Natural dyes have grown in popularity due to their eco-friendliness. They can be used as a substitute for synthetic dyes to minimize environmental pollution. This research investigates the natural ...colouring behaviour of haar singhar flower (HSF) extract in cotton dyeing. Colorant was extracted under various conditions utilizing various extraction mediums such as aqueous, basic, and acidic. On cotton, it was discovered that applying 55 mL of aqueous extract containing 1.5 g/100 mL sodium chloride for 40 minutes at 70 °C yielded the best colour output. A new hue with good colour fastness was developed utilizing chemical and bio-mordants. The existence of nyctanthin as a colouring agent in haar singhar flowers was discovered through FTIR analysis of the extract. The CIE Lab system revealed that using 2 g/100 mL of pistachio shell as a bio-mordant resulted in good quality reddish yellow hues. It was discovered that ultrasonic radiations have a high potential for isolating colourants and dyeing cotton fabric under decreased conditions of temperature, time and volume. The application of biomordants has made the procedure greener, more efficient, and safer.
The revival of natural dyes in different walks of life is due to stringent environmental standards imposed by many associations. For current studies, flowers of haar singhar (
Nyctanthes arbor-tritis
...) has been chosen for bio-dyeing of cotton fabric using microwave irradiation techniques. For this purpose, liquid extracts and fabrics were exposed to microwave for 5 min at various conditions. These treated and un-treated dye extracts obtained in respective media were employed to dye the radiated and non-radiated cotton fabrics. The characterization of extract and untreated and undyed irradiated fabrics samples was done through FTIR. Different dyeing variables were optimized under CCD response surface methodology as a statistical tool. With the introduction of new shades and improvement of colorfastness properties, different concentrations of sustainable chemical and bio-mordant were employed. All dyed cotton fabrics were exposed to CIE-color space system for estimation of color coordinates and color strength by using spectra flash SF600 and to rate colorfastness properties using ISO standard methods for light, dry and wet rubbing, washing fastness. Cotton fabric was dyed with haar singhar flower extract of 7 pH from 4 g of powder, using 1.5 g/100 mL salt solution at 60 °C for 30 min. To get acceptable shades, aqueous extract after microwave treatment for 4 min provided excellent color strength. Pistachio (
K/S
= 3.6342) is a bio-mordant with great results, and aluminum (
K/S
= 4.8205) is a chemical mordant with outstanding results. It is found that green methods for isolation of colorant and green mordants for getting new shades should be employed.
