chapter  5
16 Pages

Electrochemical Sensors for the Control of the Concentration of Bleaching Agent to Optimize the Quality of Bleached and Dyed Textile Products

I. Introduction 123

II. Bleaching Agents 124 A. Sodium hypochlorite 124 B. Sodium chlorite 126 C. Hydrogen peroxide 126 D. Bleaching with enzymes 136

References 136

I. INTRODUCTION The term “ cleaning of textiles” is understood as the series of treatments at the textile material to obtain a white, uncontaminated product. During these treat­ ments, many contaminating products are removed from the textile product. The treatments included in the term cleaning are as follows:

Unstrengthening of the textile product to remove amylum, poly(vinyl alcohol), acrylates or carboxymethyl cellulose which were affixed before weaving to strengthen the fiber against deformation and breakage [1]

Washing and cooking [2] to remove natural fats, oils, pectines, hemicelluloses, proteins, mineral compounds, and sugars

Oxidative [3] or reductive [3] bleaching to remove all the natural coloring pig­ ments which cannot be removed by the preceeding treatments

It is clear that all these processes have an influence on the quality and unifor­ mity of the treated textile product but the last mentioned process (bleaching) is the most important because it directly fixes the quality (degree of whiteness [4] and degree of desizing) of the textile product. This quality is strongly dependent on the conditions used in the process, such as concentration and type of bleaching agent, pH, temperature, and additives used [5]. Therefore, it is clear why this chapter is dedicated to the bleaching of textiles and how one can achieve the best quality for a textile product.