Fungus-Modified Lignin and Its Use in Wood Adhesive for Manufacturing Wood Composites*

Abstract Organosolv lignins were modified with different fungal species. The modified lignins were used as raw materials for preparing lignin-phenol-formaldehyde (LPF) resins. Oriented strandboard (OSB) panels were produced with these laboratory-synthesized LPF resins for evaluating the bond performance of the LPF resins in the manufacturing of wood composites. Ultraviolet spectroscopy results show that the phenolic hydroxyl contents in the lignins were changed after the lignins were treated with fungi. The lignin modified with the brown-rot fungi extended the gel time of the LPF resin compared with the corresponding unmodified lignin, while the lignin modified with the white-rot fungi shortened the gel time. The OSB test results show that the internal bond strength and the bending properties of the panels bonded with the LPF resins containing the modified lignin were comparable to or better than those of the panels bonded with the commercial phenolic resin or the LPF resin containing the unmodified ligni...