Advertisement

Holz als Roh- und Werkstoff

, Volume 63, Issue 2, pp 102–111 | Cite as

Chemical changes in hydrothermal treated wood: FTIR analysis of combined hydrothermal and dry heat-treated wood

  • B. F. TjeerdsmaEmail author
  • H. Militz
Originalarbeiten/Originals

Abstract

Wood specimens of Beech (Fagus silvatica L.) and Scots pine (Pinus sylvestris L.) modified by a hydrothermal treatment process were analysed by means of Fourier transform infra red spectroscopy (FTIR). The chemical transformation of the cell-wall material was studied and associated with improved wood qualities. For this purpose, FTIR spectroscopy was used as since this technique has been found appropriate to determine the intensity of specific bonds and functional groups within the polymeric structure. Cleavage of acetyl groups of the hemicellulose has been found to occur in the first treatment step under moist conditions and elevated temperature. This results in the formation of carbonic acids, mainly acetic acid. Most of the acetyl groups were found to be cleaved during the treatment of wood at high temperature, whereas only partial deacetylation was found to occur at moderate treatment temperature. The concentration of accessible hydroxyl groups was measured by acetylation and found reduced after treating at high temperature. Esterification reactions were found to occur under dry conditions at elevated temperature in the curing step, indicated by the increase of the specific ester carbonyl peak at 1740 cm−1 in the FTIR spectrum. The esters that were formed turned out to be mainly linked to the lignin complex, considering that the newly formed carbonyl groups were found present in heat-treated wood, yet were found to be absent in the isolated holocellulose. Esterification contributes to a decrease of hygroscopicity of wood and consequently improvements of its dimensional stability and durability. However, the role of esterification in the decrease of hygroscopicity in the hydrothermal treatment process examined is believed to be minor compared to the influence of cross-linking reactions known to occur during thermal treatment of wood.

Keywords

Hemicellulose Thermolysis Esterification Reaction Wood Specimen Beech Wood 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Veränderungen der Zellwandchemie hydrothermisch behandelten Holzes

Zusammenfassung

Das Holz hydrothermisch modifizierten Buchen- und Kiefernholzes wurde mit FTIR Spektroskopie untersucht. Die chemischen Veränderungen wurden mit dem Hintergrund veränderter Holzeigenschaften diskutiert. Abspaltungen von Acetylgruppen der Hemicellulosen finden vor allem bereits im ersten Prozessschritt unter feuchten Bedingungen und bei erhöhten Temperaturen statt. Dieses führt zur Bildung von Essigsäure und anderen Carbonsäuren. Bei niedrigeren Temperaturen werden weniger Carbonsäuren freigesetzt. Durch Acetylierung wurde der Gehalt an freien Hydroxylgruppen bestimmt. Durch die Hitzebehandlung reduziert sich der Gehalt freier Hydroyxlgruppen. Die Zunahme des Carbonylesterpeaks bei 1740 cm−1 im FTIR Spektrum lässt sich durch Veresterungsreaktionen im heißen aber trocknen Curingschritt erklären. Diese Ester sind vor allem an den Ligninkomplex gebunden und weniger an die Holocellulose. Durch Veresterungen wird ein hygroskopisches, dimensionsstabiles und dauerhaftes Material geschaffen. Die Veränderung der Materialeigenschaften beruht jedoch vor allem auch auf cross-linking Reaktionen die während des Prozesses ablaufen.

Notes

Acknowledgements

The authors would like to thank Karel van der Heijden, Clarine Sieger and Bas Holleboom for their experimental assistance.

