Simple blends of the poly(norbornenyldecaborane) (PND) boron-carbide preceramic polymer with either of the commercial poly(methylcarbosilane) (PMCS) or allylhydridopolycarbosilane (AHPCS) silicon-carbide preceramic polymers have been found to provide excellent processable precursors to boron-carbide/silicon-carbide ceramic composite materials. The blends exhibited good char yields with tunable ceramic compositions. Certain compositions of the PND/AHPCS derived ceramics also exhibited significant oxidation resistance. Nonwoven mats of PND/PMCS polymer composite fibers were readily obtained by the electrostatic spinning of polymer blend solutions. The pyrolytic ceramic conversion reactions of the PND/PMCS polymer fibers then produced mats of micro- and nanodiameter boron-carbide/silicon-carbide ceramic composite fibers.
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Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802;