Optimum Dyeing Conditions Research Articles

Dyeing Properties, Color Gamut, and Color Evaluation of Cotton Fabrics Dyed with Phellodendron amurense Rupr. (Amur Cork Tree Bark)

The application of plant dyes in the textile industry has been very limited due to their limited sources, incomplete color space, and narrow color gamut, etc. Therefore, studies of the color properties and color gamut of natural dyes and the corresponding dyeing processes are essential for completing the color space of natural dyes and their application. In this study, water extract from the bark of Phellodendron amurense (P. amurense) was used as a dye. Dyeing properties, color gamut, and color evaluation of dyed cotton fabrics were studied, and optimal dyeing conditions were obtained. The results showed that the optimal dyeing process was pre-mordanting with liquor ratio at 1:50, P. amurense dye concentration at 5.2 g/L, mordant concentration (aluminum potassium sulfate) at 5 g/L, dyeing temperature at 70 °C, dyeing time of 30 min, mordanting time of 15 min, and pH 5. Through the optimization of the dyeing process, a maximum color gamut range was obtained with lightness L* value from 74.33 to 91.23, a* value from -0.89 to 2.96, b* value from 4.62 to 34.08, chroma C* value from 5.49 to 34.09, and hue angle h° value from 57.35° to 91.57°. Colors from light yellow to dark yellow were obtained, among which 12 colors were identified according to the Pantone Matching Systems. The color fastness against soap-washing, rubbing, and sunlight on the dyed cotton fabrics all reached grade 3 level or above, further expanding the applicability of natural dyes.

Microwave-assisted sustainable exploration of cocklebur leaves (Xanthium strumarium L.) as a novel source of distinct yellow natural colorant for dyeing cotton fabric.

During current times, the use of bio-colorants attained public acceptance as a sustainable alternative to synthetic ones which in turn reduced the environmental contamination. The present study focused on the green, safe, and clean technology for the resurgence of natural colorant from cocklebur (Xanthium strumarium L.) leaves and their application to cotton fabric. Natural colorants were extracted by employing an eco-friendly microwave-assisted extraction process using an aqueous and alkaline medium. Dyeing of cotton fabric was carried out using irradiated and unirradiated cotton fabric with irradiated and unirradiated natural dyes of cocklebur leaves. The results of extraction experiments revealed that 4min microwave-assisted alkaline extract exhibited significantly outstanding color strength onto microwave-treated cotton fabric compared to aqueous one. Further to investigate the optimum dyeing conditions for cotton fabric, various dyeing variables such as dyeing time, dyeing temperature, dye concentration, and exhausting agent were monitored and found a superior result using a dye concentration of 45ml, for dyeing cotton fabric at 75°C for 50min in the presence of 4g/100ml of table salt. For improvement in color strength and color fastness properties, the effects of various bio-mordants, such as eucalyptus bark, acacia bark, turmeric rhizome, and onion shells, and chemical mordants (aluminum and copper) on dyed cotton fabric were also evaluated. It was also observed that cotton fabric dyed with alkaline extract of cocklebur leaves using bio-mordants as pre-mordants (4% acacia, 4% eucalyptus, 2% onion) and post-mordants (3% onion, 3% eucalyptus, 4% acacia) exhibited the highest color strength and various hues with acceptable colorfastness properties against light, washing, and rubbing in comparison to chemical mordants. The ISO standard for fastness also revealed that bio-mordanting has enhanced the rating from good to excellent in comparison to chemical mordants. The results provide ample scope for the extraction of yellow natural dye from the cocklebur leaves for eco-friendly coloration of fabrics using bio-mordants.

