The Treatment of Wool with Acid Permanganate Solutions

It is shown that wool can be rendered non–felting by treatment with dilute solutions of permanganate at a pH < 2, and the optimum conditions for treatment are described. Wool treated in this way does not felt when left even for very long periods in a washing machine, but felts as much as untreated wool when exposed to a milling action. Wool which has received prolonged permanganate oxidation treatment acquires some resistance to felting in a mill. Permanganate–treated wool shows no resistance to felting when washed in acid in a washing machine or a mill. The implications of these results for the theory of felting are discussed.The damage done to tho wool by permanganate treatment is slight and has been assessed in a number of different ways. The nature of the reaction has been studied from an analytical and a kinetic viewpoint, and it is shown that the chief reaction is an oxidation of the disulphide bond, the rate being controlled by diffusion.There is a fundamental difference between the actions of acid and alkaline permanganate. A secondary reaction with tyrosine is responsible for the yellowing of the wool. The yellow complex is shown to behave as an indicator.