Conversion of corncob residue to sustainable lignin/cellulose film with efficient ultraviolet-blocking property

Abstract

In the context of using biomass-derived natural polymers in material synthesis, a new UV-shielding film essentially consisted of biodegradable lignocellulosic waste was successfully fabricated. Herein, the hierarchically processed corncob residue (CR) with various lignin content was achieved by alkaline peroxide treatment (0–4 wt%). The lignocellulose films (LFs) containing lignin were easily obtained by the dissolution of cellulose-rich solid residues in ZnCl2/CaCl2 solvent followed by reconstitution with ethanol. The resulting LFs possessed tunable mechanical and UV-shielding properties, depending on the amount of lignin. CR-based film containing 6.5% lignin exhibited the relatively good mechanical property (a tensile strength of 26.9 MPa), high transmittance (66.2% at 550 nm) and haze (70.1%), and effective UV-shielding capacity (83.7% for UVB and 70.0% for UVA). This study provides a novel integrated process for the valorization of CR and a practical route for functional biomaterial production.