Dyeing Conditions Research Articles

Diversifying color palette of Prangos ferulacea colorants on wool yarns: dual mordant approach for enhanced color, antioxidant, and UV protection properties

Natural dyes have gained significant attention in recent years due to their environmentally friendly characteristics. This research paper focuses on the dyeing of wool yarns with P. ferulacea aerial part extract in conjunction with biomordants and metal mordants. The study focused on optimizing dyeing variables including pH of 2–8, temperature of 65 °C–95 °C, dye concentration of 25%–125% o.w.f., and dyeing time of 15–120 min using a one-factor-at-a-time (OFT) optimization by determining the color depth (K/S) values on wool yarns. The optimized dyeing conditions were a pH of 4, a temperature of 95 °C, a dye concentration of 75.0% (o.w.f.), and dyeing time of 60 min. The color hues, brightness, color intensity, and fastness of the samples varied significantly depending on the kind and nature of the biomordant used. Furthermore, the introduction of metal ions as pretreatment to biomordanted wool yarns exhibited unique characteristics such as the creation of new color shades, the combined enhancement of dye absorption (K/S), and increased color fastness with the most colorfast hues produced by Cr, Cu, and Fe-biomordant combinations. The antioxidant potential of biomordanted wool yarns was evaluated in terms of the inhibition of peroxidation by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity and compared to the un-dyed wool yarns. The two-step mordanting process enhanced the antioxidant activity of dyed wool yarn (up to 99.90%) compared to the unmordanted sample (58.30%) and the negative control sample (5.70%). The ultraviolet protection factor (UPF) values were found in a very good to excellent range, with a rating >40 and maximum protection (UPF = 59.80) provided by Fe-YM mordanting. The findings indicate that this efficient technique enabled us to broaden the spectrum of colors generated by the extract of P. ferulacea aerial parts on wool, while simultaneously guaranteeing outstanding antioxidant and UV protection characteristics.

A study of the effect of organic acids (gallic acid and ascorbic acid) on the coloration and functionalization of wool yarns with Millettia laurentii sawdust natural dye

Wastewater from the textile industry, especially the dyeing sector, is a major contaminant for aquatic ecosystems. Synthetic dye compounds and metal salts from leftover mordant and dyeing baths are washed into rivers, endangering aquatic life and the environment. In regards to the current study’s examination of Millettia laurentii sawdust’s potential as a natural color source, eco-friendly organic acids (gallic acid and ascorbic acid) were studied in conjunction with small amounts of metal salts (aluminum sulfate, stannous chloride, copper sulfate, and ferrous sulfate) for enhancing the color shade palette with simultaneous functionalization (antimicrobial and UV-protection) of wool yarns. The effects of metal salts up to ecologically permissible concentration limits on the dyeing and functional properties were assessed in combination with organic acids. The study focused on optimizing dyeing variables including pH (2–8), temperature (65–95 °C), dye concentration (25–125% o.w.f.), and dyeing time (15–90 min) using a one-factor-at-a-time (OFT) optimization by determining the color depth (K/S) values on the wool yarns. The optimized dyeing conditions were pH of 4, temperature of 95 °C, dye concentration of 75.0% (o.w.f.), and dyeing time of 60 min. The color characteristics (CIEL*a*b*c*ho) and fastness (Wash, rub, and light) properties are evaluated comparatively against control dyed wool yarns using standard methods. The antimicrobial activity of control dyed and mordanted dyed wool yarns was evaluated in terms of the percentage microbial reduction of bacterial colonies. Metal salts especially ferrous sulfate in conjunction with gallic acid (Fe/GA) provided the highest average color strength (13.50) with a maximum percentage microbial reduction of 96.67%. UV protection ability was assessed by an Australian and New Zealand standards (AS/NZS 4399: 1996) method in terms of UPF values. UV protection levels were significantly improved by using binary combinations of organic acids and metal salts with the maximum protection offered by Fe/GA (97.66) and Sn/GA (97.90). Dyeing outcomes were significantly impacted by the chemical structure of organic acids (gallic acid and ascorbic acid) and the type of metal salts; the research proposes a more environmentally friendly natural dyeing process for the textile industry.

