Influence of micron-sized oligomeric semisiloxane modification on surface properties of veneer and interfacial adhesion of EVA film/poplar plywood

Abstract

ABSTRACT Using EVA film as an adhesive to composite with wood veneer can fabricate e formaldehyde-free wood-based panels. In order to improve the interfacial adhesion of the thermoplastic resin plywood, micron-sized oligomeric semisiloxane (MS) solution was prepared and sprayed on the poplar veneer before bonded with the EVA film. The effect of MS solution on the surface properties of poplar and mechanical properties of MS-treated plywood by FTIR, XPS, WCA, and SEM-EDS. The results indicated that MS was successfully grafted onto the surface of veneer by covalent bonding (Si-O-C) and formed a rough hydrophobic coating on the veneer. The WCA of poplar veneer was significantly increased. As a result of the change in surface properties, poplar veneer formed a tight interfacial bonds with EVA film, which improved mechanical performance of plywood. When the MS treatment conditions were 3% silane, 15% neutral silica, and 3 h reaction times, the wet shear tensile strength and dry shear tensile strength reached 1.03 and 1.56 MPa, respectively. Compared with untreated plywood, the wet strength and dry strength were increased by 76% and 39%, respectively. In addition, Reduced gaps between MS-treated poplar veneer and EVA film and formed stronger interlock structures were observed by SEM.