Enhancing the mechanical and barrier properties of biobased polyester incorporated with carboxylated cellulose nanofibers

Most conventional plastic wraps for food packing and preservation have limited flexibility and relatively unique functions, seriously limiting their practical uses. However, smart and sustainable polyethylene 2,5-furandicarboxylate (PEF) polyester is currently employed for construction composite films to overcome this limitation. Herein, the fabrication of bio-based PEF/carboxylated cellulose nanofibers (CCNFs) blends films using PEF and CCNFs by a simple method involving layer-by-layer (LBL) assembly polymerization with exceptional mechanical and interfacial properties. In particular, the mechanical results revealed that the CP3 (1.0 wt% CCNFs) composite film had excellent mechanical properties like tensile strength (69.0 MPa), Young's modulus (4.3 GPa), and toughness (1.26 MJ/m3), which is markedly higher than that of pure PEF film. Besides, the barrier results also demonstrated that CP3 blend film reduced the CO2 and O2 barriers by 13.4% and 11.2%, respectively, compared to pure PEF film. Consequently, FTIR, XPS, SEM/EDS, and AFM characterizations provide insight into the chemical composition, elemental distribution, morphology, and structural properties of CCNF that directly affect the PEF/CCNF composite. Notably, the barrier properties and fruit experiments revealed CP3 composite film, and the shelf life of fresh mangoes was extended by at least one week under ambient conditions (i.e., a relative humidity of 90–95%, a temperature of 30 °C, and natural light). These results indicate the practical use of CP3 composite film as a food packaging in next-generation, well-coated preservation films.