Feasibility of using digital color imaging devices for the determination of cationic dyes compatibility

In the present research, the compatibility of dyes was evaluated using a scanner by the application of the method proposed by Khalili and Amirshahi, which had been proved as a novel and accurate method for evaluating the compatibility behavior of dye mixtures. A dip‐test method was employed to dye samples, compatibility panels, in binary combinations of cationic dyes on acrylic fibers. In order to use the scanner, first the device was colorimetrically characterized using a regression technique. The tristimulus values obtained from the scanner were, then, used for the reconstruction of the reflectance of the compatibility panels by principal component analysis. Next, the reconstructed reflectance of the panels were transferred to the corresponding K/S spectra and the Khalili and Amirshahi proposed method applied to the spectra in order to obtain the percentage variance (PV), which is the criterion of the dye compatibility. The comparison between the PVs obtained from the scanner and the corresponding one calculated by the spectrophotometrically measured reflectance of the compatibility panels showed a very significant correlation of the compatibility results regarding Pearson correlation coefficients and their K values. It was concluded that due to the smoothness of the reconstructed spectra and the performance of the PCA method of the reconstruction, which manifest itself in the good spectral reconstruction, the scanner method joined with the Khalili and Amirshahi proposed method can reliably be used for the determination of dye mixtures compatibility by a dip test. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 337–345, 2017     

Dye–fiber interactions in PET fibers: Hydrogen bonding studied by IR‐spectroscopy

Dye–fiber interactions are studied in poly (ethylene terephthalate) fibers by FT‐IR spectroscopy. It is shown for the first time that DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) serves as an easy applicable and accurate technique for the study of fibrous structures. This article focuses on the possible hydrogen bond interactions in the dye–fiber system, where the PET fibers are dyed with anthraquinone‐based disperse dyes. The dyes and related anthraquinone structures are studied in both the dilute solution state, the solid state, and as present in the PET fibers. It is proven that 1‐amino anthraquinones show strong “chelate‐type” intramolecular hydrogen bonding in all three states. In the fibers an important supplementary intermolecular hydrogen bonding with the C?O groups in the PET fiber is observed. The extend of hydrogen bonding seems to be prone to dye concentration variations. Further analysis by modulated differential scanning calorimetry links the hydrogen bonding to an intrinsic plasticizing effect of the dyes affecting the dye diffusion process. This thus offers a tool for the fundamental understanding of the dyeing process and possible observed differences in dyeing behavior in dye–fiber systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Desorption and transfer processes in different classes of dyes

We report an analytical approach to study dye desorption and transfer processes in aqueous environment. The study was conducted simulating standard laundry washes using two different donor textiles, a polyester textile dyed with Disperse Blue 79 and a cotton textile dyed with Reactive Red 239, and two acceptor textiles, undyed cotton and polyester, respectively. Dye bleeding/solubilization from a donor textile to the solution was investigated through UV–visible absorbance analysis, while the dye absorption onto acceptor textile was quantified by UV–visible reflectance analysis. Dye desorption and transfer processes were investigated in water and surfactant solutions at different concentrations. A desorption and transfer model for the two classes of dyes was hypothesized by performing kinetic experiments. The results show that both processes depend on the presence of surfactants for the disperse dye. Conversely, the presence of surfactants has little effect on the reactive dye. Finally, the presence of an acceptor polyester significantly increases the bleeding of the disperse dye, while the presence of an acceptor textiles less influences the total release of the reactive dye.     

Textile applications of photochromic dyes. Part 2: factors affecting the photocoloration of textiles screen‐printed with commercial photochromic dyes

The performance of five commercial photochromic dyes applied by screen printing on textiles was evaluated using a colour measurement methodology which has previously been established and validated. Printing as disperse dyes on polyester gives the strongest photochromic effect when the dye is located near the surface. However, the dyes are applied more effectively using an adaptation of a pigment printing method. Several factors influencing the photochromic properties of the printed textiles were evaluated. The ultraviolet reflecting properties of cotton give a higher level of photocoloration than on polyester. In the dyes studied, the spirooxazines show slightly faster colour development and fade much more rapidly than the naphthopyrans, and the latter show a residual colour after fading. The effect of the ultraviolet irradiation wavelength profile on the photochromic response may be correlated with the ultraviolet absorption spectra of the dyes.     

