This study investigates the thermal decomposition initiation mechanisms and kinetics of poly(α-methylstyrene) (PαMS) under isothermal conditions, using molecular dynamics simulations with the ReaxFF reactive force field. The unimolecular pyrolysis simulations show that the thermal decomposition of the PαMS molecule is initiated mainly by carbon–carbon backbone cleavage in two types at random points along the main chain that leads to different intermediates, and is accompanied by depolymerization reactions that lead to the formation of the final products. The time evolution of typical species in the process of PαMS thermal decomposition at various temperatures presents specific evolution profiles and shows a temperature-dependence effect. Isothermal decomposition kinetic analysis based on PαMS pyrolysis shows that the activation energy varies with the degree of conversion during the thermal decomposition processes, which infers that the decomposition process at different conversions may have different reaction mechanisms.

中文翻译：

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聚（α-甲基苯乙烯）等温分解的引发机制和动力学分析：ReaxFF 分子动力学研究

本研究使用 ReaxFF 反应力场进行分子动力学模拟，研究等温条件下聚 (α-甲基苯乙烯) (PαMS) 的热分解引发机制和动力学。单分子热解模拟表明，PαMS 分子的热分解主要由碳-碳主链在主链上随机点的两种类型的断裂引发，导致不同的中间体，并伴随着解聚反应，导致形成最终产品。PαMS在不同温度下热分解过程中典型物种的时间演化呈现出特定的演化曲线并表现出温度依赖性效应。