Hygroexpansive and sorptive behavior of wood modified with propylene oxide and oligomeric diisocyanate

Small wood wafers were treated chemically to reduce their hygroexpansive and sorptive behavior. Wood specimens were either ovendried or conditioned to a nominal moisture content of 12 percent, and then treated with several propylene oxide-oligomeric diisocyanate mixtures using a fixed vacuum-pressure schedule. Results indicate that all treatments used reduced the hygroexpansive and sorptive behavior of wood. Resultant anti-swelling efficiency, moisture excluding coefficients, time to half swelling, and ratios of sorption were superior when treatments were applied to ovendry in contrast to wood with an initial moisture content of 12 percent. The best treatment found in the study was a mixture of 9:1 parts of propylene oxide, and oligomeric diisocyanate.