文献类型：期刊文献

英文题名：Shear-Induced β-Form Polypropylene in Long Chain Branching Isotactic Polypropylene

作者：Zhou, Shuai[1];Wang, Weixia[1];Zhao, Shicheng[1];Xin, Zhong[1,2];Shi, Yaoqi[3]

机构：[1]E China Univ Sci & Technol, Sch Chem Engn, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Sch Chem Engn, Shanghai Key Lab Multiphase Mat Chem Engn, Shanghai 200237, Peoples R China;[3]Shanghai Res Inst Chem Ind, Shanghai Key Lab Catalysis Technol Polyolefins, Shanghai 200062, Peoples R China

年份：2016

卷号：56

期号：2

起止页码：240

外文期刊名：POLYMER ENGINEERING AND SCIENCE

收录：;EI(收录号：20155101696511);WOS:【SCI-EXPANDED(收录号:WOS:000371633600013)】；

基金：Contract grant sponsor: Fundamental Research Funds for the Central Universities of China; contract grant numbers: 22A201514016, 222201314051; contract grant sponsor: National Natural Science Funds of China; contract grant numbers: 21476085, 21306047.

语种：英文

外文关键词：Benzoic acid - Benzoyl peroxide - Chains - Cooling - Crystallization - Styrene

摘要：Long chain branching polypropylene (LCBPP) with different long chain branching (LCB) contents were prepared by reactive extrusion in the presence of styrene and benzoyl peroxide, and their shear-induced crystallization behaviors were investigated. The results indicated that the LCB structure extended the relaxation time of LCBPP in the molten state, which led to the formation of beta-form polypropylene under shear and high cooling rate. The content of beta-form (K-beta) increased with the increase of LCB content, shearing rate and cooling rate. The K-beta value of LCBPP3 whose weight average molecular weight was 920,000 g mol(-1) could be up to 52.0% with a shear rate of 60 s(-1) associated with a cooling rate of 280 degrees C min(-1). This study is expected not only to have a deeper understanding of the shear-induced crystallization behavior of LCBPP, but also provide a new strategy to obtain high level beta-form polypropylene. (C) 2015 Society of Plastics Engineers