降解PP/EPDM共混物的非等温结晶动力学

Non-isothermal crystallization kinetics of degraded polypropylene/ethylene-propylene-diene monomer blends

使用过氧化二异丙苯降解聚丙烯(PP),熔融法制备降解PP与三元乙丙橡胶(EPDM)共混物,采用广角X射线衍射及差示扫描量热法分析了降解PP/EPDM共混物的晶体结构及非等温结晶动力学。结果发现:PP降解后β晶的(300)晶面消失,导致降解PP及其共混物韧性下降、晶粒的粒径分布变宽;降解PP/EPDM共混物在非等温结晶过程中有明显的快速初级结晶和缓慢的次级结晶过程,降解PP以均相成核的三维球晶方式生长,Avrami指数与Ozawa指数相等,Jeziorny方程和Ozawa方程都可以很好地描述降解PP/EPDM共混物的非等温结晶过程。

The polypropylene（PP） was degraded by using peroxide,and then the blends of degraded PP and ethylene-propylene-diene monomer（EPDM） rubber were prepared via melting process.The crystal structure and non-isothermal crystallization kinetics of the degraded PP/EPDM blends were analyzed by wide angle X-ray diffraction（WAXD） and differential scanning calorimetry（DSC）.The results show that crystal face（300） of β-crystal of the degraded PP disappears,as a result,the toughness of the degraded PP and its blends drops and the distribution of the crystal grain diameter becomes wide.The non-isothermal crystallization process of degraded PP/EPDM blends involves obvious fast primary crystallization and slow secondary crystallization process.The degraded PP′crystallites develop in the mode of homogeneously nucleated three-dimensional spherulite.Avrami index is nearly equal to Ozawa index,and Jeziorny equation and Ozawa equation can well describe the non-isothermal crystallization process of the degraded PP/EPDM blends.