Effects of Modifying Agents on the Dyeability of Cotton Fabric using Malachite Green Dye

Changes in thermodynamic parameters as a result of modifying agents on dye uptake of cotton fabric using malachite green (MG) dye was investigated in this study. Five modifying agents {Acetic acid (CH₃COOH), hydrated Sodium carbonate (Na₂CO₃.10H₂O), Sodium Chloride (NaCl), Ammonium sulphate ((NH₄)₂SO₄) and Hydrogen peroxide (H₂O₂)} were used on cotton fabric. The equilibrium exhaustions (%E) were determined before and after modification of the cotton fabric at different concentrations which were 88.24%, 80%, 77.14%, 65.10% and 30.88% for CH₃COOH, NaCl, (NH₄)₂SO₄, Na₂CO₃.10H₂O and H₂O₂ respectively. The results also showed a correlation between the standard affinity(-Δμ^θ) of dye on cotton fabric and the equilibrium exhaustion. The values of entropy (ΔS^θ) and enthalpy (ΔH^θ) change revealed the feasibility (spontaneity) and exothermic nature of the reaction. The optimum parameters were attained in acidic solution (CH₃COOH) at the highest temperature (70 °C) of dyeing as it showed the highest % efficiency of 88.24%. This work established that modification of cotton fabric with modifying agents is one of the best route to improve the affinity between dye and fabric as it reduces stress, amount of dyes wasted in dyeing, time required to achieve satisfactory results leading to a cost effective environmental friendly approach in the field of cotton dyeing.