Molecular dynamics simulation of shish-kebab crystallization of polyethylene: Unraveling the effects of molecular weight distribution.
作者： Li Zhao , Yanling Hu , Yunqi Shao , Zhen Liu , Boping Liu
DOI: 10.1063/1.5089694
关键词:
摘要: By means of molecular dynamics simulations, extensional flow was performed on five polyethylene models with different weight distributions (MWDs) precisely designed in view Grubbs, metallocene, Ziegler-Natta, and chromium-based catalysts, while ignoring the sequence short branches to shed light mechanism MWD shish-kebab formation. The formation crystallites can be divided into three stages: emergence precursors, evolution from precursors shish nuclei, lamellar crystallites. results demonstrated that initiated trans-rich segments local order minor crystallinity grew large nuclei eventually evolved lamellae. There were more inconsecutively trans-state bonds occurring long chains rather than chains, which promoted an easier transformation nuclei. Therefore, broader MWDs make positive contributions increase crystallization speed, generation a regular, compact, thicker lamella less tie molecule fractions, final is independent MWD.
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A. Keller, J. W. H. Kolnaar, Chain extension and orientation: Fundamentals and relevance to processing and products Progress in colloid and polymer science. ,vol. 92, pp. 81- 102 ,(1993) , 10.1007/BFB0115450
M.P. McDaniel, Supported Chromium Catalysts for Ethylene Polymerization Advances in Catalysis. ,vol. 33, pp. 47- 98 ,(1985) , 10.1016/S0360-0564(08)60258-8
Thomas T Perkins, Douglas E Smith, Steven Chu, Single Polymer Dynamics in an Elongational Flow Science. ,vol. 276, pp. 2016- 2021 ,(1997) , 10.1126/SCIENCE.276.5321.2016
G. S. Y. Yeh, Strain-induced crystallization II. Subsequent fibrillar-to-lamellar transformation Polymer Engineering and Science. ,vol. 16, pp. 145- 151 ,(1976) , 10.1002/PEN.760160305
Chunli Li, Phillip Choi, P.R. Sundararajan, Simulation of chain folding in polyethylene: A comparison of united atom and explicit hydrogen atom models Polymer. ,vol. 51, pp. 2803- 2808 ,(2010) , 10.1016/J.POLYMER.2010.04.049
N. V. Pogodina, S. K. Siddiquee, J. W. van Egmond, H. H. Winter, Correlation of Rheology and Light Scattering in Isotactic Polypropylene during Early Stages of Crystallization Macromolecules. ,vol. 32, pp. 1167- 1174 ,(1999) , 10.1021/MA980737X
Motohiro Seki, Derek W. Thurman, James P. Oberhauser, Julia A. Kornfield, Shear-Mediated Crystallization of Isotactic Polypropylene: The Role of Long Chain−Long Chain Overlap Macromolecules. ,vol. 35, pp. 2583- 2594 ,(2002) , 10.1021/MA011359Q
Natalia V. Pogodina, Victor P. Lavrenko, Srivatsan Srinivas, H.Henning Winter, Rheology and structure of isotactic polypropylene near the gel point: quiescent and shear-induced crystallization Polymer. ,vol. 42, pp. 9031- 9043 ,(2001) , 10.1016/S0032-3861(01)00402-5
Baijin Zhao, Xiangyang Li, Youju Huang, Yuanhua Cong, Zhe Ma, Chunguang Shao, Haining An, Tinzi Yan, Liangbin Li, Inducing Crystallization of Polymer through Stretched Network Macromolecules. ,vol. 42, pp. 1428- 1432 ,(2009) , 10.1021/MA802679H
Toshiji Kanaya, Go Matsuba, Yoshiko Ogino, Koji Nishida, Hirohiko M. Shimizu, Takenao Shinohara, Takayuki Oku, Junichi Suzuki, Toshiya Otomo, Hierarchic structure of shish-kebab by neutron scattering in a wide Q range Macromolecules. ,vol. 40, pp. 3650- 3654 ,(2007) , 10.1021/MA062606Z