Application of D‐optimal design in the analysis and modelling of dyeing of plasma‐treated wool with three natural dyes

Both the dyeing and finishing of textiles with natural compounds are gaining increasing attention because of various environmental and health problems associated with the use of synthetic reagents. In this study, wool fibres were dyed with three natural dyes, namely, Arnebia euchroma, cotton pods and harmal seeds. Alum was used as the mordant, and samples were mordanted by the premordanting method. Oxygen plasma was employed for the surface modification of wool. Plasma treatment time, alum concentration, dyebath temperature and pH were selected as the process variables, and their effects on the K/S of the dyed samples were analysed using D‐optimal design. The surface topography, morphology and chemistry of the wool fibres after plasma treatment were studied by atomic force microscopy (AFM), scanning electron microscopy (SEM) and Fourier Transform–infrared spectroscopy (FTIR), respectively. FTIR confirmed the creation of new oxygen‐containing groups on the surface of wool fibres after plasma treatment. SEM and AFM images confirmed the surface etching and increase in the roughness of plasma‐treated fibres. Increasing the dyebath pH and temperature increased the K/S of the dyed samples. Increasing the amount of alum mordant increased the K/S of samples dyed with cotton pods but decreased the K/S of samples dyed with A. euchroma and harmal seeds. Increasing the plasma treatment time improved the K/S of samples dyed with A. euchroma and cotton pods but had no significant effect on the K/S of samples dyed with harmal seeds.     

Investigation and feed-forward neural network-based estimation of dyeing properties of air plasma treated wool fabric dyed with natural dye obtained from Hibiscus sabdariffa

In the colouring processes of textile products, more environmentally friendly chemicals and finishing methods should be used instead of conventional ones that harm the environment every day, so that alternative realistic ways to protect nature, both academically and industrially, could be possible. Due to some inconveniences caused by synthetic dyes that are widely used today, in this study, ultrasonic dyeing of wool fabric with Hibiscus sabdariffa was carried out after environmental-friendly air vacuum plasma application which increased the absorption of the dyes into the textile material. According to the performance results, colour strengths of the wool fabrics were increased significantly. Surface morphology analysis was carried out and etching effects of air vacuum plasma treatment were clearly seen on the micrographs of the treated wool fabrics. An environmental-friendly green process was achieved through this study and it was concluded that vacuum air plasma treatment could be an alternative green-process as a pretreatment to increase the dye up-take of natural dyeing treatment. Moreover, in this study, a feed-forward neural network (FFNN) model was presented and used for predicting the dyeing properties (L, a, b and K/S) of samples. The experimental results showed that the presented model achieves the regression values greater than 0.9 for all dyeing properties. Consequently, it was considered that the proposed FFNN was successfully modelled and could be efficiently utilised for dyeing characteristics of wool fabrics dyed with natural dye extracted from Hibiscus sabdariffa.     

Effect of atmospheric pressure helium plasma on felting and low temperature dyeing of wool

Wool fabrics were treated with atmospheric pressure helium glow discharge plasma in an attempt to improve felting and dyeing behavior with cold brand reactive dyes using cold pad‐batch method at neutral pH. On glow plasma treatment, the hydrophilicity of wool surface and its resistance toward felting was greatly improved without any significant damage to the cuticle layer. The color strength of the plasma treated dyed wool on the surface (in terms of K/S) was found to be nearly double of the color strength of dyed untreated wool fabric. However, the corresponding total dye uptake of the treated wool increased by a much lower value of 40%–50%. The reason behind this altered dyeing behavior was investigated by studying the dye kinetics using infinite bath and surface characteristics using SEM and SIMS. It was found that the glow plasma treatment greatly transformed the chemical surface of the wool fibers. It resulted in uniform removal of hydrophobic cuticular layer, which resulted in better diffusion of the dye molecules into the fiber, and formation of hydrophilic ? NH₂ groups near the surface, which helped in anchoring the dye molecules close to the surface giving higher color strength than expected. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Topping of naturally dyed wool fabrics with different natural dye sources

