文献类型：期刊文献

英文题名：Deformation-Induced Crystallization Behavior of Isotactic Polypropylene Sheets Containing a β-Nucleating Agent under Solid-State Stretching

作者：Ji, Huajian[1];Zhou, Xulin[1];Chen, Xin[1];Zhao, Haili[1];Wang, Yu[1];Zhu, Huihao[1];Ma, Yulu[1];Xie, Linsheng[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai 200237, Peoples R China

年份：2020

卷号：12

期号：6

外文期刊名：POLYMERS

收录：;EI(收录号：20202808928816);WOS:【SCI-EXPANDED(收录号:WOS:000554015000001)】；

基金：This research was funded by the National Natural Science Foundation of China, grant number 51273065.

语种：英文

外文关键词：solid-state stretching; beta-modification iPP sheet; phase transformation; cylindrites

摘要：The deformation-induced crystallization of an isotactic polypropylene (iPP) sheet containing a beta-nucleating agent was evaluated. The phase transformation of the beta-modifications was investigated and the crystal morphology was observed at room temperature after stretching at different temperatures. The results showed that the crystallinity increased after solid-state stretching. When the stretching temperature was below the initial crystallization temperature, stretching deformation promoted the orientation of amorphous molecular chains. When the deformation temperature exceeded the crystallization temperature, part of the beta-modifications underwent a phase transformation process and was stretched into a shish-kebab structure. However, once the stretching temperature was close to the melting point, the beta-modifications melted and recrystallized, and the shish-kebab structure underwent stress relaxation due to poor thermal stability, transforming into alpha-modifications. It was revealed that the crystal phase transformation mechanism of the beta-modifications was based on the orientation of the molecular chains between the adjacent lamellae. In addition, the shish-kebab cylindrite structure played an important role in modifying the tensile and impact properties of the iPP sheet. The tensile and impact strengths increased by as much as 34% and 126%, respectively.