Preparation and evaluation of photocatalytic activity of poly(dimethylsiloxane)–titanium dioxide composites

The poly(dimethylsiloxane)–titanium dioxide (PDMS–TiO2) composites were prepared by emulsion polymerisation of octamethylcyloteterasiloxane (D4) in the presence of TiO2 particles modified by [γ-(methacryloxy)-propyl] trimethoxysilane (γ-MPS). The structure of the prepared PDMS–TiO2 composites was characterised by fourier transform infrared (FTIR) spectra, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results show that PDMS is grafted onto the surface of TiO2 particles via γ-MPS. The photocatalytic activity of PDMS–TiO2 composites was evaluated by decomposition of methyl orange (MeO). The result indicates that PDMS–TiO2 composite is one kind of efficient catalyst for MeO decomposition and the decomposition rate constant of MeO for PDMS–TiO2 composite is ∼3 times of that for TiO2. UV-vis diffuse reflectance spectra measurements show that the absorbance of PDMS–TiO2 composites is higher than that of TiO2 in the visible light range.