Thermodynamic and kinetic parameters of polyester dyeing with Disperse Blue 56 using bio-based auxiliaries and co-solvent microemulsion

The aim of the study was to dye polyester fabric with a low molecular weight anthraquinone type disperse dye (C.I. Disperse Blue 56), with n-butylacetate as co-solvent in the microemulsion system and the presence of two bio-based auxiliaries (ortho-vanillin and coumarin), at temperatures lower than 100℃. In order to investigate the influence of temperature and auxiliaries on the kinetic dyeing process, the energy of the activation was determined by the kinetic rates constants. The activated entropy values were obtained by the theory of absolute rates of dyeing and diffusion of the activated state of the dye for the disorder state of the dyeing system. Higher activated energies were found, as well as higher activated entropy, meaning higher dye absorption, for polyester samples dyed with ortho-vanillin/n-butylacetate compared with polyester samples dyed with coumarin/n-butylacetate. Color strength values of the polyester fabric dyed using the proposed microemulsion dyeing system at low temperature (95℃) were similar to polyester fabric dyed with a conventional dyeing system at high temperature (135℃). Regarding color fastness to washing and ironing, it was found that the use of the auxiliaries did not significantly modify the fastness values of the dyed samples.