Grafting of Polymers onto Silica Gel Surface ; Polymerization of Vinyl Monomers in the Presence of Functionalized Silica Gel Prepared by Sol-Gel Process

概要

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Functionalized silica gels having alcoholic hydroxyl, mercaptopropyl, aminopropyl, chloropropyl, and methacryloxypropyl groups were successfully prepared by the copolycondensation (sol-gel process) of tetraethoxysilane with alkoxysilane (silane coupling agent). The effects of functional groups on the silica gel surface on the polymerization of vinyl monomers initiated by benzoyl peroxide or 2, 2'-azobisisobutyronitrile were investigated. The radical polymerization of vinyl monomers was considerably retarded in the presence of these functionalized silica gels and the corresponding polymers were effectively grafted onto these surfaces. The rate of polymerization, however, was not affected by the presence of unmodified silica gel and no grafting of polymers onto the surface was observed. These results indicate that the chain transfer reaction of growing polymer radical to functional groups on silica gel surface forms radicals on the surface, which then couples with growing polymer radical and/or reinitiates the polymerization to give rise to the grafting of polymers onto the surface. In the case of silica gel having methacryloxypropyl groups, the grafting based on the copolymerization of vinyl monomer with the surface methacryloxypropyl groups was considered to proceed. Polymer-grafted silica gel was found to produce a stable dispersion in good solvents for grafted chain.
Japan Society of Colour Materialの論文