Synergistic reinforcing effect of TiO2 and montmorillonite on potato starch nanocomposite films: Thermal, mechanical and barrier properties

• MMT and TiO2 improve the mechanical and thermal properties of starch films.
• Effect of MMT on barrier properties of starch film is more than TiO2.
• There is a synergistic effect in reinforcing behavior of MMT and TiO2.
• Aggregation of nanofillers at the higher loading levels weakened the properties of films.
• The nanocomposite films can be used in food packaging and drug delivery systems.

In this study, ternary potato starch (PS) bionanocomposite films containing two types of nanoparticles, sodium montmorillonite (MMT), one-dimensional (1D) clay platelets, (3 and 5 wt%) and TiO2, three-dimensional (3D) nanospheres, (0.5, 1 and 2 wt%), are prepared using solvent casting method. X-ray diffraction (XRD) test confirms the completely exfoliated structure formed in the PS-MMT nanocomposites containing 3 and 5% MMT. The success of the formation of new hydrogen bonds between the hydroxyl groups of starch and nanofillers is confirmed by Fourier transform infrared (FTIR) spectroscopy. Tensile strength (TS), elongation at break (EB), glass transition temperature (Tg), and melting point (Tm) of the films are also enhanced after MMT and TiO2 incorporation. The water vapor permeability (WVP) and the visible, UVA, UVB and UVC lights transmittance decreases upon TiO2 and MMT content increasing. Generally, a synergistic effect is observed between MMT and TiO2 at lower concentrations of MMT.