High‐strength wood‐based composites via laminated delignified wood veneers with different adhesive contents for structural applications

Abstract The processing of natural wood into a high‐performance wood‐based composite to broaden the potential applications of wood can be achieved by various techniques using bulk wood as a raw material. However, attention has seldom been paid to the use of wood veneers for preparing high‐performance structural materials. In this study, delignified birch veneers are used as raw materials to fabricate high‐strength delignified wood‐based laminated composites (DWLCs) with phenol‐formaldehyde (PF) resin as adhesive. The DWLCs with a PF resin content of 40% had high mechanical properties and displayed flexural and tensile stress of 405.8 and 324.4 MPa, respectively. The flexural and tensile stress are 1.24 and 1.21 times higher than those of natural wood‐based laminated composites (WLCs). And we confirmed that partial delignification could contribute to enhancing the mechanical properties of high‐strength wood‐based composites. By using scanning electron microscopy (SEM), and energy‐dispersive spectroscopy (EDS), the strengthening mechanisms of the high‐performance DWLCs were investigated. Due to both the surface of the cell lumen and cell walls being filled with PF resin, the wood microstructure was cured under high pressure so that the DWLCs were enhanced.