Microwave-assisted foaming of expandable polystyrene beads

A novel method for obtaining polystyrene foam, which uses microwave as the source of energy for expansion process, is developed. In this article, a method to disperse target expansion agent using two-stage bulk polymerization and free radical suspension polymerization of styrene is described. Current and proposed research uses environmentally friendly and potentially recyclable expansion agents and highly efficient volumetric heating systems. Spherical polystyrene beads containing 2-propanol as expansion agent are successfully prepared which are then expanded using microwave energy. Microwave processing conditions developed by trial experiments are reported. A brief discussion on the theory of microwave heating in the context of current research is presented for direct reference and convenience to the reader.