聚氯乙烯/蒙脱土复合材料的动态热降解动力学

Kinetic Study of Non-Isothermal Degradation of Poly(vinyl chloride)-Montmorillonite Composites

采用热重分析仪研究了聚氯乙烯(PVC)/蒙脱土复合材料的热降解过程,比较了钠基蒙脱土(MMT)和烷基季铵盐改性的有机蒙脱土(OMMT)对PVC热稳定性和PVC热降解过程的影响.采用Friedman法研究了PVC和PVC/MMT(OMMT)复合材料的热降解动力学,并计算得到其表观活化能Ea.结果表明,在PVC热降解第一阶段,MMT和OMMT均能提高PVC的热分解温度和减少质量损失,从而提高PVC的热稳定性;PVC和PVC/MMT(OMMT)复合材料的Ea基本相近;MMT和OMMT对PVC的热降解速度有影响,但并没有改变PVC热降解机理.

The non-isothermal degradation of poly(vinyl chloride)-montmorillonite composites was studied by means of thermogravimetric analysis. The effects of sodium-MMT (MMT) and alkylammonium-modified MMT (OMMT) on the thermal stability of PVC/MMT (OMMT) composites were compared. The thermal degradation of PVC/MMT (OMMT) composites and the apparent activation energies Ea were analyzed and calculated by using the Friedman method. The results show that in the first degradation stage of PVC, both MMT and OMMT can increase the onset temperature of PVC and the Ea values of the three composites are comparable, and MMT and OMMT do not change the thermal degradation mechanism of PVC, but only influence its degradation rate.