THE INFLUENCE OF SOME POWDERS ON THE ANTIMICROBIAL ACTIVITY OF PLA PACKAGING WITH OREGANO OIL ADDITIVES

This study investigates the antimicrobial potential and physicochemical performance of PLA-based biocomposite films incorporated with bioglass, oregano essential oil, and diacetin as a green plasticizer. Designed for use in food packaging applications, the films aim to serve as biodegradable, active barriers against microbial contamination while ensuring environmental compatibility and material safety. Initial microbiological screening identified the PB2 formulation comprising 70% PLA, 25% diacetin, 3% bioglass, and 2% oregano oil as the most effective antimicrobial composition. PB2 achieved a 79% inhibition of bacterial growth after two days and maintained 65% suppression after 14 days, confirming its long-term antimicrobial efficacy. To gain a comprehensive understanding of PB2’s behavior, extensive characterization was performed. FTIR spectroscopy confirmed the successful incorporation of functional groups from both PLA and active additives. TGA and DSC analyses revealed enhanced thermal stability and a delayed glass transition (Tg>83 °C), attributed to the stiffening effect of bioglass. SEM and AFM investigations demonstrated uniform nanoparticle dispersion and low surface roughness (Ra=30.1 nm), ensuring good structural homogeneity. Mechanical testing showed reduced tensile strength but significantly increased elongation at break, indicating greater ductility due to matrix amorphization promoted by diacetin. Altogether, the results support the potential of PB2 as a multifunctional, antimicrobial biocomposite film suitable for food-grade and biomedical applications.