摘要
采用在苯乙烯 (St)悬浮聚合过程中滴加甲基丙烯酸甲酯 (MMA)乳液聚合组分的悬浮 乳液复合聚合方法 ,制备大粒径聚苯乙烯 聚甲基丙烯酸甲酯 (PS PMMA)复合粒子 .研究聚合物粒径分布和颗粒形态的变化发现 ,在St悬浮反应中期滴加MMA乳液聚合组分后 ,聚合体系逐渐由悬浮粒子与乳胶粒子并存向形成单峰分布复合粒子转变 ,最终形成核 壳结构完整的大粒径PS PMMA复合粒子 ;在St悬浮反应初期滴加MMA乳液聚合组分 ,St与MMA一起分散成更小液滴 ,反应后期凝并成非核 壳结构复合粒子 ;在St悬浮反应后期滴加MMA乳液聚合组分 ,PMMA乳胶粒子与PS悬浮粒子基本独立存在 .根据以上结果 ,提出了St MMA悬浮 乳液复合聚合的成粒机理 .
Suspension-emulsion combined polymerization (SECP) process, in which methyl methacrylate (MMA) emulsion polymerization constituents (EPC) were drop-wisely added to styrene (St) suspension polymerization (SP) system at different stages of St suspension polymerization, was applied to prepare polystyrene/poly (methyl methacrylate) (PS/PMMA) composite particles. The particle features of the resulting polymer particles and the particle formation mechanism of SECP were studied. It was found that PMMA latex particles gradually coagulated with PS particles after the addition of EPC at the mid stage of St suspension polymerization, and core-shell structure PS/PMMA composite particles with greater size were finally formed. SUMMA copolymer particles composed of primary particles and imperfect core-shell structure PS/PMMA composite particles were obtained by adding EPC at the initial and late stages of St SP, respectively. According to the particle formation mechanism of St suspension polymerization and the variations of particle features of PS/PMMA composite particles, a particle formation mechanism of St-MMA SECP was proposed.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2005年第2期186-190,共5页
Acta Polymerica Sinica
