Characterization and property investigation of novel eco-friendly agar/carrageenan/TiO2 nanocomposite films

Agar/kappa carrageenan (AG/CA) nanocomposite films are prepared using thermal casting method in the presence of various concentrations of nano-TiO2 (0.5, 1, 1.5, and 2 g/100 g). As nano-TiO2 content rises from 0 to 1 g/100 g, tensile strength (TS) increases from 30.8 to 60.6 MPa. However, TS decreases gradually as nano-TiO2 content further raises. TS of films containing 1 g/100 g nano-TiO2 increases by 96.8% when compared to those prepared without nano-TiO2. The reason may be related to the formation of intermolecular hydrogen bonding and coordinate bonds between nano-TiO2 and matrix molecules. Elongation at break decreases gradually as nano-TiO2 concentration increases. The addition of nano-TiO2 improves barrier properties of films against ultraviolet light, while it decreases their transparency. Swelling and water solubility of the films containing 1 g/100 g nano-TiO2 decrease, further demonstrating that interaction forces are formed between nano-TiO2 and matrix molecules. The addition of nano-TiO2 significantly declines water vapor permeability. Overall, films containing 1 g/100 g nano-TiO2 show the best mechanical, optical, and water resistance properties. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47113.