Biomass-based strong adhesive based on supramolecular deep eutectic solvents pretreatment

Lignin-based adhesives have the advantages of high economy and low formaldehyde emission, and are widely used in furniture manufacturing, woodworking, paper making and other industries. In this study, bagasse was pretreated by supramolecular deep eutectic solvent (DES) formed by the natural compounds β-cyclodextrin and L-malic acid, and a green lignin-based adhesive (ALDES) with wide temperature adaptability (−196 to 100 °C), which can be used in many materials (such as metals, woods, and ceramics) and resistant to solvent corrosion (9 kinds of solvents) was prepared by component separation. The results showed that the adhesive strength of ALDES with moral ratio of 1:40 for wood panels reached 5.14 MPa at a curing temperature of 170 °C and a curing time of 12 h. In addition, a combination of experimental results and DFT calculations revealed that the main factor of high adhesion performance of ALDES was lignin promoted the formation of ether bond and the enhancement of electrostatic potential energy. Furthermore, the use of natural raw materials and a pretreatment process that generates no waste provides exceptional economy and environmental friendliness. This novel synthesis of lignin adhesive will provide a new strategy for the development of adhesive field.