Bleaching of Wool with Hydrogen Peroxide in Presence of Different Stabilisers

Abstract

The influence of Stabilizer C (a mixture of sodium oxalate and sodium pyrophosphate [Laporte]), sodium pyrophosphate, trisodium phosphate, and sodium silicate on the decomposition of solutions of hydrogen peroxide, as well as on the bleaching effect produced on a wool fabric, has been studied. The pH of the peroxide solutions remains constant, except for the solutions containing trisodium phosphate, whose pH increases. The release of oxygen is regulated by the nature of the stabilising anion and the pH of the solution. The presence of wool in bleaching solutions decreases the pH of the solution, the oxygen release being regulated by the nature of the stabilising anion. No relation was found between the degree of reflectance obtained and the less of oxygen from the bleaching solution. The cystine content of the wool decreases during bleaching and its alkali solubility increases, both values being related to the reflectance obtained; the tryptophan content of the wool also decreases considerably.