SPECIFIC SALT EFFECT OF LITHIUM PERCHLORATE IN LIVING ANIONIC-POLYMERIZATION OF METHYL-METHACRYLATE AND TERT-BUTYL ACRYLATE

Living anionic polymerization of methyl methacrylate can be achieved a t -40 degrees C in tetrahydrofuran (THF) and at -78 degrees C in tolue ne/THF (9/1 v/v) using (1,1-diphenylhexyl)lithium as the initiator in the presence of lithium perchlorate (LiC1O(4)) as the additive. Polyme rization of tert-butyl acrylate also proceeds in a living manner at -7 8 degrees C in THF. Polymers with narrow molecular weight distribution s and high initiator efficiencies can be obtained. The use of lithium perchlorate retards the rate of polymerization. The ratio of LiC1O(4) to initiator has a greater influence in determining the control of pol ymerization. The beneficial effect of lithium perchlorate is attribute d to its efficient interaction with growing ester-enolate ion pairs.