Appraisal of marigold flower based lutein as natural colourant for textile dyeing under the influence of gamma radiations

• Optimum absorbed dose for tuning cotton surface is 30 kGy.
• Good colour strength is obtained at 70 °C keeping M:L=1:50.
• Darker shades are obtained by dyeing for 85 min using dye bath of 5 pH.
• Optimal pre-mordant is 7% tannic acid (TA) and post-mordant is 5% Cu.
• At these condition colour characteristics has been enhanced.

Maintaining colour strength and fastness of the fabrics dyed with natural colourants had been the major constraint of utilizing plant based dyes in modern textile practices. The present study was concerned with the extraction of lutein dye from marigold (Tagetes erecta L.) flowers and role of gamma radiation in improving colour strength and fastness characteristics of the extracted dye. The investigation of dyed fabric in spectraflash showed that gamma ray treatment of 30 kGy was the optimum absorbed dose for surface modification to improve its dye uptake ability. Good colour strength was obtained when irradiated cotton (RC, 30 kGy) was dyed with extract of radiated marigold flower powder (RP) at 70 °C for 85 min, keeping M:L of 1:50 using dye bath of pH 5.0. The results from mordanting experiments revealed that 7% of tannic acid as pre-mordant and 5% of Cu as post-mordant were the best treatments to improve colour strength. It was found that gamma ray induced extraction of lutein from marigold flowers had a potential to be utilized as natural dyes in textile sector to produce yellowish green shades.