Convertibility and Barrier Performance of Novel Bio-Based Extrusion-Coated Paperboards

Conventional fossil fuel–based plastics for food packaging currently cause environmental concerns owing to poor recyclability and degradability, and new strategies are being developed to address these issues. One strategy involves the use of bioresources to produce bio-based plastics that exhibit similar performance with enhanced sustainability. However, the understanding of the properties of these materials remains limited. Consequently, the convertibility and barrier properties of three extrusion-coated paperboards before and after creasing were examined in this study. Each coating was composed of a partially bio-based polymer:low-density polyethylene (Bio-PE) and two polybutylene succinate (PBS) grades. All materials demonstrated high oil resistance and low water absorbency (Cobb1800). Certain creased samples of Bio-PE unexpectedly exhibited a higher barrier to oxygen than the unconverted material, whereas the results for the PBS grades were more consistent. In contrast, Bio-PE provided a superior barrier to water vapour compared with PBS. The tests indicated that conversion did not reduce the material barrier properties, as confirmed by the negligible surface damage observed using scanning electron microscopy. The issues encountered were attributed to deviations in the production quality of Bio-PE and insufficient adhesion of both PBS films to the substrate. Although further research is required for improving the coating uniformity and adhesion to substrate, the materials exhibit potential to advance the sustainable packaging.