Wool fabrics can be dyed with synthetic dyes and even with natural dyes. To present a different aspect to the coloration of wool, the current study was focused on a topping process (ie, the dyeing of wool that was already dyed) with different natural dye sources. For this purpose, the fabrics that were already dyed with a natural dye source were once again dyed with two different natural dyes. In bottom dyeing (bottoming), fabrics were dyed with hops (Humulus lupulus L.) in the presence of different mordanting agents. Then the dyed, washed and dried samples were once again dyed (topping) with two different natural dye sources. For topping, powdered madder and acorn were tested in direct dyeing of wool samples. Finally, the colour changes were analysed with the use of a spectrophotometer. The study demonstrates that such a process (ie, bottoming with hops in the presence of different mordanting agents and then topping with madder or acorn) can be a way of obtaining different shades and colours with sufficient/good fastness values by natural dyeing.     

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.     

Color evaluation of wool fabric dyed with Rhizoma coptidis extract

Berberine is the only cationic colorant of natural plant dyes, which lies in the roots of Rhizoma coptidis and stems of phellodendron. In this study, wool fabric was dyed with the extracts of R. coptidis. Color evaluation was characterized with ΔE, L*, a*, b*, c*, H⁰, K/S. Effects of mordant, extraction concentration, pH value of dye bath, and treatment temperature on color values were studied. Results indicated that wool fabrics dyed with mordant, or at higher temperature, or in alkali solution possessed deeper shades and darker colors. And the wool fabric showed good antibacterial property after dyeing with R. coptidis extracts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3376–3380, 2006     

Effects of lugworm protease on the dyeing properties of protein fibers

A lugworm protease, Perinereis aibuhitensis, was used to improve the dyeing properties of protein fibers such as wool and silk. The optimal condition for the activity of the lugworm protease was about 40 °C at pH 7. The wool and silk were treated with the protease extracted from a lugworm and the K/S values of the dyed wool and silk were measured using a spectrophotometer in order to compare the dye uptake. The protease treatment enhanced the dyeing properties of protein fibers without severe changes in their mechanical properties. The surface appearances of protease-treated fibers were observed via microscopy.     

Cetylpyridinium chloride cationic finishing improves the dyeing and antibacterial properties of madder dyed cotton

In this work, after cationic pretreatment of cotton fabric with cetylpyridinium chloride (CPC), the compound of citric acid (CA) and succinic acid (SUA) were used as crosslinking agents to dye cotton fabrics with natural madder dye to improve the dyeing and antibacterial properties and realise the multifunctional finishing of cotton fabric. The effects of mordant dyeing, CA + SUA crosslinked dyeing, and CPC/CA + SUA crosslinked dyeing on the microstructure and properties of cotton fabrics were compared. The dyeing by the three processes occurred primarily in the amorphous zone of the fibres, and all kept the original crystalline form of the cotton. CA + SUA crosslinked dyeing and CPC/CA + SUA crosslinked dyeing increased the thermal stability of the cotton fabric. CPC/CA + SUA crosslinked dyed cotton obtained excellent dyeing results with the colour depth value (K/S) of 12.3 and rubbing fastness and washing fastness of levels 4–5, and the levelness and dye permeability were acceptable. Furthermore, the antibacterial rate against Escherichia coli and Staphylococcus aureus reached 99.99%, and the ultraviolet protection factor (UPF) reached 50+. Moreover, the wrinkle recovery angle (WRA) increased by 55% compared with raw cotton. This showed that CPC/CA + SUA crosslinked dyed cotton had excellent antibacterial, anti-ultraviolet, and anti-wrinkle performances.     

