Effects of acrylonitrile content on the properties of clay-dispersed poly(styrene-co-acrylonitrile) copolymer nanocomposite

Clay-dispersed nanocomposites have been prepared by simple melt-mixing of two components, i.e. poly(styrene-co-acrylonitrile) copolymers with different contents of acrylonitrile comonomer and two different kinds of organophilic clay (Cloisite(R) 25A and Cloisite(R) 30A), with a twin screw extruder. Dispersion behavior of 10-Angstrom-thick silicate layers of clay in the nanocomposites was investigated by using an X-ray diffractometer and a transmission electron microscope. It was found that acrylonitrile comonomer incorporated into poly(styrene-co-acrylonitrile) copolymers accelerates intercalation of the copolymers into the galleries of silicate layers modified with an organic intercalant. The faster intercalation of a matrix polymer leads to the better dispersion of silicate layers in the matrix polymer.