Synthesis of block copolymers by combination of photoinduced and atom transfer radical polymerization routes

Block copolymers of methyl methacrylate (MMA) and styrene (St) were obtained by the combination of two different free radical polymerization processes, namely photoinduced and atom transfer radical polymerization (ATRP) methods. In the first step, hydroxy terminated polymers were prepared by photoinitiated polymerization of MMA in the presence of N, N′-dimethylethanolamine and benzophenone as the initiating system and subsequently converted to bromine ended poly(methyl methacrylate) by the esterification of the resulting polymer with 2-bromo-propionylbromide. The functionalized polymers thus prepared were used as initiators in ATRP of St, in bulk, in conjunction with CuBr/2,2′-bipyridine as catalyst. The GPC and ¹H-NMR analysis, and the kinetic studies indicate a fully controlled/"living" radical polymerization which results in the formation of block copolymers with narrow polydispersities.