References

  1. Bobleter O, Binder H (1980) Dynamischer hydrothermaler Abbau von Holz. Holzforschung 34:48–51Google Scholar
  2. Boonstra MJ, Tjeerdsma BF, Groeneveld HAC (1998) Thermal modification of non-durable wood species. 1. The PLATO technology: thermal modification of wood. International Research Group on Wood Preservation, Document no. IRG/WP 98-40123Google Scholar
  3. Bourgois J, Guyonnet R (1988) Characterization and analysis of torrified wood. Wood Sci Technol 22:143–155Google Scholar
  4. Browning BL (1967) Methods of wood chemistry. John Wiley Sons, Inc., New York, 882p.Google Scholar
  5. Burmester A (1973) Einfluß einer Wärme-Druck-Behandlung halbtrockenen Holzes auf seine Form-beständigkeit. Holz Roh- Werkstoff 31:237–243Google Scholar
  6. Burmester A (1975) Zur Dimensionsstabilisierung von Holz. Holz Roh- Werkstoff 33:333–335Google Scholar
  7. Burmester A, Wille WE (1976) Quellungsverminderung von Holz in Teilbereichen der relativen Luft-feuchtigkeit. Holz Roh- Werkstoff 34:87–90Google Scholar
  8. Burtscher E, Bobleter O, Schwald W, Concin R, Binder H (1987) Chromatographic analysis of biomass reaction products produced by hydrothermolysis of Poplar wood. J Chrom 390:401–412CrossRefGoogle Scholar
  9. Carrasco F, Roy C (1992) Kinetic study of dilute-acid prehydrolysis of xylan-containing biomass. Wood Sci Technol 26:189–208Google Scholar
  10. Davids WH, Thompson WS (1964) Influence of thermal treatments of short duration on the toughness and chemical composition of wood. Forest Prod J 8:350–356 Google Scholar
  11. Dietrichs HH, Sinner H, Puls J (1978) potential of steaming hardwoods and straw for feed and food production. Holzforschung 32:193–199Google Scholar
  12. Dwianto W, Tanaka F, Inoue M, Norimoto M (1996) Crystallinity changes of wood by heat or steam treatment. Wood Research 83:47–49Google Scholar
  13. Ellis S, Paszner L (1994) Activated selfbonding of wood and agricultural residues. Holzforschung 48:82–90Google Scholar
  14. Faix O (1988) Practical uses of FTIR spectroscopy in wood science and technology. Mikrochimica Acta 1:21–25Google Scholar
  15. Faix O, Böttcher JH (1992) The influence of particle size and concentration in transmission and diffuse reflectance spectroscopy of wood. Holz Roh- Werkstoff 50:221–226Google Scholar
  16. Fengel D, Wegener G (1989) Wood: chemistry, ultrastructure, reactions. W de Gruyter, Berlin, 613pGoogle Scholar
  17. Giebeler E (1983) Dimensionsstabilisierung von Holz durch eine Feuchte/Wärme/Druck-Behandlung. Holz Roh- Werkstoff 41:87–94Google Scholar
  18. Goyal GC, Lora JH (1991) Kinetics of delignification and lignin characteristics in autocatalyzed organosolv pulping of hardwoods. Proc Int Symp Wood Pulp Chem Melbourne, Australia 1:205–212 Google Scholar
  19. Hillis WE (1984) High temperature and chemical effects on wood stability. Wood Sci Technol 18:281–293Google Scholar
  20. Kaar WE, Cool LG, Merriman MM, Brink DL (1991) The complete analysis of wood polysaccharides using HPLC. J Wood Chem Technol 11:447–463Google Scholar
  21. Klauditz W, Stegmann G (1955) Beiträge zur Kenntnis des Ablaufes und der Wirkung thermischer Reaktionen bei der Bildung von Holzwerkstoffen. Holz Roh-Werkstoff 13:434–440Google Scholar
  22. Kollmann F (1963) Über das Sorptionsverhalten wärmebehandelter Hölzer. Holz Roh- Werkstoff 21:77–85Google Scholar
  23. Kollmann F, Fengel D (1965) Änderungen der chemischen Zusamensetzung von Holz durch thermische Behandlung. Holz Roh- Werkstoff 23:461–468Google Scholar
  24. Kollmann F, Schneider A (1963) Über das Sorptionsverhalten wärmebehandelter Hölzer. Holz Roh- Werkstoff 21:77–85Google Scholar
  25. Militz H (2002) Heat treatment technologies in Europe: Scientific background and technological state of art. In: Enhancing the durability of lumber and engineered wood products, FPS/Madison US, Conference, Florida 11–13, February 2002Google Scholar
  26. Militz H, Beckers EPJ, Homan WJ (1997) Modification of solid wood: research and practical potential, International Research Group on Wood Preservation, Document no. IRG/WP 97-40098Google Scholar
  27. Noack D (1969) Über die Heißwasserbehandlung von Rotbuchenholz im Temperaturbereich von 100 bis 180 °C. Holzforschung Holzverwertung 21:118–124Google Scholar
  28. Rowell RM (1984) The chemistry of solid wood. American Chemical Society, Washington D.C., 614p.Google Scholar
  29. Rowell RM, Tillman AM, Simonson R (1986) A simplied procedure for the acetylation of hardwood and softwood flakes for flakeboard production. J Wood Chem Technol 6:427–448 Google Scholar
  30. Runkel ROH (1951) Zur Kenntnis des thermoplastischen Verhaltens von Holz. Holz Roh- Werkstoff 9:41–53Google Scholar
  31. Runkel ROH, Witt H (1953) Zur Kenntnis des thermoplastischen Verhaltens von Holz. Holz Roh- Werkstoff 11:457–461Google Scholar
  32. Ruyter HP (1989) European patent Appl. No. 89-203170.9Google Scholar
  33. Seborg RM, Tarkow H, Stamm AJ (1953) Effect of heat upon the dimensional stabilisation of wood. J For Prod Res Soc 3:59–67Google Scholar
  34. Sjöström E (1981) Wood chemistry: fundamentals and applications. Academic Press, Inc. San Diego, 293p.Google Scholar
  35. Stamm AJ (1956) Thermal degradation of wood and cellulose. Ind Eng Chem 48:413–417Google Scholar
  36. Tjeerdsma BF, Boonstra M, Pizzi A, Tekely P, Militz H (1998a) Characterisation of thermal modified wood: molecular reasons for wood performance improvement. CP-MAS 13C NMR characterisation of thermal modified wood. Holz Roh- Werkstoff. 56:149–153Google Scholar
  37. Tjeerdsma BF, Boonstra M, Militz H (1998b) Thermal modification of non-durable wood species. 2. Improved wood properties of thermally treated wood. International Research Group on Wood Preservation, Document no. IRG/WP 98-40124Google Scholar
  38. Tjeerdsma BF, Stevens M, Militz H (2000) Durability aspects of hydrothermal treated wood. International Research Group on Wood Preservation, Document no. IRG/WP 00-4Google Scholar
  39. Wise LE, Murphy M, D’Addieco AA (1946) Pap Trade J 122(2):35–43Google Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Foundation for Timber Research SHRWageningenThe Netherlands
  2. 2.Wood Biology and Wood TechnologyUniversity GöttingenGöttingenGermany

Personalised recommendations