Development and characterization of kefiran - AlO nanocomposite films: Morphological, physical and mechanical properties.

Biodegradable kefiran films, containing different concentrations of AlO (alumina) (1, 3 and 5% w/w), were prepared by casting method and their physical, mechanical, and thermal properties were studied. Based on the results, the increase of the nano-AlO content led to a decrease in the water vapor permeability, moisture content, moisture absorption, and water solubility. The addition of nanoparticles did not affect the lightness of the films significantly (P > 0.05). The mechanical tests revealed that the addition of AlO nanoparticles to the kefiran films significantly increased both tensile strength and elastic modulus, while had no effect on the elongation at break (P > 0.05). Thermogravimetric analysis (TGA) indicated the improvement of the films' thermal stability by adding alumina. The results of X-ray diffraction (XRD) confirmed the effect of AlO on the semi-crystalline structure of kefiran. Scanning electron microscopy (SEM) images approved a uniform distribution of nanocomposites containing 1 and 3% w/w of AlO. The obtained results suggested that AlO was able to improve the characteristics of the kefiran-based films for using as food packaging material.