High efficiency ultra-deep dyeing of cotton via mercerization and cationization

A potentially environmentally responsible dyeing procedure for ultra-deep shades on cotton was developed using a cationization method in combination with mercerization. The effects of both treatments on dyeing performance and colorfastness properties of cotton fabrics dyed with reactive dyes were analyzed individually and in combination. Both mercerization and cationization have been proved to be effective in increasing the depth of shade on cotton. The colorfastness properties, except colorfastness to wet crocking, of mercerized–cationized cotton fabrics dyed without salt were much better than untreated cotton dyed using a conventional dyeing procedure. Unlike untreated cotton fabrics, the concentration of Na₂CO₃ in the dyeing process of mercerized–cationized cotton fabrics was lowered from 20 to 5 g/L without compromising dye fixation and colorfastness properties. With low concentrations of dyes and Na₂CO₃ and no electrolyte in the dye bath effluent, the dyeing procedure of mercerized–cationized cotton fabrics for ultra-deep shades is potentially a more environmentally benign method than conventional dyeing with reactive dyes.     

Effect of UV radiation on the dyeing of cotton fabric with reactive blue 13

For the present study, the cotton fabric and dye solution were irradiated to UV radiation for different times. Dyeing was performed using un-irradiated and irradiated cotton with un-irradiated and irradiated reactive blue dye. Different dyeing parameters such as temperature, pH and time were optimized using irradiated dye and irradiated cotton. The data of colour report were obtained from un-irradiated and irradiated cotton dyed with reactive blue dye using spectra flash (SF650). Colourfastness properties show that UV radiation of both cotton and dye powder has improved the grading of fastness from fair to good. It is found that UV irradiation has not only enhanced the strength of dye on irradiated fabric but also improved the dyeing properties.     

Chemical cationization of cotton fabric for improved dye uptake

Cotton fabric is usually dyed with reactive dyes. During the dyeing process, a large amount of salt is required to achieve higher exhaustion of the dye from the dyebath onto the fiber. Dyeing of cotton with reactive dyes has a substantial environmental impact due to the discharge of a large volume of highly colored and saline effluents. Chemical cationization allows cotton fibers to be dyed without salt by chemically modifying cellulosic macromolecules to introduce positively charged sites. In this study, cotton fabric was cationized using (3-chloro-2-hydroxylpropyl) trimethyl-ammonium chloride (CHPTAC). Dye uptake was assessed using two reactive dyes, CI Reactive Blue 235 and CI Reactive Blue 19. Dye exhaustion kinetics were determined using a Datacolor-HueMetrix Monitor system. Analysis of variance demonstrated significant effects of CHPTAC concentration and exhaustion time on the percent exhaustion. Color strength at the end of the dyeing cycle was significantly higher for cationized fabrics compared to the control fabric. This work shows that treatment of cotton with CHPTAC enhanced dye uptake properties due to the introduction of cationic sites and resulted in superior dyeing without the addition of salt.     

Liquid ammonia dyeing of cationic ramie yarn with triazinyl reactive dyes

Cationic ramie yarn was prepared using a 2,3-epoxypropytrimethylammonium chloride agent. Subsequently, original and cationic ramie yarns were dyed in liquid ammonia with triazinyl reactive dyes (C.I. reactive orange 5, C.I. reactive red 2, and C.I. reactive green 19). The dyeing time was varied from 10 to 600 s with 10 % dye on mass of fabric (o.m.f) and dyeing concentration ranged from 1 to 100 % dye o.m.f for 600 s dyeing time at ?35 °C at a liquor ratio of 35:1 were evaluated. After dyeing, the samples were baked at 100 °C for 10 min. The results indicated that the time taken to attain equilibrium for the original ramie yarn was 60 s and was 300 s for the cationic yarn. The cationic treatment increased the dye exhaustion and fixation and improved the wash fastness, but decreased the degree of rub staining. Pseudo first-order and second-order kinetic models were used to describe the kinetic data. The adsorption process of the liquid ammonia dyeing followed the second-order kinetics. The Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms. The experimental data for dyeing untreated ramie yarn fitted the Freundlich model, but the kinetics of the cationic ramie yarn was found to fit the Langmuir isotherm.     

