Azide Reactive Dyes Part II - Transfer-printing Properties of Sulphonyl- and Aryl-azide Dyes on Nylon 6.6

The transfer-printing properties of dyes containing the sulphonylazide (-SO₂N₃) and arylazide (ArN₃) groups have been examined for nylon 6.6 substrates. After sublimation at 200°C the azide group decomposes rapidly to a nitrene species which reacts with the polymer. Dye fixation occurs by insertion of the nitrene into the carbon-hydrogen bonds of the polymer, thus forming a nitrogen bridge. A competing reaction involves hydrogen abstraction from the substrate to give an amino derivative of the dye which is not covalently bound to the polymer. Fibre-grafting occurs to the extent of about 60–75% for both series of dyes. Unlike the sulphonylazides, the arylazide dyes show a pronounced colour change after transfer, as the thermally-generated amino group is directly conjugated with the dye chromogen.     

Fixation on Wool of Dyes Containing a Maleimide Group

The chemistry of dyes containing a maleimide group is discussed. The mechanism of dye fixation on wool in depths greater than 1. 5% has been investigated. In samples which were dyed at pH 3, 80°C, little covalent reaction took place. Extraction with solvents, used to determine the fixation ratio, caused changes in the dye, as well as some further reaction, giving rise to apparently high fixation ratios. Dyeings on nylon fibre confirmed that covalent reaction of dye with amino groups is possible, especially between pH4 and 5. The best results in terms of fixation and yield were obtained in a dyeing procedure where the pHwas raised slowly during the dyeing.     

Laser marking in dye–polymer systems

Light-induced marking in dye–polymer systems based on dye diffusion was investigated. It was demonstrated that when a dye film coated on an appropriate polymer substrate is exposed to a laser beam, marked areas are obtained. In the exposed areas the dye melts and diffuses into the substrate and also flows laterally. The dye, when diffused into the polymer, shows altered spectral characteristics, and significant changes of optical densities can occur in the marked areas. A direct optical marking process based on these phenomena is described. Good spatial resolution and adequate marking sensitivities were demonstrated as submicron marks and energy density requirements below 100 mJ/cm² were obtained.     

Determination of Acid-dye Standard Affinities for Nylon Fibres from Sorption Isotherms

The dyeing equilibria of acid dyes on nylon 6.6 are studied using a model in which the substrate is divided into solid polymer and an internal solution. A Nernst distribution is assumed for the distribution of dye between these two phases, while a Donnan equilibrium is presupposed for that between the internal and external solutions. It is shown experimentally that the Donnan coefficient of the nylon increases exponentially with the amount of fixed dye provided that the substrate is initially present in the isoelectric state. Based on this finding, the standard affinity of an acid dye for nylon 6.6 can be derived from the sorption isotherm, without the necessity of knowing the acidity and basicity of the carboxyl and amino groups respectively. The effect of introducing an alkyl group on the standard affinity is demonstrated with four anthraquinone dyes.     

Determination of the amino end groups in polyamide 6 and 6,6 with ninhydrin

The amino end groups in polyamide 6 and 6,6 were reacted in a water/methylcellosolve/propionic acid/sodium propionate/pyridine/isopropanol system for 30 min at 100°C with ninhydrin to give a dye (λ_max : 570 nm, ?₅₇₀ : 18.6 · 10³ cm² mol^?1), whose photometrically determinable concentration represented a measure of the amino end group content. Although the polymer remained undissolved during the analysis, the reaction proceeded quantitatively in all the samples studied (fibres with a maximum fineness of 44 dtex, corresponding to a diameter of 70 μm). ?-Aminocaproic acid served as a low-molecular calibration substance for the polymer. On account of its simplicity, rapidity, and good reproducibility (variation coefficient 3.4%), the ninhydrin method is suitable for the serial determination of the amino end groups in polyamide 6 and 6,6.     