Analytical Method Development and Dermal Absorption of 4-Amino-3-Nitrophenol (4A3NP), a Hair Dye Ingredient under the Oxidative or Non-Oxidative Condition.

The chemical 4-amino-3-nitrophenol (4A3NP) is classified as an amino nitrophenol and is primarily utilized as an ingredient in hair dye colorants. In Korea and Europe, it is exclusively used in non-oxidative or oxidative hair dye formulations, with maximum allowable concentrations of 1% and 1.5%, respectively. Despite this widespread use, risk assessment of 4A3NP has not been completed due to the lack of proper dermal absorption data. Therefore, in this study, both the analytical method validation and in vitro dermal absorption study of 4A3NP were conducted following the guidelines provided by the Korea Ministry of Food and Drug Safety (MFDS). Before proceeding with the dermal absorption study, analytical methods were developed for the quantitation of 4A3NP through multiple reaction monitoring (MRM) via liquid chromatography-mass spectrometry (LC-MS) in various matrices, including swab wash (WASH), stratum corneum (SC), skin (SKIN, comprising the dermis and epidermis), and receptor fluid (RF). These developed methods demonstrated excellent linearity (R2 = 0.9962-0.9993), accuracy (93.5-111.73%), and precision (1.7-14.46%) in accordance with the validation guidelines.The dermal absorption of 4A3NP was determined using Franz diffusion cells with mini-pig skin as the barrier. Under both non-oxidative and oxidative (6% hydrogen peroxide (H2O2): water, 1:1) hair dye conditions, 1% and 1.5% concentrations of 4A3NP were applied to the skin at a rate of 10 μL/cm2, respectively. The total dermal absorption rates of 4A3NP under non-oxidative (1%) and oxidative (1.5%) conditions were determined to be 5.62 ± 2.19% (5.62 ± 2.19 μg/cm2) and 2.83 ± 1.48% (4.24 ± 2.21 μg/cm2), respectively.

Modern ecofriendly approach for extraction of luteolin natural dye from weld for silk fabric and wool yarn dyeing

The increasing apprehension regarding the ecological effects of synthetic dyes has prompted a transition towards sustainable and environmentally friendly substitutes in the textile sector. This research examines the eco-friendly use of a natural pigment obtained from the weld flower for dyeing of silk fabric and wool yarn. The study investigates the use of microwave-assisted extraction to acquire the luteolin based pigment found in the weld flower. An assessment is conducted to evaluate the effectiveness of microwave radiation in improving the extraction process, emphasizing its capacity to accelerate and enhance the production of the natural colorant. Moreover, the process of optimizing dyeing conditions is carried out utilizing a response surface approach, with a specific focus on parameters including temperature, time, pH, and salt content. The study also investigates the influence of mordants, such as iron salt, and aluminum salt, on improving color fastness and attaining bright and enduring hues. The study expands its research to examine the impacts of plant-based extracts, such as madder root, and oak, as bio-mordants for producing a wide array of colors. The study additionally highlights the favorable influence on color fastness, exhibiting significant enhancements in light fastness, wash fastness, and rubbing fastness for both silk and wool. The measurable results validate the effectiveness of the suggested environmentally friendly dyeing techniques, provide numerical evidence of their suitability for sustainable textile manufacturing.

Towards environmental protection and safety coloration process in wool fibers: Role of disperse reactive dyes structure

Traditional wool fibers dyeing uses a huge amount of water and energy, and relies on lots of chemicals, which produces huge amounts of lower-biodegradable wastewater, and poses a great threat to the water environment. Here, to investigate the role of disperse reactive dyes structure on the dyeing properties, a sustainable waterless dyeing of wool fibers was investigated with four synthesized disperse reactive dyes by using supercritical CO2 as a non-aqueous dyeing medium. The effects of dyeing time, pressure, temperature and dye concentration on the dyeing properties were discussed. The results showed that K/S values up to 5.5 under the optimal dyeing condition of 383.15 K, 23 MPa, and 70 min were obtained, indicating shorter reaction time and higher K/S values compared to similar studies. Moreover, excellent colorfastness to soaping and rubbing up to 4–5 was displayed since nucleophilic substitution reaction occurs between the C atom on the triazine group of disperse reactive dyes and -NH2 on the cysteine of fiber macromolecules. This study provides an environmental protection and safety coloration process to produce high-quality wool fiber products by establishing the relationship between structure of disperse reactive dyes and dyeing properties of wool.

