A facile and efficient strategy for fabrication of silicone rubber foam based on in situ precuring‐supercritical CO2 foaming technology

Abstract In this work, a facile in situ precuring and supercritical CO 2 (sc‐CO 2 ) foaming technology is proposed to fabricate silicone rubber foam (SRF) with a tunable cell structure. Uncured silicone rubber is put into the autoclave to saturate sc‐CO 2 directly, which not only shorts the saturation time but also accelerates the curing reaction in the precuring process. In the foaming process, cell nucleation is triggered by rapid release of pressure. The cell structure of SRF samples with cell size range of 9.45 to 128.09 μm, cell density range of 3.5 × 10 5 cells/cm 3 to 5.7 × 10 8 cells/cm 3 , and porosity range of 28.35% to 77.28% are successfully fabricated by controlling of precuring time, saturation pressure and foaming temperature. To guarantee the dimensional stability and optimize surface quality of SRF samples, in situ post‐curing process is implemented within the foaming mold. With the increase of cell size from 9.91 to 128.09 μm, the compressive stress at strain of 75% decreases from 2.19 to 0.61 MPa, while the energy loss coefficient reduces from 35.4% to 16.9%, exhibiting excellent compression recovery steady. The new technique integrates the precuring, foaming process and post‐curing into an autoclave to simplify the SRF procedure.