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The Torsional Properties of Single Wool Fibers : Part III: Disulfide Reduced and Permanently Set Wool Fibers

Feughelman, M., Mitchell, T.
Textile research journal 1964 v.34 no.7 pp. 593-597
cystine, disulfide bonds, fabrics, hydrochloric acid, methylation, pH, textile fibers, wool
The torsional moduli (both wet and dry) and torsional relaxation of fibers (i) with disulfide bonds reduced and (ii) with disulfide bonds reduced and methylated and of unmodified fibers that had been "permanently" set were examined. The moduli of all the dry fibers show little change from the moduli of normal dry fibers. In water, how ever, fibers show a progressive decrease in torsional moduli with removal of cytine. Fibers that have been "permanently" set behave in torsion in the same way as fibers of low cystine and high sulfhydryl content, although analysis shows that their cystine and sulfhydryl content is about the same as that of a normal fiber. The torsional relaxation in water of the reduced and methylated fibers is almost independent of cystine content. but in reduced but unmethylated fibers there is a rapid increase of torsional relaxation with decrease in cystine and increase in sulfhydryl content. The torsional relaxation in aqueous HCl at pH 1 is lower than it is in distilled water at ∼pH 6. It is suggested that disulfide-sulfhydryl interchange explains at least a part of the torsional relaxation of fibers in water.