Influences of hair dyeing on the distribution shapes of zolpidem and methoxyphenamine in hair

In order to investigate the influences of hair dyeing on the distribution shapes of drugs in hair, different hair dyeing processes (“semi-permanent coloring without bleaching” and “permanent coloring with bleaching”) were performed in vitro on black hair specimens collected from two subjects (Asians) who took a single dose of zolpidem (ZP, 10 mg of ZP tartrate) or methoxyphenamine (MOP, 50 mg of MOP hydrochloride). Under the following three different dyeing conditions, (1) semi-permanent coloring, (2) permanent coloring (once), (3) permanent coloring (twice), drug distributions in single hair specimens were investigated using a 2-mm segmental analysis by liquid chromatography-tandem mass spectrometry. Distribution shapes of drugs changed significantly only under the permanent coloring (twice) condition, resulting in reduced peak concentration and extended distribution width. There was, however, no significant difference in the amounts of drugs in hair between non-treated and dyed specimens, suggesting the drugs hardly leaked out of hair or were only slightly degraded during dyeing. In addition, while assuming contact with aqueous environment such as daily hair washing after dyeing, dyed hair specimens were individually immersed in ultrapure water for 20 hours, then the outflow of drugs in ultrapure water as well as the distribution shapes of drugs remaining in hair were determined. The drug outflow after permanent coloring (once and twice) was significantly larger than those after semi-permanent coloring, and the outflow ratios, [outflow]/([outflow] + [amount remaining in hair]), ranged over 9.8–24% (n = 3) for ZP and 68–71% (n = 3) for MOP after permanent coloring (once), and 54–72% (n = 3) for ZP and 86–91% (n = 3) for MOP after permanent coloring (twice). The distribution shapes of drugs after 20 h of immersion tended to flatten as outflow ratios increased, resulting in no change in the shapes after semi-permanent coloring, and complete collapse of their shapes after permanent coloring (twice). Thus, the present results indicated that hair dyeing involving bleaching and subsequent contact with aqueous environment after dyeing could significantly influence distribution shapes of drugs in hair.

Colorful graphene-based wearable e-textiles prepared by co-dyeing cotton fabrics with natural dyes and reduced graphene oxide

In addition to the functionality of electronic textiles (e-textiles), their aesthetic properties should be considered to expand their marketability. In this study, premordanted cotton fabrics were co-dyed with reduced graphene oxide (rGO) and natural dyes to develop ecofriendly and colorful graphene-based wearable e-textiles. The color attributes of the textiles were analyzed in terms of the dyeing conditions, namely, rGO loading, mordant type, and natural dye type. The lightness of the dyed samples increased in the order of cochineal < gardenia blue < rhubarb. Regardless of the natural dye and rGO loading, the lightness of the fabrics mordanted with Fe was lower than that with Al and Cu. Moreover, the rhubarb- and gardenia blue-dyed fabrics exhibited broad chroma and hue dispersions, indicating the strong impact of the dyeing conditions. With increasing rGO loading, the chroma of the rhubarb-dyed fabrics substantially decreased, resulting in decreased color saturation. The initial greenish-blue color of the gardenia blue-dyed fabrics gradually changed to yellowish-green and then yellow. Regardless of the natural dye, drastic overall color changes were observed, with average values of 7.60, 11.14, 12.68, and 13.56 ΔECMC(2:1) at increasing rGO loadings of 1, 3, 5, and 7% owb, respectively.

