CHARACTERIZATION OF PF/PVAC HYBRID ADHESIVE-WOOD INTERACTION AND ITS EFFECT ON WOOD STRAND COMPOSITES PERFORMANCE By

by Yang Cao, M.S. Washington State University August 2010 Co-Chairs: Vikram Yadama Jinwen Zhang A multifunctional hybrid adhesive system developed for profiled composite manufacturing was examined in this study. A binary adhesive system, phenol formaldehyde (PF)/ polyvinyl acetate (PVAc), offers initial adhesion to improve wood-strand mat handling during the first stage of composite processing, after which a durable bond is achieved through curing of PF resin under heat and pressure. Before effectively applying this adhesive, it is important to understand adhesive-wood interaction at different scales. This thesis evaluated the physical properties of PF and PVAc resin blend as individual resin proportions were varied, and then characterized the interactions between the PF/PVAc hybrid adhesive and the wood substrate by evaluating bond strength at macro-scale, and gross adhesive penetration at micro-scale in sugar maple (tangential and radial surfaces). The bond performance and adhesive penetration of PF/PVAc were found to be comparable with that of neat PF when PVAc content was less than 50% in the resin blend, while they underwent an