Valorization of Corn Husk Waste for Textile Applications

ABSTRACT Agriculture biomass is a widely known renewable source that has a high possibility of recycling. The present investigation deals with the extraction, pre-treatment, dyeing, and characterization of natural fiber obtained from agricultural residues of corn husk. Water retted corn husk fibers were subjected to two steps of scouring and bleaching with hydrogen peroxide. The process effectively reduced non-cellulosic impurities, increased cellulose content to almost 79%, enhanced water absorption (431.5%), and increased fiber whiteness (54) with minimal impact on breaking tenacity (17.17 CN/tex). Natural dyeing was performed by using dye extracted from Sappan wood, and it was observed that fiber dyed without mordant exhibits a good color strength (K/S) of 13.21. Optimum dyeing conditions were determined by the response surface methodology, where K/S was kept as the main response. Modern spectroscopic characterization techniques were used for confirmatory analysis. The optimized recipe for natural dyeing is a 20% liquid dye concentration at 70°C for 1 hour, which achieved a K/S of 10.2–10.5 with adequate wash and light fastness properties in the range of 3–4 and 7–8, respectively. The current study will pave the way for the efficient textile application of this abundant but unnecessarily wasted biomass.

Optimized Dyeing of Cotton with semi-synthetic Embelin Ninhydrin Dye Obtained by Chemical Modification of Embelin from Embelia Schimperi

ABSTRACT Chemical modification is a promising path to address the limitations of a natural dye, such as limited shades and inadequate fastness properties. This study investigated the modification of embelin (2, 5-dihydroxy-3-undecyl-1, 4-benzoquinone) a plant-based benzoquinone compound from Embelia schimperi (Myrisinaceae family) with ninhydrin to get a semi-synthetic dye. The modified dye was applied to cotton fabric along with mordants to provide different shades. Optimum dyeing conditions were determined using Central Composite Design which showed optimum conditions of pH at 9, time of 60 min and temp of 80°C. The color fastness ratings were in the range of 4–5 evaluated on the Gray scale.

Natural dye extracted from Triadica Sebifera in aqueous medium for sustainable dyeing and functionalizing of viscose fabric

Sustainable dyeing with natural compounds has gained more attention for a wide range of functional properties and environmental benefits. The purpose of this study was to investigate aqueous extraction in an alkaline medium in order to extract natural dyes from the bark of the Chinese tallow tree ( Triadica Sebifera ) and to determine its dyeing potential on viscose fabric. The perfect conditions for dye extraction were observed at M: L ratio 1:20, temperature 90 °C, pH 10, and time 100 min. Using different mordanting techniques severe dyeing process was done by using FeSO 4 .7H 2 O, KAl(SO 4 ) 2 .12H 2 O, SnCl 2 .2H 2 O, CuSO 4 .5H 2 O, ZnSO 4 .7H 2 O for viscose fabric. Here, three varied mordanting strategies, pre-mordanting, meta-mordanting, and post-mordanting were applied. The outcome has demonstrated that the dyeing of viscose fabric through post-mordanting strategy with KAl(SO 4 ) 2. 12H 2 O in various time, temperature, pH shown the better performances as well as superior result than the other different mordant. The CIELab values and color strength (K/S) values were measured using different conditions and find out the optimized value by orthogonal experiment. The interactions of dyed particles with viscose fabrics was confirmed by FTIR analysis. The color fastness properties were also in the acceptable range of fastness ratings of 4 for light, 4–5 for wash, 4–5 for dry rubbing and 4 for wet rubbing. The dyed viscose fabric was shown an excellent UV protection properties with 48.50 ultraviolet protection factor (UPF) value. The dyeing of viscose fabric with Chinese tallow tree ( Triadica Sebifera ) are very promising and can be considered as the potential alternative candidate of synthetic dyes to meet the actual demand of viscose fabric dyeing and functionalizing in the textile industry. • Viscose fabric was dyeing using natural dyes extracted from Triadica sebifera. • The optimized dyeing conditions were achieved by orthogonal experiment. • The dyed viscose fabric shown acceptable range of fastness properties. • The dyed viscose fabric shown an excellent UV protection properties.

