Reinforcement of Mechanical Properties of Silicone Rubber Foam by Functionalized Graphene Using Supercritical CO2 Foaming Technology

Silicone rubber (VMQ)/functionalized graphene (FG) nanocomposite foams with low density and better deformation recovery capability were successfully prepared by environmental-friendly supercritical carbon dioxide (scCO2) foaming technology. The purpose of this project is to investigate the effect of the matrix strength on cell morphology, mechanical properties, and deformation recovery capability of silicone rubber foams. The analysis of rheological results showed that due to the better compatibility and interaction between the molecular chain and FG, the uniformly dispersed 3-aminopropyltriethoxysilane functionalized graphene significantly enhanced the matrix strength compared with chemical reduction graphene (rGO), and it was about 3 times higher. The improvement of matrix strength was beneficial for limiting the shrinkage of the cell wall so that VMQ/FG foams exhibited larger cell size and lighter weight than that of VMQ/rGO foams under the same foaming conditions. In addition, the great improvement in matrix strength of VMQ/FG foams contributed to resisting the external pressure and deformation recovery capability with 2% permanent compression set better than VMQ/rGO foams. Meanwhile, VMQ/FG foams also exhibited improvements in tensile strength (130%) and the corresponding elongation at break (140%) compared to VMQ/rGO foams.