Styryl dyes – synthesis and applications during the last 15 years

One of the most widely used and important groups of functional dyes are the styryl dyes and a review of this functional dye class has not been published for more than 15 years. In this review article, we describe the new trends in the synthesis of a range of novel intermediates and styryl dyes and include the most interesting examples of their high‐tech applications. However, this review is not intended to be comprehensive because of the large number of styryl dye studies that have been carried out in this time. Styryl cyanine dyes are widely used in optical recording media in laser discs, as flexible dyes, laser dyes, as optical sensitisers and in various other fields, for example dye‐sensitised solar cells and dyes with non‐linear optical properties. Additionally, the most important applications for these dyes are in bio‐labelling and in medicinal analysis.     

A Proton–magnetic–resonance Spectroscopic Investigation of Intramolecular Hydrogen Bonding in 4–Substituted–2–nitrodiphenylamine Disperse Dyes

Detection of long–range coupling constants, JNH, H5, in 100–MHz proton–magnetic–resonance spectra confirms the presence of intramolecular NH ON hydrogen bonding in some 2–nitrodiphenylamine disperse dyes. Measurements in polar and non–polar solvents on 2–nitrodiphenylamine and on twelve 4–substituted derivatives indicate weakening of the bonding, which is related to light fastness, when the 4–substituent is a strong electron acceptor.     

Industrielle Bedeutung der Vilsmeier–Haack-Reaktion in der Farbstoffchemie

Vilsmeier–Haack Formylation Reaction – Importance in Colour Industry The Vilsmeier-Haack reaction which has been discovered in 1927 is being used in industry to formylate alkylated aromatic amines and related compounds. Roughly 2000 tons of formylation products are yearly produced in the world. Preferably they are used as building blocks in dye chemistry. Many classes of dyes like cyanines, coumarin dyes, merocyanines, cationic dyes, color formers or dyes for non linear optical applications are being obtained from „Vilsmeier”︁ products. Different conditions of the Vilsmeier-Haack reaction and alternative routes for the introduction of a formyl group are discussed in this progress report.     

Properties of Monoazo Disperse Dyes,Derivatives of 3– and 4–Aminophthalimide

The synthesis of several disperse dyes, from 3–amino–12–phthalimide and its N–methyl derivative as diazo component and N, N–dialky lanilines as coupling component is described. The dyeing behaviour and some physical properties of these dyes are investigated and compared with those of isomeric dyes containing azo groups in the 4–position, previously studied [5]. These properties were found to be considerably affected by the presence of an alkyl sub–stituent on the nitrogen atom of imide group. Further, dyes containing unsubstituted –NH groups showed somewhat better thermal properties (higher melting points and dyeings of better fastness to sublimation), but at the same time their dyeability was worse for all the known processes of dyeing polyester fibres. Based on the i. r. and visible spectra of the dyes under investigation, it was concluded that the dyes containing unsubstituted –NH groups are highly associated; dyes containing azo groups in the 4–position associate to give one product, whereas association of the dyes with azo groups in the 3–position leads to two different products.     

Instrumental Colour Prediction A Potential Aid to Dye and Process Selection

A relationship has been established between the dyeing properties of fibre–reactive dyes and the spectral reflectance properties of the colours produced on machine–washable wool. The information gained in routine dye calibration for instrumental colour–prediction systems may be used by the practical dyer for dye selection. The spectral reflectance properties of the resultant dyeings are explained in terms of the diffusion, fixation and level–dyeing properties of specific fibre–reactive dyes applied to wool by exhaust and pad–dyeing processes.     

A novel method for determination of compatibility of dyes by means of principal component analysis

A novel method for determination of the compatibility of dyes in mixtures based on the application of principal component analysis is presented. The well known dip‐test method is used to dye samples in different binary combinations of cationic dyestuffs. The spectral reflectance of different samples of each mixture that dyed with a given set of dyestuffs by dip‐test method has been measured and the corresponding K/S values are calculated. The actual dimensional properties of each mixture are evaluated by using principal component analysis technique and determination of cumulative percentage variance of the eigenvalues of proposed datasets. Ideally, the K/S spectral data of fully compatible pairs scatter around one dimension, while proportional to the degree of incompatibility of dyes in the mixture, other dimensions should be taken into account and cannot be ignored. Strong correlations are found between the calculated percentage variance and the traditional compatibility values of dyes shown by K value for cationic dyestuffs. The validity of suggested technique is also reconfirmed by normalization of spectral K/S data obtained from different dye sets. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Dye binary mixture formulation by means of derivative ratio spectra of the Kubelka–Munk function