Eco-friendly natural dyeing of submicron cotton fabrics

To explore the color diversity and performance of functional submicron cotton fabric dyed with ecological natural dyes, three types of natural dyes sappanwood, madder, and gardenia and orchid, were used to dye the fabric. The optimal dyeing conditions for sappanwood were found to be an insulation temperature of 95°C, a dyeing bath pH of 5.5, and a dyeing time of 60 min, resulting in the highest apparent color value ( K/S). For madder, the optimal conditions were an insulation temperature of 90°C, a dyeing bath pH value of 6, and a dyeing time of 60 min. Similarly, for gardenia and orchid, the optimal conditions were an insulation temperature of 90°C, a dyeing bath pH value of 5, and a dyeing time of 60 min. Based on these preferred dyeing processes, the K/S value, color characteristic value, color fastness, and biodegradability of the three natural dyes were compared and analyzed with synthetic dyes. The results showed that natural dyeing resulted in higher brightness ( L* values), lower color depth ( C* values), lower red-green ( a*) and yellow-blue ( b*) values, similar hues, and lower K/S values compared to synthetic dyeing. The color fastness of the natural dyes was slightly lower than that of chemical dyes by 0.5 grade. Additionally, the average breaking strength, elongation at break, tearing strength, and bursting strength of the fabric increased by 9.34%, 5.69%, 9.75%, and 7.31%, respectively. Furthermore, the biodegradability of the natural dyes was over 93%, significantly higher than that of synthetic dyes. These findings provide a theoretical basis for the production of eco-friendly dyeing of functional submicron cotton fabrics and their textile color applicability.

Environmentally friendly greener approach toward sustainable application of amaltas brown pod-based natural colorant for wool yarn dyeing

The escalating concerns over the environmental impacts of synthetic dyes have catalyzed a shift toward sustainable and eco-friendly alternatives in the textile industry. Within this framework, the purpose of this research article is to investigate the environmentally friendly application of brown pods generated from amaltas ( Cassia fistula) as a natural pigment for the purpose of dyeing wool yarn. The purpose of this study is to investigate the possibility of obtaining the reddish-brown anthraquinone-based pigment that is found in Cassia fistula pods by the application of microwave-assisted extraction process. The efficacy of microwave radiation in enhancing the extraction process is evaluated, highlighting its potential for expediting and improving the yield of the natural colorant. In addition, the response surface methodology is utilized in order to optimize the dyeing conditions. Particular attention is paid to characteristics like as temperature, duration, pH, and salt content. In addition, the study investigates the function of mordants, notably salt of Fe, salt of Al, and tartaric acid, in the process of improving colorfastness and generating shades that are both brilliant and long-lasting. The scope of the work is expanded to include the impacts of plant-based extracts as a biomordants, such as pomegranate, red sumac, and hulela zard, for the purpose of producing a wide variety of colors. Additionally, the impact of microwave treatment on wool yarn dyeability is explored, emphasizing improvements in surface morphology and dye absorption. The yarn analysis encompasses color strength, shade variation, and surface morphology, employing techniques such as Fourier transform infrared spectroscopy (FTIR) to elucidate chemical interactions. The study’s findings contribute to the growing body of knowledge on sustainable dyeing practices, highlighting the viability of amaltas-based natural pigments and environmentally friendly mordants in textile applications. Ultimately, this research underscores the significance of adopting ecologically conscious dyeing methods and paves the way for a more sustainable approach to coloration in the textile industry.

Synergetic construction of color and multifunction for sustainable lyocell fabric by microbial nano pigment

As a kind of low-carbon, environmentally friendly and high-quality regenerated cellulose fiber derived from nature plant, the promotion and application of lyocell fiber is attracting much attention. In this paper, for the first time, microbial pigment was applied for color and multifunction construction of lyocell fabric. The size change of the pigment nano-particles during the color construction process was explored to verify the dyeing mechanism of nano-suspension system, and the optimal dyeing condition was obtained. In order to improve the dyeing effect and functionality of fabric, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used to realize the anionic modification of lyocell fabric with high strength retention rate. Under optimal color construction condition, the color depth of the modified fabric was 298.5% higher than that of the unmodified one, and the dyed fabric possessed excellent dyeing uniformity and permeability. Moreover, the crosslinking reaction between BTCA and cellulose macromolecules, as well as the pigment deposition inside the fibers were helpful to the fibrillation prevention function of lyocell fibers. Dyed fabrics inherited the antibacterial and ultraviolet absorption properties of prodigiosins. The bacteriostatic rate against Staphylococcus aureus was above than 98.5%, and the UV protection performance was obviously improved. This technology successfully realized the color and multi-functional construction of the lyocell fabric in one step by natural pigment from microorganism.

