DEVELOPMENT AND APPLICATIONS OF HIGH-SPEED LIVING AND IMMORTAL POLYMERIZATIONS

合成具有均一、可控分子量的聚合物是高分子化学领域的重要课题之一。我们已经发现，某些金属卟啉作为各种单体的活性和不灭阴离子聚合的优良引发剂。作为亲核引发剂的铝卟啉（1）与通过配位相互作用起单体活化剂作用的大体积刘易斯酸（2）结合。在这种亲核-亲电共存体系中，很可能发生这两种物质之间的降解中和，导致聚合终止。然而，该不希望的反应被引发剂中的卟啉配体和刘易斯酸中的大体积酚盐配体之间的空间排斥抑制。这就是高速活性聚合的原理，高速活性聚合可应用于甲基丙烯酸酯等单体 ...更多信息 以及腈、环氧化物、内酯和环状碳酸酯。通过改变单体与引发剂的摩尔比，可以很好地控制所生产的聚合物的分子量，其中可以在优化的条件下获得分子量>10^6的窄MWD聚合物。在手性刘易斯酸存在下，外消旋甲基丙烯酸α-甲基苄酯通过铝卟啉的高速活性聚合由于立体选择性单体活化而对映选择性地进行。氧杂环丁烷，其已被理解为仅阳离子地聚合，也可通过本发明的二元体系聚合，从而提供窄MWD聚醚。甲基丙烯酸甲酯和氧杂环丁烷的连续高速活性聚合成功地得到了一种窄分子量分布的新型聚乙烯-聚醚嵌段共聚物，大体积刘易斯酸也促进了铝卟啉/醇体系中环氧化合物的永久聚合，在适当的条件下，每个引发剂分子可得到1000个以上窄分子量分布的聚合物分子。少

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