An alternative natural dye,almond shell waste: effects of plasma and mordants on dyeing properties

In this study, the effect of the plasma process and the possibility of replacing metallic mordants with plasma treatment were investigated in natural dyeing with almond shell waste as a novel natural colorant. The use of a smaller amount of metallic mordants and plant than most of the current natural dye applications is a major advantage of dyeing with almond shell extract. Plasma‐treated and untreated wool fabrics were dyed without mordant and using a smaller amount (0.2 g/l) of alum, iron(ii ) sulfate and copper(ii ) sulfate. Three mordanting methods, namely premordanting, simultaneous mordanting and post‐mordanting, were applied. Colour measurements and light and wash fastness values were compared. Significant colour differences were observed among the mordanting methods. Simultaneous mordanting resulted in the lightest colours with all the mordants. Generally, post‐mordanting produced duller colours and lower a* and b* values than premordanting. The plasma process generated significant colour value differences and colour yield increases, giving more homogeneous dyeing visually, and also ensured a greater impact of mordanting. However, compared with metallic mordants, plasma itself did not create completely different colour shades and fastness improvement. It was necessary to use mordants in order to achieve increased fastness properties (especially light fastness) and a different colour gamut.     

Colour and fastness of natural dyes: revival of traditional dyeing techniques

Cotton and wool fabrics were dyed with nine natural dyes obtained by aqueous extraction of the original plants/insect in an attempt to reconstruct traditional textile dyeing recipes, to optimise the methodology at all stages, i.e. extraction, mordanting and dyeing, and to standardise it. Cochineal, madder, alkanna, henna, brazilwood, red sandalwood, safflower, indigo and logwood were used for the dyeings, which were carried out directly and after mordanting of the textile material. A variety of mordants, namely, aluminium potassium sulphate, potassium dichromate, copper sulphate, zinc chloride, iron(iii ) chloride, iron(ii ) sulphate and tin chloride, is anticipated to meet both early and recent requirements and options. The dyeings were evaluated through colour measurements and standard wash, light and rub fastness tests. Generally, the mordanting process known for many centuries and connected with the textile dyeing resulted in an improvement in dye absorption and fastness properties mainly for the cotton samples, as is concluded from the tests and measurement assessments.     

Light fastness of naturally occurring anthraquinone dyes on nylon

Nylon fabric has been dyed with two purified components of Indian madder, purpurin (1,2,4-trihydroxyanthraquinone) and munjistin (1,3-dihydroxy-2-carboxyanthraquinone). The light and wash fastness of dyed and mordanted samples has been studied. Purpurin showed much better resistance to photofading than munjistin. It was found that the type of mordant and the method of mordanting significantly affected the rate and extent of photofading. The use of copper or ferrous sulphate gave high resistance to fading, whereas stannous chloride or alum did not. On the other hand, light fastness was improved when postmordanting was conducted with copper or ferrous iron, but pre-mordanting was superior in the case of stannous chloride or alum.     

Metal mordanting in dyeing with natural colourants

Metal mordanting, or the application of metal salts, is a common method of improving the light fastness in dyeing with natural colourants. This review presents the results from a survey of the literature on metal mordanting to assess what levels of correlation exist between mordant‐induced effects (changes in colour and colour depth) and the changes in light fastness, what is known about the mechanisms of mordant‐induced improvements of light fastness, and how the salt levels used in coloration processes compare with the limits on metal levels in wastewater and on the dyed substrates. No strong interrelationships are found between the mordant‐induced effects and light fastness improvements. Knowledge about mechanisms of mordant effect on light fastness appears, in large part, to be derived from empirical correlations. However, as light fastness is affected by a multitude of factors, the correlations do not always hold true. It is found that residual metal contents in spent dye/mordanting liquors are generally not reported. However, with rough calculations, it is estimated that, with even the lowest reported salt concentrations, the metal contents in spent liquors exceed environmental release limits. The metal contents on dyed substrates are also not generally reported, but similar estimations show that the contents of heavy metal on dyed substrates (when copper and chromium salts are used as mordants) also exceed limits. On the basis of these observations, the authors make suggestions for elements to be included in investigations on furthering the use of natural colourants in textile dyeing.     