Low temperature reactive dyeing of silk: An investigation into dyeing conditions, and strength loss and friction damage of fabric

The low temperature dyeing of textiles has obvious energy-saving effect. Silk fabric suffers from friction damage in the rope dyeing process, and additionally silk is complained about unsatisfactory color fastness. To address the aforementioned issues, the reactive dyeing of silk fabric at low temperatures was studied in terms of dyeing conditions, dye selection, alkali resistance of silk, and strength loss and friction damageoffabric. Reactive dyes exhibited higher fixation to silk in alkaline bath than acidic and neutral baths. The breaking strength and whiteness of silk fabric was less affected by sodium bicarbonate, but greatly affected by sodium carbonate. Silk fabric treated with sodium carbonate at 50–60 ℃ had acceptable loss of breaking strength (<10 %). Silk fabric dyed at 60–80 ℃ using sodium bicarbonate exhibited higher color depth than that dyed at 50–60 ℃ using sodium carbonate. The high temperature dyeing in alkaline bath caused the friction damage and fuzz appearance of silk fabric, which did not occur in low temperature and alkaline conditions. The reactive dyes selected from commercial products could be applied at 50 ℃ and met requirements for high fixation, high color fastness and a variety of colors.

Enhancing silk dyeing with eco-friendly colorant extracted from Cassia fistula brown pods using green mordants

This research project focuses on the extraction of the natural brown colorant, anthraquinone, from Cassia fistula pods using microwave radiation as a method for dyeing silk fabric. The colorant was isolated in aqueous and acidic mediums before and after microwave radiation for up to 6 min, and subsequently used for dyeing purposes. To achieve new and diverse hues, environmentally friendly chemical mordants (iron salt, aluminum salt, and tartaric acid) and biological mordants (red sumac, pomegranate, and hulela zard) were applied in varying quantities (ranging from 0.5g to 2.5g per 100 mL). Colorfast shades were developed by employing these mordants before and after the dyeing process on silk fabric. The dyeing variables essential for shade development before and after mordant application were determined through the utilization of central composite design for statistical analysis. The results indicated that the optimal conditions for irradiating both silk and extract were 6 min, while dyeing the irradiated silk fabric should be conducted at 75 °C for 45 min using 30 mL of extract irradiated at a pH of 3, with a salt concentration of 1.5g/100 mL. The optimized dyeing conditions also showed maximum level of colorfastness properties of 5 for light, 5 for wash, 5 for dry rubbing and 4/5 for wet rubbing. As a result, the extraction of anthraquinone from Cassia fistula pods using microwave radiation has the potential to be effective and ecologically benign, allowing for the creation of bright and colorfast hues on silk fabric. The results support the development of novel and sustainable dyeing techniques in the textile sector.

Ecofriendly process optimization of natural dye extraction from clove (Syzygium aromaticum L.) using response surface methodology and artificial neural network modeling

Process optimization through statistical and machine learning techniques has been used as the recent growing interest for the researchers. Current study has been undertaken to optimize the dyeing behavior of clove (Syzygium aromaticum L.) for cotton under microwave treatment. Response surface methodology and artificial neural network modeling with simplest structure was performed to observe the significance of selected color parameters. The results reveal that if extract and fabric is simulated for optimal MW time then high yield is obtained. For shade development, dyeing of irradiated cotton at 70 °C for 50 min with irradiated extract of 7 pH, using 3 g/100 mL salt has given color fast shades. ISO standard reveal that using selected dyeing conditions with carefully chosen chemical and bio-mordants has possessed good to excellent ratings. Microwave treatment should be used to get effective yield of colorant from clove for cotton dyeing. Additionally the utilization of ecofriendly mordants to make dyeing process greener should be included. It is recommended that artificial neural network model has better predicative capacity for process optimization as compared to response surface methodology.

