Abstract:Poly (vinyl chloride) (PVC) plays a key role in the development of plastics industry for its versatility, and it is one of the five major general resins. However, poor thermal and optical stabilities of PVC seriously affect its service life. The most effective way to solve the PVC optical stability is to add light stabilizers. The commercial light stabilizers include titanium dioxide, 2′-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole, and so on. However, some of these light stabilizers are limited by their opacity, some of these light stabilizers are mostly small molecules, which are easily volatilized or migrated in the process of use, which seriously affects their optical stability. The effects of inorganic/organic composites on PVC aging properties are studied in this paper. A novel organic/inorganic composite UV absorber was prepared by combination of nano silica (SiO2) with panchromatic UV absorber polybenzimidazole (PBI), which was used to improve UV resistance of PVC. In order to improve the compatibility between nano SiO2 and PBI, silane coupling agent γ-aminopropyltriethoxysilane was used to modify nano SiO2 (MSiO2), then MSiO2 was coated by PBI (PBI@MSiO2). PVC/PBI@MSiO2 composites were prepared by melt blending, the UV absorption, mechanical properties, morphology and thermal stability of the composites were investigated and compared. The results show that PVC/(PBI@MSiO2) composites have the best comprehensive properties. The UV absorption is up to 99 % at the wavelength of 375 nm and the yield strength is 63.3 MPa when the filler content is 6 wt.%, which is higher than that of other composites.