Abstract
Polystyrene/TiO2 composite particles containing organic UV-stabiliser groups (i.e. poly[styrene-co-sodium sulfopropyl lauryl maleate-co-2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone] [poly(St-co-M12-co-BPMA)]/TiO2 composite particles) were prepared. Ultraviolet-visible absorption spectroscopy, UV-vis diffuse reflectance spectroscopy, differential scanning calorimetry, weight loss and gel permeating chromatography measurements were used to study their UV resistant performance. The results indicate that the UV-absorbing ability of the poly(St-co-M12-co-BPMA) grafted onto the surface of TiO2 was enhanced by an increase in BPMA content, and the poly(St-co-M12-co-BPMA)/TiO2 composite particles could absorb more than 90% of UV light in the 210–400 nm wavelength. The ultraviolet absorption capacity of poly(St-co-M12-co-BPMA) grafted onto the surface of TiO2 did not change between 240–280 nm after UV irradiation for 500 h but that of polystyrene increased considerably. The weight loss of the composite particles was much lower than that of polystyrene after UV irradiation, but the glass transition temperature of the composite particles did not change after UV irradiation for 500 h whereas that of polystyrene changed a lot. The molecular weight of poly(St-co-M12-co-BPMA) grafted from the surface of the TiO2 particles was higher than that of the pure poly(St-co-M12-co-BPMA), and the molecular weight of the grafted poly(St-co-M12-co-BPMA) changed little after UV irradiation. These results show that the UV-resistant performance of polystyrene can be enhanced by introducing the organic UV-stabiliser BPMA and the inorganic UV-stabiliser titanium dioxide into the polystyrene chains by covalent bonding.