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The purpose of this paper is to synthesise a tetrakisazo reactive dye and to characterise its dyeing property to meet the demand for better black reactive dyes.

The novel tetrakisazo navy-blue reactive dye based on 4,4′-diaminostilbene-2,2′-disulphonic acid was designed and synthesized. The dyeing behaviour of it on cotton fabric was discussed. The synergistic blackening effect and absorbance spectra were investigated by absorbance and reflectance spectra, K/S and colorimetric data.

The exhaustion and fixation of the designed reactive dye were higher than 20 per cent than those of the commercial reactive dye, CI Reactive Black 5. The novel reactive dye has complementary with Reactive Red SPB and Reactive Yellow C-5R in absorbance spectra from 360 to 700 nm. Three reactive dyes had synergistic effect in colour deepening properties. The dyed cotton fabric possessed high K/S value and low reflectance in the whole visual spectrum range from 360 to 700 nm.

Comparison with the commercial Reactive Black DN-RN, the blackness of the dyed fabrics with the mixture dyes was greatly improved and the fastness properties on cotton fabrics were also good.

The paper is an original research work. Because the mixture dyes had better blackness and good fastness properties, it would have wide application in the dyeing of cotton fabric.

This paper aims to examine the loss of tenacity and colorfastness properties of bleached and modified (acrylonitrile, AN and methacrylonitrile, MAN) jute fibres dyed with Reactive Orange 14 and Basic Violet 14.

Jute fibres dyed with Reactive Orange 14 and Basic Violet 14 were studied as a function of exposure to sunlight in air, washing with soap solution and spotting with acids and alkalis.

Dye absorption of Basic Violet 14 was higher compared to Reactive Orange 14 at optimum dyeing conditions. Optimum dye uptake of Reactive Orange 14 required relatively severe conditions compared to that of Basic Violet 14. Whereas, Reactive Orange 14 showed overall good colorfastness to sunlight and moderate in washing compared to Basic Violet 14. All the bleached and modified fibres showed good colorfastness to weak acids and alkalis regardless of Reactive Orange 14 and Basic Violet 14 dyes. The loss in tenacity was higher in the case of non-modified fibres, and among the modified fibres, Basic Violet 14 showed the lowest loss in tenacity in the exposure to sunlight.

Many studies have been devoted to improve the substantivity of cellulosic fibre for reactive dyes. A few efforts were made to improve the light fastness. In this work, investigation will be made on a comparative study of loss of tenacity and colorfastness properties of bleached and modified (AN and MAN) jute fibres dyed with both Reactive Orange 14 and Basic Violet 14 on exposure to sunlight, washing and acid and alkali spotting. Optimum dyeing conditions will also be investigated for economic dyeing.

New disazo and polyazo ureido reactive dyes incorporating different reactive systems were synthesized and applied to cotton fabric by the exhaust dyeing method. Different factors affecting the dye ability and fastness properties of such dyes are investigated.

Bis(monochlorotriazine) reactive dyes displayed higher primary exhaustion values compared to those obtained with bis(sulphatoethysulphone) and bis(monochlorotriazine/sulphatoethysulphone) reactive dyes under different neutral exhaustion conditions. The results obtained indicate that the fixation efficiencies of these dyes were higher than those of dyes incorporating the bis(dichlorotriazine) reactive system. The results assessed for alkaline exhaust dyeing indicate that the bis(monochlorotriazine/sulphatoethylsulphone) dye was less sensitive to the variation in fixation temperatures than the other reactive dyes. The fastness properties of the ureido reactive dyes were fair to good.

The improved dyeing performance of such type of ureido reactive dyes should lead to the design of reactive dyes with good application and fastness properties on cotton fabric, and provide practical solutions for low-salt dyeing. The present study of synthesis of disazo and polyazo ureido reactive dyes of high molecular structure, and its application to cotton fabric by the exhaust dyeing method is novel and could be applied in the industry.

