Preparation and characterization of birch plywood prepared by hot-pressed peanut meal adhesive

The preparation of birch plywood by hot-pressed peanut meal (HPM) adhesive was studied using response surface methodology. The effects of hot-pressing temperature, hot-pressing time, and hot-pressing pressure on the boiling water strength (BWS) were investigated. The BWS of birch plywood was significantly affected by hot-pressing temperature and hot-pressing time. The optimal preparation conditions for maximizing the BWS were: hot-pressing temperature of 120 °C, hot-pressing time of 80 s mm ⁻¹ and hot-pressing pressure of 1.2 MPa. Under these conditions, the BWS was 1.21 ± 0.02 MPa. The thickness expansion rate of water absorption (TS) and the wood compressibility were 6.39% and 15.8% respectively. Characterization of birch plywood showed the chemical reactions between hydroxyl of plywood, and the amino, carboxyl and azacyclobutane structures of peanut protein, forming a dense bonding surface and resulting in the higher BWS of birch plywood. This work provided an important reference for the application of HPM adhesive in the production of wood-based panels.