Mechanism of absorption of non-ionic dyes by polyethylene terephthalate

Abstract

Isotherms were measured for the distribution of three pure non-ionic dyes and their binary mixtures between polyethylene terephthalate and water in the presence and absence of benzoic acid. In each case, the equilibrium concentration of dye in the fibre was directly proportional to the concentration in the water. For a binary mixture of greatly dissimilar dyes, each behaved completely independently of the other, while for a mixture of two closely related dyes some interference was noted. The solubilities of the dyes in both the fibre and the water increased with a temperature increase and the isotherm was displaced toward the water. The presence of benzoic acid displaced all isotherms toward the water.It is concluded that sorption of non-ionic dyes by polyethylene terephthalate takes place by a solution mechanism.

Physical Chemistry of Dyeing: Kinetics, Equilibrium, Dye-Fiber Affinity, and Mechanisms

“…The dye which is present in true solution is assumed to be in a monomolecular state, both in the dyebath and in the fiber. 18 ' 93 ' 94 ' 317,319,328 Vickerstaff and Waters 38 obtained Langmuir-type isotherms for the dyeing of four related anthraquinonoid dyes on cellulose acetate. In the previous chapter, Daruwalla has discussed the experimental evidence for state of aggregation of dye in the dyebath and in the substrate.…”

A novel utilisation of principal component analysis to optimise sorption isotherms and determine diffusion coefficients of five naphthalimide disperse dyes on polyester fibres

“…Recent investigators illustrate sorption isotherms obeying only the Langmuir law, sorption isotherms of disperse dyes would obviously depend on the presence of dispersing agents, the dyeing temperature, the dye structure and the fibre type . While a simple linear isotherm is suggested for polyester‐disperse dyeing system in the absence of dispersing agents, more complex models have been found to be suitable for this system in the presence of dyeing auxiliaries .…”

Diffusion of dye mixtures in nylon 6. Binary mixtures of disperse dyes

“…However, mixture dyeing of the same fiberldye system is still subject to research. The first attempts to describe the mutual interactions of dyes on dyeing hydrophobic substrates with binary mixtures of disperse dyes were made by Vickerstaff and Waters1 and Bird and Rhyner.2 Further contributions were made, in particular, by Schuler and Remington, 3 Johnson et al,4 and Hoffmann et al 5 These equilibrium sorption stydies revealed that the saturation values in hydrophobic substrates of binary dye mixtures of certain disperse dyes are additive, but the dyes of binary mixtures of similar chemical constitution are sorbed to a smaller extent than when they are applied individually.…”