Syntheses of syndiotactic-polystyrene-graft-poly(methyl methacrylate), syndiotactic-polystyrene-graft-poly(methyl acrylate), and syndiotactic-polystyrene-graft-atactic-polystyrene with defined structures by atom transfer radical polymerization

Syndiotactic polystyrene graft copolymers, syndiotactic-polystyrene-graft-poly(methyl methacrylate), syndiotactic-polystyrene-graft-poly(methyl acrylate), and syndiotactic-polystyrene-graft-polystyrene, were synthesized by atom transfer radical polymerization using brominated syndiotactic polystyrene as initiator and CuBr combined with pentamethyldiethylenetriamine as catalyst. Both the graft density and the molecular weight of the graft segments were controlled by changing the bromine content of syndiotactic polystyrene and the amount of monomer used in the grafting reaction. The atom transfer radical polymerization mechanism for grafting was supported by NMR analysis of the end groups. The melting point behavior of syndiotactic-polystyrene-graft-poly(methyl methacrylate) depends on both graft density and graft length.