Fibre reactive dyes are very popular for cellulosic garments as they are environmentally safe and having good overall fastness properties. But application of these dyes requires a very high concentration of salt. The salt released from garment dyeing increases salinity in drain water stream which has a negative impact on environmental ecology. The present work aims to eliminate the usage of salt during dyeing of cotton goods with reactive dyes.

The methodology adopted here, for the elimination of salt in cotton dyeing, was based on the principle of cationisation (to develop a positive charge) of cotton. The same was achieved by subjecting the caustic pretreated cotton fabric samples to a treatment of 1, 2 dichloroethane followed by methylamine to introduce amino groups in the cellulose structure. The treated cotton when dyed from slightly acidic bath generates positive sites due to protonation in the amino group. The reactive dyes being anionic (negatively charged) in solution get attracted to the positive charges on the fibre which eliminates the salt requirements for satisfactory dye exhaustion.

The investigation was conducted for cold brand, hot brand and highly exhaustive reactive dyes. The modified cotton showed excellent dye exhaustion for all the dyes in the absence of salt. The treatment was found to improve the dye fixation also. The modification was assessed through elemental analysis.

This study may be further extended to viscose material after suitably modifying the treatment conditions.

A pretreatment to cotton which could eliminate the usage of salt in its dyeing with reactive dyes is revealed.

The study explored a newer technique of cotton dyeing without salt usage. Both garment dyeing units and fabric/yarn finishing industries would thus be helpful.

This paper aims to decolorize the effluents of textile Reactive Orange 5 and Reactive Red 195 dyes by using cationized sugarcane bagasse.

Cationized sugarcane bagasse was prepared and used as an adsorbent for both reactive and hydrolyzed reactive dyes. Characterization of the sugarcane bagasse structure resulted by cationization was monitored using Fourier transform–infrared, while morphologically was detected using scanning electron microscopy and X-ray powder diffraction.

The maximum adsorption capacities are 805, 1,664, 1,772 and 1,596 mg/g for Hydrolyzed Red 195, Hydrolyzed Orange 5, Reactive Red 195 and Reactive Orange 5 dyes, respectively.

Factors affecting the percentage of dye removal were optimized on different parameters such as adsorbent dose and treatment time. The data were discussed using the Langmuir and Freundlich Models of adsorption.

The reuse of hydrolyzed reactive dyebaths gives reasonably good fastness properties on nylon fabrics.

The study has enabled the production of an eco-friendly and less expensive method of reactive dye effluent decolorization.

The study provides a potentially simple approach to decolorize dye effluents of Reactive Orange 5, Red 195 dyes and also the reuse of hydrolyzed reactive dyebaths for dyeing nylon.

The purpose of this paper is to evaluate the efficiency of modifying reactive azo dyes using pyrazolo[1,2‐a]pyrazole fused systems as the chromophoric moiety which could satisfy many and varied criteria drawn from economic, synthetic, physicochemical and fastness properties.

Six novel heterocyclic disazo reactive dyes were prepared, containing monofunctional sulphatoethylsulphone (SES) and hetero‐bifunctional monochlorotriazine (MCT)/SES reactive groups. Dyes intermediates based on 4‐arylazo‐1,5‐dioxopyrazolo[1,2‐a]pyrazole chromophoric moieties are initially synthesised and coupled with two different diazonium salts having the aforementioned reactive groups, thus yielding the new target reactive dyes. The synthesised dyes are applied to cotton, wool and silk fabrics under the typical exhaust dyeing conditions and their dyeing properties were investigated.

The results assessed for dyeing indicate high‐quality dyeing properties. However, the heterobifunctional MCT/SES dyes showed higher exhaustion and fixation values, colour yields and fastness properties than those of the monofunctional SES dyes.

The method developed provided a simple and practical procedure for producing fused pyrazolo[1,2‐a]pyrazole disazo chromophoric systems that afford valuable reactive dyes. In addition, the dyes intermediates based on 4‐arylazo‐1,5‐dioxopyrazolo[1,2‐a]pyrazole as well as their disazo counterparts could be applied as acid dyes to wool and silk.

