Optimization of semi-wet hot-pressing conditions for Salix psammophila-based mycelium-bound boards via response surface methodology

Abstract

Conventional indoor wood-based materials often rely on formaldehyde-based adhesives, which pose environmental and health risks. In this study, eco-friendly mycelium-bound boards were fabricated through semi-wet hot-pressing technology using Salix psammophila as the substrate and fungal mycelium as a bio-based adhesive. The interfacial adhesion, chemical interactions, and thermal stability of the composites were systematically investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). A Box-Behnken response surface design was employed to optimize the effects of the hot-pressing parameters on the physical-mechanical properties. The optimal hot-pressing parameters (within the tested range) were determined to maximize the rupture’s modulus and minimize water absorption and thickness swelling rates, yielding an applied pressure of 10 MPa, a temperature of 194 ℃, and a time of 31 min. Under these conditions, the mycelium-bound boards exhibited a modulus of rupture (MOR) of 37.64 MPa, a water absorption (WA) of 48.1%, and a thickness swelling (TS) of 23.01%. The hot-pressing process significantly enhanced the overall board performance, with pressure and temperature exhibiting the most pronounced effects. Furthermore, thermogravimetric analysis revealed high thermal stability in the boards. This study provides valuable insights into effectively utilizing agricultural, forestry, and pastoral residues for improving mycelium-bound boards performance. In conclusion, mycelium-bound boards exhibit the potential to be used as materials for construction, furniture, and household items due to their environmentally friendly nature.