The Reactivity of the Sulphur Linkage in Animal Fibres

Abstract

In order to teat the view that reagents such as chlorine, sulphuryl chloride, and sodium hydroxide make wool unshrinkable by promoting disulphide bond breakdown in the surface of the fibres, the action of these reagents on wools containing other types of cross–linkage in place of cystine has been examined. Four kinds of wool have been used, viz. (1) wool reduced with thioglycollic acid and treated with mercuric oyanide to form –S. Hg. S– cross–linkages, (2) wool reduced with thioglycollic acid and treated with trimethylene dibromide to form bisthioether cross–linkages, (3) alkali–treated wool containing Ianthionine and, presumably, –CH: N– cross–linkages, and (4) wool treated with potassium cyanide to convert most or all of the cystine into Ianthionine. In all cases, the modified wool was more difficult to make unshrinkable than untreated wool, though the difference was small with types (1) and (2). Very successful results were obtained with the alkali–treated wool (3), and complete immunity to the action of chlorine, sulphuryl chloride, and potassium hydroxide, as regards the development of resistance to shrinkage, was obtained with wool treated with potassium cyanide (4). Since the action of potassium cyanide is to convert disulphide bonds into Ianthionine cross–linkages, there can be little doubt, therefore, that the above reagents make normal wool unshrinkable by causing disulphide bond breakdown.