Extraction and optimization of natural colorant from Garcinia mangostana Linn peels for leather dyeing

Developing an eco-benign dyeing process through natural products such as fruits is a way to achieve sustainability in the manufacturing process. The present research focuses on extracting natural dye from Garcinia mangostana Linn ( G. mangostana Linn) skin wastes for leather dyeing purposes. The aqueous colorant extract from G. mangostana Linn characterization peel waste has been extracted through green synthesis and characterized for their suitable applications. The functional annotation of the colorant shows 3398, 2926, 1708, and 1631 cm −1 stretching correspond to anthocyanin molecule. The particle size of the obtained dye measured about 420 nm in diameter. Using Response Surface Methodology, dyeing parameters such as concentration, temperature, and duration are optimized. The optimum dyeing condition is 20% dye, with a 2 h duration in the leather processing. The effect of mordants has been studied and found that there is an increase in color intensity. The results of fastness, organoleptic, and physical properties are in an acceptable range. The study provides an insight into the utilization of food wastes into high-value products for leather dyeing. • Extraction of biocolorant from food wastes. • Application of biocolorant for leather dyeing. • Biodyeing process has been optimized using biocolorant. • Cleaner and sustainable dyeing method using extracted biocolorant.

Sustainable dyeing of wool yarns with renewable sources.

Medical and healthcare fabrics are one of the most important fields in the textile industries worldwide. They are essential in all medical fields, especially where hygiene is required. Also, it is imperative to keep the ecosystem safe up to a great extent and also produce natural-based goods. Natural dyeing with plant sources can be claimed to be an excellent environmentally friendly procedure for providing healthcare fabrics. In this study, date seeds and Zenian were used as an eco-friendly mordant and dye, respectively, for dyeing wool yarns. Date seeds pre-treated wool yarns were dyed with the methanolic extract of Zenian by the exhaustion process at the optimum dyeing conditions of dye concentration 40g/L, pH = 4, time = 45min, and temperature 90°C. The pre-treating of wool yarns with date seeds not only improved the dyeability of the samples but also enhanced the colorfastness to washing and light exposure. The results also show that the pre-treated and dyed samples have effective antibacterial activity against microorganism strains. Moreover, the data confirmed the dye bath obtained from the extract of Zenian does not represent a high environmentally polluting effect, and the elaborated dyeing process enables to reduce the biological oxygen demand (BOD) and chemical oxygen demand (COD) removal values significantly. The knowledge obtained from this work presents an appropriate promising foundation for the high-added-value application of agricultural waste products.

Sustainable dyeing and functionalization of wool fabrics with black rice extract

Traditional textile colorations and functionalization consume a lot of energy, take a long time, and use a lot of chemicals; hence, cost-effective and eco-friendly natural dyeing and finishing have become a prime concern. In this study, natural dyes of black rice extract was extracted and used for the coloration and functionalization of wool fabric without using any hazardous dyes. The dyeing conditions were monitored using a one-variable-at-a-time technique, and it was discovered that the optimal dyeing conditions were M: L = 1:100, pH = 3, time = 60 min, and temperature = 90 °C. The dyed wool fabric with Al 2 (SO 4 ) 3 mordant shows higher fastness ratings of 4–5 for wash, 6 for light, 4–5 for dry rubbing & 4 for wet rubbing. SEM photographs confirmed the successful deposition of black rice extract on wool fabrics. In addition, mechanical properties, UV protection, and antimicrobial tests also revealed that the treated wool fabric has excellent UV protection capability and good antimicrobial properties along with adequate strengths. The ultraviolet protection factor was more than 35 in optimized conditions, and the strength increased more than 10% comparing untreated wool fabric. The antibacterial performances shown more than 80% reduction rate after 20 washing cycles. Therefore, the black rice extract are very promising and can be considered as the potential candidate for the sustainable dyeing and functionalization of wool fabric in the textile industry. • Black rice extract was used as sustainable dyeing and functionalize of wool fabrics. • A one-variable-at-a-time technique was employed to optimize the dyeing conditions. • The dyed fabric with mordanting showed higher fastness to wash, light and rubbing. • The treated wool fabric shown excellent UV resistant, antimicrobial, and strength.

