The reaction mechanism and performance evaluation of one-pot preparation of full biomass adhesive with defatted soybean and phytic acid

With agricultural renewable resources used to develop adhesives for artificial boards, maintaining good bonding performance and easy coating while considering antibacterial and flame-retardant properties presents a major challenge. In this study, a whole biomass-based wood adhesive (SPA) based on defatted soybean flour (SF) and phytic acid (PA) was developed and prepared via one-pot blending heating process. The microscopic chemical changes between SF and PA were revealed through Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and other analyses. PA crosslinked SF via ionic/hydrogen bonds, forming a robust network through esterification / amidation during hot-pressing, which enhanced bonding, water resistance, and multifunctionality. This structure effectively improved the bonding performance of SPA. The shear strengths of the prepared plywood under dry state, 3 h hot-water (63 °C) and 3 h boiling-water immersion conditions were 1.34, 1.22, and 1.01 MPa, respectively, which are considerably higher than the national standard requirements (GB/T 17657–2022; ≥0.70 MPa). In addition, the SPA exhibited good wettability, antibacterial, and flame-retardant properties, environmental friendliness, and sustainability advantages. These advantages demonstrate that SPA provides a simple, practical, and efficient method for developing sustainable, high-performance biomass-based adhesives, laying a preliminary research foundation for future exploration in wood processing applications. • In this study, a high-performance biomass-based wood adhesive (SPA) was prepared; it combines environmentally friendly and efficient bonding performance using sustainable raw materials defatted soybean flour and phytic acid (PA). • Through the multiple bonding between soybean protein and PA, a dense cross-linked network structure was constructed, which substantially improved the bonding performance of the adhesive. • SPA showed good wettability, antibacterial, and flame-retardant properties.