SURFACE MODIFICATION OF TITANIUM DIOXIDE FOR NOBEL WHITE PIGMENT WITH CONDENSED PHOSPHORIC ACID TREATMENT

Photocatalytically active titanium dioxide is used as a white pigment in cosmetics. However, it may promote a certain degree of sebum decomposition on the skin exposed to ultraviolet radiation in sunlight. In this work, titanium dioxide was shaken with various condensed phosphate solutions to synthesize a novel white pigment for cosmetic applications. Titanium dioxide particles were added to various solutions at a P/Ti molar ratio of 1:1, and then shaken in water at 80oC for 1 h. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the produced powders were studied. The obtained materials exhibited the XRD peaks of titanium dioxide, although the peak intensities were weakened by the formation of a surface layer of titanium phosphate. These samples consisted of particles with sub-micrometer sizes, and the photocatalytic activity of the powders was reduced sufficiently to prevent the degradation of sebum on the skin. The suitable condensed phosphate for condensed phosphoric acid treatment of titanium oxide was sodium triphosphate from the whiteness and smoothness of powders.