Synthesis of branched polymers by means of living anionic polymerization. 10. Synthesis of well-defined heteroarm star-branched polymers by coupling reaction of chain-functionalized polystyrenes with benzyl halide moieties with living anionic polymers of

The synthesis of well-defined heteroarm star-branched polymers having poly(tBMA) arms by the coupling reactions of living anionic polymers of tert-butyl methacrylate (tBMA) with chain-functionalized polymers with a definite number of benzyl halide moieties was described. The reaction of living anionic poly(tBMA) bearing potassium countercation with benzyl bromide-functionalized polystyrenes proceeded readily and quantitatively in THF at −40 °C for 1 h and −78 °C for 5 h, respectively. Similarly heteroarm star-branched polymers of AB2, AB3, AB4, A2B4, and ABC4 types with well-defined architectures were successfully synthesized. On the other hand, the same living poly(tBMA) was sluggish to react with benzyl chloride-functionalized polystyrenes, requiring 168 h to achieve quantitative formation of AB4 star polymer. Moreover, no reaction occurred between living poly(tBMA) bearing lithium countercation in the presence of LiCl and benzyl chloride-functionalized polystyrene in THF at −78 °C for 168 h.