Non-isothermal decomposition kinetics of conductive polyaniline and its derivatives

Abstract The non-isothermal decomposition kinetics of conductive polyaniline (PANI) and its derivatives, poly(o-methoxyaniline) (POMA) and poly(o-ethoxyaniline) (POEA), was investigated by thermogravimetric analysis (TGA), under inert and oxidative atmospheres, using Flynn-Wall-Ozawa’s approach to assess the kinetic parameters of the decomposition process. The order of reaction was found to be dependent on the degree of conversion indicating that both the early and the later stages of polymer degradation were next the zero or pseudo zero order kinetics, whereas the intermediate stages follow a first order kinetics. The activation energy was found to be dependent on both the degree of conversion and PANI derivative. Activation energy values vary from 125 to 250 kJ/mol, to decompositions carried out under nitrogen, and 75 to 120 kJ/mol to oxidative atmosphere. Parent PANI presented the best thermal stability and suggesting that thermal stability is also influenced by derivatization and type of atmosphere used.

摘要 本研究针对导电聚苯胺（PANI）及其衍生物聚邻甲氧基苯胺（POMA）、聚邻乙氧基苯胺（POEA）的非等温热分解动力学展开探究。实验采用热重分析法（TGA），在惰性及氧化气氛下开展测试，并运用Flynn-Wall-Ozawa法求解分解过程的动力学参数。结果表明，反应级数随转化率动态变化：聚合物降解的早期与后期阶段均接近于零级或准零级动力学，而中间阶段则遵循一级动力学。活化能同时受转化率及聚苯胺衍生物种类的影响：氮气气氛下热分解的活化能区间为125~250 kJ/mol，氧化气氛下则为75~120 kJ/mol。原始聚苯胺展现出最优的热稳定性，研究结果证实热稳定性同时受衍生化修饰方式与所用气氛类型的共同影响。