高摩尔质量PPR的非等温结晶性能

在工业化聚丙烯装置上生产了高摩尔质量乙烯无规共聚聚丙烯(UHPPR1)，用差示扫描量热仪、广角X射线衍射仪和偏光显微镜研究了UHPPR1和常规摩尔质量PPR(PPR1)的非等温结晶行为、晶体结构和形态，并测试了力学性能。结果表明，UHPPR1的刚性和韧性均较PPR1好。高摩尔质量的分子链起到成核剂的作用，有较快的结晶速率和较高的结晶温度，球晶变小；另一方面，由于UHPPR1的摩尔质量分布宽，其低摩尔质量部分易于结晶，与PPR1有相近的结晶度。

Non-isothermal Crystallization Behavior of Ethylene-propylen Random Copolymer with High Molecular Weight

Ethylene-propylene random copolymer (UHPPR1) with high molecular weight was produced with a commercial plant, and the non-isothermal crystallization behavior, crystalline morphology and structure of UHPPR1 were analyzed and compare with those of the ethylene-propylene random copolymer (PPR1) with conventional molecular weight and narrow MWD by means of DSC, XRD and PLM, the mechanical properties of UHPPR1 were also tested. The results showed the stiffness and toughness of UHPPR1 were all higher than those of PPR1.The higher molecular weight chains of UHPPR1 acted as nucleation agent, which resulted in increasing crystallization rate and decreasing spherulites in size, while the lower molecular weight chains of UHPPR1 was favorable to perfect crystalline, being helpful for retaining good stiffness in comparison with PPR1.