Improve the bonding between wood veneer and wood fiber/high‐density polyethylene composite board for decoration

Abstract

AbstractWood fiber reinforced thermoplastic composites are regarded as a kind of environmentally friendly material obtained by combining recycled thermoplastic and wood fibers together. However, they are difficult to be decorated for using due to their non‐polar, dense, and smooth surface characteristics. In this study, methods for improving the bonding strength between wood veneer and wood fiber/high‐density polyethylene (WF/HDPE) board were explored. A macromolecular coupling agent, allyl polyoxyethylene polyoxypropylene epoxy‐terminated polyether (AEPH) grafted γ‐aminopropyl triethoxysilane (KH‐550) was synthesized to treat wood veneer prior to lamination with WF/HDPE board. For further improving the bonding strength between wood veneer and WF/HDPE board, a low‐density polyethylene (LLDPE) film was inserted between as adhesive. As control, KH‐550, a commonly used coupling agent and water were also used to treat the veneer. Infrared spectroscopy measurement showed that the LLDPE film combines well with both the veneer and WF/HDPE composite board. Surface bonding strength test proved that all treated veneers significantly improved the combination with WF/HDPE substrated and the LLDPE intermediate film played a key role in it. The veneering endowed the WF/HDPE composite board much better flexural properties, up to 77.39 MPa, which is 50% higher than that of WF/HDPE substrate. The AEPH‐KH‐550‐treated veneer presented the highest bonding strength and best water resistant for glue line.