Bioactivity and mechanical properties of PDMS-modified CaO-SiO2-TiO2 hybrids prepared by sol-gel process

Hydrolysis and polycondensation of poly(dimethylsiloxane) (PDMS), tetraetho xysilane (TEOS), tetraisopropyltitanate (TiPT), and calcium nitrate gave es sentially pore- and crack-free transparent monolithics of PDMS-modified CaO -SiO2-TiO2 hybrids, when PDMS/(TEOS + TiPT) was larger than 26:74 in weight , under constant ratios of TEOS/TiPT of 9:1 in mol and Ca/(TEOS + TiPT) of 0.15 in mel. Their apatite-forming abilities in a simulated body fluid, whi ch is indicative of bioactivity, increased with decreasing PDMS/(TEOS + TiP T). Their extensibility and Young's modulus decreased and increased, respec tively, with decreasing PDMS/(TEOS + TiPT). The hybrids with PDMS/(TEOS + T iPT) of about 30:70 in weight showed fairly high apatite-forming ability, h igh extensibilities, and Young's moduli almost equal to those of the human cancellous bones. These new kind of bioactive materials with unique mechani cal properties may be useful as bone-repairing materials. (C) 2000 John Wil ey & Sons, Inc.