Modification of cellulosic material for rapid dyeability with malachite green dye

Chemical modification of cellulose fibre is one of the efficient ways to improve the dye uptake and increase the dyeability properties of the fibre. The challenge with dyeing cellulose fibres is poor dye uptake and unsatisfactory dye fixation. The major scope of this study is to determine the optimum dyeing conditions that will guarantee the dye fastness onto the cotton fabric. Four modifying agents (sodium chloride (NaCl), ammonium sulphate ((NH4)2SO4), hydrated sodium carbonate (Na2CO3•10H2O), and acetic acid (CH3COOH)) in aqueous form were employed in the treatment of the cotton fabrics in a slacked condition. The study examined changes in thermodynamic parameters due to dyeing modified cotton fabric with malachite green (MG) dye. The equilibrium percentage dye exhaustions (%E), which is a measure of dye uptake by the fabrics were determined prior to and post-modification of the cellulose at varying concentrations and temperatures. The optimum values of %E obtained for the modification agents viz: CH3COOH, NH4)2SO4, NaCl, and Na2CO3•10H2O were: 89.71%, 88.57%, 85.71%, and 68.70% at concentration 2% v/v and temperature of 70 °C. The%E of modified cotton fabric dyed with malachite green was optimum in acidic conditions (i.e.CH3COOH with%E of 89.71%) followed by (NH4)2SO4; 88.57%, which undergoes hydrolysis in an aqueous solution. This was then followed by NaClaq (i.e. a neutral solution) and Na2CO3•10H2O (i.e. an alkaline solution). However, all modifying agents used enhanced the dye uptake. The values of partition coefficient (K) were in the order of 1307.73 L.tkg−1, 1162.34 L.tkg−1, 899.69 L.tkg−1, and 329.23 L.tkg−1, respectively at 70 °C; while the values for standard affinities (-Δμθ) were 20,463.94 kJ.mol−1, 20,127.85 kJ.mol−1, 19,397.40 kJ.mol−1, and 16,530.65 kJ.mol−1. This implies a correlation between the equilibrium exhaustion and standard affinity of dyed modified cotton fabric. The values of entropy change (ΔSθ) are 175.53 J.mol−1K−1, 141.29 J.mol−1K−1, 148.16 J.mol−1K−1, 81.023 J.mol−1K−1 and 255.10 J.mol−1K−1 for the four modifying agents, respectively, which implies that the reaction is feasible (spontaneous) whereas ΔHθ are -39,729 kJ.mol−1, -28,144 kJ.mol−1, -31,531 kJ.mol−1, -11,669 kJ.mol−1 and -73,928 kJ.mol−1, respectively. The negative values of ΔHθ suggested that the reactions were exothermic. This study established that modifying agents on cotton fabric is one of the finest ways to improve the affinity between dye and fabric, thereby significantly reducing the time, cost, and stress required to achieve an optimal result in the dyeing process.

Optimization of dark dyeing poly(lactic acid) yarn with indigo dyes applied to denim fabric

The application of new environment-friendly biological fiber materials in denim industry is becoming more and more popular, then the dyeing of the new biological fiber and yarn has become the focus of research. To better expand the use of the biological-based materials in denim industry and promote the dark color dyeing of poly(lactic acid)(PLA) yarn, the effects of dyeing temperature, dyeing pH, dyeing time and dyeing times on the dye depth (K/S) and mechanical properties (breaking strength) of PLA yarns are investigated. It is found that the dye depth of PLA yarn is the best when the dyeing temperature is 110 °C, pH of dyeing solution is 5, the dyeing time is 40 min and the dyeing times is 3 times, respectively, and the K/S value reaches 11.43, the color fastness of different types of dyed PLA yarns are all above grade 4. The orthogonal experiment shows that the optimum dyeing condition to dye 1 g PLA yarn with 23 Neβ is 10 g/L synthetic indigo, 10 g/L sodium hydrosulfite, 15 g/L sodium hydroxide, respectively.

Eco-dyeing and functional finishing of wool fabric based on Portulaca oleracea L. as colorant and Musa basjoo as natural mordant

Biomass energy is the most acknowledged renewable resource due to its universality, richness, and renewability. This study utilized a Portulaca oleracea L. plant as a natural colorant for wool fabric dyeing with a high color yield at optimum extraction and dyeing conditions. To evaluate the dyeing mechanism and feasibility of the extracted dyes, we analyzed and characterized the molecular structure and nano-level particle size. The dyeing kinetics and the morphology of dyed fabrics were integratedly explored; the adsorption process of wool fabric on natural colorant molecules was increasingly in line with the pseudo-second-order kinetic adsorption model. Further, the dyeing effects of wool fabrics were compared to that of Musa basjoo mordant and synthetic dyes to confirm the superior color depth (K/S value 23.53), biological function as anti-ultraviolet (UPF value 253.47), and anti-bacterial activity (antibacterial rate of Staphylococcus aureus/Escherichia coli was 71.3%/37%). Our findings provide a feasible scheme for providing deep color and biological activity to wool fabrics. This has broad application prospects in the field of eco-friendly textile materials.

