Exploring the grafting copolymer of CNF-graft-PHEMA as a coating for packaging paper

Packaging materials are essential for protecting commodities from external environmental factors and ensuring their quality during transportation. Food and beverage products, such as fresh milk, fish, and meat, require packaging that prevents spoilage. In this study, CNF surfaces were modified to enhance hydrophobicity via free radical graft copolymerization using 2-hydroxyethyl methacrylate (HEMA) as a monomer and cerium ammonium nitrate (CAN) as an initiator. The resulting CNF-graft-PHEMA was isolated to remove homopolymers using DMF : methanol as the solvent. The isolation time and DMF : methanol ratio were varied to optimize the purity of the produced graft copolymer. Based on the viscosity and degree of grafting, the optimum conditions for CNF-graft-PHEMA were found to be a DMF : methanol ratio of 2 : 1 and an isolation time of 48 h. CNF-graft-PHEMA/cellulose acetate composites were prepared at varying cellulose acetate (CA) concentrations to evaluate their impact on the coating barrier properties via WVTR and water contact angle measurements. Based on the results of the WVTR and water contact angle tests, CNF-graft-PHEMA/CA 5 wt% exhibited an improvement in barrier properties, with a WVTR value of 1.6198 g m^-2 4 h and a water contact angle of 104.67°.