功能接枝微粒PDMAEMA/SiO_2的制备及其吸附特性初探

Preparation of Functional Grafted Particles PDMAEMA /SiO_2 and Preliminary Research of their Adsorption Character

凭借偶联剂γ-(甲基丙烯酰氧)丙基三甲氧基硅烷的媒介作用,在溶液聚合体系中,采用"接出"("graft from")法将单体甲基丙烯酸二甲氨基乙基酯(DMAEMA)接枝于硅胶微粒表面,制得了接枝微粒PDMAEMA/SiO2,重点考察了主要因素对接枝聚合的影响,并测定了接枝微粒的Zeta电位,初步考察了其吸附特性。研究结果表明,已接枝到硅胶表面的聚合物层,会对后续的接枝聚合产生阻隔作用;温度及引发剂用量等因素显著影响接枝度,在适宜条件下可制得接枝度为22g/100g的接枝微粒;在较大的pH范围内,接枝微粒的Zeta电位为较大的正值,在静电相互作用下,接枝微粒对铬酸根离子会产生强吸附作用.

The grafted particles PDMAEMA /SiO2 was synthesized by using dimethylaminoethyl methacrylate （DMAEMA） to graft on micron-sized silica gel particles in a manner of＂graft from＂in a solution polymerization system by right of the mediation of the coupling agent 3-methacryloxypropyl trimethoxysilane （ MPS）. The effects of the main factors on the graft polymerization were examined emphatically. The zeta potential of the grafted particles was determined,and their adsorption character was preliminarily explored. The results showed that during the graft polymerization,the grafted polymer layer is a hindrance to the subsequent graft polymerization,and the reaction temperature and the amount of initiator affect the graft polymerization intensively. Under the suitable conditions,the grafting degree of PDMAEMA on the surfaces of the grafted particles could get up to 22g /100g. In a wider pH range, the zeta potential of the grafted particles PDMAEMA /SiO2 was a greater positive value. By right of the strong electrostatic interaction,the grafted particles PDMAEMA /SiO2 had strong adsorption ability towards chromate anions, and the adsorption capacity could reach 160mg /g.