Microstructure of two polypropylene homopolymers with improved impact properties
Microstructure of two polypropylene homopolymers with improved impact properties
复制标题
两种具有改进冲击性能的聚丙烯均聚物的微观结构
DOI：
10.1016/j.polymer.2010.12.009
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发表时间：
2011-01
期刊：
影响因子：
4.6
通讯作者：
Xue, Yanhu
中科院分区：
文献类型：
--
作者：
Zhang, Xuequan;Bo, Shuqin;Ji, Xiangling;Fan, Y;i;Zhang, Chunyu;Xue, Yanhu
本文研究了两种聚丙烯均聚物样品A和B，它们是用非均相齐格勒-纳塔催化剂合成的。两种样品在低温下均显示出比全同立构PP改善的冲击性能。特别地，样品B表现出比样品A更好的韧性、更高的分子量和略低的挠曲性能。采用升温溶解分级法将这两种样品分别分级为6个级分。两种样品主要由级分4、5和6组成，其在高于100 °C收集并且具有高全同立构规整度。一方面，样品B的级分具有比在相同温度下收集的样品A的相应级分更高的分子量。另一方面，级分的13 C NMR和DSC分析清楚地表明，样品B的级分具有比样品A的相应级分更低的全同立构规整度和结晶度。试样A和试样B在微观结构上的上述差异应是最终导致其力学性能差异的关键因素。这两种聚丙烯均聚物都有可能成为新型抗冲聚丙烯。
Two polypropylene homopolymers, samples A and B, synthesized with heterogeneous Ziegler–Natta catalysts, are studied in this work. Both samples show improved impact properties at low temperature than isotactic PP. Particularly, sample B exhibits better toughness, higher molecular weight and slight lower flexural properties than sample A. Then, these two samples were fractionated into six fractions via temperature rising dissolution fractionation, respectively. Both samples are mainly composed of fractions 4, 5 and 6, which were collected above 100 °C and have high isotacticity. On the one hand, the fractions of sample B have higher molecular weight than the corresponding fractions of sample A collected at the same temperatures. On the other hand,13C NMR and DSC analyses of the fractions indicate clearly that fractions of sample B have lower isotacticity and crystallinity than the corresponding fractions of sample A. The above difference in microstructure between samples A and B should be the key factors resulting in their difference in mechanical properties finally. Both polypropylene homopolymers possibly become new type of impact PP.
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