Camellia meal-based formaldehyde-free adhesive with self-crosslinking, and anti-mildew performance

The development of eco-friendly adhesives from renewable biomass materials has attracted considerable attention in recent years. Many researchers continue to study and use expensive chemical crosslinking agents that release toxic VOCs and use environmentally unfriendly mildew-proofing agents that improve the bonding strength of plywood. In this study, a high-strength formaldehyde-free adhesive was prepared by using low-cost modified camellia meal, soybean meal, and a low epoxy crosslinker content. Plywood bonded using the optimum modified camellia meal with soybean meal showed a wet shear strength of 1.822 MPa, which was 93.3% higher than that of the unmodified adhesive. We found that the oxidized camellia meal could completely replace the epoxy crosslinker, and the adhesive strength reached 0.83 MPa while maintaining its adhesive properties. This study provides a new biomass self-crosslinking network design strategy for the wood-based panel industry to prepare high-performance environmentally friendly adhesives. Its excellent anti-mildew properties and low VOC content give it great potential in wood composites and allow it to be used as a substitute for formaldehyde resin adhesives.