Hu Shide, Sun Weiguo, Fu Jia, Zhang Zhanwen, Wu Weidong, Tang Yongjian
Institute of Atomic and Molecular Physics, Sichuan University Chengdu Sichuan 610065 P. R. China.
School of Sciences, Southwest Petroleum University Chengdu Sichuan 610500 P. R. China
RSC Adv. 2018 Jan 17;8(7):3423-3432. doi: 10.1039/c7ra12467h. eCollection 2018 Jan 16.
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.
本研究采用基于ReaxFF反应力场的分子动力学模拟，研究了聚（α-甲基苯乙烯）（PαMS）在等温条件下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主链上随机点处的两种类型的碳-碳主链断裂引发，导致不同的中间体，并伴随着解聚反应，最终形成最终产物。在不同温度下PαMS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。基于PαMS热解的等温分解动力学分析表明，热分解过程中活化能随转化率的变化而变化，这意味着不同转化率下的分解过程可能具有不同的反应机制。
