Photocrosslinked Poly(Vinyl Alcohol)–Tung Oil–Natural Rubber Films: A Sustainable Solution for Enhanced Water Resistance and Mechanical Properties in Biodegradable Packaging

ABSTRACT This study introduces a novel approach to addressing the water resistance limitations of poly(vinyl alcohol) (PVA)‐based biodegradable films by developing a ternary blend system incorporating tung oil (T) and natural rubber (R), forming PTR films. Photocrosslinking, combined with thermal and redox catalytic systems, facilitated the creation of enhanced network structures, as confirmed by FTIR analysis, particularly at tung oils conjugated double bonds. Dynamic mechanical analysis (DMA) revealed significant shifts in glass transition temperatures ( T g ), signifying enhanced crosslink density and interconnectivity between the components. The resulting PTR films demonstrated remarkable improvements in water resistance, evidenced by higher solid remain percentages, reduced water absorption, and significantly lower water vapor permeability (WVP). Mechanical properties, including tensile strength and Youngs modulus, improved by up to 150% (from 6.6 MPa of PT0R15‐r‐np to 16.3 MPa of PT0R15‐r‐p30) and 870% (from 6.6 MPa of PT0R15‐r‐np to 16.3 MPa of PT0R15‐r‐p30), respectively, due to the formation of robust network structures. Contact angle measurements and reduced moisture content further underscored the enhanced hydrophobic and moisture barrier properties. These findings establish photocrosslinked PTR films as a sustainable and high‐performance option for biodegradable packaging applications, offering practical advantages such as reduced processing temperatures and production times.