Biopolymer nanocomposite blends of poly(lactic acid) and polyhydroxybutyrate biopolymers reinforced with cellulose nanofibrils at low loading ratio

This study investigated the mechanical, morphological, thermal, rheological properties, and accelerated aging performance of poly(lactic acid) (PLA)/polyhydroxybutyrate (PHB) blends with cellulose nanofibrils (CNFs) at low loading ratio. According to the obtained results, the addition of both PLA and CNFs were found to generally increase the mechanical properties of the biopolymer nanocomposites (BNCs). Morphological characterization with scanning electron microscopy (SEM) exhibited that cellular structure occurred in all the BNCs with adding both PLA and CNFs. Thermal stability of the BNCs improved with PLA and CNFs. The addition of CNFs and PLA generally increased the isotherms including Tg, Tc, and Tm according to differential scanning calorimetry (DSC), and it was found that the blends' crystallinity dropped because of a poor crystallinity of PLA. The addition of both PLA and CNFs provided an improvement on the rheological and viscoelastic properties of the neat PHB. XRD pattern of all the BNCs was found to be similar to the neat blends and the BNCs. In the accelerated weathering test, the adding PLA to neat PHB was found to provide more improvement than adding of CNFs.