Nonbonded and chemically bonded organic-inorganic composite materials, ABS/SiO2 and ABSSi(OCH3)(3)/SiO2, were prepared by the sol-gel processing of tetraethoxysilane (TEOS) in the presence of ABS and trimethoxysilyl functionalized ABS, ABS-Si(OCH,),, under the catalization of NH4F. The ABS-Si(OCH3)(3) was obtained by oxidizing the cyano group in ABS with hydrogen peroxide, then subsequently underwent ring-opening reaction with 3-glycidoxypropyltrimethoxysilane (GPTS). The ABS-Si(OCH3)(3)/TEOS sol-gel liquid solution system, in which the ABS chains formed the covalent bonds with silica network and helped fix the polymer chains in the silica network, had a shorter gelation time than that of the ABS/TEOS system, which linked ABS chains to the silica network only by hydrogen bonding the cyano groups in ABS to the silanol groups. The morphology and properties of composite were characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), tensile tests, and thermogravimetry. It was found that the composite prepared from ABS-Si(OCH3)(3) had higher tensile strength, glass transition point (T-g), thermal stability, and more homogeneous morphology because of the existence of the covalent bond between ABS chains and silica network that increased the compatibility between the organic and inorganic phases. (C) 2000 John Wiley & Sons, Inc.