全同立构聚丙烯均聚物中的取向γ相

Oriented Gamma Phase in Isotactic Polypropylene Homopolymer.

作者信息

van Erp Tim B, Balzano Luigi, Peters Gerrit W M

机构信息

Department of Mechanical Engineering, Materials Technology Institute, Eindhoven University of Technology, P.O.Box 513, 5600 MB, Eindhoven, The Netherlands.

DSM Material Science Center, Urmonderbaan 22, Geleen 6167 RD, The Netherlands.

出版信息

ACS Macro Lett. 2012 May 15;1(5):618-622. doi: 10.1021/mz3000978. Epub 2012 Apr 19.

DOI:10.1021/mz3000978

PMID:35607073

Abstract

The presence of γ-phase in isotactic polypropylene is well-known but, up until now, could only be induced by specific processing conditions or material modifications. Typically, for Ziegler-Natta (ZN) iPPs pressures of 2000 bar are required, otherwise, metallocene (M) iPPs and copolymerization using olefin-type counits should be used. Here we show that crystallization under the unique combination of moderate pressure ( ≥ 900 bar) and strong shear flow oriented specimens with high contents of γ-phase are created in ZN-iPPs. The oriented morphology is qualified as a shish-kebab structure that templates densely branched γ-lamellae on parent α-lamellae as well as directly to the shish backbone.

摘要

等规聚丙烯中γ相的存在是众所周知的，但到目前为止，只能通过特定的加工条件或材料改性来诱导。通常，对于齐格勒-纳塔（ZN）等规聚丙烯，需要2000巴的压力，否则，应使用茂金属（M）等规聚丙烯和使用烯烃类共聚单元的共聚方法。在此我们表明，在中等压力（≥900巴）和强剪切流的独特组合下进行结晶时，ZN等规聚丙烯中会形成具有高含量γ相的取向试样。这种取向形态被认为是一种串晶结构，它在母α片晶上以及直接在串晶主链上形成密集分支的γ片晶模板。