PHOTOCATALYTIC ACTIVITY OF PLA/TIO2 NANOCOMPOSITES AND TIO2-ACTIVE MULTILAYERED HYBRID COATINGS

Poly(lactic acid) (PLA) has attracted increasing interests due to its biodegradability, compostable property, good mechanical properties and processability. The incorporation of nanometer sized inorganic particles, such as nano-titanium dioxide (TiO2), within PLA matrix or hybrid coating prepared by sol-gel approach represents a valuable solution to confer new functionalities such as photocatalytic activity. TiO2-based nanocomposites can have potential applications in the food packaging industry due to their antimicrobial activity. In this study, films of PLA functionalized with TiO2 nanoparticles, prepared both by direct melt processing and by depositing the active hybrid coating, were characterized and their photocatalytic activity was investigated. It has been proven that the functionalization of TiO2 particles with 1H,1H,2H,2H-perfluorooctyltriethoxysilane enhances the photocatalytic activity of deposited multilayered coating. In particular, after 10 h of UV-irradiation, only the nanocomposites loaded with 10 wt% of TiO2 particles was able to reach a decolorization degree of 80%, whereas for multilayered hybrid coatings the same decolorization degree was obtained for a TiO2 percentage content of approximately 0.002 wt%. This result can be ascribed to a better dispersion and to a higher TiO2 concentration on the surface of the film.