CERAMIC FIBERS FROM POLYMER PRECURSOR CONTAINING SI-O-TI BONDS .2. SYNTHESIS OF VARIOUS TYPES OF CERAMIC FIBERS

Polycarbosilanes containing titanium alkoxide as pendant groups (atom ratio Ti/Si = 0.07 and 0.15) were synthesized. These polymers were melt-spun and then heat-treated in a vacuum, in oxygen or ammonia gas flow, resulting in Si-Ti-C-O, Si-Ti-O and Si-Ti-O-N fibres, respectively. The pyrolysis process of the polymer is discussed in connection with the mechanical properties and the structure of the fibre. At high heat-treatment temperatures, beta-SiC and TiC (in Si-Ti-C-O fibre), anatase (in Si-Ti-O fibre) and TiN (in Si-Ti-O-N fibre) crystallized, which may be closely related to the decomposition of the Si-O-Ti bond in the fibre.