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

Adding titanium dioxide (TiO 2 ) 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 TiO 2 nanoparticles and improve the toughness of PLA as well. It was observed that TiO 2 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/TiO 2 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/TiO 2 and (PLA/TiO 2 )PU nanocomposites, which indicates that the addition of PU or/and TiO 2 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 TiO 2 nanoparticels. [ABSTRACT FROM AUTHOR]