Methyl methacrylate and acrylamide crosslinked macroporous copolymers

In this work the synthesis of a crosslinked macroporous copolymer was effected from methyl methacrylate and acrylamide. The synthesis process began with emulsion prepolymerization, followed by sol–gel copolymerization until a hard block was obtained. Determination of the properties of the obtained material was carried out by FTIR, mercury porosimetry, and SEM microscopy. The material was characterized by a porous structure with open pores. The macroporous copolymer obtained can be used for polymer–analog reactions and the transformation of amide and ester groups into acyl azide groups. It can be used as a hard inert support for the immobilization of enzymes, or other proteins, by condensation of acyl azide group on polymer with the free amino group from the base amino acid of enzyme/protein. For the immobilization of microorganisms it can be used by vacuum diffusion of microorganism suspension into the porous structure, without active group transformation reactions. With microorganisms in the polymer pores, microorganism colonies form within the copolymer by microbial fermentation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 387–395, 2004     

Design and application of a multifunctional reactive dye capable of high fixation efficiency on cellulose

A polyfunctional reactive dye containing two dichloro- s -triazine residues linked through aliphatic amino groups via a third triazine system to the chromophoric residue has been prepared. The dye was synthesised stepwise from a specially synthesised 2,4-dichloro- s -triazine dyes. The first step is the reaction of both carbon–chlorine sites in the 'parent' dye with 2 mol ethylenediamine under selected conditions of pH and temperature; these conditions ensure that only one of the amino groups in the ethylenediamine will react to give the bis-2,4-aminoethyleneaminotriazine dye. The second step is the condensation of 2 mol cyanuric chloride with the two pendant primary amino groups. The alkylamino-linked dichloro- s -triazine dyes show very different dyeing properties when compared with those shown by the parent dichloro- s -triazine dye, which has the reactive group linked directly into the aromatic chromophore; in particular, the new dyes have high fixation efficiencies when dyed on cotton at 50 °C and the dye–fibre bond stability to boiling acidic conditions is very good.     

Chemical engineering aspects of reactive dyeing

The process of dyeing with reactive dyes was formulated on the basis of diffusion of dye species in the pores of polymer phase accompanied by fixation reaction with fiber substrate on the pore wall incorporating hydrolysis of dye species. The effect of the hydrolysis on the fractional fixation was numerically analyzed under various levels of bath ratio and degree of mixing in the dyebath. The simulation model was presented to yield the unlevelness arisen from lack of uniformity of degree of mixing in the dyebath.     

Dye-fibre bond stabilities of dyeings of bifunctional reactive dyes containing a monochlorotriazine and a ß-hydroxyethylsulphone sulphuric acid ester group

The dye-fibre bond stabilities of various bifunctional dyes (commercially known as Sumifix Supra dyes) have been investigated by measuring the kinetics of dye-cotton bond hydrolysis in aqueous buffer solution at 98d?C. The stabilities are generally found to be somewhat higher than those of comparable monofunctional reactive dyes. Significantly better, however, is the fixation yield of the bifunctional dyes. Reasons for a very low uptake of a non-commercial bromamine acid-based bifunctional dye are discussed.     

Sublimation Transfer Printing of Wool with Metallizable Dyes

The transfer printing of pretreated wool using sublimable dyes that form metal complexes on the fibre during printing is described. The most successful pretreatment involved padding a mixture of chromic chloride, an an ionic surfactant, urea and lactic acid and then drying. Low molecular-weight monoazo dyes containing salicylic acid residues, or hydroxyl or amino groups on carbon atoms in two ortho positions relative to the azo group, were screen printed onto transfer papers. Optimum heating conditions for transferring dye from paper to fabric were 200d?C for 30 s. After separation of the transfer paper, the fabric was steamed at 100d?C for 30 min. Prints with good fastness properties were obtained in a wide range of colours. The method offers promise for commercial transfer printing of pure wool fabric.     

