PS/SiO2纳米复合粒子的制备及反应机理研究

采用一步法合成出PS/SiO₂纳米复合粒子,得到产物的产率和接枝效率均在95以上.与传统的预处理方法相比,一步法在工艺上简单易行,重复性好;复合粒子粒径、形态及分散状况与预处理方法无明显差别.对一步法制备中硅烷偶联剂的作用机理进行了探讨,通过调节偶联剂添加量可以使偶联剂在复合粒子中起到偶联剂或交联剂或二者兼有的作用.动力学研究表明,在实验配方条件下,反应遵循与前人类似工作截然不同的机理模型.此外,对复合粒子的形态与结构进行计算表明,在实验条件下,产物中平均每个复合粒子内含有5～6个初始的SiO₂纳米粒子,这些粒子团聚在一起形成核,PS接枝并包覆于团聚体外形成壳.

Preparation and Reaction Mechanism of PS/SiO2 Composite Nanoparticles

A novel method, i.e., batch process was used to prepare PS/SiO_2 composite nanoparticles with both yield and binding efficiency high above 95%. Compared with traditional pre-treated method, it was easy and had a good repeatability in batch process. There was little difference in average particle sizes, morphologies and dispersibility of the final composite nanoparticles obtained between two methods. The reaction mechanism of 3-methacryloxypropyltrimethoxysilane(MPTMS) in batch process was described in this report, proving that the role of MPTMS could be coupling agent, crosslinking agent or both by controlling its amount. The kinetics, which was opponent to that of some similar system reported previously, was investigated and well explained by the schematic model. The morphology and structure of composite particles were discussed as well. There are about 5-6 primary silica beads per composite particles, which formed a cluster. The core of the composite nanoparticles was made up of the cluster and PS grafted and encapsulating the cluster to form the shell.