Thermodynamic characteristics of cotton dyeing with reactive dyes in non-aqueous media

Understanding the dyeing behaviors of reactive dyes onto cotton in non-aqueous media is helpful to facilitate the development of sustainable non-aqueous dyeing. Here, the thermodynamic characteristics of cotton dyeing with reactive dyes in the non-aqueous media of liquid paraffin (LP) and decamethylcyclopentasiloxane (D5), were investigated and compared to those in aqueous medium. The results showed that the adsorption isotherms of the reactive dyes in LP, D5, and water media accorded with the Freundlich model, indicating that the dyeing proceeded via the physical adsorption of multi-molecular layers. Furthermore, the dyeing enthalpy and dyeing entropy of cotton dyeing using reactive dyes in LP and D5 media were positive, which was significantly different from those in an aqueous medium. These properties help to understand and interpret the dyeing properties and behavior of reactive dyes onto cotton in LP and D5 media.