取向等规聚丙烯退火过程中的再晶化

Recrystallization in the oriented isotactic polypropylene during ageing

采用广角X射线衍射法研究取向等规聚丙烯材料在退火过程中结晶度和织构的变化规律,并用偏光显微镜观察材料中球晶的形貌变化。结果显示,在退火初期的10 min内,试样结晶度迅速增加,材料中的轧制织构组元含量有所增大,同时材料中球晶的形貌变得清晰可辨。通过对织构组元的定量分析发现,再晶化形成的新晶体拥有与残余晶体相同的晶体取向。退火过程中的再晶化是非晶部分沿残余晶体发生择优重排的过程,新晶体的大分子链方向与残余晶体的大分子链方向相同。

The changes of crystallinity and texture in oriented isotactic polypropylene （iPP） during ageing are studied by the wide angle X-ray diffraction. The spherulites morphology of iPP samples is observed by the polarized microscopy. The results show that annealing after rolling deformation leads to the increase of crystallinity and much clear spherulites morphology during the first 10 minutes. An enhancement of the texture components is also observed in the work. The quantitative analysis of the texture components shows that the new crystalline part has the same crystallographic orientation as the existent crystalline lamellae. The recrystallization is explained as a growth selection where the amorphous component aligns along the existent crystalline lamellae, and the macromolecule of new crystalline has the same orientation as that of the existent crystalline.