Evaluation performance of soybean meal and peanut meal blends-based wood adhesive

Soybean meal-based adhesives show outstanding advantages in price and environmental protection and have the prospect of replacing the application of formaldehyde-based adhesives in the wood industry. However, low solid content, high viscosity, and poor water resistance halted the development of soybean meal-based adhesives. Based on the high globulin content of peanut meal and the low viscosity of peanut meal-based adhesive, peanut meal was used to blend with soybean meal to prepare plant meal-based wood adhesive in this study. The different weight ratios of soybean meal and peanut meal-based adhesives were prepared. Physicochemical properties including amino acid composition, molecular weight distribution, solid content, viscosity, hydrolytic stability, morphological properties, and functional groups of the resultant adhesives were characterized. Results showed that, the blended adhesive had a decreased viscosity and higher solid content than that of soybean meal adhesive. When the optimum addition of peanut meal was 20%, the wet and dry shear strength of the plywood bonded by resultant adhesive was increased by 50% (1.02 ± 0.02 MPa) and 31% (1.55 ± 0.03 MPa). The increased bonding performance was mainly due to the optimized protein structure and side chain promoting the cross-linking reaction. This study demonstrates a simple and direct method of preparing cost-effective plant meals-based wood adhesive.