Synthesis and characterizations of well‐defined branched polymers with AB₂ branches by combination of RAFT polymerization and ROP as well as ATRP

Abstract

Abstract A well‐defined branched copolymer with PLLA‐ b ‐PS 2 branches was prepared by combination of reversible addition‐fragmentation transfer (RAFT) polymerization, ring‐opening polymerization (ROP), and atom transfer radical polymerization (ATRP). The RAFT copolymerization of methyl acrylate (MA) and hydroxyethyl acrylate (HEA) yielded poly(MA‐ co ‐HEA), which was used as macro initiator in the successive ROP polymerization of LLA. After divergent reaction of poly(MA‐ co ‐HEA)‐ g ‐PLLAOH with divergent agent, the macro initiator, poly(MA‐ co ‐HEA)‐ g ‐PLLABr 2 was formed in high conversion. The following ATRP of styrene (St) produced the target polymer, poly(MA‐ co ‐HEA)‐ g ‐(PLLA‐ b ‐PS 2 ). The structures, molecular weight, and molecular weight distribution of the intermediates and the target polymers obtained from every step were confirmed by their 1 H NMR and GPC measurements. DSC results show one T = 3 °C for the poly(MA‐ co ‐HEA), T = −5 °C, T = 122 °C, and T = 157 °C for the branched copolymers (poly(MA‐ co ‐HEA)‐ g ‐PLLA), and T = 51 °C, T = 116 °C, and T = 162 °C for poly(MA‐ co ‐HEA)‐ g ‐(PLLA‐ b ‐PS 2 ). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 549–560, 2006