Development of an environmentally friendly lignosulfonate-chitosan adhesive with excellent water resistance through...

Considering both environmental sustainability and health concerns, biomass-based adhesives demonstrate significant potential for development. Here, using sodium lignosulfonate (L) as the raw material, epoxidized lignosulfonate (GL) was synthesized by reacting it with glyceryl triglycidyl ether under alkaline conditions. Subsequently, GL was crosslinked with chitosan (C) to prepare an epoxidized lignosulfonate-chitosan resin (GL-C). Analyzing its structure and curing performance, plywood was prepared using the control L-C and the GL-C resins, and their mechanical properties were evaluated. The results showed that the epoxy groups in GL reacted with the amino and hydroxyl groups in C, while the amino groups in C reacted with the carbonyl and sulfonic groups in GL, forming a dense three-dimensional network structure. When the mass ratio of GL/C is 1:1, the plywood prepared with GL-C resins exhibited excellent shear strength. Compared to the wet bonding strength of L-C resin at 63 °C, it showed an improvement of 0.66 MPa; the adhesive exhibited a denser structure and higher bonding strength.