Effects of additives on the dyeing of cotton yarn with the aqueous extract of Combretum latifolium Blume stems

Flavonoid constituents from the aqueous extract of the stems of Combretum latifolium Blume sourced in Thailand have potential use as dyestuffs for cotton dyeing. In an effort to improve current natural dyeing methods with this extract, further aspects of the process were studied. It was found that, before equilibrium was reached, an increase in temperature led to an increase in dye adsorption rate of the extract; the initial rate and extent of dye adsorption was further increased by the addition of sodium chloride to the dyebath. In addition, cotton yarn pretreated with a chitosan solution (with and without a crosslinking glyoxal solution), followed by dyeing with C. latifolium extract, provided better depth of shade and also gave better fastness to light and washing than the untreated cotton yarn. Post‐mordanting cotton yarn with a biomordant solution from Memecylon scutellatum leaves also gave good light and wash fastness of the resulting dyed cotton, comparable with the dyeing results with the less environmentally friendly alum as a mordant.     

Application of rare earth as mordant for the dyeing of ramie fabrics with natural dyes

Selecting appropriate metallic compounds as mordants is essential for dyeing with natural dyes. This paper presents the application of rare earth compounds as mordant for the dyeing of ramie fabrics with four kinds of natural dyes. The influences of pre-mordanting, simultaneous mordanting, and post-mordanting on the dyeing effect were explored. The post-mordanting was proved to give rise to the highest dye uptake. The effects of dyeing conditions including dyeing temperature and time, dyeing bath pH and the concentration of rare earth on the dye uptake were investigated systematically. The fabrics dyed with natural dyes in presence of rare earth as mordant exhibited high color shade stability in the baths with pH varying from being acidic to neutral and alkaline. Employing rare earth as mordant apparently raised the color fastness to washing, rubbing and light of the ramie fabrics dyed with the natural extracts. In comparison with the commonly used metallic salts, using rare earth chlorides as mordants can greatly reduce the ionic concentration employed in natural dyeing. This study proved that rare earth would be a kind or promising environmentally friendly mordant in natural dyeing.     

Dyes from the leaves of deciduous plants with a high tannin content for wool

The aqueous leaf extracts of five different deciduous plants, namely, silver oak, flame of the forest, tanner’s senna, wattle and serviceberry, were used on their own and in combination with aluminium sulphate, stannous chloride and ferrous sulphate to dye wool by a simultaneous mordanting technique. The washing and light fastness properties of the developed shades were moderate to good. Based on the CIE 2000 spectral colour coordinate values (K/S, ΔL, Δa, Δb and ΔE), the developed shades were classified into four groups: yellow/brown, yellow, orange and dark grey. The use of aluminium sulphate gave medium shades (K/S = 8.24), while the stannous chloride and ferrous sulphate mordants provided deep shades (K/S = 30.5). Statistical analyses have shown that only the type of mordant and not the dye source significantly influenced the development of colour on wool. Hence, it was theoretically possible to use five selected leaves as a single mixture to produce four different colours on wool.     

Pomegranate fallen leaves as a source of natural dye for mordant-free dyeing of wool

The application of metal mordants is usually necessary in dyeing of wool with natural dyes to improve the dye exhaustion and fastness properties. The majority of metal salts generally used as mordants are considered as toxic and it is important to find replacements for them. Plant sources with high content of tannins are good candidates as bio-mordant or colourant to overcome this drawback. In this study, the waste fallen leaves of pomegranate tree were used as a source of natural dye for the eco-friendly dyeing of wool fabric without the use of metal mordants. The dyeing process variables including dye concentration, dyebath pH, and temperature were optimised using response surface methodology to obtain the highest colour strength. The colour strength was increased by increasing the natural dye powder up to 100%owf while the optimum pH and dyebath temperature were 4 and 100°C, respectively. The sample dyed under the optimal condition exhibited good fastness properties against washing and light. This study approved the potential of Punica granatum fallen leaves for the dyeing of wool without any mordant, while high fastness properties were obtained.     

