Use of N,N‐dimethylaniline end‐functional polymers in photoinduced block copolymerization

Abstract

AbstractN,N‐Dimethylaniline functional polystyrenes with well‐defined structures and low polydispersities were synthesized by atom transfer radical polymerization of styrene in bulk at 110°C using 4‐(dimethylamino)benzyl 4‐(bromomethyl) benzoate as initiator in conjunction with a cuprous complex [Cu(I)Br/bipyridine]. These polymers were further used in block copolymerization with methyl methacrylate and cyclohexene oxide (CHO) by photoinduced radical and radical‐promoted cationic polymerization routes, respectively. In the former case, macroradical generation was achieved with benzophenone sensitizer by photoexcitation followed by hydrogen abstraction from amino end groups. A visible light initiating system was used in the radical‐promoted cationic polymerization of CHO. The system involves a xanthene dye (erythrosin B) as the sensitizer, an aromatic N,N‐dimethyl amino group and diphenyl iodonium hexafluorophosphate as the radical source and radical oxidizer, respectively. Whereas pure block copolymers were obtained in the free‐radical route, the free‐radical–promoted cationic polymerization yielded both block and homopolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 387–394, 2004