关键词: (甲基)丙烯酸酯, 阴离子聚合, 有机铜锂, CuSCN

Abstract: Polymerizations of methyl methacrylate(MMA) initiated by lithium homocuprate and lithium heterocuprate from cuprous thiocyanate in tetrahydrofuran solution were carried out. Polymerizations initiated by lithium homocuprate were sensitive to the mass ratio of monomer to initiator and reaction temperature. At 10 ℃, with the increase of the mass ratio of monomer to initiator, the molecular weight of PMMA increased and the color of the reaction system response got more and more darker. This was often the signal of the thermal instability of organocopper. This may hint that the living end had already been destroyed. Low reaction temperature made the initiator efficiency obviously dropping. In addition, with the decrease of reaction temperature, syndiotactic degree of PMMA increased. Polymerizations initiated by lithium heterocuprate showed that heterocuprate was more efficient initiators than homocuprate. Under the same reaction conditions, PMMA from polymerization initiated by heterocuprate had narrower MWD and higher syndiotactic degree.

Key words: MMA, Anionic polymerization, Lithium organocuprate, CuSCN