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A new kind of polymethyl methacrylate (PMMA)-TiO2 nanocomposite was synthesized through polymerization. The thermal and photic stability of this PMMA-TiO2 nanocomposites were investigated. The as-prepared samples were characterized by scanning electron microscopy (SEM), UV-Vis spectroscopy, differential thermal analysis (DTA) and the photo-induced weight loss. The results show that the photostability of the PMMA-TiO2 nanocomposite is higher than that of the pure PMMA under UV-light irradiation. The weight-loss of the pure PMMA reaches 30% after 300 h UV-irradiation, while the composite only 0.3% under the identical experimental condition. The glass transition temperature ( T g) of pure PMMA is only 80°C, while the T k of the composite reaches 258 °C. Compared with pure PMMA, the thermal stability of the composite is greatly enhanced. [ABSTRACT FROM AUTHOR]

A new kind of porous nano TiO2 composite films was prepared on the glass substrate with the water glass as binders and the sodium fluorosilicate as solidifying reagent. The morphologies of the films were studied by scanning electron microscope(SEM). The UV Vis spectrophotometer was also used to investigate the absorption of the films. The gas phase photocatalytic oxidation of nitrogen oxides on the com posite film was carried out in TiO2 UV system, and some important factors affecting the photocatalytic oxidation were also studied such as the catalyst, concentration vapor pressure and the presence of oxygen. The results showed the conver sion of NO x reached 97.5°, after 2 h UV irradiation. The final product of photo oxidation was detected to be HNO3 by FT-IR. The way of photocatalytic oxidation of NO x was possibly useful in the practical application. [ABSTRACT FROM AUTHOR]