INTERNAL PRESSURE DEVELOPMENT DURING SUPERCRITICAL FLUID IMPREGNATION OF WOOD

Abstract

Supercritical fluid impregnation has tremendous potential for effectively impregnating a variety of species, but little is known about the pressure response in wood during this process.Pressure response was studied in a number of wood species using specially designed high pressure probes, which allowed in-situ monitoring of the treatment process.Pressure response was relatively rapid in permeable species such as pine, but tended to lag in less permeable species.In some cases, the differences between surface and internal pressure exceeded the material properties of the wood, and crushing or fractures resulted.The results indicate that the rates of pressure application and release can be tailored to control pressure differentials to avoid wood damage.