Supercritical fluid impregnation of selected wood species with tebuconazole

The effects of pressure and temperature on supercritical fluid impregnation of tebuconazole were evaluated on Douglas-fir, western I ed cedar, red ald er, white spruce, and white oak. Higher pressure markedly enhanced both the retention and distribution of tebuconazole in these species. When the rate of pressure release was altered at the ends of treatments of Douglas-fir, results varied. Generally, a higher rate of venting increased the steepness of the preservative gradient inward from the surface. Elevated pressures a lso affected some wood properties. Western red cedar and white spruce showe d collapse, while the other three species were free of such defects. Modulu s of Elasticity (MOE) and Modulus of Rupture (MOR) tended to decline with h igher pressure in western red cedar and white spruce, but the differences w ere rarely significant. No significant changes in MOE/MOR occurred with the other 3 species.