Simultaneously improving toughness and UV-resistance of polylactide/titanium dioxide nanocomposites by adding poly(ether)urethane

Adding titanium dioxide (TiO2) into Polylactide (PLA) matrix is an efficient way to improve the UV-resistance of PLA for outdoor applications. In this work, soft poly(ester)urethane elastomer was used to tailor the dispersion and distribution of TiO2 nanoparticles and improve the toughness of PLA as well. It was observed that TiO2 nanoparticels are selectively located at the interface between PU dispersed phase and PLA matrix to form a so called soft core-rigid shell structure. Interestingly, the addition of PU gives a significant rise to not only toughness, but also UV-resistance of PLA/TiO2 composites. According to Fourier transform infrared spectroscopy (FTIR), the anhydride as the main photoproducts was confirmed for all the prepared samples, including PLA, PLA/PU blends, PLA/TiO2 and (PLA/TiO2)PU nanocomposites, which indicates that the addition of PU or/and TiO2 does not alter the photooxidation chemical mechanism of PLA. The enhancement of anti-UV performance is mainly ascribed to good UV-absorption ability of PU and TiO2 nanoparticels.