Kinetic and Diffusional Approach to the Dyeing Behavior of the Polyester PTT

The textile fiber made of poly(trimethylene terephthalate) came onto the market a few years ago. This fiber has certain advantages over traditional polyester, especially its greater elasticity and the fact that it can be dyed at lower temperatures. Here we study the dyeing kinetics of this “new” fiber using an azo disperse dye, C.I. Disperse Red 82, observing that the dyeing rate increases with temperature and that dyebath exhaustions only reach acceptable levels at temperatures above 80 °C. In order to quantify and compare the experimental data obtained, three kinetics models have been chosen. To fit results with models, non-linear regression methods have been applied and, to differentiate between early and final stages, two levels of exhaustion have been checked. From results obtained with the Chrastil model, apparent diffusion coefficients and the activation energy of diffusion have been calculated.