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 and antibacterial activity of atmospheric‐plasma‐treated nylon 6 fabric

Atmospheric plasma treatment as an environmentally friendly method was employed to modify the surface properties and improve the absorption of natural cationic dye on to nylon 6 fabric. Nylon fabric was treated in atmospheric air plasma, and the surface characteristics of the fabric were evaluated using attenuated total reflection Fourier Transform‐infrared analysis, scanning electron microscopy, and a wicking test. The effects of plasma treatment and mordanting with copper sulfate on the dye uptake of the samples were investigated. Plasma‐treated and mordanted samples showed the highest colour strength when dyed. The antibacterial activity of samples was evaluated according to AATCC test method 100‐2004. Premordanting with copper sulfate showed a synergistic effect on the antibacterial properties of the dyed fabric. The plasma‐treated and copper‐sulfate‐mordanted sample showed acceptable antibacterial activity against both gram‐negative and gram‐positive bacteria when dyed with an extract from Berberis vulgaris, berberine.     

Simultaneous antimicrobial and dyeing of wool: A facial method

This study is carried out to examine the effects of simultaneous dyeing and antimicrobial finishing of wool yarns. Wool yarns were dyed with acid dye along with colloidal silver nanoparticles through the exhaustion method in a one‐bath. Different concentrations of nanosilver were examined to evaluate its influences on the color and the antibacterial properties of the yarns. The antibacterial property of the sample has been tested by a Gram‐negative bacterium Escherichia coli and a Gram‐positive bacterium Staphylococcus aureus. Also, the tenacity of wool yarns, color, and rubbing fastness of the dyed yarns has been measured. The color fastness against washing and antibacterial property of the dyed yarns after 10 laundering cycles was also considered. The fiber morphology was studied by SEM pattern, EDX, and X‐ray diffractometer. The results showed that the wool yarns dyed with acid dye along with 25 ppm of silver nanoparticles exhibited a very good antimicrobial effect even after 10 laundering cycles on S. aureus while the rubbing fastness remained unchanged, and the color fastness and tenacity were even improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Natural functionalisation of a traditional textile “Ehram”

This study is focused on the natural functionalisation of a traditional woven fabric called “Ehram”. Which is a wool based woven fabric constituted from wool yarns that are originally coloured and used in different cities of the Eastern Anatolian Region, Turkey. Because these fabrics were originally coloured (pigmented), the study aimed to functionalise them with minimal colour changes from their original colour. For this aim; lavender (Lavandula angustifolia) which is also a natural source of pleasant odour was used in finishing of Ehram. The colour changes by the application of the lavender on Ehram and the benefits that come out from the use of lavender were then analysed and presented in the study. In this respect, antibacterial activities (against Staphylococcus aureus and Escherichia coli) of dyed samples were tested within the scope of the study. In addition, colour measurements (K/S and CIE L*a*b* C* and h^o) and FTIR (Fourier-transform infrared) microspectroscopy analyses of dyed fabric samples were made and microscope images were taken. It was observed that lavender with a copper-based mordanting agent can present antibacterial activity against S. aureus and E. coli in Ehram.     

Decolorisation by Bacillus flexus of exhausted dyebaths containing CI Acid Red 249 and their reuse for wool dyeing

A dyebath containing left-over CI Acid Red 249 after dyeing of wool was completely decolorised using an isolated bacteria Bacillus flexus. Optimisation was carried out by varying the pH, temperature, dye concentration, and microbial loading. Complete decolorisation of a 50 mg l⁻¹ dye solution was achieved in 8 h at pH 7 and 37 °C with 10% v/v loading of the bacteria. The decolorised bath was utilised for dyeing of wool fabric with the same dye at 5% shade. This cycle of dyeing–decolorising–dyeing was repeated 5 times. The evaluation of dyed fabric was done using K/S, colour values, and fastness to light and washing. Comparison of a sample dyed with the conventional exhaust process showed that the dyeing quality is not affected for all five successive reuse cycles. The results are important from the viewpoint of reducing water consumption and chemicals.     

