Control of Main-Chain Stereostructure of Graft Polymers via Stereospecific Anionic Copolymerization of Syndiotactic Poly(methyl methacrylate) Macromonomer Having Methacryloyl Function with Methacrylate Monomers

Abstract

Highly syndiotactic PMMA macromonomer having methacryloyl group as a polymerizable function was prepared from the corresponding living PMMA anion formed with t-C4H9Li/(n-C4H9)3Al (1/3) in toluene at −78°C. Anionic copolymerization of the macromonomer with methyl (MMA) or ethyl methacrylate was carried out with anionic initiators. Copolymerization with 1,1-diphenylhexyllithium in tetrahydrofuran at −78°C gave graft polymers with syndiotactic main chain in high yields. Copolymerization with t-C4H9MgBr in toluene at −78°C afforded graft polymers with highly isotactic main chain in good yields, although the molecular weight distributions were broad. The graft polymer with main-chain MMA units obtained in the latter system exhibited melting endotherm due to stereocomplex formation between isotactic main chain and syndiotactic side chains.