In this investigation, the effect of steaming on the water vapor diffusion coefficient of poplar wood (Populus nigra L.) was studied. The diffusion coefficients were then measured based on Fick’s law of diffusion in steadystate conditions using the cup method. | Turkish Journal of Biology Research Article Turk J Biol (2013) 37: 511-515 © TÜBİTAK doi: Modification of water vapor diffusion in poplar wood (Populus nigra L.) by steaming at high temperatures Maedeh SAYAR, Asghar TARMIAN* Department of Wood and Paper Science & Technology, Faculty of Natural Resources, University of Tehran, Tehran, Iran Received: Accepted: Published Online: Printed: Abstract: In this investigation, the effect of steaming on the water vapor diffusion coefficient of poplar wood (Populus nigra L.) was studied. Boards with dimensions of 50 × 50 × 150 (W × H × L) mm3 and average moisture content of 12% were steamed at temperatures of 120, 140, 160, and 180 °C for 1, 2, and 3 h. The diffusion coefficients were then measured based on Fick’s law of diffusion in steadystate conditions using the cup method. Results showed that the steaming of poplar wood at all mentioned temperatures can decrease the water vapor diffusion coefficient. However, no further improving effect was caused by increasing the steam temperature or duration. Some significant wood anatomical and chemical changes like cell wall collapse and holocellulose hydrolysis give some explanations for the improving effect of steaming on the diffusion coefficient. Overall, steaming at temperature of 120 °C for 1 h as the best treatment is recommended to modify the water vapor diffusion coefficient. Key words: Poplar wood, steaming, water vapor diffusion 1. Introduction Wood as an engineering material is diffusive to vapor and this property restricts it from being used for some specific applications, such as the long-term storage and carriage of some food stuffs and toxic materials. The water vapor diffusion coefficient of wood is also involved in many industrial operations (drying, bending, peeling, and coating) as well as during the lifespan of wooden structures (flooring, roof .
