes were identified that characterised the major steps of the degradation process. These were the O-H, C-H, C=O and C=C stretching modes. The mechanism observed for degradation in an inert atmosphere was in accordance with the accepted mechanism of elimination followed by pyrolisation. Evidence of conjugated polyenes, however, was not observed. For the air atmosphere, oxidation in both steps of the degradation process was observed.
P.S. Thomas, J-P. Guerbois, G.F. Russell, B.J. Briscoe, Journal of Thermal Analysis and Calorimetry 64 (2001) 501-508

A0379 – Conductive composite films of polyimide and poly (3-dodecylthiophene).

A new method of making polymer films with conductive surfaces by permeation of the conducting guest species into the host is reported. A layer of poly(3-dodecyl thiophene) (p3ddt) is embedded at the surface of polyimide by permeation of the polythiophene (in solution in tetrahydrofuran (THF)) into a solution of polyamic acid in n-methyl pyrrolidinone (NMP) or dimethyl acetamide (DMAc). The resulting composite could be imidised chemically and the conducting polymer was stable in the composite even after solvent extraction. The sheet resistance of the composite decreased rapidly upon exposure to iodine; this effect was similar to, though slower than that observed for pure dodedcyl thiophene. Also, the composite recovered conductivity after a few hours of exposure to the dopant subsequent to de-doping. The higher mobility afforded by contact in the liquid state may contribute to the entanglement between the constituents leading to greater thermal and solvent resistance of the conducting constituent
J. Wang and M. P. Srinivasan, Synthetic Metals 105 (1999) 1-7

A0378 – Polyimide films from linear and network precursors.

Pyromellitic anhydride-4,4'-diaminodiphenyl ether (PMDA-DDE) polyimide precursor was blended with mellitic acid hexamethyl ester-4,4'-diaminodiphenyl (MAHE-DDE) precursor to obtain polyimide films. The films from blends required higher temperatures for complete imidisation than those necessary for either of the pure constituents. Storage moduli and secondary glass transition temperatures improved with increase of imidisation temperature and amount of the network constituent, indicating that the latter provided some reinforcement to the mixed films. Differential thermal analysis (DTA) of the blends and the changes in morphology with composition observed by scanning electron microscopy suggested that the two constituents may be cross-linked.
J. Wang, M.P. Srinivasan and S-C. Ng, Journal of Materials Chemistry 9 (1999) 655-659

A0368 – Dégradation thermique d’un polystyrène choc ignifugé par un mélange intumescent.

The study of the thermal degradation of the fireproof polystyrene-butadiene copolymer by an intumescent system: ammonium polyphosphate (APP)-pentaerythritol (PER)-talc (TAL), was done through an experimental process. Thermogravimetry under air sweeping was used. We observed for the degradation rate of the mixture with fireproofing agents, in the field of 20 to 50% mass loss, a better linear increasing when this mixture contains more TAL and the ratio APP/PER is smaller.
L. El Watik, Y. Claire, H. Zineddine, C. Rossi, J. Kaloustian, M. Sergent, A. Périchaud, Journal of Thermal Analysis and Calorimetry 58 (1999) 19-28

A0367 – Thermogravimetric analysis of two Chinese used tires.

Two Chinese used tire samples' components have been measured by using TGA technique. In general, a tire contains approximately 65% organic materials, 32% carbon black and less than 4% ash. The most commonly used tire rubbers, such as natural rubber (NR), styrene-butadiene rubber (SBR) and polybutadiene rubber (BR), were also investigated separately under the same conditions. NR is distinguished from BR or SBR in the tires' TG/DTG curves because that the NR in tires decompose mainly at lower temperature than SBR or BR. The similar TG/DTG patterns of SBR and BR result in a difficulty in identification of these two types of tire rubber.
H. Cui, J. Yang, Z. Liu, Thermochimica Acta 333 (1999) 173-175

A0363 – Thermal and surface analytical study of flame retarded polyolefins.

