MODIFICATION OF PAN BY TITANIUM DIALKYLAMIDES - PRECURSORS FOR TITANIUM CARBIDE

Advanced ceramics (e.g., carbides, nitrides, and borides) are materials having desirable properties for a variety of applications. Their key properties are high hardness and strength along with resistance to heat, corrosion, and wear. Methods for producing these materials, particularly in fiber form, require unconventional processing techniques. In our attempt toward such fibers, we felt that if we utilized organic polymers (as a source of carbon) and suitably modified it with an organotitanium complex at the molecular level, we would have a system containing the right ingredients, i.e., Ti and C. Such a polymeric system could conceivably be processed into a fiber. Polyacrylonitrile (PAN) has pendant nitrile groups and therefore was selected as a prime candidate for modification of organotitanium complexes. PAN can also be easily fabricated into fibers and processed at elevated temperatures to produce 'carbon' which can simultaneously undergo a 'solid state' reaction with titanium. Under appropriate processing conditions it was envisaged that Ti-C would be the main constituent of the end product. Thus far we have synthesized organometallic monomers and organic polymers along with their modification; the fabrication of such modified organic polymers into fibers is followed by their thermal processing into ceramics.