STUDIES ON THE SYNTHESES OF POLYMETALLOXANES AND THEIR PROPERTIES AS A PRECURSOR FOR AMORPHOUS OXIDE .5. PREPARATION AND PROPERTIES OF POLYTITANOSILOXANES FROM SILICIC-ACID AND BIS(2,4-PENTANEDIONATO)-TITANIUM DIISOPROPOXIDE

Preparation and properties of polytitanosiloxanes (PTS) as a preceramic polymer for SiO2-TiO2 fibers were investigated. The PTS was prepared by the reaction of bis(2,4-pentanedionato) titanium diisopropoxide (PTP) with silicic acid (SA), extracted with tetrahydrofuran from an aqueous solution, in methanol. They were soluble in methanol, ethanol, and THF. The molecular weight (M(n)BAR) was 1500-4200 depending on the reaction molar ratio (SA/PTP). A concentrated methanol solution of PTS showed an appreciable stability to self-condensation and good spinnability. Dry spinning of the solution provided golden yellow precursor fibers which can be subjected to thermal-treatment to give ceramic fibers. The PTS is considered to be a copolymer formed by the condensation of oligomeric silicic acid with PTP consisting of Si-O-Ti and Si-O-Si linkages in the molecular main chain with the ligand and hydroxy groups as pendants.