Thermally Modified Timber - overview
What is Thermally Modified Timber (TMT)?
Thermally modified timber, thermowood or TMT is wood that has been treated at temperatures usually above 160 ¬įC with reduced oxygen concentration and in which essential properties are permanently changed over the entire cross-section of the wood. The various processes of thermal modification of wood lead in particular to a degradation of hemicelluloses, but changes also take place in the other main components of the wood.
In the pilot plant at the University for Sustainable Development, thermowood is produced:
- in a single-stage or multi-stage thermal treatment process
- at temperatures from 170¬įC to 250¬įC
- over a period of 2 to 48 hours
- under exclusion of oxygen
A patent application has been filed for the process, which is protected by a utility model.
How does the wood change during thermal treatment?
- The wood turns dark, depending on the intensity of treatment.
- The ability to absorb and release water is permanently reduced.
- Changes occur in dimensional stability and mechanical properties.
- The wood becomes more resistant to wood-destroying fungi and insects.
- The wood becomes brittle.
- The bending strength is reduced.
Projects related to TMT
- ‚Äč‚Äč‚Äč‚Äč‚Äč‚Äč‚Äčcompleted MWFK allocation "TMT" (BMBF project and MWFK assignment "TMT")
With funds from the Brandenburg Ministry of Science, Research and Culture (MWFK), further development of the control technology as well as economic considerations of the overall process will be carried out. Duration of the project: 01.07.2012 to 31.12.2012
- CombiMod (The development of a technology for the production of thermo-chemically modified wood for the purpose of series production of innovative wood products for outdoor use; Subproject: Development of COMBIMOD processes and treatment formulations based on biopolymers)
- CombiMod-kiln - Equipment measure (Test field for reproducible generation of optimal physical-chemical properties of wood and wood-based materials - TMT-kiln)
- QSM-TMT (Development and application of a quality assurance method for the thermal modification of wood)
Alternating Climates (Development and implementation of tests of wood products to determine the material properties under the influence of alternating climates)
Projects on musical instruments in connection with TMT
- acoustic wood (SubMat4Music - Recipes for the modification of native woods for the production of acoustic woods )
- FOMO (Development of recipe for the forming and modification process of European woods)
- clarinets (Development of alternative materials for the production of woodwind instruments and instrument cases from thermally modified and polymer-impregnated European woods)
- Swabian Rio rosewood (Development of guitars free of tropical woods by using a modification process to upgrade native woods)
- SubMat4Music - Network (Identification and development of the potentials of European woods for musical instrument making)
- TMT-Organ (Development of a process for the serial modification of resinous softwoods for the construction of organ pipes)
Head of Project and contact person
Prof. Dr.-Ing. Alexander Pfriem (Alexander.Pfriem@hnee.de)
Lothar Clauder M.Sc. (Lothar.Clauder@hnee.de)
European cooperation takes place within the framework of the FPS:
- COST Action FP1407 Understanding wood modification through an integrated scientific and environmental impact approach (ModWoodLife)
