Surface energy characterization of preservative-treated wood and E-glass/phenolic composites
Publication Name: Forest Products Journal and Index
The effects of various wood preservative systems and treatment processes on the surface energy of wood and E-glass/phenolic pultruded composite material for wood reinforcement were characterized using surface energy methods. Southern yellow pine and pultruded E-glass/phenolic FRP (fiberglass reinforced plastic) composite sheet were treated with two common wood preservative chemicals (waterborne chromated copper arsenate (CCA) and organometallic copper naphthenate (CuN)). Surface energy of the pre- servative-treated and untreated wood and FRP composite material was determined by means of static contact angle analysis using the Good-Girifalco (geometric mean) and Chang approaches. It was found that the total surface energies of the surfaces of these materials were greatly affected by preservative treatments. As preservative retentions change, the surface energies of solids were also changed. The surface energy of CCA- and CuN-treated FRP composite decreased as a result of exposure to preservative treatments, while in- creased CCA retentions resulted in increases of surface energy in southern pine wood. This difference in surface energy behavior with CCA retention is attributed to the accumulation of high surface energy metallic salts on lumen surfaces in treated wood and the CSM layer of the FRP composite. Scanning electron microscopy showed deposits of metal oxides on the cell wall of CCA-treated wood. A discussion of surface energy changes and the possible effects on wettability and bondability of treated wood and FRP composite sur- faces is presented.