Acrylic resin/titania organic-inorganic hybrid materials were prepared by mixing titania sol produced by the sol-gel process with synthesized thermoplastic acrylic resins. The effects of the amounts of water and acid on hydrolysis and condensation of the sol-gel precursor (titanium n-butoxide) were characterized by nuclear magnetic resonance, and their corresponding influences on the structure and properties of the hybrid films were investigated by small-angle X-ray scattering (SAXS), atomic force microscopy, dynamical mechanical analysis, an Instron testing machine, and ultraviolet-visible spectroscopy. SAXS indicated an open structure and nanoscale size for the titania phase of the hybrids. Higher titania content and a greater amount of water or acid in the sol-gel process resulted in titania domains that were larger size and had a more compact structure. The mechanical and UV-shielding properties of the organic polymer obviously were improved with titania embedded. As the amount of water or acid in the sol-gel process increased, integrative mechanical properties decreased, with the amount of water having a greater impact than the amount of acid on the structure and optical properties. (C) 2004 Wiley Periodicals, Inc.