Effect of plasma and cationization pre-treatiments on fastiness and UV protection of cotton dyed with madder

Abstract

To achieve good colour depth and fastness of naturally dyed fabrics is necessary to use mordants, usually metallic salts, which are potentially harmful to the environment and human health. In this work, the effect of plasma and cationization pre-treatments on cotton fabrics dyed with natural dye madder extract was investigated as environmentally sustainable alternative processes. Air atmospheric dielectric barrier discharge (DBD) plasma treatment showed a slight improvement in fastness to washing and UV light when samples were dyed at pH 11. On the other side, cationization with poly(diallyldimethylammonium chloride) (PDDA) greatly improved the dye uptake onto cotton, but with poor fastness. Meanwhile, the simultaneous pre-treatment with metallic mordants improved significantly the fastness properties, being the PDDA/Fe pre-treatment, followed by dyeing at pH 5, the process which showed the best results regarding colour strength, fastness to UV light, and UV protection.