Type and location of SS linkages in human hair and their relation to fiber properties in water
✍ Scribed by Sachio Naito; Kozo Arai
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 461 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
The changes in the mechanical properties accompanying the reduction of disulfide (SS) linkages in hair were studied. A variety of extents of thiol groups were introduced into hair by treatments with thioglycolic acid and tri-n-butyl phosphine. The reduced fibers swollen with an aqueous 11M LiBr solution containing N-ethylmaleimide showed typical rubberlike elasticity in a solution composed of equal volumes of 8M LiBr and diethylene glycol monon-butyl ether. The crosslink density was determined from the shear modulus of the swollen fiber. It was found that the S S linkages can be divided into two groups: the intermolecular linkages group ( S S , and SSz) and the intramolecular linkages group (SS,). The effect of the SS bond scission on the shear modulus of the reduced fibers in water was also studied. It was further found that intermolecular SS, linkages do not respond to the shear modulus of fiber in water, and the amounts of SS,, SSz, and SS3 are about 35, 18, and 47% of the total cystine content in hair (623 pmol/g), respectively. With respect to the location of SS linkages in hair, important suggestions were obtained the intermolecular SS1 and SSz linkages are located in the microfibril and the matrix, and the former are more accessible to water than the latter; and SS3 linkages are localized within the hydrophobic region of the matrix.