Wool bleaching with thiourea dioxide

Abstract

This paper examines the results of using thiourea dioxide as a reducing agent in wool bleaching. The first part analyses the influence of p H , temperature and concentration of thiourea dioxide in solution on its decomposition, which increases markedly at p H values above 5.5, at temperatures over 50°C and when the concentration decreases. The second part studies the influence of temperature, concentration of thiourea dioxide and time on the degree of whiteness, yellowness index, cysteine content and tensile strength of the bleached wool. A central rotatable design is used to find the response equations of the properties of bleached wool versus the variables. Finally, the optimum conditions of wool bleaching with thiourea dioxide are indicated.