, "Preparation and evaluation of the electrospun chitosan/PEO fibers for potential applications in cartilage tissue engineering" (2005). Papers in Biotechnology. 29.

Permethylated cyclooligosiloxane rings, tetraethylortosilicate (TEOS), and Ti(iPr) 2 Cl 2 were used to prepare hybrid TiO 2 -SiO 2 xerogels. A number of solvents were ineffective for leaching the organic silicon from the samples at 336 K after several hours. The nitrogen desorption isotherms of these materials reveal that microporous structures with broad pore size distributions are generated upon gelation. Characterization of the samples by means of 29 Si CP/MAS NMR shows incorporation of the "organic silicon" into the amorphous structure and also suggests a great extent of homogeneity in the proton distribution around all tetrahedral silicate centers. The thermal stability of these hybrid TiO 2 -SiO 2 materials was studied under flowing nitrogen and air by means of temperature-programmed (TP) techniques, and in situ diffuse reflectance infrared spectroscopy (DRIFTS). The stability of the Si-C bond in the absence of oxygen is hardly influenced by the presence of Ti. All Ticontaining samples undergo high-temperature pyrolytic decomposition of the Si-C bond, even when oxygen was present. In the presence of oxygen, the Ti function catalyzes the complete oxidation of the remaining alkoxide groups, rather than Si-C bond oxidation. The thermal stability of the latter and the decomposition of alkoxide groups into olefins are confirmed by both TP methods and DRIFTS.

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