Surface and bulk cotton fibre modifications: plasma and cationization. Influence on dyeing with reactive dye

The surface of cotton fabrics was functionalized through corona plasma treatments and/or by cationising the whole of the fibre with an epihalohydrin. The effects of both treatments, individually and in combination are analyzed through wettability studies, by X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and also by dyeing studies with an hetero bis functional reactive dye. Plasma improved wetting properties, exhaustion of the dyebaths and K/S_corr of the fabrics through surface functionalisation. Cationising of the cotton highly increased the exhaustion of the dyebaths and produced a dramatic improvement in K/S_corr. Plasma treatment previous to cationising increased the impregnation of the fabrics, but the effects of both treatments on dyeing parameters are additive only in column water rise and generally the effects obtained by cationising with the epihalohydrin prevail. The differences between both treatments are discussed in terms of surface functionalisation of the cotton fibres.     

Effect of mercerization and gamma irradiation on the dyeing behaviour of cotton using stilbene based direct dye

The dyeing behaviour of mercerized and gamma irradiated cotton fabric using stilbene based direct dye has been investigated. The fabric was treated with different concentrations of alkali to optimize the mercerization. The optimum mercerized cotton fabric was irradiated to absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature, time of dyeing, pH of dyeing solutions and salt concentration were optimized. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organization (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It was found that mercerized and irradiated cotton have not only improved the colour strength but enhanced the rating of fastness properties also.     

Synthesis and Properties of Novel Reactive Dyes Comprising Acyl Fluoride Group on Cotton Fabrics

Novel reactive dyes with mono- and bi-acyl fluoride reactive groups have been designed and synthesized, which are obtained by using 2-amino-8-naphthol-6-sulfonic acid or 1-amino-8-naphthol-3,6-disulfonicacid as the coupling component and 4-aminobenzoyl fluoride (PABF) as the diazo component. Their structures have been defined by nuclear magnetic resonance spectroscopy and ultraviolet–visible spectra (UV—Vis). The novel reactive dyes were evaluated on cotton by using the exhaust dyeing method. The properties were examined in detail, and the results showed that the dye concentration of 4% (o.w.f), pH = 9, and salt-free was the most effective condition. The fixation of the novel reactive dyes on cotton was 60.27% and 64.13%, respectively. The micro-fluorine-containing reactive dyes have favorable dyeing properties owing to the covalent bond formed between the reactive group of dyes and the functional group of cotton fibers, which can achieve salt-free dyeing of cotton.     

Synthesis and characterization of reactive dyes based on 2-phenyl-3-[4′-(4″-aminophenylsulphonamido)]phenyl-4(3H)-quinazolinone-6-sulphonic acid

A series of new quinazolinone based mono azo reactive dyes (D_1–10) have been prepared by subsequent diazotization of 2-phenyl-3-[4′-(4″-aminophenylsulphonamido)]phenyl-4(3H)-quinazolinone-6-sulphonic acid (C) and coupling with various 4-chloro anilino cyanurated coupling components. These dyes give purple, red, orange and yellow color shades. All the reactive dyes were characterized by their percentage yield, UV–Vis spectroscopy, elemental analysis, IR spectroscopy, ¹H NMR spectroscopy and dyeing performance on silk, wool and cotton fibres. The percentage dye bath exhaustion on different fibres has been found to be reasonably good and acceptable. The dyed fibres show moderate to very good light fastness and good to excellent washing and rubbing fastness.     

