Investigation Regarding Kinetics in the System Wool Fibre - Reactive Dyestuff

Abstract

In the investigation of kinetics of dyeing in the system wool fibre - reactive dyestuff, the fixation constant kt, the relative diffusion coefficient Drei and diffusion coefficient D is determined. It could be proved, that Crank‘s formula, modified by Rais and Militky, can be applied for the determination of diffusion coefifcient, also in the case of dyeing with reactive dyestuffs. The diffusion coefficient increases with the increase of fibre basity and the fixation constant indicates the reactivity changes of the system wool fibre - reactive dyestuff. The results obtained show, that in acidic dyeing, pH 4.15, the predominante role in the protein chain belongs to thiol-groups. The amino-groups enter the reaction only after have lost the positive charge (over the isoelectric point of wool). The most evident change of the influence of pH on the speed of establishing connection between dyestuff and wool is achieved at 80 °C. At this temperature the investigations of kinetics, of dyeing with the purpose to find out the reactivity of the system wool fibre - reactive dyestuff, can be carried out.