Preparation of Xylan–Acrylic Acid Polymer with High Molecular Weight and its Application as a Dye Removal Flocculant

Xylan is found in natural products and can be used for preparing value-added products. The main purpose of this study was to produce a xylan-based polymer (xylan–acrylic acid [Xy–AA]) as a flocculant for removing ethyl violet dye from wastewater. In this study, the polymerization reaction of xylan and acrylic acid (AA) was optimized by response surface methodology (RSM). It was indicated that the maximum charge density of –5.87?mmol/g and molecular weight of 352,028?g/mol were obtained for Xy–AA polymer under the conditions of 20.53?g/L xylan concentration, 0.31 xylan/AA molar ratio, 2.5?h reaction time, and 72?°C reaction temperature. The polymer was characterized by charge density analyzer, Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H-NMR), and thermogravimetric analysis (TGA). The application of the product as a flocculant for removing the ethyl violet from simulated dye solution was evaluated. The results showed that the optimal dye removal of 97.08% was achieved under the conditions of 50?mg/L dye concentration, 120?mg/L Xy–AA concentration, pH 10, and 30?°C. The flocculation mechanism was also discussed.     

Immobilization of enzymes onto modified polyacrylonitrile membranes: Application of the acyl azide method

Chemical reactions toward acyl azide activated polyacrylonitrile (PAN) and conditions for membrane surface modifications are described. Ultrafiltration (UF) membranes were prepared from PAN homopolymer and copolymer with methyl acrylate. Besides hydrazide formation and nitrosation, a new method to introduce acyl azide groups into carboxyl modified PAN, using azido transfer with diphenyl phosphoryl azide, was developed. Chemical conversions were characterized, especially with Fourier transform infrared spectroscopy. The heterogeneous modifications are not chemically selective due to side reactions and/or incomplete conversion. The pore structure is altered predominately via modified polymer swelling causing changed UF fluxes and selectivities. However, for the modification via PAN reaction with hydroxyl amine, acid hydrolysis, and azido transfer, the initial membrane separations performance is qualitatively preserved. Using the acyl azide ḿethod, amylo-glucosidase (AG) (EC 3.2.1.3) was immobilized onto the modified PAN UF membranes, enabling hydrolysis of starch or maltose to glucose. Enzyme activity was assayed depending on previous chemical modification (azide content) and immobilization (pH) conditions as well as hydrolysis parameters (substrate, conversion during diffusion or UF). The best results (up to 600 mU/cm² at 40°C and pH 5.0) were obtained after modification of PAN membranes via carboxyl creation and azido transfer. AG convalently bound to PAN is not influenced much in its catalytic properties (K_m = 3.48 and 3.1 mmol/L for free and bound AG, respectively, with maltose at 40°C and pH 5.0). Under UF conditions, AG effective activity can be improved by the convective flow through the membrane. UF selectivity for the polymer starch determines effective substrate concentrations in the membrane, thus affecting observed activities and product purities in the filtrate. © 1996 John Wiley & Sons, Inc.     

Self‐curable aqueous polymeric dyes for printing and dyeing applications

An epoxy resin (NPES‐904, epoxy equivalent weight is 815) with a repeating unit, n > 4 was selected as a polymer backbone of polymeric dye. Water‐reducible epoxy resin was prepared by a semiesterification of its secondary hydroxy group with succinic anhydride and then dispersed to aqueous phase after it was neutralized with triethylamine. An aqueous polymeric dye was obtained from a ring opening reaction of that epoxy resin with amino group of a direct dye (soluble dye such as C. I. Acid Blue 62, C. I. Direct Orange 39 or C. I. Direct Red 2). These aqueous polymeric dye dispersions carried the average particle sizes between 50 and 90 nm. A polyaziridine was added as a latent curing agent and forming a self‐curable system of aqueous polymeric dye solution, which was stable in aqueous phase when its pH remained above 8.0. This aqueous polymeric dye was self‐cured on drying at ambient temperature and results in the formation of waterproof and solvent‐resistant polymeric dye. These self‐curable polymeric dyes had potential for jet ink printing and dyeing applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1919–1931, 2006     

Preparation of poly(glycidyl methacrylate) grafted sulfonamide based polystyrene resin with tertiary amine for the removal of dye from water

