Flammability and thermal degradation behaviors of phosphorus‐containing copolyester/BaSO4 nanocomposites

A novel phosphorus‐containing copolyester (PET‐co‐DDP)/barium sulfate (BaSO₄) nanocomposite was synthesized by in situ polymerization. The oxygen index values of the resulting nanocomposites decreased with increasing the content of BaSO₄ nanoparticles, but their antidripping behaviors were improved obviously through the UL‐94 test. The flammability tests based on the cone calorimetry showed that the introduction of nano‐BaSO₄ to the copolyester decreased remarkably the heat release rate and effective heat of combustion. The thermal oxidative decomposition behaviors of PET‐co‐DDP/BaSO₄ nanocomposites were studied by a conventional dynamic thermogravimetric analysis in a flowing air atmosphere with a heating rate of 20°C/min. The activation energies determined from Kissinger method, Flynn‐Wall‐Ozawa method, and Friedman method had a same variation trend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 564–570, 2006     

Thermal degradation kinetics of poly(O,O‐diethyl‐O‐allylthiophosphate‐co‐acrylonitrile) in nitrogen

The nonisothermal degradation kinetics of the copolymer poly(O,O‐diethyl‐O‐allylthiophosphate‐co‐acrylonitrile), which was synthesized with O,O‐diethyl‐O‐allylthiophosphate and acrylonitrile, were studied by thermogravimetry/derivative thermogravimetry techniques. The kinetic parameters, including the activation energy and the pre‐exponential factor of the copolymer degradation process, were calculated by the Kissinger and Flynn–Wall–Ozawa methods. The thermal degradation mechanism of the copolymer was also studied with the Satava–Sestak method. The results show that the activation energies were 138.17 kJ/mol with the Kissinger method and 141.63 kJ/mol with the Flynn–Wall–Ozawa method. The degradation of the copolymer followed a kinetic model of a phase boundary reaction and the kinetic equation could be expressed as G(α) = 1 ? (1 ? α)⁴ [where G(α) is the integral function of conversion and α is the extent of conversion of the reactant decomposed at time t]. The reaction order was 4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Non-isothermal crystallization kinetics of poly(ethylene terephthalate)/mica composites

The non-isothermal crystallization kinetics of pure poly(ethylene terephthalate) (PET), PET/mica and PET/TiO₂-coated mica composites were investigated by differential scanning calorimetry with different theoretical models, including the modified Avrami method, Ozawa method and Mo method. The activation energies of non-isothermal crystallization were calculated by Kissinger method and Flynn–Wall–Ozawa method. The results show that the modified Avrami equation and Ozawa theory fail to describe the non-isothermal crystallization behavior of all composites, while the Mo model fits the experiment data fair well. It is also found that the mica and TiO₂-coated mica could act as heterogeneous nucleating agent and accelerate the crystallization rates of PET, and the effect of TiO₂-coated mica is stronger than that of mica. The result is further reinforced by calculating the effective activation energy of the non-isothermal crystallization process for all composites using the Kissinger method and the Flynn–Wall–Ozawa method.     

Synthesis,characterization, and thermal degradation kinetics of the copolymer poly(4‐methoxybenzyl methacrylate‐co‐isobornyl methacrylate)

A copolymer of 4‐methoxybenzyl methacrylate and isobornyl methacrylate was synthesized by atom transfer radical polymerization. The structure of poly(4‐methoxybenzyl methacrylate‐co‐isobornyl methacrylate) was confirmed by means of Fourier transform infrared, ¹H‐NMR, and ¹³C‐NMR techniques. The molecular weight distribution values of the copolymer were determined with gel permeation chromatography. The number‐average molecular weight and polydispersity index values of poly(4‐methoxybenzyl methacrylate‐co‐isobornyl methacrylate) were found to be 12,500 and 1.5, respectively. The kinetics of the thermal degradation of the copolymer was investigated with thermogravimetric analysis at different heating rates. The activation energy values obtained with the Kissinger, Flynn–Wall–Ozawa, and Tang methods were determined to be 166.38, 167.54, and 167.47 kJ/mol, respectively. Different integral and differential methods were used, and the results were compared with these values. Doyle approximation was also used for comparing the experimental results to master plots. An analysis of the experimental results suggested that the reaction mechanism was an R₁ deceleration type in the conversion range studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Silicon–aluminum synergistic mechanism in flame retardancy of epoxy resin

