Thermal degradation of cellulose and its phosphorylated products in air and nitrogen

The thermal degradation of cellulose and its phosphorylated products (phosphates, diethylphosphate, and diphenylphosphate) were studied in air and nitrogen by differential thermal analysis and dynamic thermogravimetry from ambient temperature to 750°C. From the resulting data various thermodynamic parameters were obtained following the methods of Broido and Freeman and Carroll. The values of E_a for decomposition for phosphorylated cellulose were found to be in the range 55–138 kJ mol^?1 in air and 85–152 kJ mol^?1 in nitrogen and depended upon the percent of phosphorus contents in the samples. The mass spectrum of cellobiose phosphate indicated the absence of the molecular ion, indicating that the compound was thermally unstable. The IR spectra of the pyrolysis residues of cellulose phosphate gave indication of formation of a compound having C?O and P?O groups. A fire retardancy mechanism for the thermal degradation of cellulose phosphate has been proposed.     

Reaction kinetics modeling and thermal properties of epoxy–amines as measured by modulated‐temperature DSC. I. Linear step‐growth polymerization of DGEBA + aniline

A mechanistic approach including both reactive and nonreactive complexes can successfully simulate both nonreversing (NR) heat flow and heat capacity (C_p) signals from modulated‐temperature DSC in isothermal and nonisothermal reaction conditions for different mixtures of diglycidyl ether of bisphenol A + aniline. The reaction of the primary amine with an epoxy–amine complex initiates cure (E_1A1 = 80 kJ mol^?1), whereas the reactions of the primary amine (E_1OH = 48 kJ mol^?1) and secondary amine (E_2OH = 48 kJ mol^?1) with an epoxy–hydroxyl complex are rate determining from about 2% epoxy conversion on. The reliability of the proposed mechanistic model was verified by experimental concentration profiles from Raman spectroscopy. When cure temperatures are chosen inside or below the full cure glass‐transition region, vitrification takes place partially or completely, respectively, as can be concluded from the magnitude of the stepwise decrease in C_p. The effect of the epoxy conversion (x) and mixture composition on thermal properties such as the glass‐transition temperature (T_g), the change in heat capacity at T_g [ΔC_p(T_g)], and the width of the glass transition region (ΔT_g) are considered. The Couchman relationship, in which only T_g and ΔC_p(T_g) of both the unreacted and the fully reacted systems are needed, was evaluated to predict the T_g– x relation by using simulated concentration profiles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:2798–2813, 2004     

Effect of particle size on thermal decomposition and devolatilization kinetics of melon seed shell

Thermogravimetric analysis (TGA) and devolatilization kinetics of melon seed shell (MSS) at different particle sizes (150?µm and 500?µm) and at different heating rates (10, 15, 20, and 25?°C/min) were investigated with the aid of TGA. The results of the TGA analysis show that the TGA curves corresponding to the first and third stages for 150?µm particle sizes exhibited some bumps that developed at the first and third stages of pyrolysis. It was also observed that at constant heating rate, the maximum peak temperature increases as the particle sizes increase from 150 to 500?µm, whereas 500?µm particle sizes exhibited higher peak temperatures compared to 150?µm particle sizes. The resulting TGA data were applied to the Kissinger (K), Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) methods and kinetic parameters (activation energy, E and frequency factor, A) were determined. The E and A obtained using K method were 74.27?kJ mol^?1 and 3.84?×?10⁵?min^?1 for 150?µm particle size, whereas for 500?µm particle size were 97.12?kJ mol^?1 and 3.74?×?10⁷?min^?1, respectively. However, the average E and A obtained using KAS and FWO methods were 82.35?kJ mol^?1, 1.29?×?10⁷?min^?1, and 88.50?kJ mol^?1, 1.32?×?10⁷?min^?1 for 150?µm particle sizes. While for 500?µm particle sizes, the E and A were 108.46?kJ mol^?1, 3.14?×?10⁹?min^?1, and 113.05?kJ mol^?1, 7.56?×?10⁹?min^?1, respectively. It was observed that E and A calculated from FWO and KAS methods were very close and higher than that obtained by K method. It was observed that the minimum heat required for the cracking of MSS particles into products is reached later at higher peak temperatures since the heat transfer is less effective as they are at lower peak temperatures.     

