Tuning Antibacterial and Physical Properties of Biodegradable Polymer Systems Incorporating Carvacrol

Abstract

The addition of antimicrobial additives in packaging systems is becoming essential, and this study aimed to incorporate carvacrol (CRV) into Poly(lactic acid) (PLA)/Poly(butylene adipate-co-terephthalate) (PBAT) blends to investigate the effects of blend composition on the resulting material's properties, with a particular focus on CRV release kinetics and antibacterial activity. The materials are prepared via melt mixing and compression molding and are thoroughly characterized through mechanical, rheological, and wettability analyses. Tensile tests reveal that adding PBAT to PLA increases flexibility, reducing modulus by 26% and tensile strength by 60%, while elongation at break rises by 550%. Adding PLA to PBAT increases stiffness, with modulus rising by 128%, but tensile strength and elongation decrease by 62% and 70%, respectively. The CRV release profile revealed that the release rate can be modulated by altering the blend composition. In vitro evaluation of antibacterial activity shows that the polymers with high PBAT content and containing CRV inhibited the growth of Listeria monocytogenes to undetectable levels (<1 Log CFU mL⁻¹). Overall, the results show that the blend formulation significantly influenced the material properties compared to the pure components, providing effective antibacterial activity against both pathogens.