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DEVELOPMENT AND APPLICATIONS OF HIGH-SPEED LIVING AND IMMORTAL POLYMERIZATIONS

高速活性不朽聚合的开发与应用

基本信息

批准号：
07555672
负责人：
AIDA Takuzo
金额：
$ 0.9万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Synthesis of polymers with uniform, controlled molecular weight is one of the important subjects in the field of polymer chemistry. We have found that some metalloporphyrins serve as excellent initiators for the living and immortal anionic polymerizations of a variety of monomers.High-speed living polymerization is realized by, e.g., aluminum porphyrins (1) as nucleophiric initiators in conjunction with bulky Lewis acids (2), which function as monomer activators through coordinative interaction. In such a nucleophile-electrophile coexisting system, a degradative neutralization between these two species, leading to termination of polymerization, is very likely to occur. However, this undesired reaction is suppressed by the steric repulsion between the porphyrin ligand in the initiator and the bulky phenolate ligands in the Lewis acids. This is the principle of the high-speed living polymerization.The high-speed living polymerization can be applied to monomers such as methacrylic esters … More and nitrile, epoxides, lactones, and cyclic carbonates. By changing the monomer-to-initiator mole ratio, molecular weight of the produced polymer is nicely controlled, where a narrow MWD polymer with a molecular weight >10^6 can be obtained under optimized conditions. The high-speed living polymerization of racemic alpha-methylbenzyl methacrylate by an aluminum porphyrin in the presence of a chiral Lewis acid proceeds enantioselectively as a result of the stereoselective monomer activation. Oxetane, which has been understood to polymerize only cationically, is also polymerizable by the present binary system, affording a narrow MWD polyether. Sequential high-speed living polymerization of methyl methacrylate followed by oxetane is successful to give a novel polyvinyl-polyether block copolymer with a narrow MWD.Immortal polymerization of epoxides by aluminum porphyrin/alcohol systems is also accelerated by bulky Lewis acids, and, under suitable conditions, more than 1000 polymer molecules with narrow MWD can be obtained per one initiator molecule. Less

合成均匀、可控制分子量的聚合物是高分子化学领域的重要课题之一。我们发现一些金属卟啉可以作为各种单体的活性和不朽阴离子聚合的优良引发剂。高速活性聚合是通过，例如，铝卟啉(1)作为亲核引发剂与大块路易斯酸(2)结合，通过配位相互作用作为单体激活剂来实现的。在这样的亲核-亲电共存体系中，这两种物质之间很可能发生降解中和，导致聚合终止。然而，这种不希望发生的反应被引发剂中的卟啉配体和路易斯酸中庞大的酚酸配体之间的空间斥力所抑制。这就是高速活聚合的原理。高速活性聚合可应用于单体，如甲基丙烯酸酯和腈、环氧化物、内酯和环状碳酸盐。通过改变单体与引发剂的摩尔比，可以很好地控制聚合物的分子量，在优化条件下可以得到分子量为bbb10 ^6的窄MWD聚合物。在手性路易斯酸存在下，铝卟啉对外消旋α -甲基丙烯酸甲酯进行高速活性聚合，这是立体选择性单体活化的结果。氧乙烷，已被理解为只能阳离子聚合，也可聚合到目前的二元体系，提供了一个窄的MWD聚醚。通过对甲基丙烯酸甲酯和氧乙烷的序贯高速活性聚合，成功地得到了一种新型的窄限长聚乙烯-聚醚嵌段共聚物。大量的Lewis酸也可以加速卟啉铝/醇体系对环氧化物的永久聚合，在适当的条件下，每个引发剂分子可以获得1000多个具有窄MWD的聚合物分子。少