Physico-chemical studies on dyeing of jute and cotton fabrics using jackfruit wood extract: Part II — Dyeing kinetics and thermodynamic studies

Abstract

Bleached jute and cotton fabrics have been double pre-mordanted applying 20﹪ myrobolan (harda) as 1ˢt mordant and 20﹪ Al₂(SO₄)₃ or 20﹪ FeSO₄ as 2ⁿd mordant and subsequently dyed with aqueous extract of jackfruit wood under optimized conditions of dyeing. The physico-chemical parameters of dyeing, such as dyeing affinity, rate of dyeing, absorption isotherms and associated thermodynamic parameters like heat of dyeing (ΔH), entropy of dyeing (ΔS) and Gibb’s free energy (ΔG), have been assessed to explain the interaction among different fibre-mordant-dye systems. It is observed that all of these dyeing processes are endothermic, ΔH values being positive. Among different fibre-mordant-dye systems studied, jute fabric double pre-mordanted with harda and FeSO₄ shows a non-linear Langmuir type dye-absorption isotherm, while dye-absorption isotherms of all other fibre-mordant-dye systems are found to be linear following Nernst absorption isotherm, indicating the formation of co-ordinated complex in jute-harda + FeSO₄ –dye sample, and hydrogen bonding in all other cases of fibre-mordant-dye systems studied. However, the negative ΔG values of all the systems studied indicate that the potentiality of chemical interaction /reaction of these fibre-mordant-dye systems in some otherwise favorable conditions of dyeing need to be further studied.