Structural, Mechanical, and Environmental Assessment of a Poly(butylene adipate-co-terephthalate) (PBAT)-Inulin Composite Material

The growing interest in mitigating the effects associated with the extensive production and consumption of fossil-based plastics has led to increasing efforts in the development of biobased and biodegradable materials. In this setting, poly(butylene adipate-co-terephthalate) (PBAT) has emerged as a viable biodegradable alternative to traditional polyesters. In this study, the manufacture of a PBAT-inulin composite film is investigated to assess its structural, mechanical, and environmental properties. A design of experiments (DoE) approach was applied to limit the number of experiments and find potential multivariate correlations (p-value <0.005) between composite formulation, e.g., inulin content, and mechanical properties. Results show that the inulin percentage has the highest influence on the strain at break, which is found to decrease as the percentage of inulin increases; as such, an ideal amount of inulin is found to be equal to 4.4-4.5% of the composite. From an environmental standpoint, results of a cradle-to-gate life cycle assessment (LCA) (1 kg of composite as the functional unit) show that PBAT production is the highest overall contributor to the impacts of the composite (68% average across categories), whereas inulin presents the highest contribution in the marine eutrophication (71%) and land-occupation (44%) categories. Among the processing steps, composite extrusion reports the highest average impacts at 14%. Also, a sensitivity analysis suggests that adopting biobased PBAT and increasing the percentage of renewable electricity consumed could reduce the cumulative environmental burdens. Overall, this integrated approach can provide valuable information for further optimization of both mechanical performance and environmental sustainability, in line with the principles of Green Chemistry and Green Engineering.