Preparation and application of a β-cyclodextrin-disperse/reactive dye complex

A disperse and a disperse/reactive azo-dyes were prepared and characterised with spectroscopic methods. The complexes with β-cyclodextrin were prepared by a dry milling method. The characterisation of the complexes in solid state was performed by ¹³C CP MAS NMR, FT-IR, Raman spectroscopies and TGA–DTA analysis. The presence of the complexes in solution was evidenced with ESI-MS experiments. The products were used to dye synthetic (nylon, PET), natural (cotton) and cotton-PET blend fibres. Colour intensity and uniformity were evaluated by means of tristimulous colorimetry. β-Cyclodextrin, used as additive in dyeing baths, enhanced the colour intensity and uniformity of dyed samples. The complexes gave rise to a generalised good result. The disperse/reactive dye showed better fastness to washing properties on nylon 6 and cotton fibres. β-Cyclodextrin easily substituted the surface active agents, normally used in industrially dyeing processes, without loss in dyeing quality as dyeing uniformity, intensity and washing fastness.     

Chemical Graft of Cellulose with the Ion-Pair Emulsion Containing the Reactive Groups and Its Dyeing Properties

Chemical graft of cellulose with ion-pair disperse emulsion containing the reactive groups was investigated. The ion-pair disperse systems were consisted of a 1,3,5-triazine derivative containing the reactive groups, 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-HTAC) and 2,4,-bichloro[(6-sulfanilic acid)-1,3,5-triazine (Bi-CSAT). Compared with unmodified cellulose, the modified cotton exhibited different behavior towards dyeing. The modified cotton could be dyed with reactive dyes without the addition of salt. The color yield was higher than that on untreated cotton, despite of the addition of large amounts of salt in the latter case. Cotton fabric modified with ion-pair disperse emulsion was imparted good level dyeing properties. The dyeing rate was slower in the presence of the ion-pair compounds than that in the present of the only cationic compounds.     

Natural Dyeing of Modified Cotton Fabric with Cochineal Dye

Natural dyes are not harmful to the environment owing to their biodegradability. For dye application to textiles, salts are necessary as mordant or electrolytes and make an environmental impact. In this paper, the influence of cationization during mercerization to the dyeing of cotton fabric with natural dye from Dactylopius coccus was researched. For this purpose, bleached cotton fabric as well as fabric cationized with Rewin OS was pre-mordanted using iron(II) sulfate heptahydrate (FeSO₄·7H₂O) and dyed with natural cochineal dye with and without electrolyte addition. For the characterization of surface changes after cationization, an electrokinetic analysis on SurPASS was performed and compared to pre-mordanting. For determination of dye exhaustion, the analysis of dye solution was performed on a UV/VIS spectrophotometer Cary 50 Solascreen. Spectrophotometric analysis was performed using a Datacolor 850 spectrophotometer, measuring remission ”until tolerance” and the whiteness degree, color parameters, color depth (K/S), and colorfastness of dyed fabric were calculated. Levelness was determined by visual assessment. Cationized cotton fabrics showed better absorption and colorfastness. Pre-mordanting and cationization showed synergism. The electrolytes improved the process of dye absorption. However, when natural dyeing was performed on cotton fabric cationized during mercerization, similar chromacity, uniform color, and colorfastness were achieved with and without electrolyte, resulting in pure purple hue of cochineal. For achieving a violet hue, pre-mordanting with Fe-salt was needed. Therefore, salt can be reduced or even unnecessary, which makes this process of natural dyeing more environmentally friendly.     

