Precise synthesis of poly(α-methylene-γ-butyrolactone) and evaluation of its characteristics

α-methylene-γ-butyrolactonc (MBL) is a polymerizable monomer obtained from tulips with similar structure to methyl methacrylate (MMA). So far, the preparation of PMBL with well-controlled molecular weight, polydispersity index and stereoregularity has not been achieved. Here we report the preparation of well-controlled PMBL by living anionic polymerization. Well-controlled PMBL could not be obtained via homopolymerization of MBL due to the poor solubility of PMBL in common organic solvents, which resulted in a heterogeneous system. Using amide-based solvents, a homogeneous reaction occurred. However, it is difficult to control the living anionic polymerization of MBL in such solvents because of the high reactivity of MBL. Well-controlled PMBL was successfully achieved when the reaction was initiated using a macro-initiator selected to improve the solubility of PMBL segments in common organic solvents. On the basis of this reaction system, we demonstrate that a block copolymer with well-controlled stereoregularity and high degree of polymerization could be synthesized that showed microphase separation.