Effects of scCO2 foaming process and post‐vulcanization method on cellular structure, mechanical properties, and thermal stability of PMVQ foams

Abstract

AbstractIn this paper, the microcellular foam materials of methyl vinyl phenyl silicone rubber (PVMQ) were prepared by supercritical foaming technology (SFT) and high temperature compression molding. The effect of supercritical carbon dioxide (scCO2) on the vulcanizing properties of PVMQ composite was investigated because vulcanization of microcellular PVMQ foams played an important role on the cellular structure and mechanical properties. It was found that the sulfurization reaction of PVMQ composite was inhibited by scCO2, which led to reduction of apparent activation energy (Ea) of PVMQ composite. Compared with the existing post‐vulcanization process, the introduction of the high temperature molding can effectively improve the degree of vulcanization of microcellular PVMQ foams, which can solve the problem that the cellular structure will be destroyed during the application of external force. What's more, the mechanical properties of microcellular PVMQ foam were obviously improved. The maximum value of tensile strength and the compressive strength of microcellular PVMQ foam with the high temperature molding respectively increase by 34.7% and 133.3% compared with that of microcellular PVMQ foams with existing post‐vulcanization.