Supercontraction of Orthocortex and Paracortex of Wool: Relative Disulfide Contents

Abstract

This paper gives supercontraction data for Lincoln and Corriedale wool fibers and for orthocortex isolated from these wools by abrasion. It is shown that the supercontraction of a Lincoln wool fiber with radial cortical asymmetry is that of its paracortex. First-stage and final levels of supercontraction are given for a number of keratins, including reduced and unreduced samples of Corriedale wool and reduced and unreduced orthocortex that had been isolated, by abrasion, from selected Corriedale fibers. It is concluded that, in this Corriedale wool, the ratio of orthocortical to paracortical cystine density is probably between 0.8 and 0.95. The suggestion is made that the “acid-labile bonds,” which have been said to limit second-stage supercontraction, are not specific chemical bonds but chiefly chain entanglements.