Antimony doped tin oxide (ATO) nanoparticles were used as nanofillers to improve mechanical properties of UV-cured polyesteracrylate films. To improve the dispersion of ATO nanoparticles in the polyesteracrylate resin matrix and to strengthen interfacial interactions between ATO nanoparticles and the resin matrix ATO nanoparticles were first organically modified with 3-methacryloxypropyltrimethoxysilane (MPS). The modification of ATO nanoparticles with MPS was confirmed by FTIR spectroscopy and thermogravimetric analysis (TGA). UV-curing behaviors of the nanocomposites films were investigated by FTIR spectroscopy. Compared with the film with neat ATO nanoparticles, the film with the same amount of MPS-modified ATO nanoparticles showed slightly higher UV-curing rate and final conversion. The mechanical properties of the nanocomposites films were measured by universal testing machine. The MPS-modified ATO nanoparticles could improve considerably the mechanical properties of the UV-cured polyesteracrylate nanocomposites films. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013