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Type and location of SS linkages in human hair and their relation to fiber properties in water
Author(s) -
Naito Sachio,
Arai Kozo
Publication year - 1996
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19960919)61:12<2113::aid-app9>3.0.co;2-d
Subject(s) - intermolecular force , polymer chemistry , materials science , intramolecular force , ether , aqueous solution , chemistry , composite material , stereochemistry , organic chemistry , molecule
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 11 M LiBr solution containing N ‐ethylmaleimide showed typical rubberlike elasticity in a solution composed of equal volumes of 8 M LiBr and diethylene glycol mono‐ n ‐butyl ether. The crosslink density was determined from the shear modulus of the swollen fiber. It was found that the SS linkages can be divided into two groups: the intermolecular linkages group (SS 1 and SS 2 ) and the intramolecular linkages group (SS 3 ). 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 1 linkages do not respond to the shear modulus of fiber in water, and the amounts of SS 1 , SS 2 , and SS 3 are about 35, 18, and 47% of the total cystine content in hair (623 μmol/g), respectively. With respect to the location of SS linkages in hair, important suggestions were obtained: the intermolecular SS 1 and SS 2 linkages are located in the microfibril and the matrix, and the former are more accessible to water than the latter; and SS 3 linkages are localized within the hydrophobic region of the matrix. © 1996 John Wiley & Sons, Inc.