Processing and properties of novel PBS/PVOH-based films for sustainable food packaging applications

The use of biodegradable or biobased materials in the packaging sector represents one of the main solutions for reducing plastic pollution. Polybutylene Succinate (PBS) is among the most promising biopolymers for food packaging due to its easy processability, good thermal stability, ductility, and flexibility, which make it suitable for film production. However, it has poor barrier properties, similar to those of Polylactic Acid (PLA). Polyvinyl Alcohol (PVOH), on the other hand, is a biodegradable polymer with excellent gas, odour, and aroma barrier properties, high mechanical strength, and chemical resistance, but it is highly water-sensitive and difficult to process. Melt blending may offer a valid strategy to combine the advantages of both materials.

In this study, PBS/PVOH blends at different weight ratios (100/0, 80/20, 60/40, 40/60, 20/80, 0/100 wt%) were prepared via melt-compounding and characterized in terms of their rheological and structural properties. Subsequently, the blends were processed into blown films, which were evaluated for their mechanical, morphological, and barrier properties, as these are critical for food packaging applications. The results showed that PBS exhibited higher viscosity and more pronounced shear-thinning behavior compared to PVOH. Furthermore, incompatibility between the two polymer phases was observed. The blends demonstrated increased stiffness, evidenced by an increase in elastic modulus and a decrease in elongation at break. The incorporation of PVOH significantly improved the barrier performance of the films, with reductions in oxygen and water vapor permeability of up to 53% and 42%, respectively. These findings underscore the potential of PBS/PVOH blends as sustainable materials for food packaging applications requiring enhanced gas barrier properties.