Synthesis of a novel biocomposite of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) reinforced with acetylated cellulose nanocrystals

A novel biocomposite of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/acetylated cellulose nanocrystals (ACN/PHBH) was prepared by solution-casting after surface modification of cellulose nanocrystals (CNCs). Acetylated cellulose nanocrystals (ACNs) exhibited improved dispersion in PHBH compared with non-acetylated CNCs, and maximum thermal decomposition temperature of ACN/PHBH was 13 degrees C higher than that of neat PHBH. Compared to the neat PHBH and CNC/PHBH, 57.6% and 24.5% improvements in tensile strength, and 52.4% and 30.6% improvements in Young's modulus were obtained for the bionanocomposites. The water-vapour and the oxygen barrier properties of ACN/PHBH improved by 76.1% and 30.4% compared with CNC/PHBH samples. Simultaneous enhancements on the thermal stability, mechanical and barrier properties were mainly caused by uniform dispersion of ACNs and solid interfacial bonding between filler and matrix. This performance of the bionanocomposite will broaden the utilization of CNCs as renewable bioresources and the practical application of PHBH-based plastics as replacements for traditional petrochemical materials. Graphic abstract