Green dyeing of microwave treated silk using coconut coir based tannin natural dye

Abstract

The resurgence of natural dyes is gaining fame in textile industry due to eco-friendly nature. The present study was done to investigate the Coconut coir as natural dye (tannin) for silk dyeing under Microwave (MW) treatment following the optimization of experimental parameters. Isolation of colorant was carried out in aqueous, acidic and organic media (methanol) under influence of MW treatment up to 6 minutes. Dyeing of silk was carried out having irradiated and unirradiated extracts. Good colour strength was achieved by dyeing unirradiated silk using methanolic extract under MW treatment for 4 minutes at 75°C. The optimal dyeing was achieved at 75 minutes at pH 8 while keeping fabric liquor ratio 1:25 having 5 g/100 ml table salt as an electrolyte. For development of shades, salts of Al and Fe and Tannic acid were used as pre- and post-chemical mordants and Acacia, Pomegranate, Turmeric and Henna as pre- and post-biomordents. Acacia (6%) as pre-bio mordant and Turmeric (6%) as post-bio mordant considerably improved the colour strength at optimal conditions utilizing irradiated extract of coconut coir (tannin) and un-irradiated silk under MW treatment at 4 minutes. ISO-standard shows good colour fastness and colour strength at optimal conditions using Acacia and Turmeric as bio-mordents. This research work gives information about tannin extracted from Coconut coir has great potential to dye silk fabric to produce reddish-brown colour under the influence of microwave treatment. FTIR spectral study revealed chemical changes in the silk fabric treated with microwave radiations.