OXIDE-CARBON COMPOSITES AND POROUS METAL-OXIDES PREPARED VIA WATER-SWELLABLE POLYMER NETWORKS

Water-swellable polymer networks (WSPN) were employed as media for lod ging metal nitrate salts or partially hydrolyzed tetraethyl orthosilic ate (TEOS), which are precursors for inorganic oxides. The loading was achieved either via the polymerization of a suitable monomer and a cr oss-linker in an aqueous solution of the precursor or, in the case of TEOS, via the simultaneous polymerization of both monomers. The pyroly sis of the precursor-loaded network under N-2 flow generated interpene trating networks of carbon and metal oxide. The combustion of the comp osite in air removed the carbon network and a porous metal oxide frame work remained. On the basis of this methodology, a coating layer of C- SiO2 composite was generated on a carbon-fiber, and porous powders of SiO2, ZrO2, MgO, and CuO-ZnO-Al2O3 oxide(s) were synthesized. It was f ound that the specific surface area of the oxides is affected by the n ature of the WSPN. Two methodologies which lead to particles were deve loped. In one of them, sedimentation polymerization, large particles o f about 1 mm size were obtained. In the other one, which starts from a n emulsion of a water solution in an organic liquid (toluene, cyclohex ane), micrometer size particles were prepared.