Valorization of Lignin from Biorefinery: Colloidal Lignin Micro-Nanospheres as Multifunctional Bio-Based Fillers for Waterborne Wood Coating Enhancement

Valorization of lignin is expected to increase the efficiency and economic viability of biorefinery. Herein, organosolv lignin generated from biorefinery was valorized to colloidal lignin micro-nanospheres (LMNS) and applied as a multifunctional bio-based filler for waterborne wood coating (WBC). The LMNS were prepared via a facile self-assembly process and comprised micro-nanospheres with an average diameter of approximately 260 nm. The polymeric matrix of the WBC was strengthened and toughened with LMNS, giving a 55% increase in tensile strength and 40% increase in elongation. The wear resistance, adhesion, and other properties of WBC when applied to wood were all significantly improved. The LMNS also blocked ultraviolet wavelengths and provided excellent protection against color changes in wood. Finally, the incorporation of LMNS into the WBC obviously enhanced the color and texture of wood. This study demonstrates the value-added utilization of lignin and suggests new approaches to the development of multifunctional WBC.