Treatment of Coffon With Chitosan - An Initiative Towards Salt Free Dyeing

Abstract

This paper presents the possibility of salt free dyeing of cotton fabric with reactive dye by treating the fabric with chitosan. In the experiment the fabric was treated with chitosan of different concentrations (1%, 2%, 3% & 4%) before dyeing. The chitosan treated fabric was then dyed with reactive dye without using salt. The dyeing performance and the fastness of shade have been analyzed by comparing the chitosan treated dyed samples with corresponding similar fabric samples dyed with salt. The dye absorption, i.e. K/S value, of chitosan treated fabrics was found as 1.6, 1.7, 2.2 and 2.9 respectively for 1%, 2%, 3% and 4% chitosan concentration whereas the K/S value of untreated fabric was 1.9. Though the fabric with lower chitosan concentration may not absorb dyes as much as the fabric dyed with salt, but when the chitosan concentration in fabric is increased, it is quite possible to obtain similar dye absorption or even better than that the fabric dyed with salt. Color fastness to washing, rubbing and perspiration were also analyzed. In case of washing and perspiration, chitosan treated fabrics have shown almost similar fastness ratings to untreated dyed fabrics. However untreated fabrics have shown better rubbing fastness specially wet rub.