Explanatory Paper on Modern Theory

Before the standard affinity of dyeing — Δü± can be determined, it is necessary to develop a theory of the dyeing process. This theory should indicate clearly the measurements that must be made and the manner in which they must be interpreted in order to determine — Δμ±. Each existing theory of dyeing provides a theoretical model of the dyeing process with which the behaviour of the real dyeing system may be compared. Only when the theoretical model is correct in every respect is — Δμ±, calculated with the aid of the model, a true thermodynamic variable, and only then can reliance be placed upon the values that are obtained for this parameter. From the variation of — Δμ± with the absolute temperatureT, it is possible to determine the standard heat of dyeing ΔH±, which then enables the standard entropy of dyeing ΔS± to be derived. The measurement and the significance of the thermodynamic variables — Δμ±, ΔH±, and ΔS± are discussed in detail, with particular reference to the mechanism of dyeing of synthetic‐polymer fibres with disperse dyes.