Thermal treatment and its effect on the gas permeability of Populus nigra

In this investigation، the effect of thermal treatment on gas permeability of Populus nigra was studied. The boards with 5×5×15 cm in dimensions were steamed under averagepressure 2-3 bar. The treatments were carried out at 4 temperatures of 120، 140، 160 and 180 ºC for 1، 2 and 3-hour. After thermal treatment، 2 cylindrical specimens with 18mm diameter and 1 mm length parallel to grain were prepared from each board، and their transverse permeability was measured. The results showed that thermal treatment did not have any effect on gas permeability at 120 and 140 ºC but it reduced the gas permeability at 160 and 180 ºC. There was not any significant difference in %95 confidence level between different periods of thermal treatment.