An innovative approach to the preparation of coloured and multifunctional silk material with the natural extracts from chestnut shell and black rice bran

In order to reutilise the byproducts of foods and crops to benefit the environment and economise on resources, the natural extracts from chestnut shell and black rice bran were applied in the simultaneous dyeing and multifunctionalisation of silk fabrics. In this work, the influence of pH value on dyeing properties was studied. The effects of the ratio of chestnut shell and black rice bran extracts and the application of mordants (aluminium potassium sulphate and ferrous sulphate) on the dyeing performance as well as anti-ultraviolet and antioxidant properties of treated silk were also discussed. The results showed that deep-coloured silk fabrics can be obtained when dyed with the two natural extracts as the pH value of the dyebath approached 3. The ratio of the two natural extracts and the use of the mordants have significant effects on colour depth, colour hue, colour fastness, and the functionalities of dyed silk fabrics. Combination dyeing and mordanting are able to enrich the colour hues of dyed fabrics. The washing, rubbing, and light fastness of the dyed fabrics after mordanting can be rated higher than grade 4. Moreover, the silk after combination dyeing has good UV protection performance (UPF > 30) and antioxidant activity. In addition, the functionalities of treated fabrics showed excellent washing fastness. This study reveals that chestnut shell and black rice bran extracts are suitable as natural colourants and multifunctional finishing agents for the preparation of coloured and multifunctional silk materials.     

Evaluation of antimicrobial and dyeing properties of walnut (Juglans regia L.) green husk extract for cosmetics

Walnut green husk is one of the main waste products from walnut and could be used as a source of natural dyeing compounds such as juglone. The present study was conducted to evaluate the effective use of walnut green husk extract as a natural hair dye. Dyeing properties, fastness and antimicrobial behaviours of dyed hair and also a skin irritation test for natural hair dye on rat skin were examined. When the extract was mixed with ascorbic acid as a developer, ferrous sulphate as a mordant, and Aloe vera extract used as a secondary mordant and also a cosmetic ingredient, the reaction resulted in a dark‐brown colour on hair samples. The dyed hair exhibited appropriate colour strength having excellent morphology for a hair surface coated with dye molecules. In addition, the dyed hair possessed good resistance to washing and daylight fastness, without any irritant properties as shown in a rat model, although high concentrations of iron‐based mordant may be problematic for long‐term usage. This paper also suggests the use of natural mordants such as lactic and oxalic acids to avoid any probable risks. Walnut green husk extract was an appropriate natural hair dyeing agent in practice and showed maximum antimicrobial activity compared with semi‐synthetic and commercial hair dyes. The results demonstrated that walnut green husk can be used as an economical, valuable, eco‐friendly and safe source of dyeing and antimicrobial agents for cosmetic products.     

Oxygen plasma pretreatment improves dyeing and antimicrobial properties of wool fabric dyed with natural extract from pomegranate peel

This paper presents the application of conventional potassium aluminium sulphate wool mordanting and a biochemical method with silver nitrate (as antimicrobial agent and mordant)_, alone and in combination with oxygen plasma, as part of comprehensive research into pretreatment processes for wool dyeing with natural extract from pomegranate peel (Punica granatum L.). Pretreatment with oxygen plasma significantly improved the hydrophilicity and tensile strength of all tested samples and showed that oxygen plasma can improve K/S, washing fastness, and even replace certain mordants in wool dyeing with natural pomegranate dye. All dyed samples exhibited good antibacterial activity against Staphylococcus aureus, which can be contributed to the phenol content in pomegranate dye. Only after 28 days of intensive ageing in natural weathering conditions did K/S and antibacterial activity against Klebsiella pneumoniae slightly decrease in dyed samples pretreated with oxygen plasma.     

Mordant dye application on cotton: optimisation and combination with natural dyes

It is well known that cotton fibres can be dyed through the formation of coordinate bonds involving cellulose chains, mordants such as alum, and natural dyes such as alizarin. Similarly, synthetic dyes known as mordant acid dyes can be used to dye wool fibres. Unlike mordant dyes on wool, the fastnesses of natural dyes on cotton are often low. Although concerns surrounding textile sustainability have sparked renewed interest in the use of natural dyes, extensive replacement of synthetic dyes with natural dyes is neither practical nor fundamentally possible. However, similarities in dyeing methods using mordant and natural dyes raise the possibility of using mordant dyes as alternatives to natural dyes in the dyeing of cotton. Further, the potential for combining suitable dyes from these two classes to expand the colour gamut currently available from natural dyes on cotton seem worthy of exploration. The results of this study indicate that shades comparable with those produced by natural dyes can be obtained on cotton using select mordant dyes following Fe²⁺ and Al³⁺ pretreatments. The best results were obtained using a two‐step/two‐bath process and dyes such as CI Mordant Blue 13 and CI Mordant Orange 6. In evaluations of mordant and natural dye combinations using the two mordant dyes logwood and Osage orange as prototypes, interesting fabric shades were obtained. However, the fastness properties of these dyes must be improved in order to produce commercially viable dyeings.     

