聚乙烯热分解反应动力学处理方法比较

The Comparetive of Various Treatment Method for Polyethylene Thermal Decomposition Kinetics

利用热重分析在不同升温速率 (5 ,1 0 ,2 0 ,40℃ /min)和氮气气氛下对聚乙烯的热稳定性进行研究 ,讨论了升温速率 β对热分解温度的影响 ,说明热分解温度随 β呈线性增加。根据热重实验曲线 ,采用 5种热分析处理动力学数据的方法 ,计算聚乙烯热分解反应活化能E、反应级数n及频率因子A ,并对处理方法进行比较。结果表明 ,采用不同的处理方法 ,得出的热分解动力学参数略有差别 ,分解活化能为 2 60～ 2 90kJ/mol,反应级数约为 1。为验证上述各方法的可靠性 ,采用二元回归法 ,对热重实验曲线直接计算 ,并以此为标准 ,对其它方法得到的结果进行误差分析。结果表明 ,在诸种处理方法中 ,以Coast-Redfern及Doyle法结果比较可靠 ,与实验值比较接近。

The thermal gravimetric analysis (TG) was used to study the thermal stability of polyethylene(PE) at heating rate of 5,10,20,40℃/min in the fluid of N_2. It has been discussed that the heating rate influences on the energy, reaction progression and preexponential factor were evaluated from common TG experiment curve by five sort of different mathematical method. The results indicate that the kinetic parameters were different by these treating method. Then by binary regresion, the kinetic parameters was worked out.