Studies on Aminoanthraquinone Compounds

The action of (a) near-ultraviolet and visible radiation and (b) short-wave ultraviolet radiation (mainly 253.7 nm) on cellulose Alms dyed with three acylaminoanthraquinone vat dyes has been studied. Photoreduction to the acid leuco derivative of the dye is observed only on exposure to 253.7-nm radiation. One dye (l-benzamidoanthraquinone) has also been studied in anaerobic ethanolic solution. On exposure of this solution to near-ultraviolet and visible radiation, the dye is readily reduced to the anthrahydroquinone. Photo-reduction occurs readily in ethanol but with considerable difficulty on cellulose. There seems to be no correlation between the ability of the vat dye to sensitise the photochemical degradation of cellulose textiles and its ability to be photoreduced on cellulose.     

Photodegradation of Cotton Cellulose

The relation between the fading and phototendering behaviour of Caledon Yellow GN, 5GK and 4G on cotton cellulose has been examined. A distinction is drawn between the reactions promoted by visible light and those promoted by ultraviolet radiation. Caledon Yellow 5GK is the most efficient phototenderer in visible light and production of the leuco dye accompanies this process. Phototendering by this mechanism can also be identified with Caledon Yellow GN, although to a much smaller extent than with 5GK, and production of the leuco form is accompanied by formation of free radicals. Regeneration of the original dye is best promoted by an atmosphere of moist oxygen. Excitation by short-ultraviolet radiation leads to irreversible chemical changes in the dyes and degradation of the cellulose. The most efficient phototenderer in visible light (Caledon Yellow 5GK) markedly inhibits the degradation of cotton by ultraviolet radiation, whereas the poor phototenderers in visible light (Caledon Yellow 4G and GN) exert no such marked protection. The mechanisms of these reactions are discussed. Hydrogen abstraction by the excited non-aggregated dye is the most probable path to the leuco dye and photodegradation in visible light, and the mechanism is thus comparable with the mechanisms elucidated for anthraquinone compounds in solution and on cellulose. Electronic-energy transfer to the cellulose, in competition with the abstraction process, would be favoured during ultraviolet irradiation, and is the mechanism suggested for the degradation of cellulose under these conditions. The influence of dye aggregation on the reactions and the mechanism of the irreversible chemical changes in the dyes are also discussed.     

Studies on Aminoanthraquinone Compounds VI—Photochemistry of N-Methyl Derivatives on Polymer Films

The effect of (a) short-wave ultraviolet radiation (mainly 253-7 mμ) and (b) near-ultraviolet and visible radiation on polymer films dyed with the two disperse dyes, 1-methylaminoanthraquinone and 1,4-bismethylaminoanthraquinone, has been studied. Dyes on nylon films undergo reduction when exposed in dry nitrogen to 253-7-mμ radiation. The effect of near-ultraviolet and visible radiation is different; in dry nitrogen, 1-methylaminoanthraquinone on N-methoxymethylnylon film is reduced to the same extent as with 253-7-mμ radiation, but on other nylon films (nylon 6, nylon 6.6, and nylon 11) the reduction observed with this dye is much smaller. There is no evidence of reduction of 1,4-bismethylaminoanthraquinone on any of the nylon films. On cellulose acetate film, neither dye is reduced on exposure in dry nitrogen, by either source of radiation. The significance of these results in relation to the photo-sensitised degradation of textile fibres is discussed.     

The Chemistry of Esters of Leuco Vat Dyes VI–The Supposed Production of Semiquinone Esters

Evidence is presented disproving the previously suggested formation of stable semiquinone esters during the oxidation of the sulphuric acid esters of leuco vat dyes (1). Under appropriate conditions it appears most likely that the leuco compound which may be produced by hydrolysis of the original ester will disproportionate to yield the vat dye and a compound at a lower oxidation level than the leuco compound.     

