Synthesis of stereoblock poly(methyl methacrylate) via transformation of isotactic‐specific living polymer anion to syndiotactic‐specific anion

Abstract

AbstractPolymerization of methyl methacrylate (MMA) by isotactic poly(methyl methacrylate) (PMMA) living anion, prepared with t‐C4H9MgBr in toluene at −60°C, was carried out at −78°C in the presence of trialkylaluminiums (R3Al; R = CH3, C2H5, and n‐C4H9) to obtain a stereoblock PMMA, isotactic PMMA‐block‐syndiotactic PMMA. Among the R3Als, (CH3)3Al gave most effectively the steroblock PMMA with narrow molecular weight distribution. The fraction of rr triad in the syndiotactic PMMA block increased with increase in the ratio of Al/Mg and reached about 76% at a ratio of Al/Mg ≥ 6. The method was also used to prepare stereoblock copolymer comprising isotactic PMMA block and syndiotactic block of butyl methacrylate. Stereocomplex formation and solution viscosity of the stereoblock PMMA were also studied.