Sustainable and environmentally friendly lignin-based degradable composites

Abstract

Abstract The fabrication of composite materials from lignin has attracted increasing attention to reduce the dependence on petrochemical-based resources toward carbon neutrality. However, the low lignin content and the compatibility of the biocomposites remain a challenge. Herein, industrial lignin is fractionated by an organic solvent to reduce its structural heterogeneity. Subsequently, the purified lignin samples are combined with polyvinyl alcohol to produce lignin-based materials with uniform thicknesses and smooth surfaces. The mechanism investigations reveal that the hydroxyl groups of lignin and PVA form hydrogen bonds, resulting internal non-covalent interactions enable the PVA/lignin composite film to achieve excellent mechanical properties. The resultant composite films exhibit stresses and strains up to 75 MPa and 1050%, respectively, which surpasses those of state-of-the art lignin-based biocomposites. Notably, the PVA/lignin compliant film is biodegradable after 92 days burial in soil. This work provides new principles for designing lignin-based films as a sustainable alternative to traditional plastics.