A fully bio-based adhesive with high bonding strength, low environmental impact, and competitive economic performance

The depletion of petrochemical resources and concerns about the emission of harmful substances have prompted a shift from formaldehyde-based adhesives to renewable bio-based alternatives in the production of wood composites. However, many bio-based adhesives suffer from limitations such as low strength, weak water resistance and poor mold resistance. This study presents a simple approach for the fabrication of entirely bio-based soybean meal (SM) adhesives, utilizing wood-derived bio-oil as both cross-linking agent and anti-mold agent. The incorporation of bio-oil resulted in a remarkable 487.5 % increase in wet bonding strength, reaching 0.94 MPa compared to the pure SM adhesive. Furthermore, the bio-based adhesive demonstrated exceptional anti-mold properties in wet environments, displaying significant efficacy in inhibiting mold growth. A life-cycle assessment of the proposed adhesive production process revealed a lower low environmental impact compared to other modified bio-based adhesives and traditional petroleum-based adhesives. Additionally, technical–economic analysis evaluated the minimum selling price of 822 $/t adhesive, revealing the excellent economic feasibility of SM-Bio adhesive. The findings underscore the environmental friendliness and sustainability of this fully bio-based wood adhesive, presenting a promising and eco-conscious alternative to conventional adhesives for the large-scale production of wood composites.