INTRODUCTION OF FUNCTIONAL-GROUPS ON MONODISPERSED COLLOIDAL SILICA COMPOSITES MODIFIED WITH CROSS-LINKED POLY(STYRENE)

Introductions of functional group, mainly amino group, on the surface of poly(styrene)-coated monodispersed colloidal silica particles (PST/SiO2) were investigated. Although surface nitration and successive reduction of PST/SiO2 composite led to introduction of amino group, the silica core of the composites was spoiled by strong acids during the reactions. Radical polymerization of styrene (ST) and divinylbenzene (DVB) with chain transfer reagent, having amino or carboxyl group, in silica colloid-ethanol solution gave dispersible PST/SiO2 composites having the functional group. However, the surface amino groups were not able to react with poly(methyl methacrylate) (PMMA-COOH) having a carboxyl end group, so that most of them were apparently buried in the PST network. Surface chloromethyl group on polymer/SiO2 composite, prepared by copolymerization of ST, DVB and chloromethylstyrene in the silica colloid solution, was converted to amino group via aminolysis of the phtalimide. The amino group formed was shown to be effective for binding PMMA-COOH by condensation.