Runtime: 01.06.2014 - 30.05.2018
Management Committee Member
- COST Action FP1302 WoodMusiCK
Runtime: 06.11.2013 - 05.11.2017
Working Group Member
- COST Action FP1303 Performance of bio-based building materials
Runtime: 22.10.2013 - 21.10.2017
Working Group Member
- COST Action FP0904 Thermo-Hydro-Mechanical Wood Behaviour and Processing
Runtime: 27.05.2010 - 26.05.2014
Working Group Member‚Äč‚Äč‚Äč‚Äč‚Äč‚Äč‚Äč‚Äč‚Äč
Hughes, M.; Hill, C.A.S.; Pfriem, A.: The toughness of hydrothermally modified wood ‚Äď A review. Holzforschung, 69 (2015) 7, S. 851‚Äď862; DOI: 10.1515/hf-2014-0184
Willems, W.; Lykidis, C.; Altgen, M.; Clauder, L.:Quality control methods for thermally modified wood. Holzforschung, 69 (2015) 7, S. 875-884; DOI: 10.1515/hf-2014-0185
Baensch, F.; Zauner, M.; Sanabria, S.J.; Sause, M.G.R.; Pinzer, B.R.; Brunner, A.J.; Stampanoni, M.; Niemz, P. Damage evolution in wood: Synchrotron radiation micro-computed tomography (SRőľCT) as a complementary tool for interpreting acoustic emission (AE) behavior. Holzforschung 69 (2015) 8, 1015-1025
Baensch, F.; Cordes, D.; Melcher, E.; Pfriem, A.: Accelerated weathering tests on thermally modified and wax-impregnated wood, 11th annual meeting of the Nordic Baltic Network in Wood Material Science & Engineering (WSE), Poznan, Poland. 14-15.09.2015
Zauer, M.; Hempel, S.; Pfriem, A.; Mechtcherine, V.; Wagenf√ľhr, A.: Investigations of the pore-size distribution of wood in the dry and wet state by means of mercury intrusion porosimetry. Wood Science and Technology. 48 (2014) 6, S. 1229-1240; DOI: 10.1007/s00226-014-0671-y
Clauder, L.; Pfriem, A.: Comparative durability tests on TMT Beech ‚Äď preliminary results. 10th meeting of the Nordic Baltic Network in Wood Material Science & Engineering (WSE), Edinburgh, Scotland, 13.-14.10.2014
Clauder, L.; Pfriem, A.: Qualit√§tssicherung ‚ÄďVorhersagbarkeit der Dauerhaftigkeit von TMT. 8. Europ√§ischer Thermoholz Workshop, 22.-23.05.2014, Dresden
Clauder; L., Pfriem, A.: Comparative durability tests on TMT Beech ‚Äď preliminary results. Final Cost Action FP0904 Conference ‚ÄúRecent Advances in the Field of TH and THM Wood Treatment‚ÄĚ 19.-21.05.2014, Skellefte√•, Sweden
Clauder, L.; Pfriem, A.: Emissions from thermally modified wood. Final Cost Action FP0904 Conference ‚ÄúRecent Advances in the Field of TH and THM Wood Treatment‚ÄĚ 19.-21.05.2014, Skellefte√•, Sweden
Br√∂sel, L.; Clauder, L.; Pfriem, A.: Flammability tests on thermally modified and untreated timbers. Final Cost Action FP0904 Conference ‚ÄúRecent Advances in the Field of TH and THM Wood Treatment‚ÄĚ 19.-21.05.2014, Skellefte√•, Sweden
Br√∂sel L., Pfriem, A., Clauder, L.: Nachweis gef√ľhrt ‚Äď Brandschutzklasse 1. Bauen mit Holz, 05 (2014), S. 38-40
Shchupakivskyy, R.; Pfriem, A.; Clauder, L.: Statistical simulation of wood density changes due to thermal treatment. 7th European Conference on Wood Modification, Lissabon, Portugal, 10.-12.03.2014
Pfriem, A.; Clauder, L.; Linke, N.; Shchupakivskyy, R.: Application of high-frequency densitometry to detect changes in early- and latewood density of oak (Quercus robur L.) due to thermal modification. 7th European Conference on Wood Modification, Lissabon, Portugal, 10.-12.03.2014
Zauer, M.; Kretzschmar, J.; Gro√ümann, L.; Pfriem, A.; Wagenf√ľhr, A.: Analysis of the pore-size distribution and fiber saturation point of native and thermally modified wood using differential scanning calorimetry. Wood Science and Technology, 48 (2014) 1, S. 177‚Äď193; DOI 10.1007/s00226-013-0597-9
