Starch-lignin network using Diels-Alder reaction for thermally debondable adhesives

Thermosetting resins are extensively used in gluing wood products due to their outstanding mechanical strength and permanent bonding capabilities. However, these same properties make recycling of wood products challenging. In this study, a novel, and sustainable adhesive based on starch and lignin has been successfully developed with detachable properties. Potato starch was esterified with 6-maleimidohexanoic acid to produce maleimide grafted starch and then combined with a furan grafted Kraft lignin to produce a thermally debondable adhesive. The adhesive’s mechanical performance was evaluated through thermal bonding and debonding on wood substrates. Tests using 20 mg of adhesive on furfurylated beech veneer showed a shear strength of 5 ± 0.5 MPa. This ligno-polysaccharides network based on Diels-Alder reaction demonstrates the ability to form strong mechanical bonds at 65°C that can be easily reversed at 135°C, making it a sustainable solution. The combination of strong adhesion and convenient detachment highlights its potential in sustainable materials research and aligns with evolving industrial needs of the wood sector.