Design,synthesis, and application of amphoteric macromolecular dyes with controllable solubility

A series of amphoteric macromolecular dyes were designed and synthesized from poly(acrylamide‐co‐vinylamine) oligomer and reactive dyes. The structure of the synthesized dyes was characterized by fourier transform infrared spectra, mass spectra, and ultraviolet–visible spectroscopy analysis. The solubility of the dyes was also investigated. The results showed that the solubility of the dyes can be controlled by tuning the ratio of amino to sulfonate groups in amphoteric macromolecular dyes. Based on the results of controllable solubility conducted by visible light transmittance measurements, amphoteric macromolecular dyes were used to dye cotton fiber; the fixation of the dye on cotton was more than 95% when crosslinking agent was added. The dyed samples exhibited good fastness to washing and rubbing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41120.     

Studies on Aminoanthraquinone Compounds

A study has been made of the action of near-ultraviolet and visible radiation on anaerobic solutions of 1- and 2-piperidinoanthraquin-ones in different organic solvents, and on polymer films dyed with these dyes. In the absence of oxygen, 1-piperidinoanthraquinone is reduced to the anthrahydroquinone on irradiation in solution and on nylon films. Under similar conditions, 2-piperidinoanthra-quinone is reduced to the anthrone in organic solvents, but the photochemical changes are more complex on polymer films. 1-Piperidinoanthraquinone doss not sensitise the photochemical degradation of nylon or cellulose acetate yarn. The results suggest that there is no definite relation between the ease of photoreduction of a dye and its ability to sensitise the photochemical degradation of textile fibres.     

Synthesis and properties of poly(styrene-co-maleic acid) macromolecular reactive dyes

To obtain a new type of macromolecular reactive dye with high fixation and good light fastness, poly(styrene-co-maleic acid) was synthesised by co-polymerisation of styrene and maleic anhydride, then, through nitration, reduction, diazotisation and coupling reaction, novel macromolecular reactive dyes were prepared with a solubility greater than 60 g/L. The dyes were used to dye cotton fabrics; the results showed their fixation was more than 92%, and both the rub and wash fastness of the dyes were good. The light fastness of the red and blue dyes with the ethoxy group on melamine was grade 4, and for the yellow dye reached grade 5. The poly(styrene-co-maleic acid) macromolecular reactive dyes exhibit very good application prospects in practice.     

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.     

Spectroscopic study of interactions between model direct dyes and cotton

Although examined for years, interactions between direct dyes and the chemical structure of cotton cellulose remain an interesting, and still not entirely known, chemical phenomenon occurring in the fiber. Ten model azo dyes have been studied in aqueous solution, as dye powders and on cotton fabric using ¹³C MAS NMR and UV–visible spectroscopy. NMR spectroscopy indicates that model azo dyes, especially dye 8, interact by π‐stacking at the central biphenyl group, and that there is hydrogen bonding with cellulose. Model azo dyes are present as the azo or hydrazone tautomer. The UV–visible λ_max indicate that shifts are attributed to adsorption of model azo dyes into cellulose surfaces. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 758–766, 2007     

多胺型交联染料在丝、棉纤维上的超高固色效应研究

该文合成了H-酸单偶氮红色、吡唑啉酮单偶氮黄色和1,4-二氨基蒽醌系蓝色四乙烯五胺型交联染料,用无盐浸染或轧染的清洁染色工艺,对所合成的多胺型可交联染料应用于丝绸和棉纤维染色,然后用硫酸酯乙烯砜型交联剂,两浸两轧、焙烘的方法使染色纤维固色。研究结果表明,在pH=4时,该类交联染料竭染率最高,用交联剂固色后交联率均大于99%,最终固色率在78%~99%,接近100%固色,染色纤维耐洗色牢度3级以上,耐摩擦色牢度3级以上,与小分子活性染料相当,还具有一定防皱整理效果。     

6‐Pyridinium benzo[a]phenazine‐5‐oxide derivatives as visible photosensitisers for polymerisation

Several 6‐pyridinium benzo[a]phenazine‐5‐oxide derivatives have been synthesised and characterised by proton nuclear magnetic resonance spectroscopy and mass spectrometry. The spectroscopic and electrochemical properties of these dyes were examined. The dyes were used as reducible sensitisers for selected electron donors (phenylthioacetic acid, phenoxyacetic acid, N‐phenylglycine, and ethyl 4‐N,N‐dimethylaminobenzoate) and as oxidisable sensitisers for electron acceptors (onium and N‐alkoxypyridinium salts). These photoredox pairs were found to be effective visible‐wavelength photoinitiators for the free radical polymerisation of trimethylolpropane triacrylate under visible light. The cationic photopolymerisation of cyclohexene oxide by the studied dyes and the onium salt photoredox pairs was ineffective. The obtained results are discussed on the basis of both free energy change for electron transfer to or from the benzo[a]phenazine dyes and the photochemical properties of the dyes, particularly their photobleaching. The proposed mechanism of dye fading is supported by density functional theory calculations and spectroscopic characterisation of the radical cation of the dye.     

