Poly (Lactic Acid)/Starch Biodegradable Blend With Antioxidant Activity: A Sustainable Alternative for Single-Use Active Plastic Packaging

A novel bio-based and biodegradable plastic based on poly(lactic acid) (PLA) and corn starch (CS) was developed as a single-use rigid packaging material. Chitosan (Q) and eucalyptus essential oil (EEO) were incorporated as antimicrobial and antioxidant agents. The effects of these additives were evaluated using a three-factor, two-level factorial design, assessing the melt flow index (MFI) and tensile properties. The optimized formulation, containing 5 wt% of EEO and 3 wt% of Q, increased the thermal stability of CS due to the PLA matrix with two degradation steps: 145°C and 318°C. It also demonstrated low water interaction, with a solubility of approximately 0.6% and a moisture content of 5%, attributed to the absence of plasticizers. Additionally, the material achieved nearly 70% antioxidant activity through the synergistic effect of EEO and Q. Successful thermoforming trials confirmed the processability of the optimized formulation. Comparative analysis with polypropylene revealed that the bio-based material exhibited higher tensile strength while offering the critical advantage of biodegradability. These findings highlight the potential of this active, thermoformable bio-based material as a sustainable alternative to conventional non-biodegradable plastics.