Effect of nano-TiO2 on the physical, mechanical and optical properties of pullulan film.

In this study, effects of nano-TiO2 on the microstructural, physical, mechanical and optical properties of pullulan films were investigated. The results showed that the addition of nano-TiO2 improved the water vapor barrier properties of the film due to the tortuous path formed by nano-TiO2. When the concentration of nano-TiO2 was 0.04 g/100 mL, the tensile strength of the film showed a maximum value (15.99 MPa). The elongation at break of the film continued to decrease with the increase of nano-TiO2. The TEM analysis showed that higher concentration of nano-TiO2 would cause greater aggregation. Meanwhile, the results of FTIR and low-field NMR indicated that the miscibility between pullulan and nano-TiO2 was due to the formation of intermolecular hydrogen bonds during film formation. Furthermore, the addition of nano-TiO2 significantly improved the film barrier properties to ultraviolet light.