A core-shell composite pigment with rutile TiO2 intensification for UV inhibition

• Core-shell composite pigments with rutile TiO 2 intensification were proposed. • Modified pigments exhibited a significant increase in UV absorption. • Decrease of the color change of coating films was achieved. • Facile sol-gel method improved UV resistance of pigments for coatings. Organic pigments generally have bright colors but poor ultraviolet (UV) resistance. To improve the UV resistance and extend the applications, a core-shell composite pigment with rutile TiO 2 intensification for UV inhibition is proposed by a facile sol-gel method in this work. A core-shell structure, with a homogeneous sol-gel TiO 2 shell containing additional nanosized rutile TiO 2 particles and with the pigment as the core, was established taking advantage of UV resistance of TiO 2 and binding ability of sol-gel. While the sol-gel TiO 2 shell alone has already shown obvious ultraviolet shielding effect, as tested over different sol-gel aging times and TiO 2 loadings, the UV resistance of the fluorescent pigments was further enhanced by binding the nanosized rutile TiO 2 in the sol-gel shell. At a sol-gel TiO 2 to rutile TiO 2 ratio of 2:1, the UV exposure time is extended about eight times compared with that of the original pigment and twice as that of the modified pigment with pure sol-gel TiO 2 for the same color change. Therefore, the novel core-shell composite pigment intensified with nanosized rutile TiO 2 particles is proved to be efficient in improving the UV resistance of organic pigments.