Polymer, Vol.43, No.25, 7179-7184, 2002
Anionic polymerization of acrylates. XII. Polymerization of methyl methacrylate and tert-butyl acrylate initiated with alkyllithiums or methyl 2-lithioisobutyrate in the presence of lithium tert-butoxide
Ligated anionic polymerization of methyl methacrylate (MMA) and tert-butyl acrylate (t-BuA) initiated either with 1,1-diphenyl-3-methylpentyllithium (DPMPLi) or alpha-methyl styryllithium (alpha-MStLi) or methyl 2-lithioisobutyrate (MIB-Li) stabilized with lithium tertbutoxide (t-BuOLi) was studied at - 60 degreesC. In combination with DPMPLi, or alpha-MStLi, stabilizing efficiency of the alkoxide is negligible; MMA polymerizes with high reaction rate, but the chains self-terminate after all the monomer has been consumed, which was tested in two-dose experiments. Ageing of mixed DPMPLi/t-BuOLi solutions as well as an excess of the alkoxide over the initiator have no effect on the stability of the growing chain-ends. In the presence of ten-fold excess of t-BuOLi, MIB-Li initiates slow polymerization of MMA with high stability of active centers. Three MMA doses were successively polymerized producing polymers with narrow MWDs in all steps, so that the active centers remained living for more than 4 h. t-BuA also polymerized in a living manner with the same system.