Coexistence of Active Species in Anionic Polymerization of Ethyl Methacrylate

Abstract

It has been suggested that the broad molecular weight distribution of poly(methyl methacrylate) prepared in toluene with anionic initiator could be explained in terms of a combination of two narrower distributions produced simultaneously occurring mechanisms(1). Cottam et al.(2) suggested the existence of two active species uncomplexed and complexed with lithium methoxide, respectively, in the polymerization of MMA with BuLi. Recently it was reported that in the polymerization of MMA in a mixture of toluene and THF with Grignard reagent the polymers obtained consist of two components, methanol-soluble and methanol-insoluble polymers, which are considered to form at two distinct and independent active centers(3). In the polymerization of methyl α-ethylacrylate by BuLi in toluene there exist two types of active species which produce isotactic and syndiotactic polymers, respectively(4).