无皂乳液聚合中单分散粒子的形成过程

在少量双官能团水溶性共单体（磺化下二酸－聚乙二醇－烯丙基缩水甘油醚酯）存在下进行ＭＭＡ／ＢＡ无皂乳液聚合，用ＣｏｕｌｔｅｒＬＳ２３０激光粒径分析仪研究了乳胶粒子的成核机理和单分散粒子的形成过程，乳胶粒子的成粒程属多步成粒机理，先均相成核，形成不稳定的初始粒子，然后凝聚成稳定乳胶粒，其粒径分布经历了先变宽后变窄的过程，这是聚合过程中成核－凝聚－增长共同作用，相互竞争的结果，它还导致聚合初期出现周期成

Formation of Monodispersed Polymer Particles in Emulsifier-free Emulsion Polymerization

The nucleation mechanism of polymer latex particles and formation processes of monodispersed latex particles in MMA/BA emulsifier free emulsion polymerization in the presence of small amount of water soluble comonomer(such as sodium sulfonated polyethylene glycol allyl ether glycerin succinate) were investigated with Coulter LS 230 laser particle size analyzer. The colloidally stable polymer latex particles were formed from multi step particle formation mechanism: the coagulation of colloidally unstable precursor particles subsequent to their formation by homogeneous nucleation, and growth due to both aggregation and propagation. The particle monodispersion was not formed in the early stage, but formed through a process of increasing and then decreasing in particle polydispersity, U= D w/ D n. This can be ascribed to the competition of homogeneous nucleation coagulation propagation aggregation, and it also leads to the periodic nucleation phenomena in the early stage of polymerization.