Potential of hardwood kraft lignin as a bio-based dye for cotton fabrics

The dyeing characteristics of hardwood kraft lignin (KL) were investigated on cotton fabrics, assessing its potential as a sustainable and environmentally friendly dye. Dyeability was evaluated by varying the KL concentrations, temperature, and time. An aqueous solution of Na2CO3 (1.0%) as the dye bath and a fabric-to-liquor ratio of 1:50 were used. Cationizing effects were studied using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC), and the mordanting effects of various mordants were also evaluated. Post-mordanting was performed with FeSO4, FeCl2, Fe-lactate (Fe-lac), MgSO4, CuCl2, CuSO4, and Al2(SO4)3. A mordant concentration of 1 mM o.w.f. (0.5 mM for Al2(SO4)3), with a liquor ratio of 1:30, at 60 °C for 30 min were employed. Suitable dyeing conditions were 2.0% o.w.b., 90 °C, and 90 min, resulting in a brownish color of the cotton fabric. The fabrics exhibited a range of light brown to light grayish brown colors and showed lighter colors than the untreated fabrics when mordanted with MgSO4 and Al2(SO4)3. The color difference (ΔE) between cationized and uncationized cotton fabrics was 3.48. From the colorfastness assessment, KL-dyed cotton fabric showed good rubbing and washing fastness for staining, but poor light and washing fastness for fading.

Potential of a new pyrene based chalcone as a dye on DSSC solar cell and optical limiting

Herin, this work focuses on the potential of a pyrene-based chalcone named EDPP1 as a sensitizer in DSSC using density functional theory (DFT) concerning FMO and UV-Vis absorption spectrum. The EDPP1 compound was synthesized using Claisen-Schmidt reaction and characterized via FTIR, UV-Vis absorption, and DFT. UV-Vis absorption spectrum revealed that the bandgap of the EDDP1 is E g = 3.5e V with fully transmittance above λ cut off = 499nm and high absorption at UV region. The energy level diagram suggests that EDPP1 is a promising sensitizer in DSSCs as it meets the required dye conditions. Additionally, optical limiting study revealed that the EDPP1 compound has the ability to limit laser power above 875 mW. Overall, these results suggest that EDPP1 has potential as a sensitizer in DSSCs and as an optical limiter.

Dyeing of cotton/acrylic blend fabric in a single‐bath‐single‐stage method using indigo dye

AbstractIn this study, an attempt has been made to dye cotton/acrylic blend fabrics in a single‐bath‐single‐stage method considering today's growing market for such blended products. Yarn‐blend cotton/acrylic fabric was produced and dyed at 3% shade using indigo dye in the exhaust method to optimise the dyeing conditions by varying the amount of reducing agent, pH, and dyebath temperature. The colour yield of both the acrylic part and cotton components of the blend was influenced by pH levels. Meanwhile, the temperature played a notable role in determining the colour yield of the acrylic portion. Optimised dyeing conditions were obtained at pH 6 and 120°C for the acrylic part, whereas pH 11 and 90°C temperature were obtained for the cotton part. These conditions involved the use of sodium dithionite (15 g/L) as a reducing agent and sodium hydroxide as an alkali. While the yarn‐blend fabrics exhibited a unique shadow dyeing effect, solid dyeing results were achieved with fibre‐blend fabrics, underscoring the versatility of this single‐bath‐single‐stage method. To assess the overall dyeing performance, comprehensive evaluations including bursting strength measurements, assessments of fastness to washing, perspiration, and rubbing were conducted, all of which provided valuable insights into the durability and colour retention of the yarn‐blend fabrics. This research not only addresses the demand for cotton/acrylic blend fabrics in today's market but also demonstrates an efficient and innovative single‐bath‐single‐stage dyeing approach using indigo dye, which holds promise for the textile industry's future sustainability and product diversity.