Study on hot air aging and thermooxidative degradation of peroxide prevulcanized natural rubber latex film

The air‐aging process at 120°C and the thermooxidative degradation of peroxide prevulcanized natural rubber latex (PPVL) film were studied with FTIR and thermal gravity (TG) and differential thermal gravity (DTG) analysis, respectively. The result of FTIR shows that the ? OH and ? COOH absorption of the rubber molecules at IR spectrum 3600–3200 cm^?1, the ? C?O absorption at 1708 cm^?1, and the ? C? OH absorption of alcohol at 1105 and 1060 cm^?1 increased continuously with extension of the aging time, but the ? CH₃ absorption of saturated hydrocarbon at 2966 and 2868 cm^?1, the ? CH₃ absorption at 1447 and 1378 cm^?1, and the C?C absorption at 835 cm^?1 decreased gradually. The result of TG‐DTG shows that the thermal degradation reaction of PPVL film in air atmosphere is a two‐stage reaction. The reaction order (n) of the first stage of thermooxidation reaction is 1.5; the activation energy of reaction (E) increases linearly with the increment of the heating rate, and the apparent activation energy (E₀) is 191.6 kJ mol^?1. The temperature at 5% weight loss (T_0.05), the temperature at maximum rate of weight loss (T_p), and the temperature at final weight loss (T_f) in the first stage of degradation reaction move toward the high temperature side as the heating rate quickened. The weight loss rate increases significantly with increment of heating rate; the correlation between the weight loss rate (α_p) of DTG peak and the heating rate is not obvious. The weight loss rate in the first stage (α_f1) rises as the heating rate increases. The final weight loss rate in second stage (α_f2) has no reference to heating rate; the weight loss rate of the rubber film is 99.9% at that time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3196–3200, 2004     

Studies on two‐dimensional coordination polymer cadmium phosphate and its high efficient adsorption of Pb(II) ions from aqueous solutions

The two‐dimensional coordination polymer cadmium phosphate with the morphology of rectangle layers was prepared by solid‐state template reaction at room temperature, and was characterized by XRD, FTIR, and TEM techniques. The as‐synthesized sample is a layered cadmium phosphate material, in which the structure is poly (CdPO₄^?) anion framework with ammonium ions and water species residing in the space between the layers, and cadmium ions are coordinated by the phosphate oxygen atoms. This article also presents the adsorption of Pb(II) ions from aqueous solution on the as‐synthesized coordination polymer cadmium phosphate, and the results showed that this inorganic polymer adsorbent had good adsorption capacity. It could reach to the saturation adsorption capacity within an hour, and its excellent adsorption capacity for Pb(II) was 5.50 mmol/g when the initial solution concentration was 1.68 × 10³ μg/mL at T = 278K. Moreover, the adsorption kinetics and adsorption isotherms were studied, it revealed that the adsorption kinetics can be modeled by pseudo second‐order rate equation wonderfully. The apparent activation energy (E_a), ΔG, ΔH, and ΔS were 3.16 kJ mol^?1, ?13.97 kJ mol^?1, ?11.84 kJ mol^?1, and 7.66 J mol^?1 K^?1, respectively. And it was found that Langmuir equation could well interpret the adsorption of the as‐synthesized coordination polymer cadmium phosphate for Pb(II) ions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Kinetic study of ytterbium(III) extraction from sulfate medium with Cyanex 923

The kinetics of ytterbium(III) extraction from sulfate medium with Cyanex 923 in heptane has been investigated with a constant interfacial cell with laminar flow, which aimed to identify the extraction regime, reaction zone and rate equations. It was found that the extraction rate of ytterbium(III) increased linearly with stirring speed and specific interfacial area. The activation energy E_a (9.56 kJ mol^?1), activation enthalpy ΔH^± (7.05 kJ mol^?1), activation entropy ΔS^±₂₉₈ (?0.31 kJ mol^?1) and Gibbs free energy of activation ΔG^±₂₉₈ (98.3 kJ mol^?1) were calculated from the dependence of extraction rate on temperature. The experiential rate equations were obtained by investigating the influence of the concentration of various species on the extraction rate. A diffusion regime has been deduced from evidence of the linear dependence of extraction rate on stirring speed and the low value of the activation energy. The liquid–liquid interface is most probably the reaction zone in view of the linear dependence of extraction rate on specific interfacial area, the high interfacial activity and low water‐solubility of extractant. Thus the mass transfer rate is controlled by interfacial film diffusion of species. Copyright © 2007 Society of Chemical Industry     

