Acceleration of poly(L-lactide) degradation by TiO2 nanoparticles in sunlight.

Poly(L-lactide) (PLA) is known to eventually be degraded into water and carbon dioxide by the microorganisms of the natural world. Titanium dioxide (TiO2) has been used in the biomedical and bioengineering fields as a photocatalyst. The purpose of this research project is to evaluate the influence of TiO2 added to PLA films both before and after irradiation of the films with sunlight. The PLA-TiO2 films were prepared by the addition of TiO2 (size: > 100 nm) nanoparticles to PLA. The surface changes of the PLA film were investigated before and after the films were exposed to sunlight. Tiny holes were observed in the PLA film without TiO2 nanoparticles after irradiation with sunlight, whereas large pits formed in the PLA-TiO2 films. It is suggested that PLA was degraded by the ultraviolet rays in sunlight. In addition, the decomposition speed was thought to be enhanced by the addition of TiO2, which acted as a catalyst.