“活”的α-甲基苯乙烯共聚物:聚合反应新化学和材料工程新技术  

A Novel Macroinitiator Based on the Copolymer of α-Methylstyrene Synthesis and Its Application in Preparing Block and Graft Polymers

作　　者：马育红[1] 张冰[1] 赵长稳[1] 刘莲英[1] 蒋姗[2] 梁淑君[3] 杨万泰[1] 

机构地区：[1]北京化工大学碳纤维及功能高分子教育部重点实验室化工资源有效利用国家重点实验室,北京100029 [2]常州大学材料科学与工程系,常州213164 [3]太原工业学院材料工程系,太原030008

出　　处：《化学学报》2013年第2期151-158,共8页Acta Chimica Sinica

基　　金：国家自然科学基金委员会创新研究群体科学基金(No.51221002-E03)资助~~

摘　　要：高于临界聚合反应温度时,α-甲基苯乙烯(AMS)单体和其聚合物处于聚合-解聚平衡.基于AMS聚合物在受热时可裂解生成大分子链自由基的特性,提出了含AMS结构单元的共聚物是一种"活"的,可作为大分子自由基引发剂的概念,并通过实验对AMS共聚物的引发性能和应用进行了研究.首先,合成了AMS与(甲基)丙烯酸酯类单体、丙烯酸、苯乙烯和马来酸酐等的共聚物.然后以上述共聚物为大分子引发剂,在90℃引发(甲基)丙烯酸酯类单体和苯乙烯等的本体聚合、溶液聚合和乳液聚合,得到了嵌段共聚物.用ESR谱证明了AMS的共聚物在加热时能裂解生成以碳原子为中心的大分子链自由基.此外,在聚合物的熔融共混中,AMS分解产生的大分子链自由基通过偶合反应形成接枝链,原位生成相容剂.AMS共聚物还可以对碳纳米管及无机粒子进行表面原位接枝改性.AMS共聚物是一类无小分子残留的绿色自由基引发剂,可以用于低成本制备两嵌段共聚物,也可以用于聚合物的熔融共混增容.Due to the steric hindrance effects in combination with stability of the tertiary benzylic α-methylstyryl radical,there is a dynamic equilibrium between the monomer α-methylstyrene（AMS） and its polymer（PAMS） when the temperature is greater than 61 ℃（the ceiling polymerization temperature）.Based on this unique feature,a novel strategy to prepare copolymers of AMS having liable bonds as potential macromolecular free radical initiators for synthesizing block and graft copolymers has been successfully developed in our laboratory.By conventional free radical polymerization,a series of AMS copolymers,including copolymers with（meth）acrylate,acrylic acid,styrene and maleic anhydride were synthesized.Typically,with the increasing of AMS fraction in monomer feed,the rate of copolymerization was significantly retarded and the molecular weight of the copolymers was reduced.However,the copolymer yield could be as high as 90%（w） with the increased addition of initiator,up to 4%（w）,and the molar fraction of AMS structural unit in AMS copolymers could be up to 25%（mol%）.It has been demonstrated that the copolymers containing AMS structural units are efficient free radical initiators when the temperature is greater than 80 ℃（much better higher than 90 ℃）.These copolymers could be exploited as macroinitiator in preparing block copolymers and core-shell polymer particles by bulk,solution and emulsion polymerization processes.In addition,the experimental results demonstrated that the molecular weight of copolymer products prepared with AMS copolymers as macromolecular initiators increased steadily with the monomer conversion.Though the polymerization initiated by AMS copolymers was not a well-controlled living system yet,it showed some characteristics of living polymerization.The ESR spectrum presented direct evidence of the generation of carbon centered radicals in the products of copolymer of AMS with glycidyl methacrylate（PAG） heated with N-t-butyl-α-phenylnitrone at 90 ℃ in toluene.

关 键 词：自由基聚合 大分子引发剂 Α-甲基苯乙烯 嵌段聚合物 接枝聚合 反应性增容 

分 类 号：O631.3[理学—高分子化学]