Preparation of functional composite grafted particles PDMAEMA/SiO2 and preliminarily study on functionality

Micron-sized silica gel particles were first surface-modified with coupling agent, gamma-methacryloylpropyl trimethoxysilane (MPS), and the polymerizable double bonds were introduced onto the surfaces of silica gel particles, forming the modified particles MPS-SiO2. Subsequently, N,N-dimethylaminoethyl methacrylate (DMAEMA) was graft-polymerized on the surfaces of particles MPS-SiO2 in the manner of grafting through, resulting in the grafted particles PDMAEMA/SiO2. The grafted particles PDMAEMA/SiO2 were fully characterized with several means. The graft polymerization process of DMAEMA on particles MPS-SiO2 was studied in detail, and the optimal reaction conditions were determined. Thereafter, the adsorption properties of the grafted particles PDMAEMA/SiO2 for chromate anion and Cu2+ ion were preliminarily examined respectively. The experimental results indicate that the PDMAEMA grafting degree on PDMAEMA/SiO2 particles is limited because an enwinding polymer layer as a kinetic barrier on the surfaces of silica gel particles will be formed during the graft polymerization, and blocks the graft polymerization. In order to enhance PDMAEMA grafting degree, reaction time and temperature, and the used amount of initiator as well as the monomer concentration should be effectively controlled. The preliminary adsorption tests show that the grafted particles PDMAEMA/SiO2 are multi-functional. They possess very strong adsorption ability for CrO42- anion by right of strong electrostatic interaction, and have also adsorption action towards heavy metal ion by dint of complexing action. (C) 2010 Elsevier B. V. All rights reserved.