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Reactive dye is widely used for cotton dyeing, but its low utilization results in vast amounts of colored effluent with high salinity discharge. Amino-modified Reactive Red 195/P(styrene-co-butyl acrylate-co-trimethyl(vinylbenzyl) ammonium chloride) nanospheres (Am-RPNs) are a kind of novel colorant that exhibit excellent dyeing ability for cotton fabrics and higher dye utilization than original reactive dyes. The colored polymer nanospheres demonstrated small size, high stability and dye content in the dispersion system when cationic polymer nanospheres were dyed at an optimal dye dosage of 100%. Transmission electron microscopy images showed that the polymer nanospheres have smooth spherical shapes. Am-RPNs with an average hydration diameter of 96.5 nm and zeta potential of −33.7 mV were fabricated after being modified with ethylenediamine at pH 11. Both analytical techniques, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, indicated the presence of –NH2 on the surface of Am-RPNs. The amino-modification mechanism of the Reactive Red 195/P(styrene-co-butyl acrylate-co-trimethyl(vinylbenzyl) ammonium chloride) nanospheres depended on the dyeing bath pH. The color depths of the cotton fabrics dyed with Am-RPNs reached up to 3.1 times higher than those with Reactive Red 195. Scanning electron microscopy images showed that Am-RPNs form stable deposits on the surface of the modified fibers. The cotton fabrics dyed with Am-RPNs possessed excellent rubbing and washing fastness, satisfactory light fastness, and desirable handle. This study provides an innovative method that employ Am-RPNs with high coloration performance to endow the cotton fabric with deep color and good colorfastness without using inorganic salt.

S-triazine di-sulfanilic guar gum (TSG) was successfully prepared by monochlorotriazine di-sulfanilic (TS) and guar gum (GG) in order to improve the printing properties in reactive printing. The results showed that the optimized synthesis condition of TSG was at sodium carbonate solution 1.2 g/L at 90℃ for 75 min through the single-factor experiment. Compared to GG, TSG had better flowability, mainly viscous effects and higher viscosity recoverability, which was more appropriate as a thickener in reactive printing. In the cotton printing experiment, TSG had higher paste add-on, color yield, penetration and levelness than GG. Furthermore, the printing effects of TSG on cotton drew near to those of sodium alginate, which could obtain evenly colored large patterns and excellent outline sharpness.

Reactive dyes maintain a long reaction with fiber and show a high dye uptake and fixation rate, and effectively decrease the dyeing waste water in siloxane reverse micro-emulsion. However, little research has been carried out into the hydrolysis reaction of reactive dyes in reverse micro-emulsion. In this study, Reactive Blue 19 was selected as a model vinyl sulfone reactive dye to study its hydrolysis in siloxane reverse micro-emulsion. The hydrolysis reaction was analyzed using high performance liquid chromatography. The results show that the hydrolysis rate of vinyl sulfone dyes in siloxane reverse micro-emulsion was slower than that in a traditional bath. Influences due to the ratio of aqueous dye solution to siloxane, non-ionic surfactant, cellulose fiber, and temperature on the hydrolysis reaction of vinyl sulfone reactive dye were also researched. The results show that with more aqueous solution emulsified in the siloxane media, the hydrolysis reaction of vinyl sulfone dye is faster. Reactive dyes were emulsified into a water micro-environment with non-ionic surfactant, which formed reverse micro-emulsion, and decreased the content of free water; this further influenced the hydrolysis of reactive dye.

Bleached cotton fabric was chemically modified (cationized)with natural amino acids extract obtained by acid hydrolysis (6N HCL) from soya bean seed waste, adding MgCl2 as an acid donor in the pad-dry-calendaring process to investigate the changes in textile properties and its dyeability with reactive dye in both a conventional alkaline dye bath and salt-free acidic dye bath. This modified cotton incorporates new functional groups producing [Formula: see text] in acid bath to obtain cationized cotton, rendering it to eco-friendly salt-free reactive dyeing at acceptable shade depth without much sacrifice of other textile-related properties. Bi-functional high exhaustion-type reactive dye shows better dye uptake than mono-functional cold brand as well as hot brand reactive dye. Moreover, the application of a specific dye fixing agent further improves surface color depth ( K/ S) of the soya-modified cotton fabric. The study of surface morphology of said chemically modified cotton substrate indicates a higher degree of surface deposition, that is, more anchorage of soya extracted amino acids on cotton fabric. Chemical anchorage as per the reaction scheme postulated for such modifications is verified with Fourier transform infrared spectroscopy. Finally, it is revealed that cotton treated with soya extract provides a new route of eco-friendly salt-free reactive dyeing with high exhaustion-type reactive dyes showing much higher dye uptake than the control cotton fabric.

