Organic-inorganic composite materials from acrylonitrile-butadiene-styrenecopolymers (ABS) and silica through an in situ sol-gel process

Nonbonded and chemically bonded organic-inorganic composite materials, ABS/ SiO2 and ABSSi(OCH3)(3)/SiO2, were prepared by the sol-gel processing of te traethoxysilane (TEOS) in the presence of ABS and trimethoxysilyl functiona lized 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-glycidoxypropyltr imethoxysilane (GPTS). The ABS-Si(OCH3)(3)/TEOS sol-gel liquid solution sys tem, 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 gela tion 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 sila nol groups. The morphology and properties of composite were characterized b y scanning electron microscopy (SEM), differential scanning calorimeter (DS C), tensile tests, and thermogravimetry. It was found that the composite pr epared from ABS-Si(OCH3)(3) had higher tensile strength, glass transition p oint (T-g), thermal stability, and more homogeneous morphology because of t he existence of the covalent bond between ABS chains and silica network tha t increased the compatibility between the organic and inorganic phases. (C) 2000 John Wiley & Sons, Inc.