Synthesis of branched polymers by means of living anionic polymerization — Part 6. Synthesis of well‐defined comb‐like branched polystyrenes and graft copolymers with highly branched architecture

Abstract

AbstractThe synthesis of well‐defined comb‐like branched polymers and graft copolymers with one branch chain per repeating unit by the methodology based on “grafting‐onto” method is described. The methodology involves three reaction steps. The first reaction step is to prepare poly(m‐tert‐butyldimethylsilyloxymethylstyrene)s with predictable molecular weights and narrow molecular weight distributions by living anionic polymerization of m‐tert‐butyldimethylsilyloxymethylstyrene in tetrahydrofuran (THF) at −78 °C. In the second reaction step, the resulting polymers are quantitatively transformed into poly(m‐chloromethylstyrene)s by treatment with BCl 3. Finally, by the reaction of the poly(m‐chloromethylstyrene)s thus prepared with living anionic polymers of styrene, isoprene, and 2‐vinylpyridine, comb‐like branched polymers and graft copolymers are synthesized. Each of all linking reactions proceeded quantitatively to afford the branched polymers with one branch chain per repeating unit. Attempts to synthesize highly branched polystyrenes having more than one branch chain per repeating unit were made by reacting poly(m‐bromomethylstyrene)s with the polymer anions prepared from polystyryllithium with end‐functionalized polystyrenes with 1,1‐diphenylethylene moiety. For the same purpose, we prepared a new polystyrene derivative having two bromomethylphenyl groups in each styrene unit to react with polystyryllithium. Copyright © 2002 John Wiley & Sons, Ltd.