The research focused on the structural, sorption and dyeing properties of enzymatically treated viscose fibers and chitosan/cellulose fibers compared to the untreated fibers. First, both fibers were treated with cellulase enzymes for 30 minutes and 90 minutes and afterwards were dyed with the commercial sample of CI Reactive Red 238 at three different dye concentrations. Comparison of the structural and sorption properties of untreated and enzymatically treated fibers showed that the enzymatic treatment lowered the degree of polymerization, as well as crystallinity degree and influenced the surface structure of fibers, resulting in enhanced sorption properties and dyeability of enzymatically treated fibers. Although the values of exhaustion and fixation were higher for chitosan/cellulose fibers because of their initial less-ordered crystalline structure, the 90 minutes of enzymatic treatment has increased the moisture content and water retention capability more for the viscose fibers and hence their dyeability compared to chitosan/cellulose fibers. The 90-minute enzymatically pretreated viscose fibers reached the same exhaustion and fixation values at lower dye concentrations as chitosan/cellulose fibers.

The influence of coloration on ultraviolet (UV) protection of cotton knitted fabrics with different knit structures incorporated with the three major stitch types, namely knit, tuck and miss stitches, are studied in four approaches. The effects of color depth and knit structures on the ultraviolet protection factor (UPF) of fabrics are investigated. The influences of hue and color depth on the UPF of fabrics are also compared. Since UV protection offered by dyes mainly depends on their chemical structures, the UPF and color strength of fabrics colored by reactive dyes that varied in reactive groups, such as mono-functional and bi-functional reactive dyes, are examined. The correlations between UPF and the CIELAB color coordinates, color strength ( K/ Ssum), are analyzed. The results show that light-colored fabrics with compact structures achieve similar or even better UV protection than the dark-colored fabrics with loose structures. This implies that color property might not be a reliable indicator for UV protection of knitted fabrics and the effect of coloration on UV protection is affected by fabric construction. The results also denote that the chemical structure of reactive dyes affects the UV protection of fabrics in a qualitative approach that depends on the unique ultraviolet radiation blocking ability of the chemical constituents. Among the color coordinates investigated, only lightness ( L*) and K/ Ssum are found to be correlated with the UPF of the fabrics, but the strength of correlations is not very strong. This is because the fabric characteristics that have significant impacts of UV protection are mostly not involved in the measurement of color properties.

To reduce environmental pollution by CI reactive red 195, solvent extraction of the dye from water was performed by using reverse micelles prepared from hexadecyltrimethylammonium bromide and amyl alcohol. The effects of dye concentration, surfactant concentration, sodium chloride concentration, and pH on the removal percentage of the dye were investigated. A pseudo-first-order kinetic model and an ion-exchange reaction model were used to fit the experimental data. Ultraviolet-visible absorption spectra and particle size distribution were analyzed to evaluate the state of the dyes in the reverse micelles. In addition, the dyes were recovered by backward extraction and then reused for dyeing cotton fabric. The removal percentage of CI reactive red 195 increased with increasing concentrations of surfactant and sodium chloride. Increasing dye concentration and pH values resulted in less removal of dyes. The dye extraction process could be described by the pseudo-first-order kinetic model and by the ion-exchange reaction equations. The state of the dye in the reverse micelles was similar to that in bulk water. The mean particle diameter of the reverse micelles was 10.8 nm. Dye recovery was improved by adding a counterionic surfactant. The recovered CI reactive red 195 had a good dyeing property for cotton fabric.

A new approach for ultraviolet (UV) protection of cotton fabrics based on TiO2 nano-sol and reactive dye was studied. Cotton fabrics were cationized with different amounts of 3-chloro-2-hydroxypropyl trimethylammonium chloride. TiO2 nano-sol was prepared by the sol-gel method using tetraisopropyl orthotitanate and applied on cationized cotton fabrics with different quantities using the same finishing formulation and treatment sequence. Treated fabrics were then dyed with various concentrations of BH-3RS-Reactive yellow 176. Samples were further tested for UV protection factor, color strength, color fastness to washing, durability and tensile strength. The chemical and morphological structures of the coated fabrics were characterized by attenuated total reflection–Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffractometry. Cationized cotton fabrics treated with TiO2 nano-sol and dyed with reactive dye showed better UV protection with slight reduction in color depth ( K/ S) and tensile strength.

