Control of the cell structure of microcellular silicone rubber/nanographite foam for enhanced mechanical performance

Microcellular silicone rubber/nanographite foam with the smallest cell diameter and the largest cell density compared to the previous studies was prepared using supercritical carbon dioxide as an environmentally benign foaming agent in this study. Both the cell microstructure and properties of porous composite were investigated in detail. In silicone rubber/nanographite system, the incorporation of nanographite into silicone rubber significantly induced heterogeneous bubble nucleation and enhanced the matrix strength, which resulted in the decreased average cell diameter from 4.97 to 1.12 μm and the increased cell density from 8.87 × 108 cells/cm3 to 1.25 × 1010 cells/cm3. The microcellular rubber foam with decreased cell size, increased cell density and narrow cell distribution was corresponded to the excellent compressive strength and higher hardness, which reduced the content of silica. Furthermore, the thermal decomposition temperature of the obtained foam increased from 380 °C to 413 °C due to the introduction of nanographite. The silicone rubber/nanographite foam with improved performance possessed potential in wide applications.