Stability of poly(l-lactide)/TiO2 nanocomposite thin films under UV irradiation at 254Â nm

Poly(l-lactide)/titania (PLLA/TiO2) nanocomposites were in situ synthesized through ring-opening polymerization of l-lactide. Two types of TiO2, anatase and rutile, were used in the synthesis of composites. The chemical structure, crystallinity, thermal stability and morphology of composite thin films were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of TiO2 on the stability of the nanocomposites under UV irradiation as a function of time were investigated by FTIR, XRD, UV absorption spectroscopy and differential scanning calorimetry (DSC). The obtained results indicated that rutile TiO2 particles have a screening effect while anatase TiO2 acts as a photocatalyst. The DSC results revealed that anatase TiO2 embedded in bulk of the films produces the same effect as rutile TiO2.