Abstract: The PVC/TiO2 composites were prepared via melt blending. The dispersion of the modified TiO2 particles in PVC was investigated with SEM. The dispersion of the TiO2 particles in PVC and mechanical properties of the composites were related to the surface modification of TiO2, When surface treated with tetrabutyl titanate (Ti(OBu)4), γ-aminopropyltriethoxysilane (KH-550), or polymethyl methacrylate (PMMA). the TiO2 particles could be well dispersed in PVC, which increased the impact strength. As the content of PMMA-modified TiO2 particles was 2.5 phr, the izod impact strength of the composite was teo times that of neat PVC. However, when modified with SLS, the particles ggregated severely and thus the mechanical properties of the composite declined.

Key words: titanium dioxide, poly（vinyl chloride）, dispersity, mechanical property