A kinetic model for pyrolysis of cellulose

It has been shown that the pyrolysis of cellulose at low pressure (1.5 Torr) can be described by a three reaction model. In this model, it is assumed that an “initiation reaction” leads to formation of an “active cellulose” which subsequently decomposes by two competitive first-order reactions, one yielding volatiles and the other char and a gaseous fraction. Over the temperature range of 259–341°C, the rate constants of these reactions, k_i (for cellulose → “active cellulose”), k_v (for “active cellulose” → “volatiles”), and k_c (for “active cellulose” → char + the gaseous fraction) are given by k_i = 1.7 × 10²¹e^{? (58,000/RT)} min ^?1, k_v = 1.9 × 10¹⁶e^{? (47,300/RT)} min^?1, and k_c = 7.9 × 10¹¹e^{? (36,600/RT)} min^?1, respectively.     

Thermal degradation behavior and kinetics of porous polymer based on high functionality components

Two kinds of porous polymer were prepared based on high functionality components. Thermogravimetric analysis (TGA) is used to compare the thermal degradation behavior and kinetics of these two materials. The thermogravimetric tests of rigid polyurethane foam (H-RPUF) and polyurea aerogel (H-PUA) were carried out in nitrogen atmosphere at different heating rates. The thermal degradation characteristics of the porous polymer were obtained. The apparent activation energy (E_a) of thermal degradation of the porous polymer was investigated by model-free methods. The results showed that the thermal degradation temperature and ash content of H-RPUF were higher than those of H-PUA, and the volatile content was lower. With the rise of heating rate, thermal hysteresis effect of the two porous polymer was relatively high, while the release amount of volatiles was unchanged. For the Kissinger method, E_a of H-PUA and H-RPUF was 212.8 kJ mol⁻¹ and 157.4 kJ mol⁻¹, respectively. According to Starink method, the average activation energy of H-PUA and H-RPUF was 220.2 kJ mol⁻¹ and 107.2 kJ mol⁻¹, respectively. Obtained by Flynn-Wall-Ozawa model, the average activation energy of H-PUA and H-RPUF was 219.0 kJ mol⁻¹ and 111.5 kJ mol⁻¹, respectively. The data obtained from the three models all show that E_a of thermal degradation of H-PUA is higher than that of H-RPUF, and it is less likely to decompose.     

The influence of chain‐ends on the thermal and rheological properties of some 40/60 PES/PEES copolymers

Four random, differently ended (? Cl, ? NH₂, ? OH, and ? COO^?), polyethersulfone/polyetherethersulfone (PES/PEES) copolymers were studied to investigate the influence of chain ends on thermal and rheological behaviors. The number average molar mass (M_n ≈ 9500 g·mol^?1) and the PES/PEES ratio (40/60) of all copolymers investigated were checked by ¹H NMR spectra. Thermal degradations were carried out in the scanning mode and initial decomposition temperatures (T_i) and activation energy values of degradation (E_a) were obtained. Glass transition temperature (T_g) was determined by differential scanning calorimetry and complex viscosity (η*) by rheological measurements in isothermal heating conditions (T = 270°C). All parameters determined were largely affected by copolymer chain ends and decreased according to the same order, ? OH > ? NH₂ > ? Cl > ? COO^?. The results were discussed and interpreted. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Thermal decomposition of cellulose ethers

The thermostability and thermal decomposition kinetics of methyl cellulose (MC), ethyl cellulose (EC), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and hydroxypropyl–methyl cellulose (HPMC) were characterized in nitrogen and air by thermogravimetry (TG). Various methods of kinetic analysis were compared in case of thermal degradation of the five cellulose ethers. The initial decomposition temperature (T_d), temperature at the maximum decomposition rate (T_dm), activation energy (E), decomposition reaction order (n), and pre-exponential factor (Z) of the five cellulose ethers were evaluated from common TG curves and high-resolution TG curves obtained experimentally. The decomposition reactions in nitrogen were found to be of first order for MC, EC, and HPMC with the average E and ln Z values of 135 kJ/mol and 25 min⁻¹, although there were slight differences depending on the analytical methods used. The thermostability of cellulose ethers in air is substantially lower than in nitrogen, and the decomposition mechanism is more complex. The respective average E, n, ln Z values for HEC in nitrogen/air were found to be 105/50 kJ/mol, 2.7/0.5, and 22/8.3 min⁻¹, from constant heating rate TG method. The respective average E, n, and ln Z values for three cellulose ethers (EC/MC/HPMC) in air are 123/144/147 kJ/mol, 2.0/1.8/2.2, 24/28/28 min⁻¹ by using high-resolution TG technique. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2927–2936, 1999     

