Formation of cylindrite structures in shear-induced crystallization of isotactic polypropylene at low shear rate

doi:10.1016/j.polymer.2006.12.025

CORC > 化学研究所 > 中国科学院化学研究所

	Formation of cylindrite structures in shear-induced crystallization of isotactic polypropylene at low shear rate
	Zhang, Chenggui ; Hu, Haiqing ; Wang, Xiaohong ; Yao, Yonghua ; Dong, Xia ; Wang, Dujin ; Wang, Zhigang ; Han, Charles C.
刊名	POLYMER
	2007-02-09
卷号	48 期号:4 页码:1105-1115
关键词	Crystallization Shish-kebab Structure Low Shear Rate
ISSN号	0032-3861
DOI	10.1016/j.polymer.2006.12.025
英文摘要	The shear-induced crystallization behavior of isotactic polypropylene (iPP) at low shear rate and low temperature was investigated by in situ optical microscopy, time-resolved small-angle light scattering (SALS) and ex situ atomic force microscopy (AFM). Some new details and insight of the cylindrites were observed, which are important to delineate the formation mechanism of the cylindrite structures. Optical microscopic measurements showed that the core of cylindrite was formed rapidly after shear cessation, at late stage the quantity of the newly formed crystals increased and these crystals impinged into each other rapidly due to the space limitation. Measurement of the length of cylindrite core from optical microscopic observation showed that the length of cylindrite core did not change or changed very slightly with crystallization time. SALS results indicated that immediately after shear flow, the highly oriented structure emerged and the scattering intensity increased with crystallization time. and eventually the scattering patterns became circularly symmetric and the anisotropic scattering decreased, indicating the impingement of different cylindrite structures. AFM observation showed that the crystalline lamellae grew both perpendicular to and along the cylindrite core. In addition, a much wider cylindrite core was observed. Compared with the radius of gyration of a molecule.. the process of shear-induced crystallization may have involved a large number of entangled molecules under a low shear rate. These evidences clearly indicate that the cylindrite cord comes from the stretched bundles of the entangled network strands but not from the extended crystals of stretched single chains. A model based on the above observations has been proposed to explain the mechanism of the cylindrite developing process at low shear rate and low temperature. (c) 2007 Elsevier Ltd. All rights reserved.
语种	英语
出版者	ELSEVIER SCI LTD
WOS记录号	WOS:000244509400021
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/44039]
专题	中国科学院化学研究所
通讯作者	Han, Charles C.
作者单位	1.Beijing Natl Lab Mol Sci, Joint Lab Polymer Sci & Mat, State Key Lab Polyner Phys & Chem, Inst Chem,CAS Key Lab Engn Plast, Beijing 100080, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100080, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Chenggui,Hu, Haiqing,Wang, Xiaohong,et al. Formation of cylindrite structures in shear-induced crystallization of isotactic polypropylene at low shear rate[J]. POLYMER,2007,48(4):1105-1115.
APA	Zhang, Chenggui.,Hu, Haiqing.,Wang, Xiaohong.,Yao, Yonghua.,Dong, Xia.,...&Han, Charles C..(2007).Formation of cylindrite structures in shear-induced crystallization of isotactic polypropylene at low shear rate.POLYMER,48(4),1105-1115.
MLA	Zhang, Chenggui,et al."Formation of cylindrite structures in shear-induced crystallization of isotactic polypropylene at low shear rate".POLYMER 48.4(2007):1105-1115.