Surface modification of mica with TiO{sub}2 powders prepared by alkoxide hydrolysis method

摘要

TiO{sub}2 powder was adsorbed on the surface of mica using the heterocoagulation method in water. TiO{sub}2 powder was prepared from hydrolysis of titanium-iso propoxide in a mixed solvent of anhydrous ethanol and water When the molar ratio of water to titanium iso-propoxide was 0.25, monodispersed spherical TiO{sub}2 particles were obtained. The prepared TiO{sub}2 powder showed anatase phase after heat treatment at 500 °C for 2h and then fully transformed to rutile phase after heat treatment at 1000°C for 2h. The iso-electric point of TiO{sub}2 and mica were pH 3.9 and pH 3.25, respectively, which were measured by Z-potential analysis in water base. The maximum Z-potential difference between two powders was observed in the range of pH 3.6 250L?.7. TiO{sub}2 powder was adsorbed on the surface of mica by heterocoagulation method in pH 3.6～3.7. The properties of prepared TiO{sub}2 powder was characterized by XRD, SEM, etc. The color change and SPF (Sun Protection Factor) indices of TiO{sub}2-adsorbed mica were examined.