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Environmental issues are rising day by day in the global community due to the cumulative effects of hazardous effluent load and due to the introduction of biological active natural products into all aspects of life. In this study, the waste tea-leaves-based tannin natural dye has been extracted under the influence of microwave treatment and employed onto bio-mordanted wool fabric. For extraction of dye, microwave (MW) irradiation up to 6 min has been employed and for improvement in color strength, bio-mordants in comparison with chemicals mordants. It has been found that acidic extract of tea leaves after MW treatment for 6 min has given excellent color depth (K/ S) on MW treated wool at 80°C. Using bio-mordants, it has been found that 4% of acacia extract, 1% of pomegranate extract and 5% of turmeric extract as pre bio-mordant, whereas 5% of acacia and 2% of pomegranate and turmeric as post bio-mordants have given excellent color strength, whereas in comparison, ferrous sulfate (2%) has given excellent results. It has been concluded that microwave treatment as an environmentally sustainable tool has not only improved the color strength of tannins dye onto wool fabric but also with the addition of bio-mordants has made the process more sustainable. [ABSTRACT FROM AUTHOR]

In the present study, cotton fabric has been dyed with aqueous extract of babul bark (Acacia nilotica) using gallnut (Quercus infectoria) as bio-mordant containing hydrolyzable tannins like gallic acid, elagic acid and polyphenolic gallotannins to produce light yellow color. On the other hand when gallnut bio-mordanted cotton is subsequently dyed with babul bark extract as a natural dye containing similar but non-hydrolyzable tannin-rich color component including small amount of catechin and epi-gallo-catechin, it produces a medium to deep brown color through formation of giant insoluble colored complex of cotton-gallotannins (gallnut)-catechin/epigallocatechin and other color components present in babul bark extract. The process variables for extraction, pre-mordanting and dyeing have been optimized to standardize this dyeing technique. Scattered CDI values for dye-bath pH and dye concentration identified them as the most important dyeing parameters that need to be controlled for obtaining uniform dyeing. High UPF value of upto 35 rendered by application of both gallnut and babul bark through preferential absorption of UV light by the gallotannins in both gallnut and babul bark indicates good UV protection properties of dyed cotton fabrics. [ABSTRACT FROM AUTHOR]

The main topic of this study is Green and environmentally wool dyeing. For this purpose, yellow and black myrobalan extract as green mordants and madder and resedaluteola as natural dyes were used. The FTIR-ATR spectra of the washed wool yarns, mordanted wool yarns and dyed wool yarns confirmed bonding of wool yarns with the green mordant and dyes through comparing chemical structures. The effective linkage between yarn, mordant and dye molecules removes the C-N peaks in FTIR-ATR spectra. After dyeing process, fastness and dyeing properties of dyed wool yarns were investigated. The K/S values of dyed wool yarns with extracted madder and resedaluteola were quantified values; and fastness properties including light, wash, and rubbing fastness were defined as per ISO standard methods. The research pointed out that the myrobalan extraction as a potential route for the development of eco-friendly dyeing in green production of dyed yarns. [ABSTRACT FROM AUTHOR]

Sustainable extraction of functional colorant from dye-yielding plant through microwave radiations is gaining popularity due to its cost, time and effective nature. Current study is concerned with the microwave-assisted exploration of Arjun bark natural colorant for dyeing of mordanted wool fabric. Extracts obtained in various media were irradiated up to 6 min and were used to dye wool. It is found that acid methanol-solubilized extract (3 pH) from 4 g powder upon irradiation for 4 min has given darker shades onto irradiated wool at dyeing for 75 min. FTIR analysis shows that there is no change in chemical nature of functional site of wool, whereas SEM analysis shows that there are some morphological changes occurring at the surface. At optimal conditions, acceptable fastness characteristics are obtained, when 9% of turmeric extracts as pre- and post-bio-mordant and 5% of Fe as pre- and 3% of Fe as post-mordant is employed. It is concluded that microwave has not only improved the functional behavior of natural colorant from Arjun bark for wool dyeing but also the addition of green mordants has made dyeing process more esthetic. [ABSTRACT FROM AUTHOR]

