Preparation and characterization of nano-TiO2/MDI-50 based waterborne polyurethane composites

Nano-TiO2/MDI-50 based waterborne polyurethane composites were prepared with MDI-50, polypropylene glycol (PPG) and nano-TiO2 as main materials. Nano-TiO2 was modified using r-aminopropyltriethoxysilane (KH550) as modifier in order to improve the dispersion of nano-TiO2 in WPU. The composites morphologies and physical states were investigated using scanning electron microscopy (SEM), thermogravimetry analysis (TG), fourier transform infrared (FTIR) spectroscopy and UV-visible (UV-Vis) spectroscopy. Scanning electron microscopy observations revealed that modified nano-TiO2 has good dispersibility. Results from FTIR and TG suggested that the modified nano-TiO2 had been successfully introduced to the polyurethane molecular chain and the thermal decomposition temperature of nano-TiO2/MDI-50 based waterborne polyurethane composites doubled under the same thermal weight loss. Results from UV-Vis suggested that when 2% of modified nano-TiO2 was added, maximum absorbance of composites were significantly improved and was twice higher than that of pure waterborne polyurethane.