Influence of hydrothermal treatment on the dimensional stability of beech wood

Hydrothermal treatment of wood material products with many interesting properties such as enhanced dimensional stability, lower equilibrium moisture content and increased biological durability. The effects of hydrothermal treatment on dimensional stability, oven dry density and water absorption of beech wood (Fagus Orientalis) naturally grown, has been studied in present research that extremely used in Iran. Hydrothermal applied to the wood samples (۲.۵Cm × ۲.۵Cm × ۲.۵Cm) in three different temperatures (۱۵۰ °C, ۱۶۰ °C,۱۷۰°C) and four different durations (۱h, ۳h, ۵h and ۷h) in reactor. Then, the samples and their controls were immersed in water at ۲۵ °C, ۶۵% relative humidity for various periods. Volumetric swelling percentage and rate of the water absorption values of the samples and their controls were measured at a period of ۲۴ hour in ۸ steps on basis of oven dried dimension. The obtained data were analyzed using Microsoft Office (EXCEL ۲۰۰۳). The data analysis indicated that best anti-swelling efficiency value was achieved at ۱۷۰ oC (treating temperature) within ۱ hour (treating time) and ۸ steps of soaking - dried measurement by hydrothermal treatment. Consequences for anti-swelling efficiency, decreasing of samples specific gravity, water absorption and water repellency effectiveness values obtained ۲۷.۹۵%, ۸.۴۹%, ۵۶.۴۱% and ۲۰.۲۰% respectively. Therefore, hydrothermal treatment showed a little decreasing at ۱۵۰ oC to ۱۷۰oC in specific gravity of treatment samples because maximum lessening of specific gravity obtained ۸.۰۲% in the highest condition of treatment after final soaking.   REFERENCES Brischke, C. and Rapp, A.O. (۲۰۰۴) Investigation of the suitability of silver fir (Abies alba Mill.) for thermal modification. IRG / WP ۰۴- ۴۰۲۷۵, IRG Annual Meeting ۶-۱۰ June, SLOVENIA. Caparro´s, S., Ariza, J., Hernanz, D., Dı´az, M.J. and Arundo donax L. (۲۰۰۶) Valorization under Hydrothermal and Pulp Processing. Ind. Eng. 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کلیدواژه ها:

Hydrothermal treatment ، Dimensional stability ، water absorption ، Specific gravity ، Beech wood