Research On Anionic Polymerization Of Methyl Methacrylate And Control Of Side Reactions

The polystyrene-b-poly (methyl methacrylate) copolymers were synthesized by anionic polymerization with n-BuLi as the initiator, tetrahydrofuran as the solvent and complex compound P as the restraining agent for side-reaction owing to its steric hindrance and special charge environment. The polystyrene-b-poly (methyl methacry-late) copolymers were characterized by gel permeation chromatography (GPC), fourier transform infrared spectrometer (FT-IR),1H nuclear magnetic resonance ('H-NMR). Results showed that side reactions of anionic polymerization of methyl methacrylate had been well retarded at high-temperature (80℃) in the high pressure reactor. Each block coincided with the design of molecular weight with narrow distribution (<1.1). The suitable molar ratio of complex compound P to initiator was 1.5:1. The side reactions of anionic polymerization couldn't be eliminated at lower-temperature (0℃and 40℃) in the three-neck flask. The designed molecular weight of PS had important influence on whether the block copolymerization of styrene and methyl methacrylate could be successfully conducted.The anionic polymerization of poly (methyl methacrylate) was synthesized with DPHLi as the initiator, tetrahydrofuran as the solvent and complex compound P as the restraining agent for side-reaction. The poly (methyl methacrylate) polymers were characterized by GPC, FT-IR and1H-NMR. Results showed the cooperation of compound P and 1,1-DPE could effectively decrease the rate of side reactions, and poly (methyl methacrylate) polymers were prepared with good control of molecular weight and relatively narrow molecular weight distribution. The existence of protons impurity was one of the reasons that lead to low conversion. After refining, water content achieved that documents required and high conversion could be achieved. The suitable molar ratio of complex compound P to initiator was 2:1 and conversion achieved 95%.