Polystyrene sacrificial interlayers for the preparation of silicon carbide membranes

Growing interest in the hydrogen economy is motivating research on inorganic, hydrogen-permselective membranes, which can be used in processes (related to H₂ production) that take place at high temperatures and pressures. A novel method for the preparation of microporous silicon carbide membranes was presented. The strategy comprises periodic coating of sacrificial interlayers and SiC pre-ceramic layers. To keep in place the interlayers, a solvent has been selected for the pre-ceramic polymer that does not dissolve the sacrificial interlayer during the dip-coating process or afterwards. The new preparation method involves first dip-coating the slip-casted supports in polystyrene (PS) solution, and then drying at 100°C. The supports were subsequently dip-coated in allylhydridopolycarbosilane (AHPCS) solution, and pyrolyzed at 750°C resulting in complete decomposition of the polystyrene, and the forming of a SiC membrane layer on the top. The procedure of coating, drying and pyrolyzing of PS and AHPCS layers was conducted for three additional times. This is an abstract of a paper presented at the AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).