Evaluation of fluid distribution in pressure treated wood in different flow directions
A Omidvar, M H Schneider
Among different methods, polymerization technique was chosen to study distribution of fluid through cell types in treated wood. Red maple wood specimens with the size of 2 by 2 by 4 cm (radial, tangential and longitudinal, respectively) were prepared. Styrene monomer was used as the fluid for impregnation; because its physical properties such as surface tension, specific gravity and viscosity fall between those of many preservatives. Before impregnation, apart from the uncoated specimens, some samples were coated with epoxy resin such that lateral flow along with longitudinal flow could be studied. Full cell process with the exception of final vacuum was applied for impregnation. Thin sections from the treated wood were prepared to be microscopically examined for distribution study. The results indicated uniform fluid distribution in lateral flow (both in radial and tangential) and non-uniform distribution in longitudinal flow as well as flow in uncoated specimens. Since uniform distribution of preservative among different cell types is very important, it is recommended that in some cases such as poles, piles, posts and sleepers, end coating of wood should be done before impregnation.