Extrusion Foaming of a Preceramic Silicone Resin with a Variety of Profiles and Morphologies

Preceramic foams with a variety of profiles and morphologies were fabricated by a continuous foam extrusion process based on a single-screw extruder. A methyl silicone resin was used as the preceramic polymer and carbon dioxide as the foaming agent. Variations of the foam morphology were achieved by changing the key process parameters carbon dioxide content, foaming pressure, and foaming temperature. Samples of different porosities, cell densities, pore sizes, and pore size gradients were obtained. From these results, conditions for the fabrication of particular foam structures can be derived. Various foam profiles as rods, tapes, and tubes were extruded and pyrolysed into ceramic foams.