Microwave-assisted enhancement of milkweed (Calotropis procera L.) leaves as an eco-friendly source of natural colorants for textile

Abstract

Application of natural colorants to textile fabrics has gained worldwide public acceptance due to the hazardous nature of synthetic dyes. Present study investigated the microwave's mediated extraction of natural colorants from leaves of milkweed (Calotropis procera L.) as well as their application to cotton fabrics assisted with biochemical mordants. Dye extraction from C. procera leaves was carried out in various mediums (alkali and aqueous), and the extracted dye as well as cotton fabrics was irradiated with microwaves for 2, 4, 6, 8, or 10 min. Effect of various temperature regimes and sodium chloride (NaCl) concentrations was also evaluated on the color strength of dyed cotton fabrics. The results revealed that extraction of natural colorants was enhanced when microwave radiations were applied for 4 min by using alkali as an extraction medium as compared to aqueous one. Optimum dyeing of cotton fabrics was achieved by using NaCl at a temperature of 55 °C. Among the chemical mordants, iron was effective for better color strength when used as pre- and post-mordant. Among the studied bio-mordants, extract of Acacia nilotica bark significantly improved the color strength and fastness properties as pre-mordant and Curcuma longa tuber as post-mordant. It was concluded that extract of C. procera leaves was a potential source of natural colorants and a high level of dye was obtained upon irradiation of alkali-solubilized extract for 4 min. Application of NaCl at concentration of 3 g/100 mL and temperature treatment of 55 °C significantly improved the color strength of dyed cotton fabrics.

Sustainable Dyeing of Cotton Fabric Using Black Carrot (Daucus carota L.) Plant Residue as a Source of Natural Colorant

“…Dyeing of fabrics with natural colorant along with bio mordanting could be a good alternative to chemical mordanting [38]. The turmeric powder containing coloring component (curcumin) was firmly bound to anthocyanin and formed a strong linkage onto cotton fabric, resulting in a dark yellow color with excellent color strength.…”

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“…Production technologies of natural colorants from plants could vary from simple solvent extraction to sophisticated techniques depends on the product requirement and its purity. The extraction procedure such as soxhlet method to obtained colour from Quercus robur L. 60 , supercritical fluid extraction and pressurized liquid extraction on annatto seeds and jabuticaba skins 61 , and microwave assisted extraction used on milkweed leaves to get its colour 62 are among several techniques commonly applied. After the extraction process, purification and drying are essential to ensure the quality of the finished product.…”

Statistical study of the effect of metallic mordants on tensile strength of wool

“…To improve the exhaustion of natural dyes onto textile fibers, different techniques have been employed. Several pretreatments like cationization [7], plasma treatment [6,[8][9], enzyme treatment [10], gamma treatment [11][12], and microwave treatment [13] are examples of techniques which have been studied to overcome this drawback. However, the most usual way to enhance the dyeing of textile fibers with natural dyes is still mordanting with metal salts.…”