Optimization of preparation process for walnut shell-based wood particleboard

Driven by the “double carbon” strategy, aiming at the potential of walnut shell, an agricultural and forestry waste, to replace wood in particleboard production, this study used walnut shell powder and wood shavings as raw materials, with melamine-modified urea-formaldehyde resin as the adhesive. A four-factor, three-level orthogonal experiment was conducted to investigate the effects of hot-pressing temperature, pressure, duration, and adhesive application level on the physical and mechanical properties of the panels. The optimal process conditions were 160°C, 4 MPA, 6 min, and a 14% adhesive application percentage. Under these conditions, the panel had a density of 0.70 g/cm³, and its modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), and 2-hour thickness swelling (2hTS) all exceeded the limits specified in GB/T 4897 (2015) by 30% to 60%. The order of influence of each parameter was hot-pressing temperature > adhesive application level > hot-pressing pressure > hot-pressing duration. This study established for the first time the optimal process window for walnut shell-based particleboard, demonstrating that a 30% wood substitution can balance performance and resource conservation, providing technical support for the green and high-value utilization of agricultural and forestry wastes.