Effects of adhesive residues in wood particles on the properties of particleboard

Waste particleboard is a valuable feedstock for the particleboards. Recycling waste panels into particleboard is hindered by adhesive residues in the particles. This study aims to investigate the effect of adhesive residues on the physical and mechanical properties of particleboard. The chemical properties and wettability of particles containing pMDI and UF residues were investigated, and these particles were further used to produce particleboards. Results revealed that the pMDI residue is incompatible with fresh UF resin and forms weak bonding in the particleboards. However, the pMDI residue can continue to react with the fresh pMDI and form strong adhesion. The UF residue cannot cross-linked with the fresh UF, and the additional hydrophilic groups, resulting in a severe reduction in the dimensional stability of the panels, but the decrease in the mechanical properties is not significant. Interestingly, the UF residue promotes the curing of fresh pMDI, thus benefiting the mechanical properties of the panels. This study can guide the selection of adhesives in producing recycled particleboard using waste particleboard, thereby promoting the efficient recycling of waste particleboard. •The interactions between residual and fresh adhesives were analyzed.•The pMDI residue is incompatible with fresh UF resin.•Both pMDI and UF residues can react with fresh pMDI to promote its curing.