A novel strategy to synthesize double comb-shaped water soluble copolymer by RAFT polymerization

A double comb-shaped water soluble copolymer, poly[poly(ehtylene oxide) methyl ehter methacrylate]-block-poly(N-isopropylacryamide)-block-poly[poly(ehtylene oxide) methyl ether methacrylate], abbreviated as [P(MA-MPEO)-block-PNIPAM-block-P(MA-MPEO)], with a controlled molecular weight and narrow polydispersity was successively synthesized using a macromonomer technique. The Co-60 gamma irradiation polymerization of MA-MPEO in the presence of dibenzyltrithiocarbonate (DBTTC) at room temperature afforded a polymer, P(MA-MPEO)-SC(S)S-P(MA-MPEO), which was subsequently used as a macro RAFT agent in the RAFT polymerization of N-isopropylacrylamide, and water soluble double comb-shaped copolymers, P(MA-MPEO)-block-PNIPAM-block-P(MA-MPEO), were successfully obtained.