Tannic acid-loaded halloysite clay grafted with silver nanoparticles improved the mechanical, antimicrobial, and degradation properties of linear low-density polyethylene films

Abstract

Synthetic polymers used for food packaging contribute to plastic pollution due to poor degradability. While they prevent the entry of microorganisms, they may not protect against spoilage microorganisms in the packed food. Nanofillers have been used to improve such properties, but end-of-life degradation remains an issue, making plastic a persistent pollutant. Here, we tested a nanocomposite (Nc) of tannic acid-loaded halloysite nanotubes grafted with silver nanoparticles as a reinforcement to enhance the mechanical, antimicrobial, and degradation properties of Linear low-density polyethylene (LLDPE) films. LLDPE films incorporated with Nc significantly improved tensile strength (TS), elongation at break (EB), and oxygen permeability rate. Nc incorporated (at 5%-and 10%) LLDPE films exhibited a 1.89-2.85 log10 reduction in multi-drug resistant Staphylococcus aureus 1158c in chicken fillets. Both film types demonstrated silver migration below the European Food Safety Authority-mandated acceptable limit. Nc/LLDPE films disintegrated faster when exposed to incandescent light for 6 h, evidenced by significant reduction of weight, TS, and EB. Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy suggested oxidative degradation and breakdown of the polymer. Conclusively, Nc improved the functional properties and degradation rate of LLDPE films when exposed to light, showing potential for enhancing the sustainability of synthetic polymers.