Performance Characterization And Enhancement Mechanism Of Protein-based Adhesive

To extend the raw materials of bio-based adhesive, three kinds of protein-based meals, soybean meal, peanut meal, and blood meal were employed as the main raw materials, and ethylene glycol diglycidyl ether (EGDE) as cross-linking agent and diethylenetriamine (DETA) as curing agent were used to prepare bio-based adhesives. The effect of different biological protein, the cross linking agent and the curing agent on the adhesion properties was studied, and the enhancement mechanism was investigated in this thesis. The main conclusions were summarized as followed:1. The cross-linking agent EGDE could obviously reduce the viscosity and increase the water resistance of the result adhesive. Because the epoxy groups of EGDE could reacted with peanut protein molecular and form a cross-linking network structure, when induced 9 wt% EGDE, the wet shear strength of the plywood bonded by the peanut meal-based adhesive was increased by 200% and reached 0.9 MPa, and that boned by the blood meal-based adhesive was increased by 388% and reached 1.27 MPa.2. The curing agent DETA could effected the wet shear strength remarkably. As the added of DETA was 0.5 wt%, the wet shear strength was increased to 1.15 MPa. EGDE, DETA and soybean protein molecular could formed a denser cured adhesive layer to increase the wet shear strength of the resultant plywood.3. The best water resistance of modified protein-based adhesives was the modified blood protein based adhesives, the next was the modified soy protein based adhesives and the low was the modified peanut protein based adhesives. The protein content of blood meal was the highest and reached 80%, and the number of hydrophobic amino acid up to 33%, followed by soy protein hydrophobic amino acids 16.77%, the higher protein content led to the more "glue nails" during curing process. Hence, the wet shear strength was increased.