苯乙烯-甲基丙烯酸甲酯悬浮-乳液复合聚合过程中聚合物复合粒子组成的变化

采用苯乙烯(St)悬浮聚合过程中滴加甲基丙烯酸甲酯(MMA)乳液聚合组分,悬浮乳液复合聚合(SECP)方法,制备大粒径聚苯乙烯聚甲基丙烯酸甲酯(PS- PMMA)复合粒子.采用FTIR、1H- NMR、13C- NMR分析方法,研究SECP各个时期复合粒子中MMA- St链节摩尔比,发现悬浮粒子中MMA St链节摩尔比逐渐增大,而PMMA乳胶粒子中逐渐减少,表明悬浮相和乳液相间存在物质传递过程.悬浮粒子中MMA链节质量与MMA总投料质量比主要由乳胶粒子生成速率和乳胶粒子向悬浮粒子凝聚速率决定.最终得到的复合粒子除含PS和PMMA均聚物外,还含少量MMA-St共聚物.

COMPOSITION VARIATION OF POLYMER COMPOSITE PARTICLES IN STYRENE-METHYL METHACRYLATE SUSPENSION-EMULSION COMBINED POLYMERIZATION

Suspension-emulsion combined polymerization(SECP) process,in which methyl methacrylate(MMA) emulsion polymerization constituents(EPC) were drop-wisely added to styrene(St) suspension polymerization system,was applied to prepare polystyrene-poly(methyl methacrylate)(PS-PMMA) core-shell composite particles with a great size.The composition of these composite particles was analyzed by FTIR,extraction, 1H-NMR and 13C-NMR methods.It was found that the molar ratio of MMA/St units in composite particles increased and the content of PMMA latex particles decreased with the increasing of polymerization time after the addition of EPC.So,it was evidenced that PMMA latex particles would coagulate with PS suspension particles in SECP polymerization and a transfer process existed between the two kinds of particles after the coagulation.The polymeric composite particles were composed of PS,PMMA and MMA-St copolymer.