Moisture and Temperature Changes of Wood during Adsorption and Desorption Processes


  • Tianxin Zhao
  • Erni Ma
  • Wenjie Zhang


Adsorption, desorption, moisture content, temperature, IR thermal imaging


Sitka spruce (Picea sitchensis Carr.) specimens, 10 mm along the grain and 20 mm in radial and tangential directions, were exposed to three different RH conditions of 22, 47, and 75% for adsorption and desorption at 30°C controlled by a self-designed temperature conditioning chamber. Specimen weight was measured and thermal images were taken at certain time intervals during the processes to investigate their moisture and temperature changes. Results showed that at the beginning of the sorption process, moisture content of the specimens changed significantly and their average temperature increased about 2-7°C for adsorption and decreased about 1-6°C for desorption. During adsorption, the temperature for the center section along the longitudinal direction of the specimens was lower than that for the surface section, whereas the opposite was true for specimens under desorption. Along with the adsorption and desorption processes, moisture content and average temperature of the specimens were gradually approaching equilibrium state.


Åström KJ, Hägglund T (2001) The future of PID control. Control Eng Pract 9(11):1163-1175.nBarkas WW (1949) The swelling of wood under stress. HM Stationary Office, London, UK. 104 pp.nBarreim E, Freitas VP (2007) Evaluation of building materials using infrared thermography. Construct Build Mater 2(1):218-224.nChristensen GN, Kelsey KE (1959) The rate of sorption of water vapor by wood. Holz Roh Werkst 17: 178-188.nEngelund ET, Thygesen LG, Svensson S, Hill CAS (2013) A critical discussion of the physics of wood-water interactions. Wood Sci Technol 47:141-161.nJönsson J (2004) Internal stresses in the cross-grain direction in glulam induced by climate variations. Holzforschung 58(2):154-159.nKelly MW, Hart CA (1970) Water vapor sorption rates by wood cell walls. Wood Fiber Sci 1(4):270-282.nKing G, Cassie ABD (1940) Propagation of temperature changes through textiles in humid atmospheres. 1. Rate of absorption of water vapor by wool fibers. Trans Faraday Soc 36:445-453.nLudwig N, Redaelli V, Rosina E (2004) Moisture detection in wood and plaster by IR thermography. Infrared Phys Technol 46(1):161-166.nMa EN, Nakao T, Zhao GJ (2009) Adsorption rate of wood during moisture sorption processes. Wood Res-Slovakia 54(3):13-22.nMa EN, Nakao T, Zhao GJ (2010) Dynamic sorption and hygroexpansion of wood subjected to cyclic relative humidity changes. Wood Fiber Sci 42(2):229-236.nMa EN, Zhao GJ (2012) Special topics on wood physics. China Forestry Publishing House, Beijing, China. 90 pp.nMacromolecule Academy (1958) Physical properties of macromolecule. Kyoritsu Press, Tokyo, Japan. 386 pp.nMeola C (2007) A new approach for estimation of defects detection with infrared thermography. Mater Lett 61(3): 747-750.nQu ZH, Wang LH (2009) Application of infrared imaging technology in the wood non-destructive testing. Forest Engineering 25(1):21-24.nSkaar C (1988) Wood-water relations. Springer-Verlag, Berlin, Germany. 283 pp.nSkaar C, Prichananda C, Davidson RW (1970) Some aspects of moisture sorption dynamic in wood. Wood Sci 2(3):179-185.nVadivambal R, Jayas DS (2011) Applications of thermal imaging in agriculture and food industry—A review. Food Bioprocess Technology 4(2):186-199.nWright T, McGechan A (2003) Breast cancer: New technologies for risk assessment and diagnosis. Mol Diagn 7(1):49-55.n






Research Contributions