Production of packaging paper from Populus deltoides NSSC pulp reinforced with rice straw cellulose nanofibrils

As a key raw material in fluting paper production, NSSC pulp from hardwoods is crucial in sustainable packaging applications. Hence, efforts are underway to increase the quality of this pulp. This study aims to enhance the physical and mechanical properties of papers produced from Populus deltoides NSSC pulp by reinforcing them with cellulose nanofibrils (CNFs) derived from rice straw. The NSSC pulping of poplar wood was optimized, and then CNFs were added at 5, 10, and 15 % to refined NSSC pulp. Papers (127 g/m 2 ) were fabricated, and the impact of CNF reinforcement on the physical and mechanical properties of papers was evaluated. Results demonstrated that the addition of CNFs significantly improved tensile, burst, and tear indices, bending stiffness, and ring crush test (RCT) by 32.46 %, 19.85 %, 18.22 %, 78.76 % and 65.71 %, respectively. Furthermore, the addition of CNF increased density (30.88 %) and simultaneously reduced thickness (20 %) and bulk (23.23 %). Cobb test showed that water absorption decreased by 35.48 %, indicating better water resistance, while drainage time increased by 87.30 %, reflecting changes in fiber network structure. CNFs facilitate extensive hydrogen bonding, yielding a denser and more robust fiber network. This study highlights CNFs’ potential as an additive for reinforcing NSSC papers and improving packaging performance.