Silicon-organic hybrid polymers and composites prepared in supercritical carbon dioxide

Silicon-containing organic/inorganic composites were prepared front poly(st yrene-co-allyl alcohol) (PSAA) and soluble starch (SS) by infusing SiCl4 in to them using supercritical carbon dioxide (SC CO2) as the carrier medium. The resulting hybrid materials were studied by Fourier transform infrared s pectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) dynamic mechanical t hermal analysis (DMTA) and elemental analysis. The results of these studies indicated that 12-15% silicon, in the form of SiO2, was homogeneously disp ersed throughout the PSAA and SS matrices. As a consequence Nle interpenetr ated SiO2 network, the solubility properties of the composites were altered relative to the virgin materials. SC COP was also employed as the reaction medium in platinum-catalyzed hyrosilation reactions. The dialyl ether of 1 ,3-bis(hexafluoro-2-hydroxy-2-propyl)benzene (1,3-HFAB) was used in a model reaction along with dimethylphenylsilane as ale sililating agent. The reac tion mixtures from hydrosilation reactions conducted in both benzene and in SC CO2 were analyzed by H-1-NMR spectroscopy. Comparison of the spectra in dicated that the SC CO2 reaction provided higher per When the 1,3-HFAB dial lyl ether was reacted with disilanes and siloxanes, silicon- anti fluorine- containing oligomers were obtained in good yields. Copyright (C) 2000 John Wiley & Sons Ltd.