The accelerating effect of a small cationic quaternary ammonium compound and the adsorption kinetics in the dyeing of silk with reactive dyes

In order to develop an eco‐friendly method for silk reactive dyeing that uses a lower accelerant dosage to achieve a higher dye fixation, hexyl dimethyl octyl ammonium chloride was synthesised as an accelerant for the dyeing of silk with reactive dyes. The accelerating effect, corresponding adsorption kinetics, and interaction mechanisms among hexyl dimethyl octyl ammonium chloride, reactive dyes, and silk were investigated. At hexyl dimethyl octyl ammonium chloride concentrations of 10.8–14.4 mm , the dye fixations for three reactive dyes were much higher than those achieved with sodium sulfate, even though the required dosages of hexyl dimethyl octyl ammonium chloride were 30–40 times lower than those of sodium sulfate. The wash fastness, rub fastness, light fastness, K/S, and colour difference values after dyeing with hexyl dimethyl octyl ammonium chloride were similar to those obtained using sodium sulfate, and silk can be dyed uniformly. The adsorption kinetics followed a second‐order kinetic model. The activation energies of surface adsorption for the three reactive dyes were lower than those of sodium sulfate. The high fixation of reactive dyestuffs and the low required dosage of hexyl dimethyl octyl ammonium chloride demonstrate that the use of this new accelerant provides a novel, highly efficient method for silk dyeing. A possible acceleration mechanism of hexyl dimethyl octyl ammonium chloride for reactive dyes adsorbed on the surface of silk was proposed, based on a series of activation parameters of the adsorption process.     

A method for dyeing cotton fabric with anthocyanin dyes extracted from mulberry (Morus rubra) fruits

For the first time, the natural anthocyanin dyes (mainly consisting of cyanidine 3‐glycoside) extracted from mulberry (Morus rubra) fruits has been successfully used to dye cotton fabric, with a dyeing property performance good enough for potential commercial applications. In this study, succinic acid was firstly incorporated into cotton fabrics by esterification to the hydroxyl groups of cellulose, forming an anionic site for the dyes. The performance of the modified material was characterised by Fourier transform infrared spectroscopy and tensile strength. Results showed that the tensile strength of cotton fabrics was mostly retained after modification. The anthocyanin extracts from mulberry fruits were used to study the dyeability of the control and modified cotton fabrics. Red and deep purple (aubergine) are two main shades of cotton fabrics dyed with mulberry fruit extracts. Most importantly, aubergine shade is rare in cotton fabrics dyed with natural dyes. Modification with succinic acid clearly increased the colour strength of the dyed cotton fabric. The colour strength of dyed cotton fabric was improved from 2.7 to 5.3 in the case of dyeing without mordants, and from 3.2 to 6.9 in the case of dyeing with tin mordanting. Meanwhile, the colour fastness was improved by 0.5–2 grades with increasing succinic acid concentration in the finish solution. The colour fastness to perspiration, crocking, light, and washing of fabric dyed with simultaneous tin mordanting and modified with 30 g l^?1 of succinic acid was found to be acceptable, with a grey scale grade of at least 3. As for home laundering, neutral soapy solution was more acceptable than alkaline soapy solution.     

Colorimetric and fastness studies and analysis by reversed‐phase high‐performance liquid chromatography with diode‐array detection of the dyeing of silk fabric with natural dye Helichrysum arenarium

In this study, silk fabric samples were dyed by various procedures using Helichrysum arenarium extracts. Alum, ferrous sulfate, stanium chloride, calcium nitrate, and potassium bitartrate were used as mordants. Reversed‐phase high‐performance liquid chromatography with diode‐array detection was utilised for identification of the dyes present in the dyed silk fabrics and the plant extracts. The extraction of dyes was carried out with a hydrochloric acid/methanol/water (2:1:1 v/v/v) mixture. The colour coordinates and K/S values, as well as wash, light, and rub fastness, were determined.     

