Accessible Unlicensed Requires Authentication Published by De Gruyter October 16, 2014

One-stage thermo-hydro treatment (THT) of hardwoods: an analysis of form stability after five soaking-drying cycles

Vladimirs Biziks, Bruno Andersons, Errj Sansonetti, Ingeborga Andersone, Holger Militz and Juris Grinins
From the journal Holzforschung

Abstract

A newly developed thermo-hydro treatment (THT) for use in a one-stage heat treatment process was examined by focusing on the form stability-related properties of European aspen (Populus tremula), birch silver (Betula pendula), and gray alder (Alnus incana). In particular, wood specimens were subjected to THT in a saturated steam atmosphere in a pilot-scale autoclave heated between 140 and 180°C for 1–3 h. Several parameters of untreated and treated samples after several soaking and drying cycles were compared, namely, the changes in the volumetric swelling, swelling in the radial and tangential directions, cell wall total water capacity, and anti-swelling efficiency (ASE). Due to repeated wetting in the cyclic water submersion-drying test, the original ASE of 73% decreased to 65% (180°C for 1 h), and the original ASE of 33% decreased to 5% (140°C for 1 h). Wood modified at 170°C presented good results that were not significantly lower than wood treated at higher temperatures while consuming less energy to deliver ASE improvement and was selected as optimum. To increase the ASE by 1%, the amount of energy consumed was decreased by 41%, 39%, and 17% compared with the treatment regimes of 160°C for 1 h, 160°C for 3 h, and 180°C for 1 h, respectively. The new THT regime led to improved long-term dimensional stability due to the cross-linking of cell wall polymers, which resulted in increased cell wall rigidity.


Corresponding author: Vladimirs Biziks, Wood Biology and Wood Product, Burckhardt Institute, Georg-August University, Göttingen, Büsgenweg 4, 37077 Göttingen, Germany, Phone: +371 26099416, e-mail:

Acknowledgments

The authors gratefully acknowledge the financial support received from the European Regional Development Fund project, “Innovative wood and its processing materials with upgraded service properties”, No. 2010/0324 2DP/2.1.1.1.0/10/APIA/VIAA/057 and from the Latvian State Research Program NatRes.

References

Baronas, R., Ivanauskas, F., Juodeikienė, I., Kajalavicius, A. (2001) Modelling of moisture movement in wood during outdoor storage. Nonlinear Anal. 6:3–14.Search in Google Scholar

Boonstra, M.J., Tjeerdsma, B.F., Groeneveld, H.A.C. (1998) Thermal modification of nondurable wood species. 1. The PLATO technology; thermal modification of wood. The International Research Group on Wood Preservation, Doc. No. IRG/WP/98-40123.Search in Google Scholar

Bourgois, J., Bartholin, M., Guyonnet, R. (1989) Thermal treatment of wood: analysis of obtained product. Wood Sci. Technol. 23:303–310.Search in Google Scholar

Bowyer, J.L., Shmulsky, R., Haygreen, J.G. (2003) Forest Products and Wood Science: An Introduction. 4th ed. Blackwell Publishing Professional, Iowa, US.Search in Google Scholar

Browning, B.L. (1967) Methods of Wood Chemistry. Vol. 1., Wiley, New York.Search in Google Scholar

Burmester, A. (1973) Einfluss einer Wärme-Druck-Behandlung halbtrockenen Holzes auf seine Formbeständigkeit. Holz Roh-Werkst. 31:237–243.Search in Google Scholar

Chaouch, M., Dumarçay, S., Pétrissans, A., Pétrissans, M., Gérardin, P. (2013) Effect of heat treatment intensity on some conferred properties of different European softwood and hardwood species. Wood Sci. Technol. 47:663–673.Search in Google Scholar

Dirol, D., Guyonnet, R. (1993) The improvement of wood durability by rectification process. The International Research Group on Wood Preservation, Doc. No. IRG/WP 93-40015.Search in Google Scholar

Esteves, B., Domingos, I., Pereira, H. (2007a) Improvement of technological quality of eucalypt wood by heat treatment in air at 170-200C. For. Prod. J. 57:47–52.Search in Google Scholar

Esteves, B., Velez Marques, A., Domingos, I., Pereira, H. (2007b) Influence of steam heating on the properties of pine (Pinus pinaster) and eucalypt (Eucalyptus globulus) wood. Wood. Sci. Technol. 41:193–207.Search in Google Scholar

Giebeler, E. (1983) Dimensionsstabilisierung von Holz durch eine Feuchte/Wärme/Druck-Behandlung. Holz Roh- Werkst. 41:87–94.Search in Google Scholar

Hill, C.A.S. (2006) Wood Modification. Chemical, Thermal and Other Processes. John Wiley & Sons Ltd., Chichester, pp 239.Search in Google Scholar

Jämsä, S., Ahola, P., Viitaniemi, P. (2000) Long-term natural weathering of coated ThermoWood. Pigment Resin Technol. 29:68–74.Search in Google Scholar

