Synthesis, microstructure and optical absorption of coatings with doping of nano-TiO2 for protection against ultraviolet irradiation

The synthesis of dispersions of MMA (methylmethacrylate) with different con centrations of oleic acid coated nano-TiO2 particles was performed by hydro lysis of TiCl4 in the mixture solutions of MMA, oleic acid and H2O with var ious concentrations. When MMA :oleic acid : H2O : TiCl4 1.00 : 0.064 : 0.01 : 0.032 (by mol fraction), the dispersion of MMA with oleic acid coated na no-TiO2 particles was very stable. Optical absorption result showed that th e absorption band was located in the ultraviolet range from 200 to 400 nm. This dispersion was added to a kind of automobile surface lustering agent ( type II), and then this lustering agent with nano-TiO2 was coated on the su rface of automobile surface paint. When the doping amount of the dispersion in the lustering agent=10 vol. pet, the state of paint (color and glossine ss) did not present any change after irradiation of an ultraviolet lamp wit h the power of 1000 watt for two days. The sample with surface paint and lu stering agent doped by 10 percent dispersion after suffering from irradiati on of the sunlight for half a year (from May to November) kept the original state. However, for the samples with automobile paint and lustering agent without doping of nano-TiO2, the color and glossiness lost easily after irr adiation of an ultraviolet lamp. These results prove that nano-TiO2 is a ki nd of high-efficient additive of paint for protection against ultraviolet i rradiation.