Due to an increase in awareness of harmful aspects of synthetic dyes among the global community, the demand of natural dyes in textile sector has been dramatically increased. The current study has been conducted to explore new eco-friendly source of natural brown colorant from arjun bark for textile. Both bark powder and silk fabrics were microwave irradiated for 1–6 min. Dyeing was performed at different variables onto irradiated and un-irradiated silk using extracts obtained from irradiated and un-irradiated powder. To make the dyeing process more sustainable, two chemical and bio-mordants were employed at optimal conditions. The results show that acidified methanolic extract from irradiated powder (RP, 8g) has given high color strength if irradiated silk (RSi) is dyed for 65 min. at 65°C using dye bath of 1 pH in presence of 7% of Na2SO4 as exhausting agent. Good shades and improved fastness characteristics have been obtained by employing 1% of Fe (iron sulfate) and Al (aluminum sulfate) as Chemical and 1% of turmeric and pomegranate extracts as bio-mordants. Hence, microwave radiation has not only explored the coloring efficacy of arjun bark as potential source of natural brown dye but also made its applicability under sustainable conditions. [ABSTRACT FROM AUTHOR]

Food products as a source of natural colorants are gaining widespread popularity around the globe due to their ayurvedic and eco-friendly nature. Current study is aimed with the utilization of food products (Saffron and madder) as a source of dye for woolen yarn. It is found that, for Saffron, irradiation of yarn for 6 min gives high color strength by dyeing for 45 min in the presence of 2% of salts using un-irradiated dye bath of 1 pH, whereas for madder, 4 min is optimal irradiation time for extract to dye irradiated yarn for 25 min in the presence of 6% of salts using the irradiated dye bath of pH 1. The mordanting carried out at optimal conditions show that using both extracts, woolen yarn dyed at optimal conditions has given good color characteristics. It is concluded that microwave radiation has not only improved natural dyeing process but also make the process more eco-friendly and sustainable as well. [ABSTRACT FROM AUTHOR]

The resurgence of natural colorant in textile dyeing is gaining popularity due to their ecofriendly benefits. The current study has been concerned with dyeing of silk fabric using extract obtained from safflower (Carthamus tinctorius L.) which was microwave irradiated for 1–5 min. To make dyeing process more ecofriendly, bio-mordants and chemical mordants have been employed at optimal conditions. It is found that microwave treatment to the extract for 3 min is suitable to get darker shades with acceptable color characteristics using un-irradiated silk. It has been found that dyeing of un-irradiated silk fabric for 60 min using acidic extract of Safflower (pH 2) has given high color strength. Rating of colorfastness reveals that 7% of curcumin and lawsone as bio-mordant has not only given high color depth but also rated excellent fastness properties as compared to chemical mordants used. It is found that microwave treatment has not only improved the dyeing behavior of carthamin but also enhanced the color characteristics. [ABSTRACT FROM AUTHOR]

The revival of natural dyes in textiles is gaining popularity due to their sustainable nature. The current study has been undertaken to improve the dyeing behaviors of cochineal-based natural dye (carminic acid) for wool dyeing under the influence of microwave treatment. For the purpose, wool fabric and extract obtained from cochineal insects (Dactylopius coccus costa) were irradiated for 1–6 min. The nature of dye bath (pH) and dyeing temperature were optimized using optimal irradiation conditions. To make dyeing process more sustainable and eco-friendly, bio-mordants and chemical mordants have been employed at optimal conditions. It is found that microwave treatment of extraction for 5 min is suitable to get darker shades with acceptable color characteristics using unirradiated wool fabric. K/S was found using acidic dye bath of cochineal insect of pH 1 for dyeing unirradiated fabric at 70°C using acidic extract of Cochineal bugs. Suggested ISO standards for color fastness revealed that 5% of henna and 3% pomegranate as bio-mordant have not only given high color depth but also rated excellent fastness properties as compared to chemical mordants used. It is found that MW treatment has not only improved the dyeing behavior of carminic acid but also enhanced the color characteristics. [ABSTRACT FROM AUTHOR]