In this article, the Kissinger method and the Flynn‐Wall‐Ozawa method were used to calculate the activation energy of thermal degradation process. Similar results were found in above two methods that the flame retardants polyepoxyphenylsilsesquioxane (PEPSQ) and aluminum hydroxide (ATH) improved the activation energy of epoxy resin (EP). The Flynn‐Wall‐Ozawa method further revealed that the addition of PEPSQ and ATH played an important role in improving the heat resistance and thermal stability of the system and produced synergistic effect in flame retardancy of EP through the significantly increment of the activation energy, especially in the final stage of the EP thermal degradation process. POLYM. COMPOS., 35:1553–1558, 2014. © 2013 Society of Plastics Engineers     

Synthesis,characterization, and thermal degradation kinetic of polystyrene‐g‐polycaprolactone

In the present study, it has been demonstrated that polystyrene‐g‐polycaprolactone (PS‐g‐PCL) was successfully prepared by “click chemistry.” For this purpose, first, poly(styrene‐co‐4‐chloromethylstyrene) (P(S‐co‐CMS)) with 4‐chloromethylstyrene content (10%) was synthesized. Second, alkyne‐functionalized polycaprolactone (PCL) was obtained using propargyl alcohol and caprolactone. P(S‐co‐CMS) and PCL were reacted in N,N‐dimethylformamide for 24 h at 25°C to give PS‐g‐PCL. The synthesized polymer was characterized by nuclear magnetic resonance (¹H‐NMR), gel permeation chromatography, Fourier transform infrared spectroscopy and thermogravimetric analysis. The apparent activation energies for thermal degradation of PS‐g‐PCL were obtained by differential (Kissenger) and integral methods (Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, Tang, Coats–Redfern, Van Krevelen et al.). The decomposition mechanism and pre‐exponential factor were calculated in terms of Coats–Redfern method. The most likely decomposition processes of first and second degradation stages were A_n type and F₃ type, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A study on the curing kinetics of epoxycyclohexyl polyhedral oligomeric silsesquioxanes and hydrogenated carboxylated nitrile rubber by dynamic differential scanning calorimetry

A new organic–inorganic hybrid material was prepared through reactive blending of hydrogenated carboxylated nitrile rubber (HXNBR) with epoxycyclohexyl polyhedral oligomeric silsesquioxanes (epoxycyclohexyl POSS). The structure of the composite was characterized by Fourier transform infrared spectroscopy (FTIR) and solid‐state ¹³C Nuclear Magnetic Resonance spectra (solid‐state ¹³C‐NMR). The differential scanning calorimetry (DSC) at different heating rates was conducted to investigate the curing kinetics. A single overall curing process by an nth‐order function (1 ? α)ⁿ was considered, and multiple‐heating‐rate models (Kissinger, Flynn–Wall–Ozawa, and Crane methods) and the single‐heating‐rate model were employed. The apparent activation energy (E_a) obtained showed dependence on the POSS content and the heating rate (β). The overall reaction order n was practically constant and close to 1. The isoconversion Flynn–Wall–Ozawa method was also performed and fit well in the study. With the single‐heating‐rate model, the average E_a for the compound with a certain POSS content, 66.90–104.13 kJ/mol was greater than that obtained with Kissinger and Flynn–Wall–Ozawa methods. Furthermore, the calculated reaction rate (dα/dt) versus temperature curves fit with the experimental data. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Activation energies for the epoxy system BADGE n = 0/m‐XDA obtained using data from thermogravimetric analysis

In this article we study the kinetics of thermal degradation of the epoxy system BADGE n = 0/m‐XDA using different kinetic methods with data from thermogravimetric analysis (TGA) in dynamic conditions. Activation energies obtained using different integral methods (Flynn‐Wall‐Ozawa and Coats‐Redfern Methods) are in good agreement with the value obtained using the Kissinger method (204.44 kJ/mol). The solid‐state decomposition mechanism followed by this epoxy system is a decelerated R_n type (phase boundary controlled reaction). We have also calculated activation energies using the Van Krevelen and the Horowitz‐Metzger methods. These last methods corroborate the decelerated behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 776–782, 2001     

