Synthesis and Evaluation of Physicochemical and Antimicrobial Properties of Bionanocomposites Based on Carboxymethylchitosan Biopolymer - Montmorillonite Nanoclay in the Presence of TiO₂ Nanoparticles

In this research, an antimicrobial bionanocomposites based on carboxymethyl chitosan biopolymer-montmorillonite nanoclay was synthesized in the presence of titanium oxide nanoparticles. Investigation of surface morphology images with scanning electron microscopy (SEM) shows the rough and heterogeneous surface of nanocomposites in comparison with pure carboxymethyl chitosan. The results of the XRD test showed that the diffusion of nanoclay in the presence of TiO2 nanoparticles changed from full sheets to between layers sheets. The addition of TiO2 nanoparticles caused a significant increase (p˂0.05) in turbidity in nanocomposites. The effect of TiO2 nanoparticles on reducing the amount of Gram-positive bacteria of Staphylococcus aureus is more than the effect of TiO2 nanoparticles on reducing the amount of gram-negative bacteria of Escherichia coli. By increasing the percentage of TiO2 nanoparticles, its efficacy in removing colonies of both bacteria is increased. Water solubility and Vapor permeability of nanobiocomposite films decreased with increasing weight percentage of TiO2. The tensile strength of the film containing TiO2 nanoparticles is more than the tensile strength of neat carboxymethyl chitosan film, which is statistically significant (p˂0.05). The study demonstrated the high potential of bionanocomposites in preventing the growth of pathogenic bacteria and showed that such packages could be used to increase the shelf-life of food.