Effects of Titanium-Silica Oxide on Degradation Behavior and Antimicrobial Activity of Poly (Lactic Acid) Composites

A mixed oxide of titania-silica oxides (Ti_xSi_y oxides) was successfully prepared via the sol-gel technique from our previous work. The use of Ti_xSi_y oxides to improve the mechanical properties, photocatalytic efficiency, antibacterial property, permeability tests, and biodegradability of polylactic acid (PLA) was demonstrated in this study. The influence of different types and contents of Ti_xSi_y oxides on crystallization behavior, mechanical properties, thermal properties, and morphological properties was presented. In addition, the effect of using Ti_xSi_y oxides as a filler in PLA composites on these properties was compared with the use of titanium dioxide (TiO₂), silicon dioxide (SiO₂), and TiO₂SiO₂. Among the prepared biocomposite films, the PLA/Ti_xSi_y films showed an improvement in the tensile strength and Young's modulus (up to 5% and 31%, respectively) in comparison to neat PLA films. Photocatalytic efficiency to degrade methylene blue (MB), hydrolytic degradation, and in vitro degradation of PLA are significantly improved with the addition of Ti_xSi_y oxides. Furthermore, PLA with the addition of Ti_xSi_y oxides exhibited an excellent antibacterial effect on Gram-negative bacteria (Escherichia coli or E. coli) and Gram-positive bacteria (Staphylococcus aureus or S. aureus), indicating the improved antimicrobial effectiveness of PLA composites. Importantly, up to 5% Ti_xSi_y loading could promote more PLA degradation via the water absorption ability of mixed oxides. According to the research results, the PLA composite films produced with Ti_xSi_y oxide were transparent, capable of screening UV radiation, and exhibited superior antibacterial efficacy, making them an excellent food packaging material.