Preparation of highly selective solid-phase extractants for Cibacron reactive dyes using molecularly imprinted polymers

Selective polymeric extractants were prepared for preconcentration of Cibacron reactive red dye, a dye that is often applied with Cibacron reactive blue and Cibacron reactive yellow for dyeing of fabrics. The best extractant was fabricated (in chloroform) using methacrylic acid (as monomer), ethylene glycol dimethacrylate (as crosslinker), AIBN (as initiator for polymerization), and red dye as template molecule, with a molar stoichiometric ratio of 8.0:40.0:2.5:0.63, respectively. The structure of the molecularly imprinted polymer (MIP) was robust, and resisted dissolution up to 260 °C. Compared with the un-imprinted polymer, the imprinted product has a large specific surface area which improved its adsorption capacity. The effect of imprinting was obvious from the adsorption capacity measured at pH 4 for red dye (the imprinted molecule), which was increased from 24.0 to 79.3 mg g⁻¹ after imprinting. Equilibrium adsorption studies revealed that the dye-imprinted-polymer enables efficient extraction of red dye even in the presence of blue and yellow dyes which have similar chemical natures to the red dye. The selectivity coefficients S _{red dye/dye}, were 13.9 and 17.1 relative to the yellow and blue dyes, respectively. The MIP was found to be effective for red dye preconcentration, with a preconcentration factor of 100, from tap water and treated textile wastewater. The factors affecting extraction of red dye by the MIP were studied and optimized. Under the optimized extraction conditions, red dye was selectively quantified in the presence of other competing dyes at a concentration of 20 μg L⁻¹ from different water systems with satisfactory recoveries (91–95%) and RSD values (∼5.0%).     

Macro-Reticular Ion Exchange Resins for Recovery of Direct Dyes from Spent Dyeing and Soaping Liquors

Dyes are a major class of organic pollutants that are well-known for their harmful impact on aquatic life and humans. Several new strategies for removing colours from industrial and residential effluents have recently emerged, with adsorption being the best option. The current study looked at the recovery of direct dyes from aqueous streams for reuse using macro-reticular ion exchange resins (IERs). The investigation includes dyeing single jersey cotton grey textiles with direct dyes from the Isma dye Company in Kafr El Dawar, Egypt. After centrifuging and separating the supernatant liquid, solutions from thirteen different dyes, produced at an average concentration between the wasted and soaping liquor concentrations, were calculated spectrophotometrically from the first dyeing trials. Kinetic data were well fitted with pseudo-second-order rate kinetics. The amounts of dye retained by the anion exchangers increased with a rise in temperature in the case of Strong Base Resin (SBR) and vice versa for Weak Base Resin (WBR). Batch adsorption experiments with SBR and WBR were conducted for each dye, and both Freundlich and Langmuir isotherms were constructed. It was found that adsorption obeyed both isotherms, that monolayer adsorption took place, and that the dye molecular weight, structure, and solubility, as well as the type of anionic resin used, had varying effects on the extent of absorption. The monolayer sorption capacities Q₀ determined from the Langmuir isotherm model for the strongly and weakly basic anion exchangers were found to be 537.6 and 692 mg/g for Direct Yellow RL, respectively. As a result, Yellow RL exhibited the greatest adsorption on both SBR and WBR. Orange GRLL, Blue 3B, and Congo Red, on the other hand, were the poorest colours absorbed by the IERs, whereas Blue RL demonstrated good adsorption by SBR and accelerated adsorption by WBR. Most of the dyes may be recovered and reused in this manner.     

Synthesis and dyeing performance of a novel polycarboxylic acid azo dye

A novel reactive polycarboxylic acid dye was synthesized by the reaction of polymaleic anhydride（PMA） with 3-methyl-1-（4- sulfonylphenyl）-4-（4-aminophenylazo）-2-pyrazoline-5-one.The structure of the novel dye was characterized by FTIR,UV-vis and ¹³C NMR spectra.The dyeing properties of dye on cotton were tested,and the novel dye possessed high fixation and good fastness.     

Synthesis,characterization and dyeing assessment of novel acid azo dyes and mordent acid azo dyes based on 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid on wool and silk fabrics

Novel acid mono azo and mordent acid mono azo dyes were synthesized by the coupling of diazonium salt solution of different aromatic amines with 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid. The resulting dyes were characterized by spectral techniques like elemental analysis, IR, ¹H-NMR and UV visible spectroscopy. The dyeing performance of all the dyes was evaluated on wool and silk fabrics. The dyeing of chrome pre-treated wool and silk fabrics showed better hues on mordented fabrics. Dyeing of wool and silk fabrics resulted in pinkish blue to red shades with very good depth and levelness. The dyed fabrics showed excellent to very good light, washing, perspiration, sublimation and rubbing fastness.     

