Deep eutectic solvent modulated lignin-based films for UV shielding and food preservation

To solve the problems of low transmittance and poor mechanical properties of functional films brought about by the introduction of lignin, deep eutectic solvent (DES) modulation of lignin was used to construct lignin-PVA composite films. The effect of deep eutectic solvent lignin (DESL) on the properties of lignin-PVA membranes was investigated, including UV barrier properties, mechanical properties, gas permeability, oxidation resistance, solvent resistance, and antimicrobial properties. Compared with pure PVA film, the introduction of DESL improved the UV barrier (63.64%), visible light transmission (92.51%) and mechanical properties of the composite film. It also endowed the DESL/PVA film with good DPPH radical scavenging (60.92%) and reducing ability. In addition, composite films have excellent antimicrobial capacity (51.08%) and flexibility (elongation up to 142%), which can be used as biodegradable antimicrobial biomaterials for food packaging applications.