Recent Development in Forest Biomass Derived Phenol Formaldehyde (PF) Resol Resin for Wood Adhesives Application

In recent years, forest biomass materials, including wood, bark, lignin, tannins, are explored intensively as bio-derived phenolic compounds for PF resin synthesis. Liquefaction, pyrolysis and extraction are some frequently used methods to convert these forest biomass materials into phenol substitutes in the resin formulation. The inclusion of these bio-derived phenolic compounds, either in the form of extractives or as liquefied or pyrolyzed products, resulted in bio-based PF resins with different molecular weight, viscosity, gel time, curing behavior from typical commercial PF resins. In some cases, up to 50 wt% of substitution of phenol by the bio-derived phenolic compounds had not caused any significantly downgrading in bonding performance. Overall, the bio-based PF resins derived from forest biomass materials showed a great promise as environmentally friendly and lower cost alternatives to PF resins formulated solely from fossil fuel derived phenol. However, significant challenges exist due to the complexity associated with large variations in origin, chemical composition, and reactivity of the biomass materials for commercially adaption. The bio-based PF resins present opportunities to have higher value-added applications for the forest biomass materials.