Effect of enzymatic Pre-treatment on dyeing of wool with natural dye madder (Rubia cordifolia) using natural mordants

The present investigation was undertaken to study the effect of enzymatic pre-treatment with protease enzyme on pure wool before dyeing with madder dye. The conditions for enzymatic pre-treatment were optimized after studying the change in the physical properties such as weight loss, strength loss, loss in thickness, moisture absorption and flexural rigidity. The optimized conditions included, 8.4 pH media, 1% enzyme concentration and 45 minutes treatment time. The treated and the untreated wool fabrics were dyed with madder dye using each of the four natural mordants- arjun, babool, eucalyptus and amla, after optimizing the dyeing and mordanting conditions. The effect of enzymatic pre-treatment on the dyeing properties was studied after comparing the CIE LAB values and the colour fastness properties of both the pre-treated and the untreated dyed wool samples. It was observed that as a result of enzymatic pre-treatment darker shades can be obtained on wool dyed with madder and mordanted with arjun and amla whereas lighter and subdued shades can be obtained using babool and eucalyptus mordants. Moreover, many of the colour fastness properties also improved because of enzymatic pre-treatment.