Sillimanite‐mullite transformation observed in synchrotron X‐ray diffraction experiments

High‐resolution synchrotron powder X‐ray diffraction (XRD) experiments were conducted to clarify the transformation of sillimanite to mullite (mullitization) and determine the mullitization temperature (T_c). We were able to distinguish sillimanite and mullite in the XRD patterns, despite their very similar crystallographic parameters, and to detect the appearance of small mullite peaks among sillimanite peaks. Analysis of the Johnson‐Mehl‐Avrami (JMA) equation for mullitization ratio (ζ) revealed that at temperatures T≥1240°C the mullitization had the same kinetics. The activation energy E at T≥1240°C obtained from the Arrhenius plot was 679.8 kJ mol^?1. In analysis using a time‐temperature‐transformation diagram for mullitization, a mullitization curve of ζ=1% can be described as where t is time, n is a reaction‐mechanism‐dependent parameter determined as 0.324 by JMA‐analysis, k₀ is the frequency factor, E_A is the activation energy for atomic diffusion, and represents the activation energy for nucleation. The results of fitting the data to this equation were T_c=1199°C, A=3.9×10⁶ kJ mol^?1 K^?2, E_A=605 kJ mol^?1, and k₀=3.65×10¹⁵. We conclude that the boundary between sillimanite and mullite+SiO₂ in the phase diagram is ~1200°C.     

Water sorption in amorphous poly(ethylene terephthalate)

The water sorption characteristics of poly(ethylene terephthalate) (PET) amorphous samples of 250 μm thickness have been studied at various temperatures in a saturated atmosphere. Concerning diffusivity, one can distinguish the following two domains characterized by distinct values of the activation energy: E_D ≈ 36 kJ mol⁻¹ at T > 100°C, and E_D ≈ 42 kJ mol⁻¹ at T < 60°C, with a relatively wide (60–100°C) intermediary domain linked to the glass transition of the polymer. The crystallization of this latter occurs in the time scale of diffusion above 80°C but doesn't change the Fickian character of sorption curves. The equilibrium concentration m_∞ is an increasing function of temperature, but the solubility coefficient S decreases sharply with this latter, with the apparent enthalpy of dissolution ΔH_s being of the order of −28 kJ mol⁻¹ at T < 80°C and −45 kJ mol⁻¹ at T > 80°C. Density measurements in the wet and dry states suggest that water is almost entirely dissolved in the amorphous matrix at T < 80°C but forms partially a separated phase at T > 80°C. Microvoiding can be attributed to crystallization-induced demixing. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1131–1137, 1999     

Synthesis,physical properties,and crystallization of optically active poly(L‐phenyllactic acid) and poly(L‐phenyllactic acid‐co‐L‐lactic acid)

Optically active poly(L ‐phenyllactic acid) (Ph‐PLLA), poly(L ‐lactic acid) (PLLA), and poly(L ‐phenyllactic acid‐co‐L ‐lactic acid) with weight‐average molecular weight exceeding 6 × 10³ g mol^?1 were successfully synthesized by acid catalyzed direct polycondensation of L ‐phenyllactic acid and/or L ‐lactic acid in the presence of 2.5–10 wt % of p‐toluenesulfonic acid. Their physical properties and crystallization behavior were investigated by differential scanning calorimetry, thermogravimetry, and polarimetry. The absolute value of specific optical rotation ([α]) for Ph‐PLLA (?38 deg dm^?1 g^?1 cm³) was much lower than that of [α] for PLLA (?150 deg dm^?1 g^?1 cm³), suggesting that the helical nature was reduced by incorporation of bulky phenyl group. PLLA was crystallizable during solvent evaporation, heating from room temperature, and cooling from the melt. Incorporation of a very low content of bulky phenyllactyl units even at 4 mol % suppressed the crystallization of L ‐lactyl unit sequences during heating and cooling, though the copolymers were crystallizable for L ‐phenylactyl units up to 6 mol % during solvent evaporation. The activation energy of thermal degradation (ΔE_td) for Ph‐PLLA (200 kJ mol^?1) was higher than that for PLLA (158 kJ mol^?1). The ΔE_td for the copolymers increased with an increase in L ‐phenyllactyl unit content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Differential Scanning Calorimetry Cure Studies of Tetra-N-glycidyldiaminodiphenylmethane Epoxy Resins. Part 1 - Reaction with 4,4′-Diaminodiphenylsulphone