In this study, sodium alginate (SA) and xanthan (XG), selected as two typical pastes, were intensively investigated by steady, transient, and dynamic rheological methods. Compared with SA, in the steady-shear tests it was found that XG showed a prominent shear-thinning feature at low shear rates and low concentrations. In addition, the transient tests suggested that XG had more remarkable hysteresis thixotropy and that the structural viscosity needed more time to return to its original level after shears. What is more, two pastes in the same concentration performed totally different viscoelastic behaviors from the dynamic tests. SA exhibited more viscous behavior and XG more elastic behavior. Furthermore, experimental data have been correlated with different models: flow curves with the Cross and power-law model, mechanical spectra with the Friedrich–Braun model and Generalized Maxwell model. The relationship between dynamic and steady-shear properties (Cox–Merz rule) was satisfactory for SA while undesirable for XG. Through the rheological properties, it may be inferred that those who show weaker elasticity, stronger viscosity, relatively steady viscoelasticity, and the structural viscosity liable to restore the original level after shears may be more appropriate as the pastes to achieve better printing qualities on cotton printing with reactive dye.

The removal of the color of dye from wastewaters is one of the main problems of the textile industry for both colorists and manufacturers. In this study, ozone gas was used to decolorize the reactive dye effluents. Nine commercial dyes were used for preparing the reactive dye effluents. These dyes have different three anchors (monochlorotriazine, vinylsulphone, monochlorotriazine-vinylsulphone) and three chromophore groups (monoazo, diazo, azo-cu). Thus, in this study, the effect of ozone treatments was investigated on the decolorization efficiency of dyes having different chromophore and anchor groups. In addition, the effect of ozone on the decolorization efficiency depending on the presence of ultrasound energy and dyeing auxiliaries was studied. The results showed that ozonation treatment was an effective method for the decolorization of reactive dye effluents and, generally, the presence of ultrasound had generally positive effect on the efficiency of decolorization.

In this study, ozonation process was used for decolorization of five commercial reactive dyes (Remazol Brilliant Red 3BS-A 150%, Remazol Yellow 3R-SA 133%, Remazol Blue R Special, Remazol Turquoise G 133% and Remazol Brilliant Blue BB), having various chromophore groups (monoazo, anthraquinone, phthalocyanine, formazan copper complex). The aim of the study was to examine in detail the effect of the major system parameters on the decolorization efficiency of ozone and to compare the effectiveness of ozone in decolorization of reactive dye effluents depending on the dye chromophore. The parameters, which were examined separately, are the solution pH and the ozonation time. Ozonation process was carried out in batch system and the ozone production rate was 1000 mg/h. In the study, it was found that color removal efficiencies, depending on the dye chromophore, vary from 83% to 96% and 34% to 93% in the ozonation processes carried out with and without pH adjustment, respectively. Furthermore, according to the experimental results, it can be concluded that the ozonation process could be effectively used in decolorization of reactive dyes especially having copper formazan and anthraquinone chromophores.

The decolorization of solutions containing the textile reactive dye Orange II by the bacteria Geobacillus stearothermophilus (UCP 986) was investigated. The experiments were statistically evaluated by two-level-four factor (2 4) full factorial design, as aeration, azo dye concentration, inoculum size, and culture media. The best results were with Luria Bertani (LB) medium under aeration, and the decolorization efficiency meant that 96—98% of the azo dye was removed after 24 h of incubation. The efficiency of LB medium in color reduction was due to a co-metabolic process. Sulphanilic acid (4-aminobenzene sulphonic acid) was not detected. The testing for toxicity using the brine shrimp Artemia salina showed the absence of toxic metabolites during the decolorization process; however, when the concentration of the dye and agitation were high (0.050 mM and 150 rpm) the shrimp showed high mortality rates (LC50 (lethal dose — assay concentration able to cause 50% of death) 49.28% v/v). The parameters such as culture medium and agitation are significantly important to the decolorization of the Orange II process. G. stearothermophilus (UCP 986) showed a high biotechnology potential for textile bioremediation of azo dye under the co-metabolic process.