Dyeing behaviour of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves (Lawsonia inermis)

Dyeing behavior of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves has been investigated. Cotton and dye powder are irradiated to different absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. The dyeing parameters such as dyeing time, electrolyte (salt) concentration and mordant concentrations using copper and iron as mordants are optimized. Dyeing is performed using un-irradiated and irradiated cotton with dye solutions and their color strength values are evaluated in CIE Lab system using Spectraflash –SF650. Methods suggested by International Standard Organization (ISO) have been employed to investigate the colourfastness properties such as colourfastness to light, washing and rubbing of irradiated dyed fabric. It is found that gamma ray treatment of cotton dyed with extracts of henna leaves has significantly improved the color strength as well as enhanced the rating of fastness properties.     

The accessibility of cellulose as determined by dye adsorption

The accessibility of cotton cellulose was determined after it had been mercerized both in the slack and tension states. Mercerized samples were either dried or retained in the undried state before dyeing to determine their accessibilities by the adsorption of Direct Blue 1. Samples were characterized also by techniques such as moisture adsorption, water retention value (WRV) and X-ray analysis. It appeared that the crystallinity of cotton mercerized under tension was slightly increased during dyeing. Dye adsorption increased in the order nonmercerized <tension-mercerized <slack-mercerized. Products mercerized and not dried adsorbed more dye than counterparts given the same swelling treatment but dried after mercerization. The presence of dye in a sample mercerized and undried before dyeing did not affect its crystallinity. From both the dye adsorption and WRV data it was concluded that structural collapse of the fibre is greater for the slack-mercerized product than its tension-mercerized counterpart after it is dried. It was also concluded from dye adsorption and water adsorption data that about 34% of the internal surface of cotton and mercerized cotton, available for water adsorption, is inaccessible to Direct Blue 1.     

分散染料染色法制备的彩色聚(苯乙烯-丙烯酸)纳米球

在低于聚合物纳米球玻璃化转变温度(110.69 ℃)的条件下,用两种分散染料对聚(苯乙烯-丙烯酸)[P(St-co-AA)]纳米球染色,研究了染色温度(75~95 ℃)和染料用量(1%~5%)对纳米球上染料吸附量的影响。 结果表明,染色温度越高,分散染料用量越大,所得到聚合物纳米球的颜色越深越鲜艳。 分子结构中氨基和羟基数量多的分散蓝2BLN在纳米球上的吸附量低于相同染料用量时分散红FB的吸附量。 经过染色后纳米球的表面变得很粗糙,粒径增加23 nm。 用彩色纳米球对经过阳离子化处理的棉织物进行染色,利用很少量的彩色纳米球,就可以使织物获得较深且鲜艳的颜色。     

Improvement of colour strength and colourfastness properties of gamma irradiated cotton using reactive black-5

The dyeing behaviour of gamma irradiated cotton fabric using Reactive Black-5 dye powder has been investigated. The mercerized, bleached and plain weaved cotton fabric was irradiated to different absorbed doses of 100, 200, 300, 400, 500 and 600 Gy using Co-60 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature of dyeing, time of dyeing and pH of dyeing solutions were optimised. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organisation (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It is found that gamma irradiated cotton dyed with Reactive Black-5 has not only improved the colour strength but also enhanced the rating of fastness properties.     

蓝色盐VB和快磺素的可见-紫外定量测定法

建立了快磺素的可见-紫外定量测定方法。蓝色盐VB转变成快磺素再测定。在波长265nm或427nm处,样品浓度5～40mg·L-1时,浓度与吸光度呈线性,可用于工业分析。