膨胀聚苯乙烯泡沫热氧化分解动力学研究

Kinetics of the Thermo-Oxidative Decomposition of Expanded Polystyrene Foam

用非等温热重分析方法对膨胀聚苯乙烯泡沫的热氧化分解特性进行了研究.样品在空气气氛下由10,℃/min、20,℃/min、40,℃/min和50,℃/min共4个升温速率从室温加热至800,℃.分别使用积分等转化率方法中的Flynn-Wall-Ozawa(FWO)和Kissinger-Akahir-Sunose(KAS)方法以及基于动力学补偿效应的恒定动力学参数方法(invariant kinetic parameter method,IKP)计算膨胀聚苯乙烯非等温热氧化分解的动力学参数.由等转化率方法得到的结果可认为膨胀聚苯乙烯泡沫在空气气氛下主要为一步反应.FWO方法和KAS方法得到的平均活化能与IKP方法得到的活化能具有较好的一致性.由IKP方法和常用固相反应机理函数在不同升温速率下动力学参数的对应准则可确定膨胀聚苯乙烯泡沫热氧化分解过程可由成核和核生长控制的机理函数(Avrami Eroféev方程)A1.7描述.

The thermo-oxidative decomposition of expanded polystyrene foam （EPS） was studied using non-isothermal thermogravimetric analysis at the heating rates of 10 ℃/min, 20 ℃/min, 40 ℃/min and 50 ℃/min under the air atmosphere within the temperature range from room temperature to 800 ℃, respectively. The kinetic parameters were calculated by the isoconversional methods （i.e. Flynn-Wall-Ozawa（FWO）and Kissinger-Akahir-Sunose （KAS）） and the invariant kinetic parameter method （IKP） which is based on the kinetic compensation effect. The re- suits obtained from the isoconversional methods show that the EPS primarily decomposes in a single step. The values of invariam activation energy are in good agreement with those determined by the isoconversional methods. With the aim of determining the kinetic model, the IKP method was associated with the criterion of coincidence of the kinetic parameters of the known solid-state conversion functions for all heating rates. Finally, the nucleation and nuclei growth （Avrami Erofrev equation）A1.7 mechanism was obtained to describe the thermo-oxidative decomposition of EPS.