Characteristics of the wood adhesion bonding mechanism using hydroxymethyl resorcinol
Publication Name: Proceedings of Wood Adhesives
Publication URL: https://www.fs.usda.gov/treesearch/pubs/27353
A recent collaborative effort among the U.S. Forest Products Laboratory, Virginia Tech, and the University of Maine has explored the possible bonding mechanisms contributing to durable wood adhesive bonding using hydroxymethyl resorcinol (HMR) surface treatment. Current adhesive bonding mechanisms include: mechanical interlocking, electronic or electrostatic theory, adsorption, thermodynamic or wetting theory, diffusion theory, chemical (covalent) bonding theory, theory of weak boundary layers and interphases. In this paper, the findings of the research project will be presented and categorized relative to current adhesion bonding mechanism theories. In addition, consideration will be given to HMRs impact on adhesion bonding relative to interactions across different length scales from molecular to macroscopic. HMR has been shown to diffuse into the wood cell wall on the molecular scale and appears to associate with lignin based on similar solubility behavior. Within the cell wall, HMR chemically crosslinks contributing both to an increased stiffness of the wood material and improved dimensional stabilization on a macroscopic scale.