The hydrolysis of the chelate of acetylacetone of aluminum

which is prepared by aluminum-iso- propanol and acetylacetone

results into alumina sol An organic-inorganic sol (OIS) can thus be prepared by the alumina sol crosslinking with the residual hydroxyl groups of poly(vinyl butyral)．The OIS

after molding and drying

gives easily transparent

solvent-resistant membrane and high-elastic fiber

those are actually the organic-inorganic hybrid polymers．When coated on carbon fibers

followed by drying and heat treatment

the OIS forms very fine and thin amorphous alumina-carbon film

which obviously improves the fibers’resistance to oxidation at high temperature and fiber’s surface properties．