Utilization of Red Apple Peel Extract in Dyeing of Wool Fabric

ABSTRACT The utilization of natural colorants in textile dyeing and printing has come to the forefront of production of textile goods. Extractions of natural dyes from waste materials and their utilization in coloration of textiles have positive impact economically and ecologically. In this study, red apple (Malus domestica) peel extract was used in dyeing of wool fabric in presence of mordant. Adopting pre-, meta-, and post-mordanting methods; four mordants were used; namely, Fe+2, Cu+2, Al+3, and Sn+2, were used in dyeing of wool with red apple peel (RAP) extract. The effects of various dyeing conditions; namely, dye concentration, pH, time, and temperature of dyeing on the dyeability of wool with RAP extract were studied. The dyeing characteristics of the dyed wool fabrics were assessed by determination of their color strength and the CIELAB color system. The kinetics of dye adsorption were investigated at the assigned optimum dyeing condition. Results of this study proved that the dyeing operation of wool fabric with RAP extract fits well with a second-order reaction. Wool fabrics dyed using meta-mordanting method exhibited adequate to very good fastness properties against washing, rubbing, perspiration, and light.

Mordant-free dyeing of nylon fabric with mahogany (Swietenia mahagoni) seed pods: A cleaner approach of synthetic fabric coloration

The extraction and consequent application of natural colorants obtained from mahogany ( Swietenia mahagoni) seed pod powder is described here. The colored solution was extracted by facile boiling in an acidic medium. Fourier-transform infrared spectroscopy indicated that the mahogany seed pod extract contained lignocellulosic substances. The typical strong broad band for -OH stretching vibration appeared at around the 3400 cm−1 region in the spectra indicating the presence of alcoholic groups in the substance. The acidic boiling of the mahogany seed pod extract showed the color bearing character at λmax 400–480 nm in the visible range of the ultra-violet spectrum. Subsequently, commercial single jersey-knitted nylon fabric was dyed with the mahogany seed pod extract. The effects of temperature, pH, and time were investigated meticulously for the above dyeing. The optimum conditions for nylon fabric dyeing with the mahogany seed pod extract were selected as the temperature of 100°C, dyeing time of 60 min, and dyebath pH 4.5. The results were interpreted in terms of color strength and fastness properties. The color fastness to wash and perspiration of nylon fabric dyed with mahogany seed pod extract was found to be moderate to good in the grey scale rating 3–4 to 4 grade in the case of optimum dyeing condition whereas color fastness to light was observed to be poor in the blue wool scale rating 2 grade. It was observed that dyeing time, temperature, and pH had profound influences on the color strength of the dyed material. The color strength was increased with the increase of dyeing period and dyebath temperature. The acidic dye liquor produced the darker hues while the alkaline condition had no effect on color yielding. The fabric was dyed uniformly, confirming the evenness of dyeing which is very important for successful commercial dyeing.

ECO-FRIENDLY DYEING OF COTTON FABRIC WITH WASTE TEA LEAVES BASED TANNIN NATURAL DYE

<p>Natural products have always been appreciated due to the awareness about environmental standards for global health by using green technologies in their isolation and extraction. Thereupon natural dyes have been used in all fields due to having ecofriendly, therapeutic and aesthetic nature. For the current study, microwave radiations (MW) have been used as a green extraction tool to explore the natural coloring potency of Tea leaves for the dyeing of cotton fabrics. For isolation of natural dye from tea leaves in aqueous and basic media MW irradiation for 1-6 min has been given and used to dye cotton fabric. It has been evaluated that an increase in color yield (K/S) with the use of 6 min of microwave energy when basic extract of tea leaves was used to dye onto cotton fabric. It has been also revealed that in the case of the pre-mordanting method, 6% of Cu and 8% of Fe as a post mordanting method give the best fastness properties and the highest color yields. It is concluded that MW energy has an excellent ability for isolation of colorant from Tea leaves for dyeing of cotton fabric under reduced optimal dyeing conditions.</p>