Poly(glycidyl methacrylate) was grafted onto crosslinked poly(styrene) beads through the 2-chloroethyl sulphonamide (CSA) groups present in the resin using ATRP polymerization method. A beaded polymer with a poly(glycidyl methacrylate) surface shell was prepared in three steps, starting from poly(styrene-DVB) (10% crosslinking) based beads with a particle size of 420–590 μm, according to the synthetic protocol; chlorosulfonation, sulfamidation with 2-chloroethylamine hydrochloride and grafting reaction of poly(glycidyl methacrylate).The polymeric resin was prepared with 147.8% of grafted glycidyl methacrylate and subsequent modified with diethyl amine to introduce tertiary amine groups. This resin has also been demonstrated to be an efficient dye sorbent, able to remove dye from water even at ppm levels. The dye sorption capacity under non-buffered conditions is around 0.90 g dye/g resin.     

7-氨基-1-羟基萘-3-磺酸(γ酸)衍生的酸性染料的合成及其性能研究

本文涉及由γ酸衍生的,在分子中含有磺酰胺基的红色酸性染料的合成。该类染料构想用来在弱酸性染浴中染聚酰胺和羊毛纤维。通过检测染料的应用性能。坚牢度和光谱特性,发现磺酰胺基和在它的氮原子上的取代基会影响该类染料的性能。     

Dyeing of nylon 6 and silk fabrics with a model disulphide bis(ethylsulphone) reactive disperse dye

The synthesis of a new reactive disperse dye containing the disulphide bis(ethylsulphone) group is described. The dye has been applied to nylon 6 and silk fabrics at a variety of pH and temperature conditions. Optimum dye exhaustion and fixation were achieved at pH 8 and 130 °C. The results of dyeings on both substrates indicate that the model disulphide bis(ethylsulphone) reactive disperse dye shows a higher degree of exhaustion and fixation on silk than on nylon 6. The fastness and levelling properties on both fabrics were good.     

The affinity of direct dyes for cellophane under high hydrostatic pressure

The affinities of direct dyes, such as CI Direct Blue 1, Red 2 and Yellow 12 for cellophane under high hydrostatic pressures up to 600 MPa at 55d?C are presented. The pressure dependence of the affinities are discussed in terms of the change of the volume of substrate available for dye adsorption, ΔV.     

Reaction and diffusion of reactive disperse dye in nylon 6

The diffusion of a reactive disperse dye with a vinylsulfonyl group accompanied by simultaneous reaction with the amino end groups in nylon 6 was examined by the method of cylindrical film roll at 70°C and pH 2.2–8.0. The experimental diffusion profiles of the active and fixed species of the dye in nylon 6 were confirmed to be described by the diffusion equation accompanied by the chemical reaction with substrate taking the limited amount of the end groups into account, where the active species of dye were assumed to react only with the free base of amino end groups. The completion of the reaction with the amino end groups was observed in the first layer from the surface at pH 6.0–8.0. The value of diffusion coefficient was constant (8.0 × 10^?10 cm²/s) at all the pH's. The product of the second-order rate constant, k₂, of reaction of the dye and the dissociation constant, K_a, of the amino end groups was constant (k₂K_a = 4.0 × 10^?9 s^?1) at pH 2.2–8.0. The k₂ values of the reaction with various substrates for vinylsulfonyl and monochlorotriazinyl-reactive dyes were compared and the practical dyeing conditions were discussed.     

The use of reflectance measurements in the determination of diffusion of reactive dyes into cellulosic fiber

Reactive dye fixation and color yield of a dyed cellulosic fiber significantly depend on the dye diffusion into the fiber polymer system. In case of pad‐dyeing processes, dye diffusion exerts a more significant influence on dye fixation and hence color yield. This article proposes a new method for determining the extent of diffusion of reactive dyes into the fiber in pad dyeings using Kubelka–Munk equation. The K/S values are used as in an equation, %D (extent of dye diffusion) = 100 ? [(K/S_{diffusion index})/ (K/S_reference) × 100]. The article introduces and explains how to determine the new K/S variables used in this equation. The new method is simple, nondestructive, relatively faster, and applicable to industrial dyehouses, and was validated by a microscopic analysis of dyed fiber cross‐section carried out in this work and to the dye manufacturer's recommendations for dyebath‐ingredient concentrations. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 63–69, 2014     

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.