Effect of Mixed Oxide-Based TiO2 on the Physicochemical Properties of Chitosan Films

The physicochemical, mechanical, and structural properties of chitosan-based films (CS) alone or CS-films with mixed oxide nanoparticles (TiO2-ZnO-MgO, TZM; CSTZM) at different concentrations (125, 250, and 500 μg mL−1) were investigated. The addition of nano-TZM promoted a color change (from colorless to white) in the film-forming solution, which increased its turbidity and it decreased viscosity. CSTZM were semitransparent (transmittance, T% decreased up to 49%) compared to CS-based films (T% = 95.5). CSTZM (particularly at a concentration of 500 μg mL−1) exhibited an improvement in the moisture content (decreased from 12.6 to 9.67%), water solubility (decreased from 14.94 to 10.22%), degree of swelling (increased from 19.79 to 36.28%), water vapor barrier (decreased from 6.62 x 10−16 to 4.33 x 10−16 g m−1 h−1 Pa−1), thermal stability (the endotherm peak increased from 99.5 to 157.7 °C), and mechanical properties (tensile strength and elongation at break increased from 4.15 to 4.98 kPa and 6.96 to 56.18%, respectively, while the modulus of elasticity decreased from 144 kPa to 4.11 kPa), without toxicity effects on Artemia salina (93.33% survival). X-ray diffraction and Fourier transform infrared studies demonstrated an interaction between CS-based films and nano-TZM. Overall, this film exhibited great potential for diverse industrial applications.