Synthesis of Amphiphilic Miktoarm ABC Star Copolymers by RAFT Mechanism Using Maleic Anhydride as Linking Agent

The preparation and characterization of amphiphilic ABC miktoarm star copolymers based on polystyrene, and poly(ethylene oxide), poly(methyl acrylate) or poly(N-isopropylacrylamide) blocks are described in this paper. First, macrotransfer agent polySt-MAh-S-C(S)Ph with maleic anhydride and a dithio group at one end of polymer chain was synthesized by the reaction of a dithio group at the end of the polystyrene with maleic anhydride (MAh) in tetrahydrofuran solution. The second, reversible addition−fragmentation chain transfer polymerization of methyl acrylate or N-isopropylacrylamide was carried out in the prescence of polySt-MAh-S-C(S)Ph and benzoyl peroxide. Finally, the anhydride group at the joint of two blocks was reacted with terminal hydroxyl group of poly(ethylene glycol methyl ether). The obtained ABC star copolymers were characterized by 1H NMR spectroscopy and gel permeation chromatography.