Foaming of Polystyrene with Supercritical Carbon Dioxide

Abstract

General Purpose Polystyrene (GPPS) and High Impact Polystyrene (HIPS) were foamed with supercritical carbon dioxide in the batch foaming process. Foaming behaviors of GPPS and HIPS were investigated. The cell diameters and cell densities of GPPS and HIPS vary strangely with foaming conditions and can be explained by the classical nucleation. The competition between cell growth and cell nucleation is used to explain these strange foaming behaviors. The glass transition temperature (Tg) almost remains constant with the foaming temperature rising.