Digital and conventional printing and dyeing with the natural dye annatto: optimisation and standardisation processes to meet future demands

The plant colorant annatto was investigated to determine its potential use as a natural dye for conventional and novel textile applications. Alum was selected as a mordant. Different techniques of mordanting and a broad set of variations in the dyeing recipes were applied to achieve optimisation and an improvement in colour fastness properties. Quality control of all dyeings was performed using standard fastness tests and colour measurements. Printing of cotton fabrics was also achieved with annatto using the flatbed screen‐printing technique. Measurement of the rheological and physical properties of the annatto printing paste confirmed its stability and suitability for conventional printing. Fastness properties of the conventionally printed annatto fabric were also measured. A novel water‐based digital printing ink using annatto was prepared and applied to cotton fabric using a digital printing application. The physical properties of the annatto ink‐jet ink were also measured. Wash, light and rub fastness properties of the annatto digitally printed fabric were determined and compared with those of conventional printing methods. The results were promising for annatto as a natural colorant, which possibly paves the way for the development of a new range of natural environmentally friendly dyes.     

Extraction of polyphenolic dyes from henna,pomegranate rind,and Pterocarya fraxinifolia for nylon 6 dyeing

Acid and disperse dyes are two well‐known synthetic materials that are primarily used for dyeing of nylon 6 fibres. Despite their good performance, several negative impacts on the environment, including air and water pollution, are major concerns to researchers. An alternative ecofriendly approach to the dyeing of nylon 6 is the use of natural dyes, given their abundant natural sources, biocompatibility, biodegradability, non‐toxicity, non‐allergic responses, and non‐carcinogenic effects on human life. Based on these advantages, we extracted polyphenolic dyes from henna leaves, pomegranate rind, and Pterocarya fraxinifolia leaves and studied the dyeability on nylon 6 fabric using three compounds of aluminium sulfate, tannic acid, and tin chloride as toxic and non‐toxic mordants before dyeing. Fourier transform infrared spectra of the nylon 6 fabric confirmed the coordination complexes and π–π bonding between the mordants and the dyes. Colorimetric and fastness results showed that the mordants increased the colour strength and improved the fastness properties of the fibres. Our results suggest that tin chloride and aluminium sulfate as metal mordants can be successfully replaced with tannic acid as a biomordant in the natural dyeing of nylon 6. Also, cost assay showed that dyeing of nylon 6 with extracted natural dyes from waste leaves could be a sustainable and economical substitute for synthetic dyeing.     

用红木叶生态染料染棉的工艺探讨

用生态染料红木叶对棉进行染色,采用不同的媒染剂,分别为明矾、氯化亚锡、氯化钙、硫酸铜和硫酸亚铁,不同的媒染剂浓度;同时结合预媒、同媒和后媒三种媒染方法进行试验,对试样在水洗、摩擦、日晒以及汗渍牢度等方面的性能差异进行了对比。     

Dyeing properties of textiles by Turkish hazelnut (Corylus colurna): leaves,coat, shell and dice

Turkey has a great number of hazelnut trees that possess nutritious components. However, only the inside part of the hazelnut is used as a nutrient, while the rest of it is waste. This study suggests that the waste parts of the Turkish hazelnut could be used as a natural dye for dyeing textile fabrics. The dyeing properties of the leaves, coat, shell and dice of the hazelnut were studied on wool, cotton and viscose fabric by using three different mordants: copper sulphate, iron sulphate and aluminium sulphate. The selected dyed fibre sample surfaces were observed using a scanning electron microscope. The colour strength (K/S), light, washing, rubbing, and perspiration fastness levels of the dyed fabrics were investigated. The experimental natural dyeing results indicate that waste hazelnut‐based products can be used as a natural dye for textile coloration.     

Natural dyeing with anthocyanins from Hibiscus rosa sinensis flowers

A new approach for natural dyeing with anthocyanin has been discussed along with a convenient method of extraction. Anthocyanin from Hibiscus flowers has been extracted by developing a method using methanolic solution of 4% citric acid. The new method gave better yield of anthocyanin as compared with methanolic solution of 0.1% hydrochloric acid. It has been also shown that pH of the extract plays an important role on the dye, thus by adjusting the pH of the extract at 4, dyeing of cotton and silk together with metal mordanting gave different colors. The best dyeing results were obtained for stannous mordanted fabrics in terms of fastness properties. The role of metal ion complexation of stannous salt with the dye extract has been confirmed through UV‐Vis and FTIR spectra. Antioxidant activity of the anthocyanin extract seemed to have contributed to enhance the fastness properties of the dyed fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011