Cotton fabric was alkaline scoured with sodium hydroxide and bioscoured with acid or alkaline pectinases. In addition, the scoured fabrics were bleached with hydrogen peroxide (HP) or peracetic acid (PAA). The cotton fabric was treated simultaneously with pectinases and PAA in a one-bath process. The CIE whiteness, water absorbency, weight loss, tenacity at maximum load, and dyeability with a reactive dye were evaluated on differently pretreated samples. The remaining scouring and bleaching baths were analyzed for ecological parameters including pH, total organic carbon (TOC), chemical oxygen demand (COD), and biological oxygen demand (BOD5). The quantity of water and energy used for different processes was estimated. The water absorbency of all scoured fabrics was satisfactory. The degree of whiteness of all bleached fabrics was improved. The highest degrees of whiteness were from HP bleached samples. Less whiteness was achieved in PAA bleached samples. The whiteness was greater in the alkaline scoured fabrics relative to the enzymatic scoured fabrics. One-bath processes produced whiteness values comparable to alkaline scouring and bleaching with PAA. Neither of the processes had little effect on the tenacity at maximum load. All samples were evenly dyed with reactive dye. There was a remarkable color difference between samples that were alkaline or enzymatically scoured before dyeing and between differently bleached samples. On the other hand, there was no noticeable color difference between samples that were scoured and bleached in two-bath or one-bath processes before dyeing. In comparison to conventional pretreatment, less energy and water is used in enzymatic and/or PAA treatments since they proceed at 60°C and at a pH between 6 and 8. Therefore, neutralization is unnecessary. The remaining baths are biodegradable. During the one-bath scouring/bleaching process, the consumption of water and energy was even lower and the production time was shorter.

Environmental and public health issues associated with dyes and their effluents are problematic areas for any dyehouse. If the toxicity and color of dyeing effluent can be predicted quantitatively before dyeing, one can select suitable dyes to reduce envi ronmental pollution. This study examines the acute toxicity of dyes and associated auxiliaries in terms of EC50, and these data are used to predict the toxicity of the dyeing effluent. The prediction accuracy is satisfactory when some statistical ap proaches, such as linear and nonlinear regression, are used. Furthermore, in order to make the toxicity data much easier to understand and much more directly comparable with each other, a toxicity index has been created according to the EC50 values in this study. Incorporating the toxicity information of the dyes with a computer color matching system permits the prediction of effluent toxicity generated by colorant recipes. This should assist colorists to select a "greener" formula while satisfying basic color quality requirements and will let colorists know well ahead of time the impact of toxicity from the effluent on the environment.

Cotton is subjected to one-bath dyeing and durable press finishing (ODF) with dialde hyde and a monochlorotriazinyl reactive dye. Results indicate that an optimal curing temperature is 150°C to simultaneously fix dialdehyde and reactive dye on cotton.- Changing the immersion temperature and time (40°C for 20 minutes) in the treatment bath greatly enhances the efficiency of the ODF process with dialdehyde and reactive dye.

Kinetic and optical behaviors of Cibacron™ Yellow R, Scarlet 2GE, and Blue TRE are studied individually and in mixtures. In mixtures, these dyes deviate from their individual behaviors. A method for determining these deviations and for correlating the optical and kinetic deviations is demonstrated. This method is valuable because it allows the kinetic behavior of dyes in mixtures to be characterized from simple optical measurements.

An attempt was made to dye alkali swollen and alkali swollen solvent exchanged cotton with a C.I. Reactive Blue 5 dye from the mixture of dimethylformamide and various nonpolar solvents. At a suitable dimethylformamide-nonpolar solvent ratio and alkali concentration used for cotton pre-swelling, it was possible to get 100% dye bath exhaustion and dye fixation as high as 77%. The dyeability of cotton was dependent on the dielectric constant of the nonpolar solvent and its absence in the internal liquid phase closely associated with the fiber as demonstrated by the im bibition values.

Reactive dyes are strongly covalently bonded with fibers, which ensures an exceptionally high dyefastness with regard to many physico-chemical factors, but with the exception of lightfastness. This article deals with the specific features of reactive dye fading on textile materials, depending on the nature of the bond between the dye and fiber, the dye concen tration in the fiber, and the spectral characteristics of the dyes exposed to mono- and polychromatic light.

