LAUSR

Study of dyeing process variables and its standardization is essential for establishing scientifically reproducible standard method of dyeing cotton fabric with specific natural dye like babul bark containing vegetable gallic/tannic acid residue besides natural color component. Effects of different single and combined double mordanting and dyeing process variables on surface color strength and color fastness properties after dyeing cotton khadi fabric with aqueous extract of Babul Bark (Acacia Nilotia L.) as natural dye were studied in the present work. Potash alum, aluminium sulphate and stannous chloride were used as metallic salt mordant and Harda (Myrobolan) was used as natural mordant assisting agent. Relevant results indicate that application of overall 15% dosages of Harda and aluminium sulphate in 75:25 ratio offers maximum K/S value (5.44) and overall good color fastness (3–4 or higher) than other combination studied. After finalizing the mordants, dyeing process variables were studied for standardization of the dyeing process using babul bark extract. Relevant results indicate that this particular natural dye (babul bark) renders better color strength for optimized conditions of dyeing with dyeing time: 60 min, dyeing temperature: 65 °C, at MLR: 1:30, dye bath pH: 5.0, optimum dye conc.: 30% (based on dry weight of source materials) and common salt—5%. Study of FTIR and Atomic absorption spectrophotometry (AAS) for the said natural dyed cotton khadi fabric with babul bark indicate presence of metallic mordant and tannin content for explaining the observed results showing dye-fibre-mordant complex formation besides hydrogen bonding as well.