Tailoring graphitized cellulose nanocrystal morphologies for robust barrier and mechanical enhancement of PPC...

Both nanocellulose and graphene nanosheets serve as exceptional fillers for biopolymers. However, there are limited materials that effectively combine the properties of these two fillers in Poly (propylene carbonate) (PPC) to enhance their overall properties. This study presents a meticulous approach to producing graphitized nanocellulose (GCNC) with tailored rod-like (R-GCNC) and spheres-like (S-GCNC) under low-temperature and ambient-pressure conditions. The formation and integration of the reinforcement network within the PPC matrix were compared by modulating these morphologies. The R-GC_3%, with its stronger hydrogen bonding interactions, achieved a more optimal combination of properties than S-GC_3%. Significantly, R-GCNC and PPC formed a robust reinforcement network, resulting in remarkable reductions of approximately 153 % in water absorption and 1669 % in water vapor permeability. Significantly, the mechanical properties of PPC were improved by 95 % in tensile strength and 1038 % in Young's modulus due to improved dispersion of R-GCNC with higher aspect ratio. In addition, R-GC_3% had the highest glass transition temperature of 35.1 °C, and a maximum degradation temperature increased by 16.5 °C. The PPC/GCNC composites exhibited outstanding UV shielding, antioxidant properties, and rapid degradation rates. This study introduces a practical method for choosing suitable GCNCs as reinforcing agents to produce innovative green materials for the active packaging.