表面引发接枝聚合法制备高接枝度的接枝微粒SiO2-g-PMAA

将偶联剂γ-氨丙基三甲氧基硅烷(AMPS)键合在硅胶微粒表面,得到改性微粒AMPS-SiO2;使改性微粒表面的氨基与溶液中的过硫酸铵构成氧化-还原引发体系,实现了甲基丙烯酸(MAA)在硅胶微粒的表面引发接枝聚合,制得了高接枝度(0.30 g/g)的接枝微粒SiO2-g-PMAA;研究了影响表面引发接枝聚合的主要因素。 结果表明,适宜的温度为40 ℃。 已接枝到硅胶表面的聚合物层对后续的接枝聚合产生阻隔作用。 适宜的引发剂用量为单体质量的1.1%,适宜的单体质量分数为5%左右。

Preparation of Grafted SiO2-g-PMAA Particles with High Grafting Degree via a Surface-initiated Graft Polymerization Method

Coupling agent γ-aminopropyltrimethoxysilane(AMPS) was firstly bond onto the surface of silica gel particles forming modified AMPS-SiO2 particles. With the presence of ammonium persulphate in the solution, a redox initiating system was then achieved and allowed the surface-initiated graft polymerization of methacrylic acid(MAA) on the silica gel particles with a high grafting degree(0.30 g/g). The effects of different factors on the whole process were investigated in depth. The experimental results show that an optimal temperature for the surface-initiated graft polymerization system is 40 ℃. At higher temperature, the graft degree will decline due to the heat decomposition of ammonium persulphate. In addition, the grafted polymer layer hinders further polymerization. The appropriate reaction conditions are: 1.1% of the initiator and nearly 5% of the monomer concentration.