Preparation of silicone rubber foam using supercritical carbon dioxide

Silicone rubbers were successfully foamed by supercritical carbon dioxide (SC CO2). Samples were precured and fully cured before and after the basic foaming process with SC CO2. The effects of precuring time and soaking pressure on the density and pore morphology of prepared silicone rubber foams were investigated. It was found that a crosslinked network structure affected by precuring time played an important role in the foaming process. In current study, 5 min was the optimum precuring time for foaming and the corresponding minimum sample density was 0.239 g/cm3. The best prepared foam had polygonal pores and the pores were interconnected. Our results indicate that SC CO2 foaming technology can be used to prepare crosslinked elastomer foams by appropriately controlling the crosslinked network structure.