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Holz als Roh- und Werkstoff

, Volume 52, Issue 2, pp 83–86 | Cite as

A study of strength, hardness and deformation of acetylated Scandinavian softwoods

  • P. Larsson
  • R. Simonson
Originals

Abstract

In this work, properties such as bending strength (expressed as modulus of rupture and modulus of elasticity), hardness, and deformation under cyclic relative humidity have been studied for acetylated Scandinavian pine and spruce. The acetylation was performed with a limited amount of liquid acetic anhydride without addition of catalyst or organic cosolvent. The weight gain due to acetylation was 19.1% for the pine samples. Two kinds of spruce samples were acetylated to 18.2% (narrow annual rings) and 23.3% (broad annual rings), respectively. The results indicated that only small changes in strength were obtained. For pine, modulus of rupture decreased with about 6%, and increased with about 7% for spruce. The modulus of elasticity also decreased for pine but increased for spruce. For practical applications, these properties can be considered unaltered. Acetylated pine wood showed increased Brinell hardness. Acetylated spruce wood did not tend to deform as much as unmodified wood when exposed to moisture cycled between 40 and 90% relative humidity

Keywords

Acetic Anhydride Annual Ring Weight Percent Gain Beech Wood Brinell Hardness 
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.

Festigkeit, Härte und Verformung von acetyliertem skandinavischem Kiefern- und Fichtenholz

Zusammenfassung

An acetylierten Proben von skandinavischem Kiefern-und Fichtenholz wurden mechanische Eigenschaften (MOE, MOR), Härte und Verformung unter zyklischen Feuchtebedingungen gemessen. Die Acetylierung erfolgte mit reduziertem Anteil an flüssigem Acetanhydrid und ohne Zugabe eines Katalysators oder anderer organischer Lösemittel. Der Gewichtszuwachs betrug bei Kiefernholz 19,1%, bei Fichtenproben 18,2% (enge Jahrringe) bzw. 23,3% (weite Jahrringe). Nur geringfügige Veränderungen der Festigkeitswerte wurden beobachtet. Die MOR-Werte fielen bei Kiefernholz um 6% ab; bei Fichtenholz stiegen sie um 7%. Die MOE-Werte verhielten sich ähnlich. Für praktische Zwecke kann man die mechanischen Eigenschaften als unverändert ansehen. Die Brinellhärte des Kiefernholzes stieg nach der Acetylierung an. Die Verformungstendenzen unter zyklischem Wechselklima (40/90) wurden durch die Behandlung verringert.

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References

  1. Dreher, W. A.; Goldstein, I. S.; Cramer, G. R. 1964: Mechanical properties of acetylated wood. For. Prod. J. 14:66–68Google Scholar
  2. Goldstein, I. S.; Jeroski, E. B.; Lund, A. E.; Nielson, J. F.; Weaver, J. W. 19961: Acetylation of wood in lumber thickness. For. Prod. J. 8:363–370Google Scholar
  3. Kollman, F. F. P.; Coté, W. A. Jr. (ed.) 1968: Principles of Wood Science and Technology. I. Solid Wood, Springer Verlag, Berlin-New York: Chapter 7Google Scholar
  4. Militz, H.: Improvements of stability and durability of beechwood (Fagus sylvatica) by means of treatment with acetic anhydride. Int. Research group on wood preservation, 22nd Annual Meeting, Kyoto, Japan, Document No: WP 3645Google Scholar
  5. Nilsson, T.; Rowell, R. M.; Simonson, R.; Tillman, A. M. 1988: Fungal Resistance of Pine Particle Boards Made from various Types of Acetylated Chips. Holzforschung. 42(2):123–126CrossRefGoogle Scholar
  6. Rowell, R. M. (ed.) 1984). The Chemistry of Solid Wood. Advances in Chemistry Series No.207, American Chemical Society, Washington, D.C. Chapter 5Google Scholar
  7. Rowell, R. M.; Simonson, R.; Tillman, A. M. 1986a: A Simplified Procedure for the Acetylation of Hardwood and Softwood Flakes for Flakeboard Production. J. Wood Chem. Techn. 6(3):427–448.Google Scholar
  8. Rowell, R. M.; Simonson, R.; Tillman, A.M. 1986b: A Simplified Procedure for the Acetylation of Chips for Dimensionally Stabilized Particleboard Products. Paperi ja Puu. 68(10):740–744Google Scholar
  9. Wood Handbook 1987: Wood as an engineering material. U.S. Department of Agriculture, Forest Service, USDA Agriculture Handbook. 72; Washington, D.C. Chapter 4Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • P. Larsson
    • 1
  • R. Simonson
    • 1
  1. 1.Department of Forest Products and Chemical EngineeringChalmers University of TechnologyGöteborgSweden

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