A Hydrogen Bonding Mechanism for the Permanent Setting of Wool Fibers

Abstract

It is shown that wool fibers in which the cystine linkages have been permanently broken can be given a set in boiling water equal to that of normal fibers. Set imparted by water or steam can be released by further treatment at 10° to 20° C. above that used in setting. Boiling solutions of reducing agents begin to impart permanent set in less than 15 sec., and a very high degree of permanent set is obtained within 30 sec. A high degree of permanent set can be imparted in a short time at low temperatures by treatment of extended fibers with a solution of urea containing a reducing agent. The resultant set is greater than that obtainable with boiling water after prolonged treat ment, or with boiling alkaline solutions. The results are readily explained by breakdown and reformation of hydrogen bonds following scission of some cystine linkages.