Preparation of functional grafted particles PVA/SiO _2 with high grafting degree and preliminary research of their adsorption character

摘要

Micro-sized silica gel particles were surface-modified with coupling agent γ-Aminopropyltrimethoxysilane (AMPS), obtaining the modified particles AMPS-SiO_2, on which primary amino groups were chemically attached. Distilled water and DMSO were used as mixed solvents, and a redox initiation system was constituted with the amino groups on the surfaces of AMPS-SiO _2 particles and ammonium persulphate in a solution. This practice realized the surface-initiated graft-polymerization of vinyl acetate (VAc), and prepared the grafted particles PVAc/SiO_2 with a high grafting degree (about 32 g/100 g) of PVAc. PVAc can be transformed into PVA by the alcoholysis reaction, which results in functional grafted particles PVA/SiO_2 with high grafting degree. The grafted particles PVAc/SiO_2 were characterized by FTIR, SEM and TGA. The effects of main factors on the graft-polymerization of vinyl acetate were investigated emphatically, and their adsorption character was preliminarily explored. The experimental results show that the mixed solvents composed of water and DMSO along with a redox initiation system constituted with the amino groups on the surfaces of AMPS-SiO _2 particles and ammonium persulphate in a solution realize highly effective surface-initiated graft-polymerization of vinyl acetate which is an oil-soluble monomer. By virtue of the hydrogen bonding interaction, the particles PVA/SiO_2 can produce strong adsorption ability for pirimicarb and terbuthylazine which are nitrogenous organic molecules. Relying on the strong coordination chelating action, the particles PVA/SiO_2 exhibit strong adsorption ability towards heavy metal ions.