Substitution of Fossil Layers with Biobased Ones in Sustainable Cellulosic Packaging for Dairy Products

Home-compostable, biobased films were developed by blending poly(lactic acid) (PLA) with poly(butylene succinate-co-adipate) (PBSA). Among the formulations, the PLA/PBSA 60/40 blend demonstrated strong potential for industrial film production due to its enhanced flexibility and tear resistance. Thanks to their thermoplastic nature, these films can be applied to various substrates—such as paper or paperboard—and are easily recyclable within industrial processing environments. In this study, nanostructured clay and talc were incorporated into PLA/PBSA 60/40-based films to produce composites, which were evaluated for their effectiveness in limiting the diffusion of moisture from high-humidity soft cheeses. The materials’ melt fluidity and tensile properties were also characterized, and the composite morphology was examined using electron microscopy. The results revealed that the filler type significantly affected both the morphological structure and barrier performance, highlighting the critical role of material composition in the development of effective and environmentally sustainable packaging solutions. The biobased PLA/PBSA (60/40) films, particularly those filled with talc, exhibited high processability, flexibility, and effectiveness as a moisture barrier for dairy packaging. Although not yet feasible as a direct LDPE substitute without increasing their thickness, their low mass loss points to their strong potential for sustainable applications—especially when paired with paperboard in rigid packaging.