Effective Grafting of Polymers onto Ultrafine Silica Surface: Photopolymerization of Vinyl Monomers Initiated by the System Consisting of Trichloroacetyl Groups on the Surface and Mn_2(CO)_10

摘要

The effective grafting of vinyl polymers onto an ultrafine silica surface was successfully achieved by the photopolymerizaiton of vinyl monomers initiated by the system consising of trichloroacetyl groups on the surface with Mn_2(CO)_10 under UV irradiation at 25 deg C. The introduction of trichloroacetyl groups onto the surface of silica was achieved by the reaction of trichloroacetyl isocyanate with surface amino groups, which were introduced by the treatment of silica with 3-aminopropyltriethoxysilane. During the polymerization, the corresponding polymers were effectively grafted onto the surface, based on the propagation of polymer from sruface radicals formed by the interaction of trichloroacetyl groups and Mn_2(CO)_10. The percentage of poly(methylmethacrylate) grafting onto the silica reached 714.6% after 90 min. The grafting efficiency (proportion of grafted polymer to total polymer formed) in the polymerization of methyl methacrylate was very high, about 80%, indicating the depression of formation of ungrafted polymer. Polymer-grafted silica gave a stable colloical dispersion in good solvents for grafted polymer.