Application Of Supercritical Fluid In Wood Preservative Impregnation

Application of supercritical fluid to wood preservative impregnation is one of the new techniques in wood science field.In this paper,SCF-CO₂ is used to impregnate preservatives into wood. The aim is to enhance the grade of decay resistance. The effect of different technical conditions on the preservative retention has been studied, and the optimum condition for symmetrical preservative distribution is obtained. The composite mechanism has also been studied. The result of this research can offersome theoretical bases for application of supercritical fluid to wood preservation.Based on the research on preservative impregnation with supercritical fluid into Populus nigra L. and Schima Superba, the results are as follows. Compared with traditional treatment, the advantage of impregnation by supercritical fluid treatment is to make the preservative distribution symmetrical, and free of poisonous wastewater. The preservative distribution is relative to the pressure and its falling rate. The optimum temperature and time for treatment vary with the species of wood. In the process of impregnation, the preservative retention will increase if co-solvent is used.Impregnation with supercritical fluid will not ruin the mechanical properties of the wood. The permeability of the wood will be improved after the treatment with supercritical carbon. Whether TEB or IPBC, its leachability resistance is good. FTIR analysis showed that chemical function between wood and TEB is not formed but hydrogen bond between wood and IPBC will probably form.