No abstract

Amphiphilic heteroarm star-shaped polymers have important theoretical and practical significance. In this work, amphiphilic heteroarm star-shaped polymer was synthesized by the use of polyfunctional chain transfer agent via sequential free radical polymerization in two steps. First, conventional free radical polymerization of methyl methacrylate (MMA) initiated by 2,2 0 -azobis (isobutyronitrile) (AIBN) was carried out in the presence of polyfunctional chain transfer agent, pentaerythritol-tertrakis (3-mercaptopropinate) (PETMP). At appropriate monomer conversion, about two-arm s-PMMA having two residual thiol groups at the chain center was obtained. Second, the s-PMMA obtained above was used as macro-chain-transfer agent for free radical polymerization of acrylic acid (AA). The heteroarm star-shaped polymer with the hydrophobic PMMA segment and the hydrophilic PAA segment was obtained. The successful synthesis of heteroarm star-shaped polymers, (PMMA) 2 (AA) 2 , was confirmed by 1 H-NMR and its self-assembly behavior in different solvents.