Poly (lactic acid)/D‐limonene/ZnO bio‐nanocomposites with antimicrobial properties

Antimicrobial films of poly (lactic acid) (PLA)/D‐limonene/zinc oxide (ZnO)‐based bio‐nanocomposites were prepared via melt compounding and subsequent thermocompression. D‐limonene was incorporated at concentrations of 10 or 20 wt%, and ZnO pure nanoparticles and those organically modified with oleic acid (O‐ZnO), with an average diameter of 13.5 nm, were included at concentrations of 3, 5, and 8 wt%. The plasticizing effect of D‐Limonene was corroborated by a decrease in the glass transition temperature compared to pure PLA. The presence of ZnO and O‐ZnO in the PLA matrix promoted a slight increase in the degree of crystallinity due to its nucleant performance. Although ZnO and O‐ZnO induced lower thermal stability and slightly decreased microhardness in the composites, excellent antimicrobial performance was demonstrated. Both ZnO and O‐ZnO nanocomposites reached 99.9% of effectiveness for nanoparticles content above 5 wt%, regardless of the source of irradiation, D‐limonene concentration, and nanoparticle modification. Therefore, these bio‐nanocomposites will allow for future advances in sustainable antimicrobial materials for the medical or food packaging fields.