ANIONIC-POLYMERIZATION OF PRIMARY ACRYLATES AS PROMOTED BY LITHIUM 2-(2-METHOXYETHOXY) ETHOXIDE

Some primary acrylates, such as methyl, ethyl, n-butyl, and n-nonyl ac rylate (MA, EA, nBuA and nNonA, respectively) have been anionically po lymerized by using diphenylmethyl lithium (DPMLi) as an initiator, in the presence of a chelating mu-sigma dual ligand, i.e., a polydentate lithium alkoxide, at low temperature. It has been found that lithium 2 -(2-methoxyethoxy) ethoxide (LiOEEM) is a very efficient ligand in pre venting the anionic polymerization of these monomers from being distur bed by significant secondary transfer and termination reactions. Even for the difficult cases of ethyl and methylacrylate, that approach pro vides high polymerization yields and low polydispersity, allowing the molecular weight to be predetermined. LiOEEM/initiator molar ratio, so lvent polarity, temperature and monomer concentration have proved to b e key parameters in the control of the polymerization process. The eff iciency of that control is however dependent on the monomer structure and improves with the length of the n-alkyl substituent, i.e., MA < EA < nBuA < nNonA. (C) 1997 John Wiley & Sons, Inc.