A mixed oxide of titania-silica oxides (TixSiy oxides) was successfully prepared via the sol-gel technique from our previous work. The use of TixSiy 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 TixSiy oxides on crystallization behavior, mechanical properties, thermal properties, and morphological properties was presented. In addition, the effect of using TixSiy 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/TixSiy 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 TixSiy oxides. Furthermore, PLA with the addition of TixSiy 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% TixSiy 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 TixSiy oxide were transparent, capable of screening UV radiation, and exhibited superior antibacterial efficacy, making them an excellent food packaging material.
Keywords: antimicrobial activity; hydrolytic degradation; photocatalytic degradation; silica; titania; titanium silicon oxide.