The tensile modulus of Lincoln wool fibers immersed in a range of neutral salt solutions has been investigated as a function of time and solution concentration. Salt solutions with high water activity, reduced ionic strength, and low viscosity will lead to favorable conditions for the penetration of ions into the fibers. The reduction in tensile modulus when salts penetrate wool fibers can be fully accounted for by the increased regain and associated swelling of the fibers. It appears unlikely that the breaking of salt links or destabilization of the α-helices plays a significant role in reducing the tensile properties of wool fibers in neutral salt solutions.
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References
1.
Baddiel, C.B. , Structure and Reactions of Human Hair Keratin: Analysis by Infrared Spectroscopy, J. Mol. Biol.38, 181-199 (1968).
2.
Baddiel, C.B. , and Park, A.C., TheContribution of Salt Links to the Longitudinal Strength of Single Hair Fibres , J. Textile Inst.65, 146-148 (1974).
3.
Baddiel, C.B. , Bennett, A., and Park, A.C., Changes in the Elastic Modulus of Single Hair Fibres Arising from their Exposure to Saturated Electrolyte Solutions , J. Textile Inst.66, 55-61 ( 1975 ).
4.
Bronsted, J.N. , Solubility of Salts and of Strong Acids and Bases in Water, in "International Critical Tables of Numerical Data Physics, Chemistry and Technology," vol. IV, E. W. Washburn, Ed., McGraw-Hill Book Co., London, 1928 , pp. 216-249.
5.
Corbet, M.J. , and Yu, T.M., Orthocortical Staining of Wool with Chromic, Cobaltous, Cupric, Ferric, or Manganous Ions in Acidic Nitrite Solution, Textile Res. J.34, 655 (1964).
6.
Delminico, J. , and Peters, R.H., Application of the Donnan Equilibrium to the Distribution of Dye and Inorganic Ions Between Wool and Solutions, Part I: Inorganic Ions, Textile Res. J.34, 207-219 ( 1964).
7.
Deutz, H., Thermische und Mikroskopische Charakterisierung von Keratinen, Doctoral Thesis, Rheinisch-Westfalischen Technischen Hochschule , Aachen, 1993.
8.
Erlander, S.R. , Explanation of Ionic Sequences in Various Phenomena, III: Salting-in and -out of Amino Acids, J. Macromol. Sci. Chem. Ed. A2, 1181-1193 ( 1968 ).
9.
Feughelman, M. , TheMechanical Properties of Set Wool Fibers and the Structure of Keratin , J. Textile Inst.51, T589-T602 ( 1960).
10.
Feughelman, M., and Robinson, M.S., TheRelationship Between Some Mechanical Properties of Single Wool Fibers and Relative Humidity, Textile Res. J.37, 441-446 (1967).
11.
Feughelman, M., and Robinson, M.S., SomeMechanical Properties of Wool Fibers in the "Hookean" Region from Zero to 100% Relative Humidity, Textile Res. J.41, 469-474 (1971).
12.
Feughelman, M., Mechanical Hysteresis in Wool Keratin Fibers , J. Macromol. Sci. Phys. Ed. B7, 569-582 (1973).
13.
Glasstone, S. , "Textbook of Physical Chemistry," 2nd ed., Macmillan, London, 1948, p. 1254.
14.
Greenberg, D.M. , The Interaction between the Alkali Earth Cations, Particularly Calcium, and Proteins, in "Advances in Protein Chemistry," vol. 1, Academic Press, NY, 1944, pp. 121-151.
15.
Haly, A.R., and Feughelman, M., Physical Properties of Wool Fibers at Various Regains, Part II: Recovery from Extension, Textile Res. J.31, 135-140 ( 1961 ).
16.
Haly, A.R., and Snaith, J.W., Differential Thermal Analysis of Wool—The Phase-Transition Endotherm Under Various Conditions, Textile Res. J.37, 898-907 ( 1967).
17.
Jurdana, L.E. , Ghiggino, K.P., Leaver , I.H., Barraclough, C.G., and Cole-Clarke , P., Depth Profile Analysis of Keratin Fibers by FT-IR Photoacoustic Spectroscopy , Appl. Spectrosc.48, 44-49 ( 1994).
18.
Kracek, F.C. , P-T-X Relations for Systems of Two or More Components and Containing Two or More Phases, in "International Critical Tables of Numerical Data Physics, Chemistry and Technology," Vol. III, E. W. Washburn, Ed., McGraw-Hill Book Co., London, 1928 , pp. 351-385.
Rodriguez, F. , "Principles of Polymer Systems." McGraw-Hill, London, 1970, p. 158.
27.
Sookne, A.M. , and Harris, M., Stress-Strain Characteristics of Wool as Related to its Chemical Constitution, J. Res. Natl. Bur. Stand.19, 535-549 (1937).
28.
Speakman, J.B. , and Cooper, C.A., TheAdsorption of Water by Wool, Part III: The Influence of Temperature on the Affinity of Wool for Water, J. Textile Inst.27, T191-T196 (1936).
29.
Speakman, J.B. , and Whewell, E.. TheAction of Potassium Chloride on Keratin , J. Text. Inst.41, T329-T330 ( 1950).
30.
Steele, R., Recent Developments in the Structure of Keratin Fibers, J. Soc. Cos. Chem.3, 99-107 (1952).
31.
Swift, J.A., The Histology of Keratin Fibres, in "Chemistry of Natural Protein Fibers," R. S. Asquith, Ed., Plenum, NY, 1977, pp. 81-146.
32.
Tanford, C., "Physical Chemistry of Macromolecules," John Wiley , London, 1961, p. 243.
33.
Warburton, F.L., A Direct Measurement of the Transverse Swelling of Wool Fibres in Water Vapour, J. Textile Inst.38, T65-T72 (1947).
34.
Williams, V.A. , WoolShrinkproofing Studies, Part I: The Influence of Inorganic Salts on the Reaction of Potassium Permanganate with Wool in Neutral Solution. Textile Res. J.32, 977-985 ( 1962).
35.
Wortmann, F.-J. , Rigby, B.J., and Phillips , D.G., GlassTransition Temperature of Wool as a Function of Regain, Textile Res. J.54, 6-8 (1984).