Shchupakivskyy, R.; Clauder, L.; Linke, N.; Pfriem, A.: Application of high-frequency densitometry to detect changes in early- and latewood density of Oak (Quercus robur L.) due to thermal modification. European Journal of Wood and Wood Products, 72 (2014) 1, S. 5-10 DOI:10.1007/s00107-013-0744-x
Zauer, M.; Pfriem, A.; Wagenf√ľhr, A.: Toward improved understanding of the cell-wall density and porosity of native and thermally modified wood determined by gas pycnometry. Wood Science and Technology, 47 (2013) 6, S. 1197-1211, DOI:10.1007/s00226-013-0568-1
Maksymiv, V.; Pfriem, A.; Shchupakivskyy, R.; Clauder, L.; Kijko, O.; Andrashek, J.: Statistical simulation of wood density changes due to thermal treatment. XXI. Symposium Adhesives in Woodworking Industry, Zvolen, Slovakia, 26.-28.06.2013
Clauder, L.; Richter S.; Unger, W.; Pfriem. A.: Application of a model for the prediction of fungal degradation of thermally modified timber by Trametes versicolor. International Research Group on Wood Protection 44rd Annual Meeting, Stockholm, Sweden, 16.-20.06. 2013
Pfriem, A.; Clauder, L.; Linke, N.; Shchupakivskyy, R.: Anwendung der Hochfrequenz-Dichtemessung zur Erfassung der lokalen Dichte√§nderung von Eichenholz infolge einer thermischen Modifikation. Holztechnologie, 54 (2013) 3, S. 30-34
Clauder, L.; Pfriem, A.: Determination of dimensional stability of thermally modified beech and spruce wood. COST Action FP0904 Workshop ‚ÄúEvaluation, processing and predicting of THM treated wood behaviour by experimental and numerical methods‚ÄĚ, Iasi, Romania, 09.-11. April 2013
Pfriem, A.: Holzkundliche Untersuchungen zu Ver√§nderungen im Holz w√§hrend der thermischen Modifizierung ‚Äď Application of High-Frequency Densitometry to detect Changes in Early- and Latewood Density of Oak (Quercus robur L.) due to Thermal Modification. 2. Dresdner Holzanatomisches Kolloquium, Dresden, 18.-19.10.2012
Zauer, M.; Pfriem, A.; Wagenf√ľhr, A.: Alteration of the pore structure and the capillarity of wood due to thermal modification. 6th European Conference on Wood Modification, Ljubljana, Slowenien, 16.-18.09.2012
Clauder, L.; Shchupakivskyy, R.; Pfriem, A.: Application of High-Frequency Densitometry to detect the change in Early- and Latewood Density of Oak (Quercus Robur L.) due to thermal treatment. 8th meeting of the Nordic Baltic Network in Wood Material Science & Engineering (WSE), Kaunas, Litauen, 13.-14.09.2012
Clauder, L.: Guideline for Environmental Product Declaration for Thermally Modified Timber. International Research Group on Wood Protection. 43rd Annual Meeting, Kuala Lumpur, Malaysia, 6.-10.05.2012
Zauer, M.; Pfriem, A.; Wagenf√ľhr, A.: Alteration of the pore structure and the capillarity of wood due to thermal modification. COST Action FP0904 Workshop ‚ÄúCurrent and Future Trends of Thermo-Hydro-Mechanical Modification of Wood Opportunities for new markets? Nancy, France, 26.-28.03.2012
Pfriem, A.: Alteration of Water Absorption Coefficient of Spruce (Picea abies (L.) Karst.) due to Thermal Modification. DRVNA INDUSTRIJA 62 (2011) 4, 311-313, DOI:10.5552/drind.2011.1109
‚Äč‚Äč‚Äč‚Äč‚Äč‚Äč‚ÄčHerold, N.; Peters, J.; Zauer, M.; Fischer, S.; Pfriem, A.: Improving of the mechanical properties of thermally modified wood by a prior chemical treatment. COST Action FP0904 Workshop ‚ÄúHierarchical structure and mechanical characterization of wood‚ÄĚ Helsinki, Finnland, 24.-26.08.2011, Link zur Pr√§sentation