A kinetic analysis on thermal degradation of poly(phenylene sulfide ether)

Thermal degradation of poly(phenylene sulfide ether) (PPSE) was investigated by using thermogravimetry (TG) under air and nitrogen atmosphere. It was found that the existence of oxygen depressed the thermal stability of PPSE and changed the mechanism of thermal degradation. The influences of molecular weight and heating rate on the decomposition of PPSE were also investigated under N₂ atmosphere. The results showed that the thermal stability of PPSE was excellent and can be further enhanced by increasing molecular weight. A simple kinetic model concerning two parallel reactions in overall temperature range was proposed to describe the thermal degradation process of PPSE in nitrogen. Kinetic analysis of the dynamic TG curves for PPSE was carried out by using Kissinger, Flynn–Wall–Ozawa, and Coats–Redfern methods. The kinetics of PPSE degradation displayed that the two parallel reactions were in accordance with the first‐order equation. The kinetic model was further validated by comparing the experimental and calculated results. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of Hyperbranched Poly (Trimellitic Anhydride Ethylene Glycol) Epoxy (HTME) on Thermal Degradation Activation Energies of HTME/Diglycidyl Ether of Bisphenol-A Epoxy Hybrid Resin by Kissinger and Flynn–Wall–Ozawa Method

The thermal degradation behavior and kinetics of hyperbranched poly (trimellitic anhydride ethylene glycol) epoxy (HTME)/diglycidyl ether of bisphenol-A epoxy (DGEBA) hybrid resin was investigated with thermogravimetric analysis (TGA) by using Kissinger method and Flynn–Wall–Ozawa method. The results show that the thermal degradation activation energies of DGEBA, 9 wt% HTME-1/91wt% DGEBA, 3 wt% HTME-2/97 wt% DGEBA, 9 wt% HTME-2/91 wt% DGEBA, 15 wt% HTME-2/85 wt% DGEBA, and 9 wt% HTME-3/91wt% DGEBA are 152.5, 144.4, 135.4, 133.2, 121.8 and 143.0 kJmol^?1, respectively, by Kissinger method. and the activation energies are 173.3, 165.0, 163.2, 151.7, 137.7 and 159.7 kJmol^?1, respectively by Flynn–Wall–Ozawa method. With the increase of HTME content, the activation energies of HTME/DGEBA hybrid resin decrease. Although molecular weight or generation of hyperbranched epoxy resins (HTME) has little effect on the thermal degradation activation energies and other kinetics data.     

Kinetics of thermal degradation of nanometer calcium carbonate/linear low‐density polyethylene nanocomposites

To improve the thermal properties of linear low‐density polyethylene (LLDPE), the CaCO₃/LLDPE nanocomposites were prepared from nanometer calcium carbonate (nano‐CaCO₃) and LLDPE by melt‐blending method. A series of testing methods such as thermogravimetry analysis (TGA), differential thermogravimetry analysis, Kim‐Park method, and Flynn‐Wall‐Ozawa method were used to characterize the thermal property of CaCO₃/LLDPE nanocomposites. The results showed that the CaCO₃/LLDPE nanocomposites have only one‐stage thermal degradation process. The initial thermal degradation temperature T₀ increasing with nano‐CaDO₃ content, and stability of LLDPE change better. The thermal degradation activation energy (E_a) is different for different nano‐CaCO₃ content. When the mass fraction of nano‐CaCO₃ in nanocomposites is up to 10 wt %, the nanocomposite has the highest thermal degradation E_a, which is higher (28 kJ/mol) than pure LLDPE. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal oxidative degradation kinetics of PP and PP/mg (OH)2 flame‐retardant composites

The thermal stability and thermal oxidative degradation kinetics of polypropylene (PP) and flame‐retardant PP composites filled with untreated and treated magnesium hydroxide (MH) in air were studied by thermogravimetric analysis (TGA). The effect of the heating rate in dynamic measurements (5°C–30°C/min) on kinetic parameters such as activation energy was also investigated. The Kissinger and Flynn–Wall–Ozawa methods were used to determine the apparent activation energy for the degradation of neat PP and flame‐retardant PP composites. The results of TGA showed that the addition of untreated or treated MH improved the thermal oxidative stability of PP in air. The kinetic results showed that the apparent activation energy for degradation of flame‐retardant PP composites was much higher than that of neat PP, suggesting that the flame retardant used in this work had a great effect on the mechanisms of pyrolysis and combustion of PP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1978–1984, 2007     