In this study, a new method is introduced for the determination of dye concentration in fabrics dyed with bicomponent dye mixtures. The reflectance spectra of the samples dyed with different binary mixtures of dyes were recorded between 400 and 700 nm. The obtained spectra were divided by a standard spectrum of each of the components in the mixtures and the derivative spectra were calculated. The amounts of dyes were determined by measurements in suitably selected wavelengths in the acquired derivative ratio spectra. The obtained results indicate that the developed derivative ratio spectra method is more accurate than the normal Kubelka–Munk method. The proposed derivative method is simple, accurate, and suitable for quantitative analysis of samples dyed with binary mixed shades. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Monitoring the effects of selective laser sintering (SLS) build parameters on polyamide using near infrared spectroscopy

Near infrared spectroscopy has been used to monitor the effects of changing build parameters on the sintering process of selective laser sintering components. The surface roughness of the parts produced has been studied whilst modifying laser scan speed and laser power build parameters. Near infrared spectroscopy is shown to be a powerful tool in detecting subtle variations in the coalescence of particles that form the surface topology of the component. Principal component analysis (PCA) performed on the diffuse reflectance spectra obtained from the surface of the components shows a strong correlation between near infrared (NIR) spectra and build parameters. Using the chemometric model produced from the PCA analysis it is possible to calculate build parameters for unknown components, making NIR a useful aid for quality control of additive manufacturing technologies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The Dyeing of Wool–Polyester Blends with Reactive Disperse Dyes

The dyeing behaviour of the Procinyl (ICI) range of reactive disperse dyes on wool–polyester blends is described. Two of the dyes were found to dye both components of such blends to approximately the same depth, whilst the remaining three dyes in the range strongly favoured the wool component.     

Prediction of dye concentrations in a three‐component dye mixture solution by a PCA‐derivative spectrophotometry technique

Derivative spectrophotometry is one of the most important techniques that can be used to determine the dye concentration. In addition, principal component analysis (PCA) is a linear method to condense the dimensionality of large numbers of absorbance spectra. In this work, PCA and derivative spectrophotometry techniques are used to improve the accuracy of Beer's law prediction of the concentrations in three‐component dye mixtures. The performance of the new method is compared with the normal Beer's law by calculation absolute error, relative error, and ternary relative error of prediction. As obtained results indicate, the prediction accuracy of dye concentration prediction in PCA‐derivative spectrophotometry method is higher than normal Beer's law method. © 2009 Wiley Periodicals, Inc., Col Res Appl, 2010.     

Activation Energies of Light Fading of Non–ionic Disperse Dyes in Hydrophobic Polymers

Eight non–ionic (disperse) dyes adsorbed in films of cellulose acetates, nylon and poly(ethylene terephthalate) (PET) have been faded by visible and near–ultraviolet radiation at temperatures in the range 15 to 100°C, and in atmospheres of relative humidities (r. h.) from zero to saturation. Fading is accelerated by rise in temperature, and, at r. h. above 5%, by rise in r. h. Activation energies of fading (Ef) (r. h. > 5%) range between about 3 and 18 kcal/mole, and depend on the nature of the substrate rather than on the structure of the dye. Values rise with increasing crystallinity of the polymer structure, except for PET which gives anomalously low values. The extent of dye–fibre interaction is at a minimum with PET and the rate–controlling step is a purely photochemical one. With the other substrates, the rate of fading is controlled by the dye–substrate interaction. The accelerating action of atmospheric humidity over normal ranges is partly due to its influence on the dye–substrate bonding and partly to its effect in swelling the substrate and thus increasing the diffusion coefficient of oxygen.     

Exhaust dyeing of polyester‐based textiles using high‐temperature–alkaline conditions

The factors affecting the dyeability of polyester‐based textiles with disperse dyes in an alkaline medium were studied. It was found, for a given set of dyeing conditions, that (a) the appropriate conditions for attaining a higher color yield were 45 min at 130°C with pH 9 using a material‐to‐liquor ratio of 1/10; (b) increasing the Diaserver® AD‐95 concentration to 2% ows (based on weight of substrate) as well as including triethanolamine to 2% ows in the dyeing formulations bring about a significant improvement in the dye uptake; (c) both a preheat setting from 160 to 200°C/30 s and an alkaline weight reduction have a positive impact on postdyeing with the used disperse dye; (d) the extent of dye uptake as well as the color strength are governed by the type of substrate, that is, knitted fabric > spun yarn > woven fabric, nature of the dye stabilizer, that is, EDTA > Diaserver® AD‐95 > Tinoclorite® CBB > citric acid > none, as well as kind of the disperse dye; (e) direct reuse of the disperse dyebaths, without reconstitution, in the dyeing of the used substrates was shown to be feasible in a single shade and in the reverse‐order dyeings (dark → light); (f) one‐bath, one‐step exhaust dyeing of polyester/cotton‐knitted fabric using selected disperse reactive dyes combinations under high‐temperature alkaline conditions is feasible; and (g) the color and fastness properties of the resultant dyeings depend on the type of the used auxiliaries, in addition to the nature of disperse/reactive dyes combinations as well as compatibility with other ingredients. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3563–3573, 2003     