The effect of mordant salts on antibacterial activity of wool fabric dyed with pomegranate and walnut shell extracts

Natural dyes have attracted increasing worldwide attention because of the carcinogenicity and environmental effects of synthetic dyes. In this study, wool fabric was treated with tannin‐rich extracts of Punica granatum peel and walnut shell in combination with some mordants. The effect of various mordants on the colorimetric and antibacterial properties of wool fabrics was investigated. The results showed that pretreatment with metallic mordants substantially improved the dyeing and fastness properties of wool fabrics. The extracts of Punica granatum peel and walnut shell showed a significant antibacterial activity at 5% concentration. In addition, antibacterial activity was dramatically enhanced using metallic salts. The antibacterial activity of samples dyed with natural dyes and without any mordant was not good, while the mordanted samples with copper, aluminum and tin salts obtained considerable antimicrobial properties following lightening and washing fastness. The extracts of Punica granatum peel and walnut shell can be considered as viable alternatives instead of artificial antibacterial agents for hospital textiles as well as an effective anti‐odour agent for sports and household textiles.     

Improving the UV resistance of aromatic poly(l,3,4‐oxadiazole) fiber using a disperse dye modified with octavinyl POSS. Part 1: Preparation of dye and dyeing

Modified dyes were obtained by grafting of disperse dyes with octavinyl polyhedral oligomeric silsesquioxanes (POSS) using a Friedel‐Crafts alkylation reaction and using different ratios of POSS and the original disperse dye. The modified dyes are used to dye aromatic poly(l,3,4‐oxadiazole) (p‐POD) fiber to improve its UV resistance. Then the structure of the modified dye is characterized by Fourier transform infrared spectroscopy and NMR, and the effects of the structure of the modified dye and the dyeing conditions on the UV resistance and color strength (K/S value) of the dyed samples are investigated. The results indicated that the UV adsorption peaks of the modified dye solutions are located at the specified UV wavelengths. The UV resistance of the p‐POD fiber dyed with the modified dye (1:3) can be effectively improved, and the dyed p‐POD fiber can obtain a higher K/S value simultaneously. During the dyeing process, increasing the dyeing temperature and prolonging the dyeing time are both beneficial in improving the anti‐UV ability of the dyed p‐POD fiber; these changes can effectively promote the fixation of dye molecules into p‐POD fibers due to stimulating the motion of dye molecules and p‐POD macromolecules. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44745.     

A significant approach to dye cotton in supercritical carbon dioxide with fluorotriazine reactive dyes

A series of fluorotriazine reactive dyes have been synthesized and applied to dye cotton in supercritical carbon dioxide (scCO₂) with good dyeing results. The pieces of cotton to be dyed were previously presoaked in a protic solvent and cosolvents were applied during dyeing. The colour strength of the dyeings was evaluated by K/S measurements. The K/S values achieved on cotton dyed were up to 35.8 ± 4.2. Even after the cotton was subjected to a Shoxlet extraction at 358 K for 1 h, a maximum K/S value of 20.2 ± 1.8 was measured. The percentage of dye molecules chemically fixed to the cotton was on average 85%. The excellent reactivity of fluorotriazines allowed a reduction of 3 h on the dyeing time. It is noticeable that a dye concentration of 10% on weight of the fibre (owf) can be applied to dye cotton with fluorotriazines, since no damage of the cotton fibres occurred, as observed for the chlorotriazines at this high dye concentration.Dyes with fluorotriazine as reactive group were found to be the most preferable dyes for dyeing cotton in scCO₂, as they were able to exceed the limitation of the reaction with the cotton.     

Dyeing,fastness, and deodorizing properties of cotton,silk, and wool fabrics dyed with coffee sludge (Coffea arabica L.) extract

