A novel nanocomposite that consists of polysilicic acid nanoparticles (PSA)/waterborne polyurethane (WPU) was prepared. The nano-size distribution of PSA particles were measured using the dynamic light scattering method. Nanocomposites were monitered and characterized by Fourier-Transform Infrared spectrophotometer (FT-IR). Si-mapping was used to elucidate the dispersion of silica in the nanocomposite. Morphological investigations revealed that PSA nanoparticles were well dispersed in waterborne polyurethane matrix on the nano-scale (100 nm). Thermal characteristics indicated that adding PSA increased the thermal degradation temperature by 43 degrees C when the content of polysilicic acid nanoparticles was 5 wt%. Mechanical property tests demonstrated that adding polysilicic acid nanoparticles improved the tensile properties (by more than 100%), and reduced the wear index. Oxygen permeability tests showed that introducing the PSA nanoparticles increased the oxygen permeability of the nanocomposite. (c) 2005 Springer Science + Business Media, Inc.