A New View of the Initiation and Propagation in Anionic Polymerization
A New View of the Initiation and Propagation in Anionic Polymerization作者机构：Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials ofMinistry of Education School of Materials Science and Engineering East China University of Science and Technology Shanghai 200237 China
出 版 物：《Chinese Journal of Chemistry》 (中国化学（英文版）)
年 卷 期：2013年第31卷第3期
页 面：393-400页
核心收录：
学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070304[理学-物理化学(含∶化学物理)] 070305[理学-高分子化学与物理] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学]
基 金：Financial supports for this work from the Nature Science Foundation of China for the Major Program (No. 50933002) the National High Technology Re-search and Development Program of China (863 Pro-gram No. 2012AA040306) and Shanghai Leading Academic Discipline Project (No. B502) are gratefully acknowledged
主 题：anionic polymerization initiation mechanism in situ 7^Li NMR organolithium supramolecular aggre-gator
摘 要：This work confirms the new view of the initiation and propagation mechanism of the anionic polymerization previously proposed, based on the investigation of anionic bulk-polymerization of styrene and α-methyl styrene with the help of a self designed microflow device and characterized by GPC and in situ ^7Li NMR. It was found that n-BuLl tended to form the hexameric-aggregated structure and even to form the huge aggregated structure based on the former. These aggregations of initiators could directly initiate the anionic polymerization and form the su-pramolecule aggregations. The supramolecule aggregations inevitably blocked the diffusion of the monomers to the ion-pairs and resulted in a stationary-conversion platform. Then the aggregators were dissociated completely into equal binary-aggregated species, and the polymerization continued again rapidly before the termination. Tetrahy-drofuran （THF） acted as the electron donator, which could push the electron cloud to Li cation and make the aggre- gated ring of the active species rather loosened and facilitated the monomer to insert in. Therefore, a little THF can greatly promote the anionic polymerization. However, further addition of THF might block the channel between the ion-pairs and decrease the propagation rate. It was also found that the aggregated structure of the active species during the anionic polymerization only depends on the initiator aggregations which were formed before the polym-erization.
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