Electron Microscopy Study of Hardboards

Authors

  • Lidija Murmanis
  • John A. Youngquist
  • Gary C. Myers

Keywords:

Hardboards, wet-formed, dry-formed, structure, resin distribution, electron microscopy

Abstract

Wet-formed and dry-formed aspen fiber hardboards are examined by transmission electron microscopy to obtain information on the hardboard internal structure and fiber-resin interactions. These factors, when related to strength and dimensional properties of hardboards, may be helpful in determining hardboard quality and suitability for structural use.

During hardboard manufacturing, the wood cells break apart at the middle lamella and come in contact again when subjected to pressure during hot-pressing. Occasionally fibers remain attached in bundles. Various stages of middle lamella degradation can be observed. When totally disintegrated, middle lamella appears as dark granular material. Voids of variable size exist in medium- and high-density wet- and dry-formed hardboards. In wet-formed boards the resin (which has high electron opaqueness and appears black) shows even distribution. In dry-formed boards the resin shows uneven distribution; it is present as large accumulations in some areas but absent in others.

References

American Society for Testing and Materials. 1978. Standard methods for evaluating the properties of wood-based fiber and particle panel materials. ASTM D 1037-78, Philadelphia, PA.nKruse, J., and N. Parameswaran. 1978. Mikrotechnologische Untersuchungen an Rindenplatten. Holz Roh- Werkst. 36:225-233.nMollenhauer, H. H. 1964. Plastic embedding mixtures for use in electron microscopy. Stain Technol. 39:111-114.nMyers, G. C., and J. B. Crist. Feasibility of manufacturing hardboard from short rotation intensively cultured Populus. (In preparation)nParameswaran, N., and M. Himmelreich. 1979. Mikrotechnologische Untersuchungen an Sulfit-ablauge-gebundenen Holzwerkstoffen. Holz Roh-Werkst. 37:57-64.n

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Published

2007-06-28

Issue

Number 3 / July 1986

Section

Research Contributions

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