Ibbett, R.N., Kaenthong, S., Phillips, D.A.S., Wilding, M.A. (2007) Solution adsorption and exclusion studies of the structure of never-dried and re-wetted cellulosic fibres. J. Mater. Sci. 42:6809–6818.Search in Google Scholar

Kim, G.Y.K., Kim, J. (1998) Effect of heat treatment on the decay resistance and the bending properties of radiata pine sapwood. Material und Organismen 32:101–108.Search in Google Scholar

Kocaefe, D., Poncsak, S., Boluk, Y. (2008) Effect of thermal treatment on the chemical composition and mechanical properties of birch and aspen. BioResources 3:517–537.Search in Google Scholar

Korkut, S., Akgü, M., Dündar, T. (2008) The effect of heat treatment on some technological properties of Scots pine (Pinus sylvestris L.) wood. Bioresour. Technol. 99:1861–1868.Search in Google Scholar

Metsä-Kortelainen, S., Antikainen, T., Viitaniemi, P. (2006) The water absorption of sapwood and heartwood of Scots pine and Norway spruce heat treated at 170°C, 190°C, 210°C and 230°C. Holz Roh-Werkst. 64:192–197.Search in Google Scholar

Militz, H, Tjeerdsma B. (2002) Heat treatment of wood by the Plato process. In: Review on Heat Treatments of Wood, Proceedings of the special seminar of COST Action E22, Antibes, France.Search in Google Scholar

Militz, H. (2008) Processes and properties of thermally modified wood manufactured in Europe. ACS Symp. Ser. 982:372–388.Search in Google Scholar

Mohhebby, B., Sanaei, I. (2005) Influences of hydro-thermal treatment on physical properties of beech wood (Fagus orientalis).The International Research Group on Wood Preservation; IRG Document No.: IRG/WP 05-40303.Search in Google Scholar

Ohmae, K., Minato, K., Norimoto, M. (2002) The analysis of dimensional changes due to chemical treatments and water soaking for Hinoki (Chamaecyparis obtuse) wood. Holzforschung 56:98–102.Search in Google Scholar

Rautkari, L., Honkanen, J., Callum, A.S.H., Ridley-Ellis Hughes, M. (2014) Mechanical and physical properties of thermally modified Scots pine wood in high pressure reactor under saturated steam at 120, 150, and 180°C. Eur. J. Wood Prod. 72:33–41.Search in Google Scholar

Ruyter, H.P. (1989) European Patent Appl. No. 89-203170.9.Search in Google Scholar

Scheiding, W. (2010) Entwicklung des TMT-Sektors seit 2008. 6th Europäischer TMT-Workshop. Dresden, Germany. 1–6.Search in Google Scholar

Stamm, A.J. (1956) Thermal degradation of wood and cellulose. Ind. Eng. Chem. 48:413–417.Search in Google Scholar

Tjeerdsma, B.F., Boonstra, M., Pizzi, A., Tekely, P., Militz, H. (1998) Characterisation of thermally modified wood: molecular reasons for wood performance improvement. Holz Roh-Werkst. 56:149–153.Search in Google Scholar

Tuong, V.M., Li, J. (2010) Effect of heat treatment on the changes in color and dimensional stability of acacia hybrid wood. Bioresources 5:1257–1267.Search in Google Scholar

Unsal, O., Ayrilmis, N. (2005) Variations in compression strength and surface roughness of heat-treated Turkish river red gum. J. Wood Sci. 51:405–409.Search in Google Scholar

Usta, I. (2007) Theory of aesthetics – charm in furniture and an aesthetic evaluation of bleaching of natural color of wood through the application of experimental bleaching process. 38th Annual Meeting of the International Group on Wood Protection, Wyoming, USA. Doc. No. IRG/WP 07-30424.Search in Google Scholar

Wang, J., Cooper, P.A. (2005) Effect of oil type, temperature and time on moisture properties of hot oil-treated wood. Holz Roh- Werkst. 63:417–422.Search in Google Scholar

Weiland, J.J., Guyonnet, R. (2003) Study of chemical modifications and fungi degradation of thermally modified wood using DRIFT spectroscopy. Holz Roh-Werkst. 61:216–220.Search in Google Scholar

Welzbacher, C.R., Brischke, C., Rapp, O.R. (2007) Influence of treatment temperature and duration on selected biological, mechanical, physical and optical properties of thermally modified timber. Wood Mat. Sci. Eng. 2:66–76.Search in Google Scholar

Willems, W. (2009) A novel economic large scale production technology for high quality thermally modified wood. Stockholm, Sweden. 31–35.Search in Google Scholar

Zaman, A., Alén, R., Kotilainen, R. (2000) Heat behaviour of Pinus sylvestris and Betula pendula at 200–230°C. Wood Fiber Sci. 32:138–143.Search in Google Scholar

Wood Products Prices in The UK& Holland: Tropical hardwood faces mounting competition from heat treated wood. (accessed 06.03.2014).Search in Google Scholar

Received: 2014-3-19
Accepted: 2014-9-23
Published Online: 2014-10-16
Published in Print: 2015-7-1

©2015 by De Gruyter