Porous silicon oxycarbide (SiOC) ceramics with controllable open-cell content were made by compounding, foaming, and pyrolyzing polysiloxane and metallocene-polyethylene (mPE) polymer blends. Aimed at the development of desired foamable polysiloxane-polyolefin blends, the rheological properties of the polysiloxane and the mPE polymer were characterized, and the effects of mPE content and processing temperature on the compounding behaviors of the polysiloxane-mPE blend system were investigated. Furthermore, porous preceramics were fabricated from the polysiloxane-mPE blends with high pressure CO2 using batch foaming technology. Finally, the preceramic foams were converted to porous silicon oxycarbide ceramics by completing the organic-inorganic transition via controlled pyrolysis, and open-channels were made in the cell walls by burning out the sacrificial dispersed mPE phase during pyrolysis.

Keywords: Porous ceramics, Silicon oxycarbide, Foaming, Polysiloxane, Polyethylene