An attempt was made to dye an aqueous alkali swollen cotton with CI Reactive Red-31 from polar/nonpolar solvent mixtures. For this purpose acetone was selected as the nonpolar solvent and the various polar solvents were water, formamide, di methylsulfoxide, dimethylformamide, and dimethylacetamide. At a suitable ratio of solvent mixture and alkali concentration used for cotton preswelling, it was possible to get 100% dye bath exhaustion and dye fixation of 79-82%, except from dimeth ylformamide-acetone and dimethylacetamide-acetone solvent mixtures. The propor tion of polar-nonpolar solvent necessary to get highest dye bath exhaustion and dye fixation was dependent on the dielectric constant of the polar solvent. Some of the polar solvents were good swelling agents for cotton as indicated by their imbibition values and high dyebath exhaustion. It was therefore possible to carry out dyeing without water preswelling; however, since the alkali used for dye fixation was insoluble in the solvents, aqueous alkali preswelling was essential. Concentration of alkali re quired during preswelling to get maximum dye exhaustion and fixation was different for different polar solvent-acetone mixtures. This was attributed to the desorption and readsorption of alkali from the solvent mixtures to different extents.

A unique system for simultaneously dyeing and texturing polyester/viscose blended yarn is reported. Dyeing and texturing were accomplished by pad-thermosol and alkali shock treatment. A single bath was used, containing a mixture of disperse and reactive dye, along with dimethyloldihydroxyethyleneurea and an acid catalyst. Dye fixation and texturing were achieved by baking the treated yarn on a Scragg Mini bulk machine using a heater temperature of 210°C for 2.5-5 seconds; however, higher color yields and wash fastness were obtained by post-alkali shock treatment. The results of continuous dyeing and texturing also show a very uniform coloring and high color yield as compared to that obtained by the cross-dyeing involving high temperature dyeing followed by pad-alkali shock treatment of textured yarns. The crimp rigidity and the tensile properties of simultaneously dyed and textured yarns were also not affected in any way, because the dyeing step was incorporated with texturing.

A new microscopical technique for differentiating the skin—core structure of viscose rayon fibers is described. Slide preparations mounting fiber cross sections are stained with an alkaline solution of Procion Black HGS, which is a Procion dye recently mar keted by ICI as a chemically reactive dye for cellulose fibers. This technique is found to furnish a staining entirely selective for the skin area in a simple and rapid way. Since it is well established that Procion dyes do react chemically with cellulose mole cules under alkaline conditions, it is highly probable that the differential staining pro duced by the present technique is due to a definite difference existing between the skin and the core with respect to the chemical reactivity toward the dye employed. This differentiation mechanism appears to be quite different from that which is generally accepted to be the case in the previously described techniques using ordinary dyes. Typical results are presented for several types of cellulose rayons showing various staining behaviors. It is seen that these results are in good agreement with those obtained by other stain methods. The same procedure, when applied to a variety of fibers other than cellulosics, is found to give positive staining reactions only to wool, silk, regenerated protein, and Vinylon fibers. Although most of these findings are as yet not satisfactorily explained, reactive dye staining of this kind seems to be of much promise in the field of fiber micros copy.

The effect of urea on formation and cleavage of a covalent bond between a reactive dye and cellulose has been investigated. The evidence presented is consistent with the view that urea increases the bonded dye yield by keeping the reactive dye in solution during the diffusion of the dye to its reaction site. Urea does not increase the water content of the fabric by retarding evaporation during drying; with urea, the water content of the fabric is lower. Urea can also decrease the bonded dye yield. In combination with alkali and heat, urea enhances cleavage of an ether-type dye-cellulose bond, but has only a slight effect on an ester-type bond. The over-all effect of urea on reactive dyeing is shown to depend upon the solvolytic stability of a dye-fiber bond under specific dyeing conditions.

The manipulation of the physical characteristics of nonwovens and paper by variation of fiber and web geometry is briefly reviewed in terms of a new system of bonding in which the adhesive interfiber forces are a consequence of ionic chemical bonds. These bonds were created by the sequential covalent introduction of anionic sites onto the interior and exterior surfaces of microporous pulp and rayon fibers using a chloro-s-triazinyl fiber reactive dye and subsequent stoichiometric reaction with crosslinking polycations derived from ethylenimine. The tensile properties of both the pulp and rayon fiber assemblages were significantly augmented as a result of the development of both ionic inter- and intra-fiber bonds.

A novel type of fiber reactive dye is described which eliminates chloride, alkoxide, or arylovide ions to produce a dyed fiber in which the amino groups of the fiber constitute a part of the chromophoric system. 3-Chloro-, 3-alkoxy-, and 3-aryloxy-Δ 1.α-indenemalononitriles and Δ1,2'-indene-1,3-indandiones had weak absorption maxima below 300 nm and dyed cellulose ester and polyester fabrics had pale yellow-orange shades. Dyeings on nylon 66 resulted in displacement of the 3-suhstituents by the amino groups of the fiber to give intense violet or blue dyeings. These compounds are members of a new class of fiber-reactive dyes.