Living anionic polymerization of methyl methacrylate in the presence of polydentate dilithium alkoxides

Abstract

Living anionic polymerization of methyl methacrylate is achieved using (1,1-diphenylhexyl)lithium as initiator in the presence of dilithium triethylene glycoxide as an additive in tetrahydrofuran at –40, –20, 0 and 30°C. High initiator efficiencies and poly(methyl methacrylate)s with narrow molecular weight distributions (1.1 < Mw/Mn < 1.3) were obtained. The efficiency of the dilithium salts of glycol and diethylene glycol as additive in the polymerization of MMA was found to be poor. The beneficial effect of dilithium triethylene glycoxide was attributed to the better coordination with enolate ion pairs providing stabilization to ligand-complexed ion pairs. As, the polymerization is very fast, the mode of monomer addition and the initiator concentration play a major role in controlling the polymerization in the presence of polydentate dilithium alkoxides.