Scale-Up Preparation of Biobased Poly(ethylene furanoate) Biaxial Orientation Films with Enhanced Mechanical and Barrier Properties for Packaging

Poly(ethylene furanoate) (PEF) films, recognized for their promising barrier and mechanical properties, offer a sustainable alternative to conventional petrochemical-based poly(ethylene terephthalate) (PET). In this study, the effects of biaxial orientation parameters on the properties of biaxially oriented PEF (BOPEF) and PET/PEF/PET multilayer coextrusion films were comprehensively investigated to explore the potential of PEF for high-barrier packaging materials. Optimized conditions for BOPEF films were achieved at a stretch ratio of 3.5, a temperature of 105 °C, and a rate of 100%/s, which enhanced the tensile strength to 145 MPa, the modulus of elasticity to 4.1 GPa, and the elongation at break to 88%. Moreover, these films exhibited superior barrier properties with an oxygen permeability of 0.0083 barrer, a carbon dioxide permeability of 0.0031 barrer, and a water vapor permeability of 5.54 × 10–15 g·cm/(cm2·s·Pa). Under the same conditions, the mechanical properties and barrier properties of PET/PEF/PET films were further improved by adding 20% PEF to PET/PEF/PET films. The barrier properties of oxygen, carbon dioxide, and water vapor were improved by 32%, 50%, and 74%, respectively. The pilot-scale production validated the laboratory findings, demonstrating stability in film performance and consistent barrier properties, thus confirming the feasibility of industrial-scale production for applications in packaging. The findings from this study not only underscore the potential of PEF as a high-performance material in packaging applications but also illustrate the critical importance of process optimization in achieving the desired material properties. These results build a solid foundation for the broader industrial application of PEF, enhancing its viability as a scalable and environmentally friendly alternative in the packaging industry.