Vat dyeing of lyocell fabric with high temperature dyeing technique

Successful dyeing of lyocell, a biodegradable regenerated cellulose fiber, in fabric form is still a challenging job. Here in, we report successful dyeing of lyocell fabric with vat dyes by conventional batchwise method. To assess the dyeability of lyocell fabric, a woven lyocell fabric was dyed with three different colorants (Blue Yellow and Red) of vat dyes by using previously determined procedure for vat dyeing on cellulose fabric. Dyeing parameters (temperature and time) were regulated to attain optimal dyeing conditions. Color yield of dyed lyocell fabric was analyzed using Kubelka–Munk equation, and durability of dyed fabric was examined by standard colorfastness properties. Lyocell fabric dyed with vat dyes displayed excellent color strength and remarkable fastness properties under optimized dyeing conditions. SEM results revealed smooth surface morphology after dyeing. The dye effluent analysis showed that dyeing of lyocell fabric with vat dyes is eco-friendly.

A natural yellow colorant from Buddleja officinalis for dyeing hemp fabric

Natural dyes are more eco-friendly alternatives to synthetic dyes. This research focuses on natural dyes and improved dye craft using plants employed by various ethnic groups in Southwestern China. In this study, we assessed the suitability of dried extracts from Buddleja officinalis flowers for dyeing hemp fabric. and valuated indicators including color strength (K/S), color characteristics, and fastness properties in response to washing, rubbing, and perspiration using metallic and natural mordants under pre-, post-, and simultaneous mordanting conditions. Specifically, we investigated the pigment compound crocin by ultraviolet-visible spectroscopy and Fourier transform–infrared spectroscopy analysis before using it to dye hemp fabric. Optimum dyeing conditions including staining temperature, staining duration, and pH have been identified using an orthogonal array experimental design. Optimum results were achieved when dyeing at pH 5, and at 60 °C for 90 min. Hemp fabric dyed without mordant had a shade of yellowness, while fabric mordanted with gum rosin, plant ash, KAl(SO4)2, and Chaenomeles speciosa had a variety of pale to dark yellowness color shades. A darker yellow–green color shade was obtained with FeSO4 mordant. The color change of washing fastness was mostly very poor, while the color stain of washing and perspiration fastness were good to excellent, and rubbing fastness was also good to excellent. The color fastness was kept and improved by the three natural mordants, especially gum rosin and plant ash, but reduced by FeSO4. Those results show that the use of aqueous extract from B. officinalis flowers combined with natural mordants represents a promising approach for textile dyeing, revealing an alternative method that could improve and extend the dyeing properties of this indigenous dye plant. In addition, our findings lay the foundation for further basic studies and demonstrate the utility of preserving natural dye plants, along with the related traditional knowledge of indigenous groups in Yunnan, China.

Study of the Dyeing Properties of Annatto and Ultrafiltrated Annatto as Colourants for Natural Fibres

ABSTRACT Cotton and wool fabrics have been dyed in the absence of mordants with annatto and ultrafiltrated annatto powder. Τhe optimum dyeing conditions were determined as far as the quantity of salt and dyebath pH are concerned. The dyeing properties of annatto and ultrafiltrated annatto were studied by monitoring the dye uptake in various time intervals and temperatures of dyeing. The adsorption isotherms for both annatto and ultrafiltrated annatto were studied. It was found that adsorption of annatto on cotton follows a BET-type adsorption isotherm indicating a multilayer formation of molecules onto cotton, whereas the adsorption of ultrafiltrated annatto follows a Freundlich-type monolayer adsorption. Adsorption of both annatto and ultrafiltrated annatto on cotton occurs through the formation of Van der Waals forces between annatto molecules and cotton substrate. The adsorption on wool of both annatto and ultrafiltrated annatto follows a Freudlich-type adsorption isotherm indicating a monolayer formation occurring between the positively-charged wool substrate and the negatively-charged annatto molecules. The dyeing behavior of natural annatto resembles that of the synthetic direct and acid dyes commonly applied for dyeing cotton and wool. Thus, annatto and ultrafiltrated annatto can successfully replace the synthetic yellow dye component in the dyeing of cotton and wool fibers.

