Polymer Design by Iniferter Technique

利用各种热引发剂和光引发剂，研究了新型聚合物的合成和设计。主要研究结果如下：1.研究了苯偶氮三苯甲烷和四苯基丁二腈作为热引发剂对甲基丙烯酸甲酯（MMA）活性自由基聚合的诱导作用。所得齐聚物和聚合物可进一步作为苯乙烯（St）聚合的引发剂，有效地合成了AB嵌段共聚物.二乙基二硫代氨基甲酸苄酯和对亚二甲苯基双（二乙基二硫代氨基甲酸酯）被观察到充当St和MMA的优异的光引发剂，导致分别由均聚物和无规或交替共聚物序列组成的AB和阿坝嵌段共聚物。当使用四（二乙基二硫代氨基甲酰基）苯作为四官能光引发剂时，产生星星或交联聚合物。此外，以乙烯基苄基二乙基二硫代氨基甲酸酯为引发剂，可实现接枝共聚物的定制化合成。由于用引发剂法很难合成不含均聚物的嵌段共聚物，因此不可能制备纯的多嵌段共聚物。因此，使用通过可水解的酯间隔基连接到聚苯乙烯凝胶的二硫代氨基甲酸酯引发剂。在重复聚合和萃取之后，通过碱水解分离纯的三嵌段和四嵌段共聚物。

Studies on novel polymer synthesis and design were investigated by using various thermal and photo-iniferters. The results obtained are summerized as follows.1. Phenylazotriphenylmethane and tetraphenylsuccinodinitrile were found to serve as thermal iniferters and to induce living radical polymerization of methyl methacrylate (MMA). The oligomer and polymer obtained could further act as iniferters of the polymerization of styrene(St), and the AB block copolymer was obtained efficiently.2. Benzyl diethyldithiocarbamate and p-xylylene bis(diethyldithiocarbamate) were observed to serve as excellent photo-iniferters of St and MMA leading to AB and ABA block copolymers consisting of homopolymer and random or alternating copolymer sequence, respectively. When tetrakis(diethyldithiocarbamyl)benzene was used as a tetrafunctional photoiniferter, the star or cross-linked polymer was produced. Moreover, the tailor-made synthesis of graft copolymer was possible by using vinylbenzyl diethyldithiocarbamate as a monomer-iniferter.3. Since it was difficult to synthesize block copolymers free from homopolymers by iniferter technique, the preparation of pure multiblock copolymers was impossible. So, the dithiocarbamate iniferter attached to a polystyrene gel through a hydrolyzable ester spacer was used. After repeated polymerizations and extractions, pure tri- and tetrablock copolymers were isolated by alkaline hydrolysis.