The method for producing novel disazo reactive dyes could find numerous applications for affording a variety of reactive dyes with different binding linkages and structural reactivity. These could be valuable as reactive dyes with different colour shades.

Reactive and direct dyes are the most frequently used dyes for cotton fabrics. Cellulosic fibers pose a great affinity toward them. However, both dyes consume large quantities of salts for exhaustion; these electrolytes (salt) are discharged as effluents posing environmental problems and disorders in aquatic life. Therefore, this study aims to explore alternative approaches to minimize salt consumption.

For this study, the combination of chitosan and keratin, being sustainable biopolymers, are used as mordants instead of salts for the cationization of 100% cotton and chief value cotton (CVC) during dyeing with direct and reactive dyes. Color strength, exhaustion rates and color fastness to washing, rubbing and perspiration have been evaluated in this paper. In this research, keratin solution is applied on cotton and CVC (with the cotton to polyester ratio of 80%:20%) fabrics by pad-dry-cure, while chitosan solution has been applied with the exhaust method. The pretreated fabrics are dyed with both direct and reactive dyes with 2% and 4% depth of shade (DOS). The performance of the cationized fabrics with salt-free dyeing method was compared with the conventional dyeing.

The results of this study showed positive impact on exhaustion rates ranged from 19% to 69% of the values obtained without salt in 2% DOS and a range of 22%–47% in 4% DOS of reactive and direct dyes with treated samples. Color fastness to crocking results indicated the improvement of results by a factor of 0.5–1 after treatment and good wash fastnesses rating (4.5/5) were achieved for the chitosan-keratin treated fabrics equivalent to untreated samples. In addition, antimicrobial testing was performed on both treated and untreated fabrics of cotton and CVC. The results indicated that chitosan treated samples showed greater inhibition toward microbial activity as compared to keratin treated samples. Fourier transform infrared (FTIR) spectroscopy was used to identify the functional groups of chitosan and keratin treated fabric samples to confirm their presence. In the FTIR spectra, the chitosan was characterized by its hydroxyl, carbonyl and amide III peaks indicating the presence of chitosan and keratin was detected by the presence of primary amines. Scanning electron microscopy analysis was conducted in which it was visibly seen that the fibers have been coated with chitosan and keratin laid after being dyed.

For the first time, direct and reactive dyes are applied on chitosan and keratin-treated cotton and CVC to obtain multifunctional and eco-friendly fabrics.

This study aims to synthesise and characterise new reactive dyes based on thiazole derivatives which act as chromophoric moieties. These dyes were applied to cotton fabric, resulting in the dyed fabrics exhibiting good colour strength, light fastness and other fastness properties. The antibacterial activity of the dyed cotton fabric was evaluated against gram-negative and gram-positive bacteria.

The dyes were synthesised in two steps. First, the coupling compound was formed by adding H-acid solution to cyanuric chloride in an ice bath at pH 5 then adding 4-aminobenzenesulphonic acid portion-wise at room temperature and at pH 6-7. Second, different diazonium salts 4-phenylthiazol-2-amine (2a) and 4-(4-methoxyphenyl) thiazol-2-amine (2b) were coupled with the coupling compound at pH 5. The resultant monochlorotriazine (MCT)-reactive dyes (6a, 6b) were formed. The synthesised dyes were applied onto cotton fabric under typical exhaust dyeing conditions and their dyeing properties were investigated.

High antimicrobial activity, dye exhaustion and fixation yield on cotton fabric were recorded for each dye. All dyes showed high stability against washing, rubbing, perspiration and light fastness.

Dyeing of cotton fabric with these dyes which have higher fastness, higher exhaustion and higher antibacterial activity is considered one of the most important reactive dyes species.

The preparation procedure showed the synthesis of the novel MCT-reactive dyes derived from thiazole derivatives followed by the application of these dyes on cotton fabrics.

