Effectiveness of Different Mordants and Concentrations on the Dyeing Properties of Jackfruit (Atrocarpus heterophyllus) Bark on Silk

Abstract

A study was carried out to assess the effect of different mordants and concentrations on the colouring characteristics of jackfruit bark dye on silk. Six types of mordants, viz. citric acid, alum, ferrous sulphate, aluminum sulphate, copper sulphate and potassium dichromate (K2Cr2O7) were used, each at 1, 2 and 3% of weight of the fabric (o.w.f.). The material liquor ratio was maintained at 1: 40. The Hunterlab colour scale was used to analyse the variations in colour and intensities. The results indicated that the maximum change in colour with respect to the undyed silk fabrics was for 2% alum treated samples with the ΔE* value of 27.08±0.29. However, the values were not significantly different from the samples treated with FeSO4 mordant at 2% and 3% levels, CuSO4 mordant at 2% level and alum at 3% level. The change in chroma (ΔC*) value was maximum for the alum (2%) mordant (24.44±0.2). The analysis on colour fastness with respect to washing, rubbing and sunlight also indicated that all mordants and concentrations used in the study excepting 1% alum offered adequate fastness characteristics. The unmordanted samples exhibited moderate fastness. In view of the colour fastness with respect to washing, rubbing and exposure to light, the jackfruit bark dye can be applied on silk with any of the selected mordants at 3% level.