Processing,Characterization, and Modeling of Room‐Temperature‐Vulcanized Silicone‐Derived Ceramic Foams

A novel method was developed to produce ceramic foams from a silicone precursor which was foamed and vulcanized at room temperature. Silicone foams were prepared by platinum‐catalyzed cross‐linking and dehydrogenation of reactive polysiloxanes. Silicone foams were converted to ceramic foams after being pyrolyzed at 1200°C in argon. Near‐net‐shape polymer‐to‐ceramic conversion was achieved when SiC particles were added to the polymer as a solid filler. A simple physical model was created to describe the rising and pyrolysis of the silicone foam, and was validated by experimental data. Foam density was largely dependent on the content of ethanol, which was used as a chemical blowing agent. Up to 1.8 wt% ethanol was effective in driving foam rising without leading to foam collapse. SiC filler helped reduce weight loss and volumetric shrinkage during pyrolysis, and slightly increased foam density. Scanning electron microscopy indicated that although incorporating a solid filler helps to reduce the bulk shrinkage, it cannot prevent local microcracking and residual porosity.