Thermal decomposition kinetics of thermotropic poly(oxybenzoate‐co‐trimethylene terephthalate)

A new kind of thermotropic liquid crystalline, poly(oxybenzoate‐co‐trimethylene terephthalate), was prepared from p‐hydroxybenzoic acid (B) and poly(trimethylene terephthalate) (PTT or T) by melting polycondensation. The monomer ratio of B to T is 60:40. The dynamic thermogravimetric kinetics of the copolymer B/T (60:40) and PTT in nitrogen were analyzed by four single heating rate techniques and two multiple heating rate techniques. The effects of the heating rate and the calculating technique on the thermostable and degradation kinetic parameters of the B/T copolymer and PTT are systematically discussed. The four single heating rate techniques used in this work include Friedman, Freeman‐Carroll, Chang, and the second Kissinger techniques, whereas the two multiple heating rate techniques are the first Kissinger and Flynn‐Wall techniques. Additionally, the isothermal thermogravimetric kinetics of B/T (60:40) in nitrogen were investigated by the Flynn technique. The activation energy, the order, and the frequency factor of the degradation reaction for B/T (60:40) copolymer are determined to be 185 kJ/mol, 1.8, and 7.14 × 10¹³ min⁻¹, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2025–2036, 2000     

Processing thermal stability and degradation kinetics of poly(vinyl chloride)/montmorillonite composites

Thermal stability of polyvinyl chloride (PVC) based montmorillonite composites with either sodium montmorillonite (MMT) or alkyl ammonium ion modified montmorillonite (OMMT) were investigated by thermogravimetric analysis. The apparent activation energies associated with the first thermal degradation stage were calculated by the methods of Flynn–Wall–Ozawa and Kissinger in nitrogen atmosphere at several different heating rates. The processing thermal stability of PVC and PVC/MMT(OMMT) composites was also discussed. Increase of mixing torque did not result in a larger intercalation extent of PVC on MMT; instead, it unexpectedly induced discoloration of PVC and then deteriorated the processing stability, especially in the presence of OMMT. The apparent activation energies in the first thermal degradation stage exhibited little difference among PVC, PVC/MMT, and PVC/OMMT composites, and the kinetic compensation effect of S_p^* kept a constant value, indicating that the thermal stability and thermal degradation mechanism of PVC were not affected by the presence of either MMT or OMMT, although the processing discoloration of PVC is observed for PVC/OMMT composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1521–1526, 2004     

Schiff base‐substituted polyphenol: synthesis,characterisation and non‐isothermal degradation kinetics

BACKGROUND: Polymers of phenols and aromatic amines have emerged as new materials in fields such as superconductors, coatings, laminates, photoresists and high‐temperature environments. The stability, kinetics and associated pollution of the thermal decomposition of oligophenols are of interest for the aforementioned fields. RESULTS: A new Schiff base polymer, derived from N,N′‐bis(2‐hydroxy‐3‐methoxyphenylmethylidene)‐2,6‐pyridinediamine, was prepared by oxidative polycondensation. Characterisations using Fourier transform infrared, UV‐visible, ¹H NMR and ¹³C NMR spectroscopy, thermogravimetric/differential thermal analysis, gel permeation chromatography, cyclic voltammetry and conductivity measurements were performed. The number‐average (M_n) and weight‐average molecular weight (M_w) and dispersity (D = M_w/M_n) of the polymer were found to be 61 000 and 94 200 g mol^?1 and 1.54, respectively. Apparent activation energies of the thermal decomposition of the polymer were determined using the Tang, Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose and Coats–Redfern methods. The most likely decomposition process was a D_n deceleration type in terms of the Coats–Redfern and master plot results. CONCLUSION: The mechanism of the degradation process can be understood through the use of kinetic parameters obtained from various non‐isothermal methods. Copyright © 2009 Society of Chemical Industry     

The kinetics of the thermal decomposition of poly(3‐hydroxybutyrate) and maleated poly(3‐hydroxybutyrate)

