Polyurethane(PU) and titanium dioxide(TiO2) nanocomposites are successfully synthesized using prepolymerized method by means of surface modified TiO2 nanoparticles as the inorganic fillers. X-ray diffraction(XRD) and scanning electron microscope(SEM) detections show that the prepared TiO2 is anatase structure and uniform particles with a size of about 13 nm. The mechanical and thermal properties of the PU/TiO2 composites are investigated,and the TiO2 nanoparticles have been uniformly distributed in the PU m...