End‐functionalization of syndiotactic polystyrene by vinylsilane inducing selective chain transfer reactions |
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Authors: | Ting‐Jui Hsiao Jing‐Cherng Tsai |
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Institution: | Department of Chemical Engineering, National Chung Cheng University, Chia‐Yi 62142, Taiwan |
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Abstract: | Structurally well‐defined end‐functionalized syndiotactic polystyrene (sPS) can be prepared by conducting a simultaneous selective chain transfer reaction during the syndiospecific polymerization of styrene in the presence of vinylsilanes. The production of vinylsilane end‐capped sPS involves a unique selective chain transfer pathway via the incorporation of a terminal vinylsilane unit at the polymer chain end by 2,1‐insertion. This unusual insertion pattern situates the bulky silyl functional group at a closer β‐position from the active catalyst center, thus deactivating the propagating chain by a steric jam between the vinylsilane end group and the active catalyst. Subsequently, chain releasing by hydrogen addition (in the presence of H2) or by β‐elimination (in the absence of H2) can take place, which leads to the production of end‐functionalized sPS with precise controls of stereoregularity and of the location of functionality. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1690–1698, 2010 |
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Keywords: | end‐functionalized sPS functionalization of polymers polystyrene selective chain transfer stereospecific polymer syndiotactic syndiotactic polystyrene |
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