An effective approach for lignin-based bamboo adhesive preparation via swelling crosslinking

The preparation of lignin-based adhesives from sustainable lignin sources has garnered increasing attention from many researchers in recent years. However, developing high-performance and environmentally friendly lignin-based adhesives through a simple and efficient approach remains a significant challenge. In this study, aminated corn stover lignin (ACSL) was prepared by aminating corn stover lignin (CSL) using glutaraldehyde and ethylenediamine. Subsequently, ACSL was covalently crosslinked with trimethylolpropane triglycidyl ether (TMPEG) through simple stirring at room temperature to fabricate a formaldehyde-free adhesive, namely the ACSL-TMPEG adhesive. This adhesive was then hot-pressed directly into bamboo composites. The obtained formaldehyde-free bamboo composites exhibited robust adhesive properties, with the dry strength and wet strength reaching 8.26 MPa and 5.81 MPa, respectively, outperforming many other bio-based adhesives. This study presented a convenient and efficient strategy for synthesizing lignin-based adhesives, thus offering a cost advantage compared with other alternatives and exhibiting the potential for large-scale production.