二氧化硅/聚苯乙烯单分散性核/壳复合球的制备

采用无皂乳液聚合包覆 ,制备了二氧化硅 聚苯乙烯单分散核 壳 (SiO2 PS)复合颗粒 ,包覆层厚度达到 10 0nm .选择 80～ 2 5 0nm二氧化硅粒径作为核颗粒 .为提高包覆效率 ,二氧化硅颗粒先用偶联剂甲基丙烯酰 (3 三甲氧基硅烷 )丙酯 (MPS)进行不同程度的表面改性 .控制MPS的结合率和单体的初始浓度可提高包覆效率 ,同时得到了单分散性复合颗粒 ,用透射电镜 (TEM)观察复合粒子的核 壳形态 .用动态光散射法 (DLS)测量表明所得复合颗粒具有单分散性 .

PREPARATION OF THE CORE/SHELL DISPERSION COMPOSITE PARTICLES

Stable dispersions of silica were coated with polystyrene by emulsifier-free polymerization,and the monodisperse composite spheres were obtained,whose thickness is about 100 nm.Silica ranging from 150 to 250 nm was core particles.To achieve a high coating efficiency,silica was first modified with 3-(trimethoxysilyl)propylmeth-acrylate (MPS) coupling agent at three different degrees of coupling.The presence of the bound MPS agent and of the polymer at the silica surface was determined by the infrared spectroscopy,and the bound amount of MPS was calculated from mass losses of thermogravimetric analysis (TGA).Coating efficiency and the monodispersion of the composite particles were enhanced by the degree of MPS coupling and by initial concentration of the monomer.The morphology of the composite particles were determined by transmission electron microscopy (TEM),and their monodispersities was measured by dynamic light scattering (DLS).