Rates and extents of cure are determined using differential scanning calorimetry in the isothermal mode over the temperature range 170–220°C, and from d.s.c. scans at various heating rates. The isothermal data are consistent with an autocatalytic mechanism at conversions up to about 20–30%. Data from d.s.c. scans fit a simple kinetic model which indicates that the apparent activation energy (E) for cure increases with increasing conversion, consistent with an increasing degree of diffusion control. At low levels of conversion the isothermal and dynamic data both provide estimates for E of about 70 kJ mol^?1. The heat of cure is about 105 kJ mol^?1 epoxide, and is constant over a wide range of amine concentration. This indicates that any parallel or competing processes which occur must have the same heat of reaction.     

Study of the kinetics of sewage sludge pyrolysis using DSC and TGA

Thermogravimetry and differential scanning calorimetry were used to examine, in nitrogen, four sewage sludges at modest heating rates. A mechanism consisting of two independent reactions was derived for an undigested sludge. The parameters are: n₁ = 10, E₁ = 130 kJ mol^?1, A₁ = 1 × 10¹⁸s^?1, n₂ = 15, E₂ = 250 kJ mol^?1, A₂ = 1 × 10²⁵s^?1, with initial weight fractions of W₁ = 0.20, W₂ = 0.43, the remainder being non-reactive ash. Analysis was performed by comparing Friedman multiple-heating-rate analyses of experimental and model curves in an iterative manner. DSC experiments provide an understanding of the pyrolytic reaction mechanism and heat transfer in the thermogravimetric analyser. DSC analysis of sewage sludge was sensitive to decomposition reactions of small quantities of organic salts in the sludge. Sewage sludge could be a profitable pyrolysis feedstock if mixed with municipal solid waste.     

Reaction kinetics of epoxy resin modified with reactive and nonreactive thermoplastic copolymers

An epoxy resin system based on a triglycidyl p‐amino phenol (MY0510) was crosslinked using stoichiometric amounts of 4,4′‐diaminodiphenyl sulfone. The epoxy was modified with random copolymers, polyethersulfone‐poly(ether‐ethersulfone) (PES:PEES), with either amine or chlorine end groups, at 10 and 20 wt %. The reaction kinetics for both unmodified and modified epoxy systems were studied using differential scanning calorimetry in isothermal and dynamic conditions. The results show that the degree of conversion in thermoplastic‐modified epoxies at any reaction time is smaller compared with the unmodified resin. Gel point (GP) determination was done from rheological measurements. The modified system containing 20% of the PES:PEES additive showed considerable increase in the GP. The reaction rate shows the characteristic of an autocatalytic reaction where the product acts as catalyst. The activation energy, E_a calculated from the isothermal reaction depends on the extent of conversion and increases with increasing PES:PEES content. For unmodified epoxy system, the average E_a is 67.8 ± 4.1 kJ mol^?1 but for systems modified with 20 wt % of amine and chlorine PES:PEES, the value increased to 74.1 ± 3.3 and 77.9 ± 4.4 kJ mol^?1, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Cure kinetics and catalyzed effect of hydroxyl group of LC diglycidyl ether of bisphenol‐S with aromatic diamines

