Preparation and properties of acrylic polymers/titania hybrid materials prepared by the in situ sol-gel process

摘要

Hybrid inorganic-organic materials based on a methyl methacrylate-n-butyl methacrylate-methacrylic acid terpolymer have been prepared by the in situ sol-gel process in the presence of tetrabutyltitanate. The whole hydrolysis-condensation process results in homogeneous and semi-transparent films with amounts of titania ranging from 4.5 to 22%. Infra-red spectroscopic results show that COO-Ti bonds are formed and that chelating ones are stable up to 200 deg C. Thus far, it had not been possible to separate the contributions of the acid groups from the catalyst (acetic acid) and those from the polymer. However, solvent extraction results undoubtedly proved a strong interaction between the polymer and the inorganic phase through COO-Ti bonds. Mechanical properties of the hybrid films have also been investigated through microhardness measurements and dynamic mechanical analysis. The results show that the tensile properties of the composites are strongly enhanced above the glass transition temperature (T_g) of the polymer. Below T_g, the tensile properties are not significantly affected.