Lignin/zinc oxide nanoparticles for use as UV-resistant and antioxidant agents for bio-plastic composites

A new sustainable approach to producing lignin/ZnO nanoparticles has been developed through research using black liquor from the soda pretreatment process of oil palm empty fruit bunches. This approach reduces the number of preparation processes and waste generated during processing. This research studied the influences of temperature, reaction time, and mass ratio of lignin to zinc on the characteristics of the obtained nanoparticles using various analytical techniques, including a color spectrophotometer, X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray spectroscopy (EDS) analysis, Fourier transforms infrared (FTIR), Atomic Absorption Spectrophotometer (AAS), thermal gravimetric analysis (TGA), and UV-Visible spectroscopy. The lignin/ZnO nanoparticles that were produced were utilized as additives to improve the UV resistance and antioxidant characteristics of polylactic acid (PLA) films via solvent casting. The resulting PLA-based composite films showed superior UV resistance and antioxidant properties compared to neat PLA films, while also exhibiting enhanced hydrophobicity and mechanical characteristics due to the added nanoparticles. This cost-effective and environmentally friendly method for producing lignin/ZnO nanoparticles holds great potential for various industries, including smart packaging and cosmetics.