Rheological Properties of Chemically Modified Wood: Relationship Between Dimensional and Creep Stability

Authors

  • Misato Norimoto
  • Joseph Gril
  • Roger M. Rowell

Keywords:

Rheology, creep, dimensional stability, chemical modification

Abstract

A typology of chemical modifications of wood based on the interaction of water with the molecular constituents of the lignocellulosic material is proposed. The model accounts for both the moisture expansion and the so-called mechanosorptive creep induced by moisture changes under load. Anti-creep efficiency (ACE) values were obtained for wood specimens modified with fourteen different types of chemical treatments and subjected to a 4-day creep-recovery test under cyclic humidity conditions. The relationship between dimensional stability, as measured by anti-swelling efficiency (ASE), and ACE was determined for the different treatments. Treatments such as polyethylene glycol impregnation or etherification with epoxides, in which the hydrophilic nature of the bulking agent is not counter-balanced by crosslinking, yielded high ASE values but increased mechanosorptive creep instead of reducing it.

References

Armstrong, L. D., and R. S. T. Kingston. 1960. Effect of moisture changes on creep in wood. Nature 185(4716): 862-863.nGril, J. 1988. A modelling of the hygro-rheological behavior of wood based on its micro-structure. June 1988. Ph.D. dissertation, University of Paris, France.nGrossman, P. U. A. 1976. Model for mechano-sorptive behaviour. Wood Sci. Technol. 10:165-168.nNorimoto, M., and J. Gril. 1989. Wood bending using microwave heating. J. Microwave Power Electromag. Energy 24(4):203-212.nNorimoto, M., J. Gril., T. Sasaki, and R. M. Rowell. 1988. Improvement of acoustical properties through chemical modifications. Pages 37-44 in European colloquium on mechanical behavior of wood, Bordeaux, France, June 8-9, 1988.nNorimoto, M., J. Gril., K. Minato, K. Okamura, J. Mukudai, and R. M. Rowell. 1987. Suppression of creep of wood under humidity changes through chemical modification. Mokuzai Kogyo (Wood Industry). 42:504-508.nRowell, R. M., and W. B. Banks. 1985. Water repellency and dimensional stability of wood. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, General Technical Report FPL 50. Madison, WI. 24 pp.n

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Published

2007-06-28

Issue

Number 1 / January 1992

Section

Research Contributions

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