【作者】 李晨；

【导师】 郑安呐；

【作者基本信息】 华东理工大学 ， 材料科学与工程， 2011， 硕士

【摘要】 本文采用阴离子溶液聚合法,以正丁基锂(n-BuLi)为引发剂,四氢呋喃(THF)为极性调节剂,引入一种具有较大空间位阻和特定结构的P配合物作为抑制剂,实现了苯乙烯(St)与甲基丙烯酸甲酯(MMA)的嵌段共聚合。采用GPC、FT-IR、1H-NMR等手段对样品的结构及分子量进行了表征和分析。结果表明,高温(80℃)耐压釜中添加P配合物可以有效抑制MMA中酯羰基的副反应,所得共聚物各链节的分子量与设计分子量接近,分子量分布系数<1.1。适宜的P配合物与引发剂摩尔配比为1.5：1。中低温(0℃和40℃)玻璃三口烧瓶中共聚反应副反应无法完全消除,聚苯乙烯(PS)链段设计分子量大小对PS活性链能否顺利与MMA进行嵌段共聚具有重要影响。采用空间位阻较大的1,1-二苯基己基锂(DPHLi)作为引发剂,THF为极性调节剂,继续添加P配合物作为抑制剂,在0℃下玻璃三口烧瓶中进行了MMA的阴离子均聚合。采用GPC、FT-IR、1H-NMR等手段对样品的结构及分子量进行了表征和分析。结果表明,P配合物与DPHLi配合可以有效抑制MMA中酯羰基的副反应,所得聚合物分子量接近设计分子量且呈理想的单峰分布。体系中微量水份等质子杂质的存在确实是导致转化率不高的原因之一,精制方法优化后单体与溶剂(THF除外)中水含量均可达到文献所要求的5-10ppm以下,并因此可以得到高转化率的PMMA均聚物。P配合物与引发剂的摩尔配比以2：1最佳,此时转化率达到95%。更多还原

【Abstract】 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%.更多还原