Expendable Broadband Projectors for Undersea Warfare

Not Available Graphitization-resistant isotropic pitch-based carbon fibers are proposed as a replacement for rayon-based carbon fibers in carbon-phenolic composites used in heat shields and exhaust systems of missiles. Fibers spun from isotropic (non-mesophase) petroleum and coal tar pitches have mechanical properties very similar to carbon fibers made from unstretched rayon but may tend to graphitize and become thermally conductive when exposed to high temperatures. The objectives of the proposed Phase I project will be identify chemical treatments for precursor pitches that result in graphitization-resistant, low thermal conductivity carbon residues; identify spinning and stabilization parameters for making fibers from the modified pitch; document alternative natural or synthetic pitches that form graphitization-resistant carbons; and review non-woven fabrication techniques as alternatives to spinning and weaving multifilament yarns. To prepare for Phase II, the potential advantages of isotropic pitch-based carbon fibers as reinforcements in ceramic matrix composites for rocket propulsion components will be preliminarily evaluated.