Abstract: Block copolymers were synthesized by conventional free radical polymerization in two steps by using polyfunctional chain transfer agent. In the first step，free radical polymerization of methyl methacrylate was carried out in the presence of a chain transfer agent，1，2-ethanedithiol. Hence，PMMA with residual thiol groups at the chain end were obtained at appropriate monomer conversions. Thus prepared PMMA with residual thiol groups at the chain end was subsequently used in the second step as a macro-chain transfer agent，where conventional free radical polymerization of styrene was carried out yielding block copolymers of PMMA with polystyrene successfully.

摘要： 以偶氮二异丁腈为引发剂，乙二硫醇（EDT）为链转移剂进行甲基丙烯酸甲酯（MMA）的自由基聚合，得到了含有残余巯基的聚甲基丙烯酸甲酯大分子链转移剂（HS-PMMA），继而以HS-PMMA作为大分子链转移剂进行苯乙烯的自由基聚合，采用普通自由基聚合方法合成了结构可以设计的嵌段共聚物。