Exploring the utilities of rice straw black liquor (part XVI): nano (zinc/lignin) hybrid for safe polyurethane films with enhanced antimicrobial, mechanical, and UV-protecting properties

Green composites are increasingly attracting interest due to their potential to address environmental issues by merging sustainable fillers with biodegradable polymers. The current study investigates the incorporation of zinc lignin hybrid (Zn-LSF) nanoparticles into a polyurethane matrix at varying ratios. The hybrid's elemental composition was determined using X-ray fluorescence (XRF), and Energy-dispersive X-ray spectroscopy (EDAX). The functional groups of both the hybrid and the prepared polyurethane films were identified by Fourier-transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was employed to analyze the morphology of the Zn-LSF/polyurethane films. Mechanical properties and permeability were also evaluated. Furthermore, the antimicrobial activity and toxicity of the composites were assessed. The results demonstrated that the zinc lignin hybrid is non-toxic, provides antimicrobial properties, and enhances the mechanical strength of polyurethane along with a UV-shielding effect for the prepared polyurethane films. These findings suggest that, the prepared composites have potential as a sustainable, multifunctional additive for safe polyurethane food packaging.