Allyl-Terminated Polypropylene Macromonomers: A Route to Polyolefin Elastomers with Excellent Elastic Behavior

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• 作者：Hisashi Ohtaki ; Fanny Deplace ; Giang D. Vo ; Anne M. LaPointe ; Fumihiko Shimizu ; Toshihiko Sugano ; Edward J. Kramer ; Glenn H. Fredrickson ; Geoffrey W. Coates
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：October 27, 2015
• 年：2015
• 卷：48
• 期：20
• 页码：7489-7494
• 全文大小：348K
• ISSN：1520-5835

文摘

We report the design, synthesis, and physical/mechanical properties of graft copolymers containing semicrystalline polypropylene side chains and amorphous ethylene/伪-olefin copolymer backbones. These materials, a new class of semicrystalline, polyolefin-based thermoplastic elastomers, are made in two steps. First, allyl-terminated syndiotactic or isotactic polypropylene macromonomers are synthesized with controlled microstructure and molecular weight using bis(phenoxyimine)titanium or chiral ansa-zirconocene catalysts, respectively. Second, a pyridyl-amido hafnium catalyst is used to copolymerize the macromonomer, ethylene, and an 伪-olefin with precise control of composition and side chain incorporation. With highly crystalline polypropylene side chains and amorphous backbones of low glass-transition temperatures (<鈭?5 掳C), the samples have strain-to-break values up to 1400% and elastic recovery above 85% at maximum strains up to 1000%. The synthetic method described herein does not require the use of a living polymerization catalyst; in addition, the mechanical properties of these graft copolymers exceed those of the best linear block polyolefins.