A significant approach to dye cotton in supercritical carbon dioxide with fluorotriazine reactive dyes

A series of fluorotriazine reactive dyes have been synthesized and applied to dye cotton in supercritical carbon dioxide (scCO₂) with good dyeing results. The pieces of cotton to be dyed were previously presoaked in a protic solvent and cosolvents were applied during dyeing. The colour strength of the dyeings was evaluated by K/S measurements. The K/S values achieved on cotton dyed were up to 35.8 ± 4.2. Even after the cotton was subjected to a Shoxlet extraction at 358 K for 1 h, a maximum K/S value of 20.2 ± 1.8 was measured. The percentage of dye molecules chemically fixed to the cotton was on average 85%. The excellent reactivity of fluorotriazines allowed a reduction of 3 h on the dyeing time. It is noticeable that a dye concentration of 10% on weight of the fibre (owf) can be applied to dye cotton with fluorotriazines, since no damage of the cotton fibres occurred, as observed for the chlorotriazines at this high dye concentration.Dyes with fluorotriazine as reactive group were found to be the most preferable dyes for dyeing cotton in scCO₂, as they were able to exceed the limitation of the reaction with the cotton.     

Synthesis and dyeing properties of polyvinylamine dyes for cotton

Novel polyvinylamine dyes were designed and synthesised from poly(N‐vinylformamide‐co‐vinylamine) and reactive dyes, then used to dye cotton fibres by the dip‐pad‐steam process, with the dyeing methods being examined in detail. Each polyvinylamine dye was fixed to cotton without a crosslinking agent through covalent bonds formed between the reactive group of the dye and the cotton fibres. A fixation of 99% was achieved, with grades of 4 and 4‐5 wash and dry‐rub fastness, respectively.     

Electrostatic self‐assembly dyeing of cotton fabrics

A new approach to the dyeing of cotton fabrics using an electrostatic self‐assembly method was evaluated. Cotton fabrics were pretreated with 2,3‐epoxypropyltrimethylammonuium chloride and cationic charges were produced on the fabric surfaces. For the dyeing of cotton fabric, reactive and acid dyes were used. Oppositely charged anionic reactive/acid dyes and cationic poly(diallyldimethylammonium chloride) were alternately deposited on the surface of cationised cotton fabrics. Ten multilayer films of dye/poly(diallyldimethylammonium chloride) were deposited on the cotton fabric surfaces using a padder. The build‐up of the multilayer films and the level of colour strength (K/S) achieved are discussed. Samples of cotton fabrics were also dyed with the same dyes, but using the exhaust method, and both types of dyed samples were compared. The washing, rubbing and light fastness properties were evaluated for the dyed fabrics.     

A novel resist technique based on secondary amines for the printing of cotton with reactive dyes

In an earlier paper we have described sulphite‐based resist printing using ink‐jet procedures. This paper describes an alternative approach to sulphite inactivation of vinylsulphone dyes by using secondary amines to inactivate fluoro‐s‐triazine dyes while maintaining the reactivity of the vinylsulphone dyes. Monofluoro‐s‐triazine reactive dyes are padded onto cotton fabrics and then deactivated by ink‐jet printing with a suitable secondary amine formulation to produce a white image on a solid ground colour after appropriate fixation and soap‐off procedures have been undertaken. A coloured image can be achieved by overprinting the resist‐printed areas with a coloured ink formulation containing a β‐sulphatoethylsulphone‐type reactive dye; such dyes form a β‐bis‐alkylaminoethylsulphone dye via reaction with the secondary amine. This latter dye ‘unblocks’ during a mildly acidic steaming process to form the reactive vinylsulphone dye, and so, unlike the monofluoro‐s‐triazine dye, is not deactivated towards subsequent covalent reaction with the cotton substrate.     

