INFLUENCE OF DIRECT AND REACTIVE DYES ON THE ENZYMATIC-HYDROLYSIS OF COTTON

Cotton fabric is subjected to enzymatic hydrolysis with cellulases bef ore and after dyeing. The effects of direct dyes of increasing molecul ar size on the rate of the enzymatic hydrolysis reaction are investiga ted, along with mono-and bifunctional reactive dyes with different fun ctional groups. All reactive dyes studied, and especially bifunctional reactive dyes, have a decelerating influence on enzymatic attack. The effect of the direct dyes depends strongly on the enzymatic treatment duration. Moisture regain values of enzyme treated fabric suggest a t ransient state of somewhat increased disorder of the cellulose structu re at a specific stage of hydrolysis, which is alleviated by longer in cubation times. At this stage, direct dyed fabric shows a hydrolysis r ate approximately equal to or slightly higher than undyed fabric.