Atom transfer radical polymerization of methyl methacrylate catalyzed by cobalt catalyst system

Abstract

A new catalyst system, CoCl2/tris(2-(dimethyl amino) ethyl)amine (Me6 TREN), was used to catalyze the polymerization of methyl methacrylate (MMA) successfully through atom transfer radical polymerization mechanism. The control over the polymerization was not ideal, the molecular weight distribution of the resulting polymer (PMMA) was relatively broad (M w/Mn = 1.63-1.80). To improve its controllability, a small amount of hybrid deactivator (FeBr3/Me6TREN or CuBr 2/Me6TREN) was added in the cobalt catalyst system. The results showed that the level of control over the polymerization was significantly improved with the hybrid cobalt-iron (or cobalt-copper) catalyst system; the polydispersity index of the resulting polymer was reduced to a low level (Mw/Mn = 1.15-1.46). Furthermore, with the hybrid cobalt-iron catalyst, the dependence of the propagation rate on the temperature and the copolymerization of methacrylate (MA) with PMMA-Br as macroinitiator were also investigated. © 2005 Wiley Periodicals, Inc.