“Soft-rigid” synergistic reinforcement of PHBV composites with functionalized cellulose nanocrystals and amorphous recycled polycarbonate

Abstract Herein, both rigid cellulose nanocrystal with photoactive groups (CNC-Cc) and amorphous polycarbonate (extracted from discarded CD) were functionalized as reinforcing agents to obtain poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polycarbonate/CNC-Cc (PHBV/PC/CNC-Cc) composite films via a Pickering emulsion approach. With the addition of PC and CNC-Cc, an obvious “soft-rigid” synergistic effect on the performances of PHBV matrix was found. Compared to neat PHBV, the best mechanical strength/toughness of PHBV/PC/CNC-Cc-7 increased by 273.8%/821.9%. Meanwhile the PHBV/PC/CNC-Cc-7 nanocomposite showed excellent UV shielding, antioxidant, and antibacterial abilities, due to dynamic competition effect of amorphous PC and rigid CNC-Cc on the PHBV microstructure and interaction. Therefore, this work could solve the current problems of poor mechanical flexibility of biopolymers for potential applications in easy-oxidized food packaging.