Mechanical, thermal, structural and barrier properties of crab shell chitosan/graphene oxide composite films

To enhance the thermo-mechanical properties of food packaging materials, chitosan-based nanocomposite films were prepared by blending crab shell chitosan (CS) and graphene oxide (GO) nanosheets in solution at selected concentrations (0.5, 1 and 2% w/w). The addition of GO did not influence the mechanical rigidity of the CS/GO blend in solution although the dielectric properties were influenced. Mechanical, thermal, structural, and barrier properties of blended films were compared with the neat film. By introducing GO, a more compact CS/GO network structure was formed with improved tensile properties and glass transition temperature (T_g) for the composite films. The addition of GO to the CS significantly lowered the lightness (L*) value and UV light transmittance. GO was effective in enhancing the tortuosity of the diffusive path for the oxygen and water vapours to diffuse through the CS nanocomposite film. Fourier transform infrared spectroscopy (FTIR) indicated an intermolecular hydrogen bond formation between CS and GO. The presence of GO clusters in the composite films and the change in the topography of CS/GO films were visualized through SEM and AFM measurements.