A natural colorant was extracted from Coffea arabica L., using water as extractant at 90°C for 90 min. Studies have been made on the dyeing, color fastness, and deodorization properties of cotton, silk, and wool fabrics dyed with Coffea arabica L. extract solutions. The best mordants were found to be FeSO_4, CuSO₄, and SnSO₄ for improving the color strength (K/S) of cotton, silk, and wool fabrics. Mordants MnSO₄, ZnSO₄, and NiSO₄ for cotton (Rating 3), and all mordants except MnSO₄ for silk (Rating 3), mordants CuSO₄, FeSO₄, CoSO₄, Al₂(SO₄)₃, and MnSO₄ for wool (Rating 4) were the best mordants to improve the light fastness. It was found that FeSO₄ and CuSO₄ were the best mordants for the improvements of color strength (K/S) and light fastness for silk and wool fabrics. In addition, it was found that cotton, silk, and wool fabrics dyed with the Coffea arabica L. extract showed good deodorization performance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 251–257, 2007     

A novel strategy to improve the dyeing properties in laccase-mediated coloration of wool fabric

Enzymatic coloration of fabrics has received worldwide attention in recent years. In order to improve the dyeing properties of enzymatically coloured fabrics, a novel strategy using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), a biological coupling agent, to pretreat wool fabric was employed in this paper. Enzymatic coloration of wool fabrics with syringic acid was carried out in the presence of laccase from Trametes versicolor. The effect of different periods on laccase-catalysed polymerisation of syringic acid was examined by UV-vis spectroscopy. Enzymatic coloration results of dyed wool fabrics were evaluated by means of K/S value and colour difference (∆E*). Process parameters, including the dosages of syringic acid and incubation time, that influenced the colour depth were studied. Meanwhile, the colour fastness and levelness of dyed wool fabrics were tested. The results showed that the UV-vis absorbance of reaction solution increased as oxidation time elapsed, and a new peak appeared at 360 nm. After pretreatment, the K/S values and colour difference values of wool fabrics dyed with poly(syringic acid) improved appreciably compared with the control samples without any pretreatment. Moreover, pretreated wool fabrics showed better dyeing fastness and levelness than control samples.     

Energy‐efficient dyeing of nylon 6 using indigo powder dyestuff after atmospheric plasma treatment at ambient pressure

Nylon 6 was treated with a dielectric barrier discharge, i.e. atmospheric plasma at ordinary air pressure. Factors influencing the dyeing process of nylon 6 using indigo blue powder were studied. The mechanism and effect of this dyeing technology were compared with those of conventional technology. Dyeing after plasma treatment at 30–50 °C can produce high dye uptake in a short time. Notably, dyeing after plasma treatment is beneficial for energy conservation. However, at 60–70 °C, the K/S values of plasma‐treatment dyeing sharply increased over a short time, after which they remained largely unchanged. This finding indicated that the dyeing mechanism changed. The speed constant of dyeing after plasma treatment is 2.8 times that of conventional dyeing. The K/S values of dyeing samples after plasma treatment approached the dyeing saturation K/S value in a short time; therefore, this method of dyeing after plasma treatment achieves energy conservation and efficiency in a brief period of time. Conversely, conventional dyeing is more effective at high temperatures but consumes more energy. The adaptive electro‐discharge condition is achieved under the treatment conditions of 375 W for 2 min. The chromatic aberration of the dyed samples after plasma treatment is smaller than that of conventional dyeing at 50 °C for 75 min.     

Dyeing transition temperature of wools treated with low temperature plasma,liquid ammonia,and high‐pressure steam in dyeing with acid and disperse dyes

Wool fibers treated with oxygen low‐temperature plasma, liquid ammonia (NH₃), and high‐pressure (HP) steam were dyed with two acid and three disperse dyes. Rate of dyeing, saturation dye uptake, and dyeing transition temperature were measured. Rate of dyeing of the O₂ plasma, NH₃, and HP steam‐treated wools increased with acid dyes, whereas it did not increase with disperse dyes. Although dyeing transition temperature for acid dyes was decreased by the plasma, NH₃, and HP steam treatments, the temperature for disperse dyes was not changed by the treatments. Therefore, it seems that acid dyes penetrate by the intercellular diffusion through the interscale Cell Membrane Complex (CMC) of wool, whereas disperse dyes penetrate by the intracellular diffusion through the intrascale cuticle surface independently with CMC relaxation by the treatments. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1058–1062, 2001