EFFECT OF PROCESS VARIABLES ON SUPERCRITICAL-FLUID IMPREGNATION OF COMPOSITES WITH TEBUCONAZOLE

This study examines the effects of pressure, temperature, and treatmen t time on supercritical fluid impregnation of such composites as plywo od, particleboard, flakeboard, and medium-density fiberboard. Carbon d ioxide with methanol as a cosolvent was used as the supercritical flui d, with tebuconazole as the biocide. Biocide distribution, as measured by extraction and analysis, generally increased with pressure, temper ature, and treatment lime, although the retentions sometimes decreased at the highest pressure tested (4500 psig). In general, biocide reten tions were far above those required for fungal protection, and the dis tribution was more uniform than that found with conventional pressure treatments, The results suggest that supercritical fluid impregnation represents a simple method for impregnating composites with biocides w ithout the permanent damage typical of other treatment systems.