Use of reactive dyes will bring a number of benefits to society including higher fastness and higher antibacterial activity so, and these dyes can be used for dyeing cotton.

In this work, the new reactive dyes derived from thiazole derivatives were synthesised and their structures were confirmed by the analytical and spectral data. Such compounds are considered to be excellent reactive dyes with different colour shades and higher antibacterial activity.

The purpose of this paper is to synthesise, characterise and find out properties of some new bifunctional dyes bis (monochlorotriazine) using tetrahydrobenzo[b]thiophene systems as the chromophoric moiety, bearing good colour strength, lightfastness, and other favourable properties.

The novel reactive dyes were prepared, containing bis monochlorotriazine as reactive groups. The dye is synthesised by diazotization and coupling reactions. Firstly the authors synthesised the ethyl 2‐amino 4,5,6,7‐tetrahydrobenzo[b]thiophen‐3‐carboxylate chromophoric moiety compound which in turn underwent diazotization and coupling then diazotized and coupled reaction with either 1‐amino‐8‐naphthol‐3,6‐disulphonic acid (H‐acid) and or 2‐amino‐8‐naphthol‐6‐sulphonic (γ acid) to give the monoazo dye intermediates compounds. The latter products reacted with 2,4,6‐trichloro‐1,3,5‐triazine in 1:1 molar ratio afforded, via nucleophilic displacement when subjected to condensation 2,4,6‐trichloro‐1,3,5‐triazine in 1:1 molar ratio afforded via nucleophilic displacement, which reacted with 1,4‐phenylenediamine in 2:1 molar ratio to give reaction with the 1,4‐phenylenediamine in 2:1 molar ratio, the bisazobifunctional bismonochlorotriazine reactive dyes.bisazo bifunctional bismonochlorotriazine reactive dyes thus yielding the new target reactive. The synthesised dyes were applied onto cotton fabric under the typical exhaust dyeing conditions and their dyeing properties were investigated.

The results assessed for dyeing indicate high quality dyeing properties However, the homobifunctional (bis MCT) dyes showed higher exhaustion and fixation values, colour yield and fastness properties.

The described method showed the synthesis of bis monochlorotriazines derived from the tetrahydrobenzo[b]thiophene derivative 3 followed by their application towards cotton fabric.

Social implications are to prepare new reactive dyes having higher fastness and uses for dyeing cotton which is the commonest fabric use.

In this work, the novel reactive dyes derived from the tetrahydrobenzo[b]thiophene derivative 3 were synthesized and their structures were based on the analytical and spectral data. Such a group of compounds are considered to be excellent reactive dyes with different colour shades.

Reactive dyes are believed to have great potential for nylon dyeing, but these anionic dyes tend to rush toward the nylon at the beginning of the process, resulting in uneven dyeing. Achieving uniformity gets even harder when the dyeing is performed under exposure to eco-friendly technique microwave irradiations. This study aims to achieve rapid and homogenous results by intermittent shaking and non-continuous exposure to microwave.

A set of reactive red dyes, based on the same chromophore and different substituents in the auxochrome part, was applied to the nylon fabric without any leveling agent. A series of experiments were designed to investigate the effect of different dye structures, exhaustion pH, liquor ratio, exhaustion time and fixation time to obtain an optimum recipe under the microwave dyeing technique.

Dyeing performance was characterized based on the color strength, exhaustion and fixation percentages and color fastness values. The characterization showed that better results can be achieved at a liquor ratio of 1:15 at exhaustion pH 2.7 which is also the isoelectric point of nylon, with 5.5 to 7 min of exhaustion and 6 to 8 min of fixation time for different dyes. Microwave dyed samples secured higher color strength values and provided better exhaustion and fixation than the conventional dye samples. Furthermore, the X-ray diffraction results verified that there was no considerable difference in the morphological structure of nylon with microwave exposure.

An applied technique is disclosed in this work to achieve uniform dyeing on nylon 66 with reactive dyes without any leveling agent under exposure to eco-friendly rapid heating microwave irradiations.