Pentaerythritol may react with tetraethoxy-silane and ammonium-polyphosphate in flame retarded polyolefins and an interfacial layer can be formed around the ammonium-polyphosphate particles. It is advantageous to study such systems using methods of thermal and surface analysis together.
Gy. Marosi, I. Csontos, I. Ravadits, A. Tohl, P. Anna, F. Sommer, M. Botreau, M.D. Tran, Journal of Thermal Analysis and Calorimetry 56 (1999) 1071-1080

A0356 – Comportement thermique du polypropylene au cours du vieillissement

Several samples of polypropylene were studied by thermal analysis. The photo-oxidation and the aging of polypropylene films showed a mass loss more than 7% in heating from 20 to 220°C (5°C min-1), cooling to 20°C and reheating to 220°C. The authors observed also a decrease of the melting and crystallization temperatures. The non aged samples or these ones with preservatives are thermo-oxidised and presented an exothermic peak at about 200°C in DTA heating.The DTA-TG simultaneous apparatus is very useful in the study of polypropylene oxidation by making comparative trials according to a well definite procedure
J. Kaloustian, P. Antonetti, A. Berrada, Y. Claire, A. Perichaud, Journal of Thermal Analysis 52 (1998) 327-340

A0355 – Etude de la dégradation thermique du polystyrène choc ignifugé

The authors studied the ignifugation and the kinetic of thermal degradation of the Styrene-Butadiene copolymer with an intumescent system Ammonium polyphosphate-Pentaerythrinol-Melamine. For that, they used the thermogravimetric and oxygen index techniques. The best formulation of intumescent system which can give the optimum results is proposed.
L. El Watik, P. Antonetti, Y. Claire, H. Zineddine, J. Kaloustian, C. Rossi, A. Périchaud, Journal of Thermal Analysis and Calorimetry 53 (1998) 297-308

A0334 – Thermal behaviour of cotton-modacrylic fibre blends : kinetic study using the invariant kinetic parameters method.

This work studies the thermooxidative degradation of cotton and modacrylic fabrics and of a cotton-modacrylic blend. The association in a blend of modacrylic with cotton fibres is used to improve the fire behaviour of the latter. Using the IKP method which allows the degradation of the material to be modelled, we demonstrate that better thermal stability does not imply better fire-proofing properties, but that these are controlled by the fuel flow rate feeding the flame.
L. Richard-Campisi, S. Bourbigot, M. Le Bras, R. Delobel, Thermochimica Acta 275 (1996) 37-49

A0298 – Carbon from phenolic resins : carbon yield and volatile components – recent studies

On a déterminé le rendement en carbone lors de la pyrolyse de résines phénoliques, avec ou sans oxygène, par comparaison avec les résines furanniques. L'identification des constituants volatils libérés lors de la pyrolyse ne peut se faire qu'à partir d'essais spécifiques. On montre que ces sous-produits de pyrolyse ne sont pas complexes et ont peu tendance à former des hydrocarbures polycycliques. Le rendement en carbone et la qualité dépendent du type de résine pyrolysé, de son taux de réticulation, de l'atmosphère de traitement et de la présence d'éléments en traces.
A. Gardziella, J. Suren, M. Belsue, Interceram. 41 (1992) 461-467

A0294 – Synthetic resins as carbon forming agents for various refractories (carbon yields, analytical methods, structures and emissions)

A. Gardziella, R. Solozabal, J. Suren, V. in der Wiesche

A0293 – Charakterisierung von organokieselsäurepolymeren durch thermoanalytische untersuchungen

Four organosilicate polymers synthesized by addition of vinyl- and H-substituted double four-ring silicic acid derivatives were characterized using DSC and simultaneous TG-DTA measurements. Thermooxidative decomposition proceeds in several steps: Oxidation of (Si-H) groups, oxidation of (Si-CH2-CH2-Si) bridges, and oxidation of (Si-CH3) groups, with formation of new (Si-O-Si) bonds. 29Si-NMR-spectroscopic measurements confirm this interpretation. Thermoanalytical methods of investigation proved useful to characterize these organosilicate polymers.
P. Kölsch, I. Pitsch, D. Schultze, D. Heidemann, D. Hoebbel, Journal of Thermal Analysis 41 (1994) 789-806

