Improvement of anti-aging property of UV-curable coatings with silica-coated TiO2

A series of SiO2 coated TiO2 particles (TiO2@SiO2) were prepared by depositing SiO2 layer on the surface of TiO2 particles via an in-situ hydrolysis condensation of tetraethyl silicate, which was used as UV-shielding fillers to prepare UV-curable coatings. The effect of SiO2 layer on the photocatalytic activity, UV-shielding ability and dispersibility of TiO2 particles was systematically explored. The anti-aging property of the UV-cured coating was determined by color change, surface gloss loss, and surface morphology via accelerated UV aging test. It was found that the presence of a continuous and dense SiO2 layer on TiO2 surface could not only improve the dispersibility of TiO2, but also effectively inhibit the photocatalytic activity of TiO2 without sacrificing its UV-shielding ability, thereby significantly enhancing the anti-aging property of UV-curable coatings. Salt spray test shows that the aged UV-cured coating with TiO2@SiO2 exhibited better corrosion protection behavior than the aged pure resin coating as well as the aged TiO2 coating.