title: Apatite-forming ability and mechanical properties of PTMO-modified CaO-SiO2 hybrids prepared by sol-gel processing: effect of CaO and PTMO contents.
abstract: Transparent monolithics of triethoxysilane end-capped poly(tetramethylene oxide) (Si-PTMO)-modified CaO-SiO2 hybrids were successfully synthesized by hydrolysis and polycondensation of Si-PTMO, tetraethoxysilane (TEOS) and calcium nitrate. As for the samples with varying (Ca(NO3)2)/(TEOS) molar ratios under constant ratio of (Si-PTMO)/(TEOS) of 2/3 in weight. the apatite-forming ability in a simulated body fluid (SBF) which is indicative of bioactivity. remarkably increased with increasing CaO content, although the tensile strength and Young's modulus decreased. The hybrid with (Ca(NO3)2)/(TEOS) = 0.15 in mol formed an apatite on its surface within only 1 day. For this series of samples, the strain at failure which is a measure of capability for deformation of material, was found to be about 30% and almost independent of CaO content. As for the samples with varying (Si-PTMO)/(TEOS) weight ratios under constant ratio of (Ca(NO3)2)/(TEOS) of 0.15 in mol, the strain at failure increased with increasing Si-PTMO content, but the apatite-forming ability, tensile strength and Young's modulus decreased. Thus, the synthesis of the hybrids exhibiting both high apatite-forming ability and high extensibility can be achieved by selecting suitable CaO and Si-PTMO contents. These new kind of hybrid materials may be useful as bioactive bone-repairing materials.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Japan. miyata@sung7.kuic.kyoto-u.ac.jp
authors.forename: Noboru
authors.initials: N
authors.lastname: Miyata
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Fuke
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kawashita
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kokubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D001031:Apatites / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry; D001826:Body Fluids / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D005782:Gels; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry* / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D017610:Calcium Compounds; D005782:Gels; D010087:Oxides; C404813:polytetramethyloxide; D012822:Silicon Dioxide; C016538:lime