Flexible Nanobiocomposite Coating Based on Recycled Can Waste as Antimicrobial Active Packaging Materials

ABSTRACT The accumulation of aluminium waste in landfills constitutes a significant environmental challenge due to its substantial presence as solid waste. Conventional disposal and recycling techniques have been employed to mitigate this issue; however, they often result in secondary environmental pollution. In this study, eco‐friendly and cost‐effective aluminium oxide nanoparticles (Al 2 O 3 ‐NPs) were synthesized via a green synthesis approach utilizing date palm seed extract. Flexible polystyrene (FPS) was fabricated through in‐situ polymerization in the presence of varying concentrations of Al 2 O 3 ‐NPs to develop active nanobiocomposite coatings. The physicochemical characteristics of the synthesized Al 2 O 3 nanoparticles were comprehensively analysed using multiple advanced techniques, including dynamic light scattering (DLS), Brunauer–Emmett–Teller (BET) surface area analysis, X‐ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy‐dispersive X‐ray spectroscopy (EDX) and transmission electron microscopy (TEM). XRD analysis confirmed a rhombohedral crystal structure with an average particle size of 32 nm. Fourier transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS) further validated the structural composition of the synthesized Al 2 O 3 nanoparticles. Additionally, thermogravimetric analysis (TGA) was employed to assess the thermal stability of the FPS/Al 2 O 3 bionanocomposite coating, revealing excellent thermal resistance withstanding temperatures ≥ 240°C. DLS measurements indicated a uniform particle size distribution with stable zeta potential, while BET analysis demonstrated a substantial surface area ranging between 62 and 147 m 2 /g. Furthermore, the antimicrobial efficacy of Al 2 O 3 nanoparticles was investigated by determining their minimum inhibitory concentration (MIC) against both Gram‐positive and Gram‐negative bacteria. The antimicrobial assessment revealed that Gram‐negative bacteria exhibited greater resistance compared to Gram‐positive bacteria and yeast. Migration analysis demonstrated that the percentage of migrated material was within acceptable limits as per European Commission (EC) regulations. These findings suggest that the developed flexible nanobiocomposite‐coated paperboard holds significant potential as an advanced active packaging material.