Hybrid nanocomposites based on polystyrene and a reactive organophilic clay

The preparation of new hybrid nanocomposites, by emulsion polymerization of styrene in the presence of a reactive organophilic clay, and their charact erization are described. The reactive organophilic clay is synthesized by e xchanging the inorganic cations in the interlayer structure of a natural cl ay with the quaternary salt of the aminomethylstyrene. This salt is prepare d by a Gabriel reaction starting from the (chloromethyl)styrene. The polyme ric matrix of the resulting materials was found to be constituted by polyst yrene homopolymer and by a blocky copolymer of styrene and quaternary salt of the (aminomethyl)styrene units. The glass transition temperature of the nanocomposites increase as the percentage of organophilic clay increases, a lthough the average molar masses of the polymeric matrix decrease, because of termination and/or chain-transfer reactions caused by the organophilic c lay during the polymerization. Accordingly, the inherent reinforcing action due to the presence of the reactive organophilic clay is higher than the o bserved one. (C) 1998 Kluwer Academic Publishers.