The Influence of pH, Temperature and Time on Dyeing of Silk Fabric by Black Bean Anthocyanin-rich Extract as Colorant

Anthocyanins are natural dye substances that provide attractive colors from red to blue. However, large quantities of Anthocyanins have been found in wastewater from soaked black beans, resulting in environmental pollution. The utilization of theses wastewaters would therefore be an effective way of reducing environmental pollution, and the water could be used to dye silk fabric, displaying a more sustainable use of resources. In this paper, the effects of pH, temperature and time for dyeing of silk fabric were investigated. It was found that the optimum dyeing conditions were pH 3 at 60 oC for 60 min to achieve the best colors and the most effective color fastness on silk. Moreover, Anthocyanins were the potential to reduce 80% gram-negative and gram-positive bacteria. These results improved our understanding of dyeing conditions using Anthocyanins in the wastewater from soaked black beans, which plays an important role in reducing pollution, reducing costs and improving the quality of the related dyeing fabric families.

New class of magenta dyestuffs based on azomethine pyrazolone disperse dyes: Synthesis, characterization, and dyeing performance on polyester fabrics with ultraviolet protection and pH-dependent properties

Eight azomethine pyrazolone magenta dyes with iminodiethanol groups have been synthesized from 1,3-disubstituted- 1H-pyrazol-5( 4H)-ones in good yield. The newly synthesized dyes were characterized using spectroscopic data and elemental analyses techniques. All dyes have been successfully applied to polyester fabrics as disperse dyes where their dyeing performances have been discussed and evaluated in detail. The shades of these dyes ranged from red violet, purple and dark purple colors with good depth, brightness and good leveling properties. Multifunctional properties such as color representation, colorimetric data (L*, a*, b*, C*, h*, K/S), fastness properties of the dyed samples with respect to washing, perspiration, rubbing and light fastness have been discussed and evaluated in detail. The degree of exhaustion and fixation was also achieved after establishing the optimal dyeing conditions at 130°C, high pressure, 2% shade, and pH ≈5. As well, the influence of the dye bath pH on the K/S percentage and color intensity was estimated and discussed. Furthermore, the dyed fabrics were tested for ultraviolet protection factor and the results showed that these dyes gave excellent ultraviolet protection.

Dyeing of cotton fabric with Euclea divinorum extract using response surface optimization method

PurposeThe majority of the synthetic dyes have been found to be non-biodegradable, toxic and carcinogenic. As a result, there has been a growing trend toward the use of natural dyes as alternates to synthetic dyes. This shift calls for more research to come up with more sources of natural dyes to satisfy their increasing demand. Euclea divinorum plant has been used traditionally as a source of dye, however, its textile dyeing properties have not been studied. This study aims to determine the textile dyeing properties of E. divinorum extract.Design/methodology/approachOptimization of dyeing conditions of Euclea divinorum natural dye extract on the cotton fabric was done using response surface methodology (RSM). The combined effects of examined dyeing conditions on the relative color strength (K/S) were studied using a central composite experimental design. Analysis of variance (ANOVA) was used to determine the significance of the statistical model generated for the study. Mordanting effects were measured using standard ISO wash, rub and lightfastness tests.FindingsThe optimum dyeing conditions were found to be 68 min, pH 3.3 and 82°C with color strength 0.609. Temperature and pH showed some interaction effects during the dyeing experiments. The predicted optimum K/S value was validated experimentally using the optimum conditions and was found to be in agreement with the experimental values. All the metallic mordants used enhanced the color strength and provided a variety of brown shades, therefore, a suitable alternative for the toxic synthetic dyes.Originality/valueOptimization of dyeing conditions of Euclea divinorum dye on cotton using RSM and mordanting at optimal conditions has not been done elsewhere.