RESPONSE OF COLOUR AND HYGROSCOPIC PROPERTIES OF SCOTS PINE WOOD TO ΤHERMAL ΜODIFICATION

Yıl 2012, Cilt: 14 Sayı: 22, 96 - 103, 01.06.2012

Vasiliki Kamperıdou İoannis Barboutıs Vasileios Vasıleıou

Öz

The effect of heat treatment on wood surface colour and hygroscopic properties of pine wood were
investigated in this study. Boards of Scots pine wood (Pinus sylvestris L.) were subjected to thermal
treatment at 200 °C, for 4, 6 and 8 hours. The change of equilibrium moisture content and density
values of the specimens, due to the thermal treatment were recorded, in order to facilitate the
understanding of the treated material behavior. The colour parameters L*, a* and b*, used to depict
the total colour change (ΔΕ) of wood surface, were proved to change proportionally to the treatment
intensity. Moreover, the swelling in tangential and radial direction and the absorption of the specimens
as well, appeared to be enhanced in great extent by the thermal treatment process. Mean value of
Swelling percentage in tangential direction decreased 10.26%, 17.22% and 19.60% for specimens
treated for 4, 6 and 8 hours, respectively, referring to the final measurement after 72 hours of
immersion. In radial direction, mean value of Swelling percentage decreased 19.56%, 32.75% and
34.65% for treated for 4, 6 and 8 hours specimens, respectively, after 72 hours immersion, which
attests the swelling decrease and the improvement of the hygroscopic behavior of Scots pine wood.

Anahtar Kelimeler

Thermal treatment

RESPONSE OF COLOUR AND HYGROSCOPIC PROPERTIES OF SCOTS PINE WOOD TO THERMAL MODIFICATION

Öz

The effect of heat treatment on wood surface colour and hygroscopic properties of pine wood were
investigated in this study. Boards of Scots pine wood (Pinus sylvestris L.) were subjected to thermal
treatment at 200 °C, for 4, 6 and 8 hours. The change of equilibrium moisture content and density
values of the specimens, due to the thermal treatment were recorded, in order to facilitate the
understanding of the treated material behavior. The colour parameters L*, a* and b*, used to depict
the total colour change (ΔΕ) of wood surface, were proved to change proportionally to the treatment
intensity. Moreover, the swelling in tangential and radial direction and the absorption of the specimens
as well, appeared to be enhanced in great extent by the thermal treatment process. Mean value of
Swelling percentage in tangential direction decreased 10.26%, 17.22% and 19.60% for specimens
treated for 4, 6 and 8 hours, respectively, referring to the final measurement after 72 hours of
immersion. In radial direction, mean value of Swelling percentage decreased 19.56%, 32.75% and
34.65% for treated for 4, 6 and 8 hours specimens, respectively, after 72 hours immersion, which
attests the swelling decrease and the improvement of the hygroscopic behavior of Scots pine wood.

Anahtar Kelimeler

Colour, Hygroscopic properties, Modification, Scots pine, Thermal treatment

Kaynakça

• Ahajji, A., Diouf, P.N., Aloui, F., Elbakali, I., Perrin, D., Merlin, A., George, B., 2009. Influence of heat treatment on antioxidant properties and colour stability of beech and spruce wood and their extractives. Wood Sci Technol (2009) 43:69–83.
• Akgül, M., Korkut, S., 2012. The effect of heat treatment on some chemical properties and colour in Scots pine and Uludağ fir wood. International Journal of Physical Sciences (IJPS), 7(21): 2854-2859, ISSN:1992-1950.
• Aksou, A., Deveci, M., Baysal, E., Toker, H., 2011. Colour and gloss changes of Scots pine after heat modification. Wood Research 56 (3):2011 p.329-336.
• ASTM D 1536-58 T 1964. Tentative method of test color difference using the colormaster differential colourimeter.
• Awoyemi, L., Jones, I.P., 2010. Anatomical explanations for the changes in properties of western red cedar (Thuja plicata) wood during heat treatment. Wood Sci Technol. DOI 10.1007/s00226-010-0315-9.
• Esteves, B., Domingos, I., Pereira, H., 2008. Heat treatment of Pine wood. BioResources 3(1), 142-154.
• Gunduz, G., Aydemir, D., Karakas, G., 2009. The effects of thermal treatment on the mechanical properties of wild Pear (Pyrus elaeagnifolia Pall.) wood and changes in physical properties. Materials and Design 30 (2009) 4391–4395.
• Johansson, D., 2005. Strenght and Colour Response of Solid Wood to Heat Treatment. Doctoral thesis. Luleå University of Technology LTU Skelleftea. 2005:93 / ISSN:1402-1757.
• Nuopponen, M., Vuorinen, T., Jamsa, S., Viitaniemi, P., 2003. The effects of a heat treatment on the behaviour of extractives in softwood studied by FTIR spectroscopic methods. Wood Sci Technol 37 (2003) 109–115.
• Şahin, H.T., Arslan, M.B., Korkut, S., Şahin, C., 2011. Colour Changes of Heat-Treated Woods of Red-Bud Maple, European Hophornbeam and Oak, Color Research & Application 36(6): 462-466, ISSN: 0361-2317.
• Stingl, R., Smutny, R., Treberspurg, M., Teischinger, A., 2007. Sustainable Use of Heat Treated Wood as Façade Material - Preliminary Results of Weathering Tests. European Conference on Wood Modification 2007 p.195-199.
• Tremblay, C., 2007. Physical Properties of Jack Pine Thermally Modified at Three Temperature Levels. European Conference on Wood Modification 2007 (p.183-186).
• Vukas, N., Horman, I., Hajdarević, S., 2010. Heat Treated Wood. 14th International Research/Expert Conference, TMT 2010, Mediterranean Cruise11-18 September 2010, p.121-124.
• Yao, C., Yongming, F., Jianmin, G., Houkun, L., 2010. Coloring characteristics of in situ lignin during heat treatment. Wood Sci Technol DOI 10.1007/s00226-010-0388-5.
• Yongming F, Jianmin G, Yao C (2010). Colour responses of black locust (Robinia pseudoacacia L.) to solvent extraction and heat treatment. Wood Sci Technol (2010) 44:667–678.