A Study of Wool's Tensile Strength in Early Stage Processing

Abstract

The tensile strength of wool during pre-spinning processing is examined in this paper. Both single fiber breaking load and fiber bundle strength are studied. The results confirm that carding causes more fiber damage or strength loss than other processes examined. The breaking load of fibers in combed sliver may be significantly higher than that in carded sliver, because combing breaks weak fibers damaged in carding and increases the average fiber diameter in combed sliver by removing some fine fibers. An attempt is made to generate an ideal bundle strength profile from single fiber tensile curves. Compared with the tensile curve of the ideal fiber bundle, the tensile curve of an actual wool bundle shows a relatively higher elongation and lower tenacity, probably due to the between-fiber interactions and relatively poorer fiber orientation in the actual wool bundle. A method of minimizing fiber interaction during bundle strength testing is proposed.

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References

Aldrich, D.V. , Kruger, P.J. , and Turpie, D.W.F. , The Carding and Combing of Wools of Different Fiber Lengths, SAWTRI Technical Report no. 136, June 1970.

ASTM standard, D2524-91 : Breaking Tenacity of Wool Fibers, Flat Bundle Method—1/8-in. (3.2-mm) Gauge Length, D 1294-86: Breaking Tenacity, and Tensile Strength of Wool Fibre Bundles—1-in. (25.4-mm) Gauge Length, Annual Book of ASTM Standards, V.07(02), 1993.

Coleman, B.D. , On the Strength of Classical Fibers and Fiber Bundles, J. Mech. Phys. Solids 7, 60-70 (1958).

Gharehaghaji, A. , and Johnson, N.A.G. , Wool Fibre Microdamage Caused by Opening Processes, Part 2: A Study of the Contact Between Opening Elements and Wool Fibre in Controlled Extension, J. Textile Inst. 86, 402-414 ( 1995).

Harrowfield, B.V. , Early Stage Worsted Processing— From Scoured Wool to Top, Wool Sci. Rev. 68, 44-80 ( 1987).

Hearle, J.W.S. , Can Genetic Engineering Enhance the Miracle of Wool? Part 3: Why Worry About Fibre Strength?, Textile Horiz., August/September, 12-16 (1997).

Oxtoby, E. , "Spun Yarn Technology," Butterworths & Co Ltd ., London, 1987.

Smuts, S. , Hunter, L. , and van Rensburg, H.L.J. , Some Typical Single Fibre Tensile Properties for Wools Produced in South Africa, SAWTRI Technical Report, No. 482, September 1981 a.

Smuts, S. , Hunter, L. , and van Rensburg, H.L.J. , The Effect of Fibre Diameter and Crimp on Some Single Fibre Tensile Properties of Wool, SAWTRI Technical Report, no. 485, 1981b.

10.

Wang, L.J. , and Wang, X. , The Diameter and Strength Distributions of Merino Wool in Early Stage Processing, Textile Res. J. 68 (2), 87-93 (1998).

11.

Wang, X. , and Wang, L.J. , Investigation of Combing Forces, Part V: Fiber Tension during Top Combing , J. Textile Inst., 89 (Part 1) (1), 155-166 (1998).

12.

Wang, X. , and Johnson, N.A.G. , Investigation of Combing Forces, Part I: Fibre Tension, J. Textile Inst. 82, 399-408 (1991).

13.

Yan, Y. , and Johnson, N.A.G. , The Behaviour of Fibers Struck by High-speed Pins, Part I: Theory, J. Textile Inst. 83, 1-24 (1992).