Studies on Aminoanthraquinone Compounds IV–Photochemistry of some Simple Derivatives in Solution and on Polymer Films

An attempt has been made to determine the validity of the concept of the dye–ethanolsystem as a model for the photochemical degradation of textile materials sensitised by anthraquinone vat dyes. The action of (a) near–ultraviolet and visible radiation and (b) short–wave ultraviolet radiation (mainly 253–7 mμ) on anaerobic solutions of 1–aminoanthraquinone in ethanol, n–hexane, ethyl acetate, and carbon tetrachloride has been studied. Extensive fading of the dye occurs in these solvents with both typesof radiation. In the hydrogen–containing solvents characteristic spectra of reduction products of 1–aminoanthraquinone are produced, whereas in carbon tetrachloride there is extensive general destruction of the absorbing systems. The spectral changes occurring on the irradiation under anaerobic conditions of 1, 5–diaminoanthraquinone and 2–aminoanthraquinone in solution in ethanol and dyedon polymer films of N–methoxymethyl nylon, nylon 6. 6, and secondary cellulose acetate are compared. Only with 1, 5–diaminoanthraquinone and 1–aminoanthraquinone on N–methoxymethylnylon film are the changes on irradiation in dry nitrogen similar to those in ethanol. It is concluded that the photochemical behaviour ofanthraquinone dyes in organic solvents and in polymer systems can show considerable differences.     

Study on analytical methods for quantifying the non‐adsorbed reactive dye forms in an exhausted dyebath

Reported herein are the results of an analysis of the compatibility of three methods for quantifying the non‐adsorbed forms of reactive dyes, in an exhausted dyebath, of the type monochlorotriazine/β‐sulphatoethylsulphone used in dyeing cellulosic fibres (cotton). The first method is based on spectrophotometric analysis and involves measuring the absorbance of the residual dyebath (after the dyeing process), the second is based on colorimetric analysis and involves measuring the reflectance of the dyed fabric and the third is based on high‐performance liquid chromatography. The purpose of the latter is to identify and quantify the non‐adsorbed dye forms in the residual dyebath. The calculated exhaustion values unequivocally prove the reliability and compatibility of these methods.     

Structure–property relationships for azo disperse dyes on polyurethane fibre

Using two series of monoazo disperse dyes, the relationships between the molecular structure of dye and its dyeing properties, such as adsorption behaviour, fastness properties and distribution on polyurethane–polyester blends, were thoroughly investigated. Correlation analysis of experiment data revealed that the partition coefficient between octanol and water (CLogP) is the main factor affecting dye sorption. A greater level of CLogP tends to have a greater isotherm coefficient and better rubbing and washing fastness on polyurethane fibre, as well as a greater distribution ratio between the components of the blend. The dye dipole moment is negatively correlated with various degrees of washing fastness. The dye with two terminal hydroxy groups exhibited notable sorption on the polyurethane component and has the largest partition ratio on polyurethane–polyester in the blend. Corresponding regression analysis equations were identified.     

Natural dyes in madder (Rubia spp.) and their extraction and analysis in historical textiles

Textiles coloration using extracts from the roots of various madder species (Rubia spp.) has been performed for centuries. To date, 68 anthraquinone colorants have been detected in Rubia spp. used to dye textiles. Many of these dyes are sensitive to hydrolysis and degradation from enzymes, extraction chemicals and processing temperatures, and are often overlooked as colorants in historical textiles. Conclusions in literature of the past 30 years concerning colorants present in planta and, particularly, in madder‐dyed artefacts are being challenged as new analysis methods are developed. The recent advent of ‘soft’ extraction techniques has demonstrated that anthraquinone glycosides and other sensitive molecules, such as carboxylated compounds, need to be preserved; this valuable chemical information embedded in the dye structure may be lost if extraction and analysis is too harsh. Some compounds thought to be present in madder and madder‐dyed artefacts are in fact degradation products resultant from the extraction process, and degradation pathways have been developed to better understand the reactivity and stability of these compounds. Detailed analysis of dyes in textile artefacts can reveal important cultural and heritage information concerning historical textiles relative to the specific dye species, the area of the world where this may have grown, how and where it was dyed, and, perhaps, where it was traded. Understanding the precise molecular structure of these dyes and their chemical reactivity is important to provide knowledge of their interactions with physical substrates, such as textile fibres, which could be used to develop superior techniques for analysis of artefacts.