Effects of temperature and time of thermal modification on density and colour of Pinus insularis and Dacrycarpus imbricatus wood
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Abstract
The Pinus kesiya and Podocarp (Dacrycarpus imbricatus) woods were obtained from the plantations of the Southeast region of Vietnam, with the initial humidity of 80 - 85%. The wood was cut into boards with dimensions of 40 x 80 mm to 120 x 500 mm. In this study, the Pinus kesiya and Podocarp woods were thermally treated at with high temperatures ranging from 161oC to 218oC and the duration from 7.5 h to 13 h. The experiment results showed that the oven-dry density of pine and Podocarp tended to decrease when it was treated at high temperatures during long periods of time. In particular, the density of Pinus kesiya and Podocarp woods decreased about 3.17 - 17.3% and 3.45 - 20.73%, respectively, compared with the control samples. In the thermal modification process, under the effects of high temperature Pinus kesiya and Podocarp woods became darker than the modified wood.
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References
Bekhta, P., & Niemz, P. (2003). Effect of high temperature on the change in color, dimensional stability and mechanical properties of Spruce wood. Holzforschung 57, 539-546. https://doi.org/10.1515/HF.2003.080
Bengtsson, C., Jermer, J., & Brem, F. (2002). Bending strength of heat-treated spruce and pine timber. Proceedings of The International Research Group on Wood Preservation Document No. IRG/WP 02-40242. Wales, UK.
Bruno, E., Idalina, D., & Helena, P. (2008). Pine wood modification by heat treatment in air. BioResources 3(1), 142-154.
Esteves, B., Idalina, D., & Helena, P. (2007). Improvement of technological quality of Eucalypt wood by heat treatment in air at 170-200oC. Forest Products Journal 57(1/2), 47-52.
Johansson, D., & Moren, T. (2006). The potential of colour measurement for strength prediction of thermally treated wood. Holz Roh-Werkst 64, 104-110. https://doi.org/10.1007/s00107-005-0082-8
Hamiyet, S. K. (2010). Characteristics of heat-treated Turkish pine and fir wood after ThermoWood processing. Journal of Environmental Biology 31(6), 1007-1011.
Hill, C. A. S. (2006). Wood modification - chemical, thermal and other processes. Chichester, UK: Wiley and Sons.
Rusche, H. (1973). Thermal degradation of wood at temperature up to 200oC. Part I. Strength properties of wood after heat treatment. Holz als Rohund Werkstoff 31(7), 273-281.
Stamm, A. J., & Hansen, L. A. (1937). Minimizing wood shrinkage and swelling: Effect of heating in various gases. Journal of Industrial and Engineering chemistry 29(7), 831-833. https://doi.org/10.1021/ie50331a021
ThermoWood® (2003). ThermoWood® Handbook. Helsinki, Finland: ThemoWood association.
Tiemann, H. D. (1920). Effect of different methods of drying on the strength and hygroscopicity of wood (3rd ed.). Pennsylvania, USA: Joshua Ballinger Lippincott Company.
Vasiliki, (2014). Influence of thermal treatment on mechanical strength of Scots pine (Pinus sylvestris L.) wood. Wood Research 59(2), 373-378.
Vasiliki, K., & Panagiotis, B. (2015). Correlation between the changes of colour and mechanical properties of thermally-modified Scots pine (Pinus sylvestris L.) wood. Pro Ligno 11(4), 360-365.
VNS (Vietnamese National standards). (2009). TCVN 8048-2:2009: Determination of density for physical and mechanical tests. Ha Noi, Vietnam: Vietnam Standards and Quality Institute.