Abstract
Fibres (tracheids) of spruce (Picea abies [L.] Karst.) were isolated by means of two isolation techniques. On the one hand, a soft chemical treatment with Jeffrey solution was used. The isolation was carried out with a reduced time of treatment (2 h), just to achieve the state where the fibres could be separated easily with tweezers. On the other hand, fibres were directly peeled out with tweezers, taking advantage of the low shear strength between them. Following this approach, a chemical treatment could be avoided completely. In order to compare the isolation techniques, single tracheids from tissue types with different microfibril angle (earlywood, latewood, juvenile wood, opposite wood, compression wood) were tested in the dry state. The microfibril angles were determined by X-ray diffraction. Single tracheids handled with both isolation techniques were strained in microtensile tests and load-strain diagrams were obtained. The chemically treated fibres were found to have much lower strength and stiffness compared to the mechanically isolated fibres, even though the influence of microfibril angle was still obvious for both kinds of treatment. The results clearly show the importance of single fibre extraction to preserve as much as possible the original properties.
Key words
Chemical maceration - mechanical isolation - single fibres - tensile tests - microfibril angle - spruce
References
-
01 Niklas, K. J.. (1992) Plant biomechanics. Chicago; Chicago Univ. Press 607 p.
-
02
Jayne, B. A..
(1960);
Some mechanical properties of wood fibres in tension.
Forest Products Journal.
10
316-322
-
03
Schniewind, A. P..
(1966);
Über Unterschiede in der Zugfestigkeit von Früh- und Spätholztracheiden.
Holz Roh- Werkst..
24
502-506
-
04
Page, D. H.,, El-Hosseiny, F.,, and Winkler, K..
(1971);
Behaviour of single wood fibres under axial tensile strain.
Nature.
229
252-253
-
05
Mott, L.,, Shaler, S. M.,, Groom, L. H.,, and Liang, B.-H..
(1995);
The tensile testing of individual fibres using environmental scanning electron microscopy and video image analysis.
Tappi.
78
143-148
-
06
Reiterer, A.,, Jakob, H. F.,, Stanzl-Tschegg, S. E.,, and Fratzl, P..
(1998);
Spiral angle of elementary cellulose fibrils in cell walls of Picea abies determined by small-angle X-ray scattering.
Wood Sci. Technol..
32
335-345
-
07 Lichtenegger, H.,, Reiterer, A.,, Tschegg, S. E.,, and Fratzl, P.. (1998) Determination of spiral angles of elementary fibrils in the wood cell wall: comparison of small-angle x-ray scattering and wide-angle X-ray diffraction. Microfibril angle in wood. Butterfield, B., ed. New Zealand; Christchurch, University of Canterbury pp. 140-156
-
08 Gerlach, D.. (1969) Botanische Mikrotechnik. Stuttgart; Thieme Verlag
-
09 Kersavage, P. C.. (1962) The effect of some chemical methods of fiber preparation on the tensile strength of Douglas fir fibers. Berkeley, California; M.S. Thesis, University of California
-
10 Groom, L. H.,, Shaler, S. M.,, and Mott, L.. (1995) The mechanical properties of individual lignocellulosic fibers. Proceedings of the Forest Products Society, No. 7293. Madison, Wisconsin; Woodfiber-plastic composites pp. 33-40
-
11 Shaler, S. M.,, Groom, L. H.,, and Mott, L.. (1995) Microscopic analysis of wood fibers using ESEM and confocal microscopy. Proceedings of the Forest Products Society, No. 7293. Madison, Wisconsin; Woodfiber-plastic composites pp. 25-32
-
12 Perez, L.,, Pittet, V.,, and Navi, P.. (2000) Fibre behaviour under tensile force, experimentation and modelling. Proceedings of the Int. Conf. Wood and Wood Fiber Composites. Aicher, S., ed. Stuttgart; Otto-Graf-Institut, Universität Stuttgart pp. 47-58
-
13
Page, D. H., and El-Hosseiny, F..
(1983);
The mechanical properties of single wood pulp fibres. Part VI. Fibril angle and the shape of the stress-strain curve.
Journal of Pulp and Paper Science.
9
1-2
I. Burgert
Institute of Meteorology and Physics
University of Agricultural Sciences
Vienna
Austria
Email: ingo.burgert@mail.boku.ac.at
Section Editor: A. M. C. Emons
