Current utilization of waste biomass as filler for wood adhesives: A review

Filler is one of the most important additives for wood adhesives. The introduction of filler offers various functions for wood adhesives, such as the increase of initial viscosity, the decrease of permeability, the improvement of bonding strength, and the reduction of production cost. However, flour, a grain resource, is widely used as a filler that is added to polymers in the production of wood-based panels. As a result, a large number of edible resources are wasted every year. Waste biomass that biomass residues are abandoned in nature are a promising filler that can be used to replace flour. The utilization of waste biomass as filler for wood adhesives to prepare wood-based panels not only improves its mechanical strength, but also reduces formaldehyde emissions. However, most waste biomass shows disappointing prepressing properties. Advances in the use of waste biomass as an alternative filler for wood adhesives were reviewed. In addition, the current limitations and future prospects of waste biomass were discussed. Recycling waste biomass is a useful way to avoid the enormous amount of waste generated by different industries and control environmental pollution. It contributes to the practical development of circular economy.