The curing reactions of liquid crystalline 4,4′‐bis‐(2,3‐epoxypropyloxy)‐sulfonyl‐bis(1,4‐phenylene) (p‐BEPSBP) with 4,4′‐diaminodiphenylmethane (DDM) and 4,4′‐diaminodiphenylsulfone (DDS) were investigated by nonisothermal differential scanning calorimeter (DSC). The relationships of E_a with the conversion α in the curing process were determined. The catalyzed activation of hydroxyl group for curing reaction of epoxy resins with amine in DSC experiment was discussed. The results show that these curing reactions can be described by the autocatalytic ?esták‐Berggren model. The curing technical temperature and parameters were obtained, and the even reaction orders m, n, and ΔS for p‐BEPSBP/DDM and p‐BEPSBP/DDS are 0.35, 0.92, ?81.94 and 0.13, 1.32, ?24.45, respectively. The hydroxyl group has catalyzed activation for the epoxy–amine curing system in the DSC experiment. The average E_a of p‐BEPSBP/DDM is 67.19 kJ mol^?1 and is 105.55 kJ mol^?1 for the p‐BEPSBP/DDS system, but it is different for the two systems; when benzalcohol as hydroxyl group was added to the curing system, the average E_a of p‐BEPSBP/DDM decreases and increases for p‐BEPSBP/DDS. The crystalline phase had formed in the curing process and was fixed in the system. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere

A series of silica-supported nickel catalyst precursors was synthesized with different SiO₂/Ni molar ratios. Reduction of Ni catalyst precursors with different SiO₂/Ni molar ratios under a hydrogen atmosphere was investigated at different heating rates. Kinetic parameters were determined using Kissinger–Akahira–Sunose isoconversional and invariant kinetic parameter methods. It was found that for all molar ratios, the apparent activation energy (E_a) is practically constant in the conversion range of 0.20 ≤ α ≤ 0.80. In the considered conversion range, following values of E_a were found: 134.5 kJ mol^?1 (SiO₂/Ni = 0.20), 139.6 kJ mol^?1 (SiO₂/Ni = 0.80), and 128.3 kJ mol^?1 (SiO₂/Ni = 1.15). It was established that the reduction of Ni catalyst precursors with different SiO₂/Ni molar ratios is a complex process and can be described by the ?esták–Berggren autocatalytic model. It was found that the reaction is more Langmuir–Hinshelwood type, as hydrogen dissociates rapidly on surface nuclei and the dissociated hydrogen reacts with the Ni–O active system. It was concluded that the reduction process proceeds through bulk nucleation, which is a dominant mechanism, where three-dimensional growth of crystals with polyhedron-like morphology exists. It was found that the Ni/Si ratio decreases after the reduction process. This has been explained by low Ni and higher Si surface concentrations. It has been disclosed that Ni dispersion decreases.     

Thermal degradation kinetics of thermotropic poly(p‐oxybenzoate‐co‐p,p′‐biphenylene terephthalate) fiber

An advanced heat‐resistant fiber (trade name Ekonol) spun from a nematic liquid crystalline melt of thermotropic wholly aromatic poly(p‐oxybenzoate‐p,p′‐biphenylene terephthalate) has been subjected to a dynamic thermogravimetry in nitrogen and air. The thermostability of the Ekonol fiber has been studied in detail. The thermal degradation kinetics have been analyzed using six calculating methods including five single heating rate methods and one multiple heating rate method. The multiple heating‐rate method gives activation energy (E), order (n), frequency factor (Z) for the thermal degradation of 314 kJ mol⁻¹, 4.1, 7.02 × 10²⁰ min⁻¹ in nitrogen, and 290 kJ mol⁻¹, 3.0, 1.29 × 10¹⁹ min⁻¹ in air, respectively. According to the five single heating rate methods, the average E, n, and Z values for the degradation were 178 kJ mol⁻¹, 2.1, and 1.25 × 10¹⁰ min⁻¹ in nitrogen and 138 kJ mol⁻¹, 1.0, and 6.04 × 10⁷ min⁻¹ in air, respectively. The three kinetic parameters are higher in nitrogen than in air from any of the calculating techniques used. The thermostability of the Ekonol fiber is substantially higher in nitrogen than in air, and the decomposition rate in air is higher because oxidation process is occurring and accelerates thermal degradation. The isothermal weight‐loss results predicted based on the nonisothermal kinetic data are in good agreement with those observed experimentally in the literature. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1923–1931, 1999     

Differential scanning calorimetric study of curing of acrylated epoxy resin with benzoyl peroxide

The curing reaction of the acrylated diglycidyl ether of bisphenol-A (DGEBA) with benzoyl peroxide has been investigated by differential scanning calorimetry at three different heating rates. The overall cure kinetics were found to be first-order, with Arrhenius parameters E=83 kJ mol^?1 and In A = 16.5 min^?1, independent of the scan rate, up to at least 90% conversion.