The combined effect of H2O2 and light emitting diodes (LED) process assisted by TiO2 on the photooxidation behaviour of PLA

The overall objective of this work was to study the combined effect of hydrogen peroxide (H2O2) and light emitting diodes (LED) process assisted by titanium dioxide (TiO2) on the photo-oxidation behaviour of polylactic acid (PLA). The photochemical behaviour of PLA in a TiO2 suspensions was studied by irradiation under photo-oxidative conditions (λ > 454 nm, ambient temperature and with or without the presence of H2O2). The chemical and thermal properties induced by LED irradiation process were analyzed using fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the presence of photoactive TiO2 particles, combined with H2O2 leads to strong impact on the physicochemical properties of the samples during photochemical ageing. A new comprehensive mechanism for the photo-oxidation of PLA for these conditions was discussed.