Decay Resistance and Bonding Properties of Structural Flakeboard
T F Shupe, Chung-Yun Hse
Experimental structural flakeboard panels consisting of differing furnishes and resins were produced and tested for internal bond, linear expansion, thickness swell, and decay resistance. One group of panels was produced with recycled CCA-treated wood as the furnish and commercial phenol formaldehyde (PF) resin as the binder. Other groups of panels were produced with either mixed hardwoods or southern pine as the furnish and then sprayed with a co-reacted soy-flour PF resin or a commercial face or core resin. The recycled CCA-treated panels contained 5 different furnish ratios (0:100, 25:75, 50:50, 75:25, and 100:0) of recycled CCA-treated southern pine and virgin, untreated southern pine. Tests on the panels bonded with co-reacted soy flour PF indicated that 30% substitution of phenol with soy flour in the resin system did not appreciably promote decay or reduce IB strength. As expected, panels produced with a higher ratio of recycled CCA-treated wood furnish, were generally subject to less weight loss during decay tests for brown rot (Gloeophyllum trabeum, ATCC 11539) and white rot (Trametes versicolor, ATCC 42462) but yielded lower IB values. Research in currently in progress to assess the resistance of all the aforementioned panel types to the Formosan subterranean termite (Coptotermes formosanus Shiraki).
Keywords: Flakeboard, internal bond, linear expansion, thickness swell, weight loss