Thermal stability and theoretical analysis of madder dye absorption pattern on cotton fabric

In this investigation woven cotton fabric was dyed with madder dye under different dyeing conditions such as in the presence of without mordant, single mordant and mixed mordant. The thermal behaviour of non-mordanted,single mordanted and mixed chemical mordanted with madder dyed cotton fabrics were investigated through thermogravimetric analysis. Further, the fundamental molecular arrangement of dyed cotton fabric was confirmed by the Fourier transformer–Infrared spectroscopy, and the electronic orientation of dye molecule, and after adsorption of cellulose structure is confirmed from Ultra–Violet spectroscopy. HOMO and LUMO calculations are evaluated from the gaussian software. The interaction and binding energies between inhibitor (dye molecule) and cellulose surface are evaluated from molecular dynamic simulation using BIOVIA material studio software.

Textiles Dyeing with Pomegranate (Punica granatum) Peel Extract Using Natural Mordant

ABSTRACT Agricultural waste represents a potential source of raw materials as natural dyes. The peel from pomegranate (Punica granatum) is a waste product, it is used in the textiles industry as dye. The objective of the study is to improve dyeing properties of pomegranate peel dyed silk fabric. We analyzed the pigment composition of pomegranate peel extract through ultraviolet-visible and Fourier-transform infrared (FTIR) spectroscopy; evaluated natural mordants and metallic mordants on fabrics dyed with pomegranate peel extracts by testing the K/S value, color characteristics, and color fastness; examined the morphology of dyed fabrics before and after color fixing treatment by scanning electron microscopy. The major pigment component in pomegranate peel is ellagic acid. An orthogonal array experiment revealed that the optimum dyeing conditions were pH 9, 60°C 60 min for silk fibers. Under the natural mordant, the K/S value of dyed fabric could acquire maximum (8.70). Moreover, the K/S value and color fastness of dyed fabrics could be further enhanced to 11.74 and level 5 by color-fixing treatment of natural gum rosin. Overall, the dyed silk samples with pomegranate peel represented good dyeing properties with natural mordant and natural color-fixing agent of gum rosin.

Comparative study on dyeing conventional polyester and microfibre polyester with disperse dye and evaluate different dyeing effects

In this study, an attempt was taken to dye conventional and microfibre polyester filaments with disperse dye and evaluate their different dyeing effects in similar dyeing condition. The main attention was given to find out K/S values, color difference and different color fastness properties (light and wash fastness) and also the amount of dyes addition required for microfibre polyester filaments to get the same depth of shade as conventional one’s. There were three different hues (Red, Navy and Green) of 5 different shades (0.5%, 1.5%, 3%, 4% and 6%) were used. The result shows that, microfibre polyester requires higher amount of dyes due to more surface area and greater absorbing capability of it. Almost similar light fastness was found in both conventional and microfibre polyester filaments and lower wash fastness properties of microfibre filaments when compared to those of conventional polyester.

Synthesis of novel carbene dyes and investigation of their dyeing properties and reaction mechanism for various fabrics

Week interactions between traditional dye molecules and synthetic fibers requires addition of numerous chemical additives during the dyeing process, resulting in the generation of a significant amount of printing and dyeing wastewater, thereby causing environmental pollution. Herein, three novel carbene dyes containing diazirine were rationally designed, whose decomposition into carbenes at 145 °C subsequently forms covalent bonds with the C–H bonds present in the fibers. The structure-property relationships of the dyes were analyzed based on the results of density functional theory (DFT) calculations. Additionally, the calculations of Yoshida correlations demonstrated that all three dyes exhibit non-explosive properties, thereby indicating their feasibility for large-scale production. The dyeing process of polyester (polyethylene terephthalate/PET), polypropylene (PP), aramid, spandex, and polyester/spandex (P/S) blended fabrics was performed using a non-aqueous solvent dyeing method without the addition of any additives, and the optimal dyeing and color fixation conditions were determined. The samples dyed with carbene dyes displayed similar K/S values compared to conventionally dyed samples, higher color fixation rates, and improved blended dyeing effects, and the reaction mechanism between the carbene dyes and the fibers was elucidated, which proved the versatility and environmental friendliness of the novel carbene dyes and non-aqueous solvent dyeing method. Furthermore, it is noteworthy that all of these dyed fabrics exhibited exceptional color fastness, highlighting the immense potential of the novel carbene dyes in promoting green production in the textile industry.