A0285 – Etude ATD-ATG du polyéthylène ignifugé par l’hydroxyde de magnésium

Fire resistance of polyethylene is realized by magnesium hydroxide which is distinguished from halogenated fire-proofing agents by its lower cost and its non toxicity. Magnesium hydroxide decomposed by an endotbermic reaction with liberation of water, contributing to ttre proofing. The sample used (Kisuma 5A-N*) is constituted from a powder (0.6-0.8 micrometre) its surface is treated by plastic material in order to ameliorate its compatibility. We studied the thermal decomposition by DTA and TG, of mixtures constituted by polyethylene and magnesium hydroxide. A sudden decomposition began at 385°C for pure polyethylene and decomposition took place at 429°C for the mixture polyethylene-Kisuma (50-50). Incorporation of magnesium hydroxide in polyethylene increases fire resistance.
E. Renacco, J. Kaloustian, C. Arfi, A.M. Pauli and J. Pastor, Journal of Thermal Analysis 41 (1994) 881-888

A0229 – Etude de la stabilité thermique du poly(styrène covinyl benzyl diethyl phosphonate)

La copolymérisation du styrène et du vinyl benzyl diéthyl phosphonate permet d'obtenir un produit qui comporte environ 15% de groupes aromatiques phosphorés. Le produit a été caractérisé par GPC (w = 560000 et n = 110000), RMN et l'étude de sa stabilité thermique a été entreprise. La première étape de la dégradation commence à 300°C et se termine vers 375°C, elle est probablement due à des impuretés ou à des produits de faibles masses. La deuxième étape débute à 400°C et se termine vers 500°C. Il s'agit essentiellement d'une réaction de dépolymérisation. L'énergie d'activation est de 44 kcal mol-1. L'incorporation de groupes phosphonates permet d'augmenter la stabilité du polymère comparativement à celle du polystyrène.
B. Boinon, B. Benayad and J.P. Montheard, Thermochimica Acta 117 (1987) 177-185

A0224 – Etude de la décomposition thermique des polyhétéroarylènes

An investigation was made of the thermal and thermooxidative decompositions of polybenzimidazopyrrolones and polybenzimidazobenzoquinolines, as well as a number of heterocyclic compounds modelling the linkages and individual fragments of these polymers. It was established that in the pyrolyses of the polyheteroarylenes and the corresponding model compounds the destruction of cycles occurs either simultaneously with cleveage of the Car--H bond or at a higher temperature. It was shown that the completely aromatic compounds and the heterocyclic compounds condensed with the benzene nucleus are the most therrnostable of the investigated compounds. A comparative study revealed a correlation between the structures and thermal stabilities of the studied compounds.
D.M. Mognonov, J. Varga, A.I. Batotsyrénova, V.G. Samsonova et A.A. Izynéev, Journal of Thermal Analysis 30 (1985 ) 1053-1062

A0223 – Studies of interfacial properties in polyepoxyde/carbon or glass fiber composites by means of microgravimetric techniques

The microweighing techniques have been chosen to analyze the interface problem of composite materials with polyepoxyde matrix and fibrous reinforcement, particularly the surface interactions and the wetting of carbon and glass fibers with some reactive groups of the organic matrix. The experimental data deal with the nature and energy of interactions, the hydrophilic or hydrophobic behaviour of the surfaces, the wetting angle. The surface of the fibers is modified by various treatments : oxidation, laying of a coating agent. The results allow to make propositions on the role of these treatments during the making of the composite and they also allow to analyze the differences between carbon and glass behaviour.
M. Escoubes, B. Chabert and D. Sage, Thermochimica Acta 103 (1986) 97-106

A0220 – Dégradation thermique des trois isomères : Ortho, Meta, Para du polymethoxymethylstyrene

Une étude cinétique de la réaction globale de dégradation thermique des trois isomères ortho, méta et para du polymethoxyméthylstyréne a été entreprise. Il n'y a pas d'ordre apparent pour l'isomère ortho, alors que l'ordre apparent est un pour les isomères méta et para, dans un large domaine de perte de masse. Pour ces derniers, les énergies d'activation sont respectivement de 32,5 et 31 kcal mol-1. Les composés volatils, identifiés par Chromatographie en phase gazeuse couplée à la spectrométrie de masse, sont constitués essentiellement de monomères. La réaction est donc essentiellement une réaction de dépolymérisation, associée à des réactions de pontages interchaînes pour les polyméres méta et para.
B. Boinon, D. Ainad-Tabet and J.P. Montheard, Thermochimica Acta 112 (1987) 325-334