The thermal decomposition mechanism of maleated poly(3‐hydroxybutyrate) (PHB) was investigated by FTIR and ¹H NMR. The results of experiments showed that the random chain scission of maleated PHB obeyed the six‐membered ring ester decomposition process. The thermal decomposition behavior of PHB and maleated PHB with different graft degree were studied by thermogravimetry (TGA) using various heating‐up rates. The thermal stability of maleated PHB was evidently better than that of PHB. With increase in graft degree, the thermal decomposition temperature of maleated PHB gradually increased and then declined. Activation energy E_a as a kinetic parameter of thermal decomposition was estimated by the Flynn‐Wall‐Ozawa and Kissinger methods, respectively. It could be seen that approximately equal values of activation energy were obtained by both methods. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1789–1796, 2002; DOI 10.1002/app.10463     

Thermal degradation of environmentally friendly phenolic resin/Al2O3 hybrid composite

An environmentally friendly phenolic resin/Al₂O₃ hybrid composite was prepared. Al₂O₃ particles were pretreated with a silcane coupling agent, then the mixture of paraformaldehyde and treated Al₂O₃ was grinded with ball crusher for several hours, and added during the phenolic resin polymerization process, finally got the hybrid composite. The kinetic parameters of thermal degradation were calculated by the methods of Kissinger, Flynn‐Wall‐Ozawa and Crane. The thermal degradation activation energy of environmentally friendly phenolic resin/Al₂O₃ hybrid composite is approximate three times of pure phenolic resin. The results show that the heat resistance is obviously improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of different ionizable groups on the thermal properties of waterborne polyurethanes used in bulletproof composites

The thermal stability of the resin matrix is an important factor affecting the safety performance of fiber‐reinforced bulletproof composites (FRBCs) during their service period. In this study, two kinds of waterborne polyurethanes based on polyester diol (PEDL218) and isophorone diisocyanate were synthesized; these were used as the matrix of para‐aramid FRBCs. Their thermal stability and thermal decomposition behaviors in a nitrogen atmosphere were studied by dynamic thermogravimetric analysis techniques. The kinetic parameters, including the activation energy (E) and pre‐exponential factor (A), were calculated by the Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, Kissinger, and ?atava–?esták methods. The results show that the cationic waterborne polyurethane with quaternary ammonium groups has better thermal stability than the anionic waterborne polyurethane with carboxylate groups. Their nonisothermal decomposition mechanisms were studied, and the kinetic parameters were also calculated; this will offer theoretical reference for the manufacturing and application of FRBCs based on waterborne polyurethane. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42374.     

Thermal degradation kinetics of poly(N‐adamantyl‐exo‐nadimide) synthesized by addition polymerization

The thermal decomposition behavior and degradation kinetics of poly(N‐adamantyl‐exo‐nadimide) were investigated with thermogravimetric analysis under dynamic conditions at five different heating rates: 10, 15, 20, 25, and 30°C/min. The derivative thermogravimetry curves of poly(N‐adamantyl‐exo‐nadimide) showed that its thermal degradation process had one weight‐loss step. The apparent activation energy of poly(N‐adamantyl‐exo‐nadimide) was estimated to be about 214.4 kJ/mol with the Ozawa–Flynn–Wall method. The most likely decomposition process was an F1 deceleration type in terms of the Coats–Redfern and Phadnis–Deshpande results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3003–3009, 2007     

Thermal stability and kinetics analysis of epoxy composites modified with reactive polyol diluent and multiwalled carbon nanotubes

The effect of polyether polyol and amino‐functionalized multiwalled carbon nanotubes (NH₂‐MWCNTs) on the thermal stability of three‐phase (epoxy/polyol/NH₂‐MWCNTs) epoxy composites was investigated. Thermal stability and degradation characteristics of polyol/MWCNTs modified epoxy composites was evaluated using thermogravimetric analysis. The kinetics of thermal degradation was assessed from data scanned at 5, 10, and 20°C/min. Activation energy for degradation of epoxy nanocomposites was calculated using different differential and integral methods, that is, Kissinger's, Flynn–Wall–Ozawa, Coats–Redfern, and Horowitz–Metzger methods. In addition, the integral procedure decomposition temperature was determined to evaluate the inherent thermal stability of the modified composite system. Rate of thermal degradation in MWCNT/Polyol samples was found to be reduced significantly while activation energy of degradation was increased compared to unmodified epoxy composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41558.