Behavior of chemically modified cellulose towards dyeing. IV. Dyeability of poly(methyl vinyl pyridine)-cellulose graft copolymers before and after treatment with epichlorohydrin

Grafting of 2-methyl-5-vinyl pyridine (MVP) onto partially carboxymethylated cotton having 6 meq COOH/100 g cellulose (PCMC) was effected by a Fe²⁺-H₂O₂ redox system. Different graft yields were obtained by varying MVP concentration from 10 to 100 wt % PCMC. In a subsequent step these graft copolymers were treated with epichlorohydrin. Dyeing of untreated cotton, PCMC, PCMC grafted with MVP, and epichlorohydrin-treated poly(MVP)-PCMC graft copolymers was carried out at room temperature (27°C) for varying lengths of time (2.5–60 min) in the absence of alkali catalyst or any other additives. Three reactive dyes, Procion Red M-GS, Procion Orange Brown H-2GS, and Remazole Brilliant Blue; a direct dye, Orangé Solophényle 2RL; and an acid dye, Erio Blue Marine 2GR were used at a concentration of 2% by weight of material. It was found that none of the three reactive dyes or the acid dye interacts with untreated cotton or PCMC. In contrast, the direct dye did. PCMC grafted with MVP, on the other hand, showed a substantial extent of dye exhaustion regardless of the dye used. After-treatment of poly(MVP)-PCMC graft copolymers with epichlorohydrin significantly enhanced the extent of dye exhaustion. The latter reacted almost 100% with all the dye examined, irrespective of the graft yield, which varied from 1.6% to 63%. Dyeings for reactive dyes withstood soaping for 1 hr at boil and extraction with 50% dimethylformamide, whereas dyeings for the direct dye and the acid dye failed to do so. It is believed that the presence of pyridine moieties in the graft act as an internal, built-in catalyst for expediting the reaction of reactive dyes with cellulose hydroxyls and behave as a weak base capable of salt-linkage formation in case of the acid and direct dyes.     

The Photochemistry of Dyes. IV—The Role of Singlet Oxygen and Hydrogen Peroxide in Photosensitised Degradation of Polymers

The effect of sensitising dyes on the photochemical degradation of textile fibres is discussed. The degradation is dependent upon the presence of oxygen, and is accelerated by water vapour and rise in temperature. The study of simple model photochemical systems intended to simulate the dyed fibre system indicates that there are significant differences between the two systems. The sensitising effect of dyes in the textile systems seems to be due to the formation of excited singlet oxygen and hydrogen peroxide. The latter is not formed in the absence of water vapour.     

Ecofriendly ultrasonic natural dyeing of cotton fabric with enzyme pretreatments

Ecofriendly ultrasonic textile dyeing with natural dyes such as Acacia catechu and Tectona grandis show better and faster dye uptake after enzyme pretreatment on cotton fabric, and results of dyeing are better than metal mordanted fabric. It is observed that there is marked improvement in wash-fastness and light-fastness. The role of enzyme pretreatment is primarily for better absorbency, adherence and dyeability of these dyes on cotton fabric, thereby completely replacing metal mordants with enzyme for adherence of natural dyes on cotton. Scanning electron microscopy show surface characteristics at different stages of dyeing. The effect of sonication on the dyeing is compared with conventional heating. The study also shows enhancement in CIELab values.     

Synthesis and application to cotton of a polymeric black colorant prepared by grafting of reactive dyes to polyvinylamine

A novel polymeric black dye was synthesised by grafting yellow, orange, red, and blue reactive dyes onto polyvinylamine. Such a polymeric black dye takes the onus away from dyers to worry about the compatibility of individual dyes. The polymeric black dye was characterised by Fourier transform infrared, ultraviolet‐visible, and nuclear magnetic resonance spectroscopy. The absorption of the polymeric black dye in aqueous solution was nearly constant across the wavelength range 400–700 nm. Compared with a black mixture of reactive dyes with low fixation on cotton, which was prepared by mixing yellow, orange, red, and blue reactive dyes, the polymeric black dye reached 99% fixation on cotton through the use of a crosslinking agent. The colorimetric properties of cotton dyed with the polymeric black dye and with the black mixture of reactive dyes showed that better blackness can be obtained by using the polymeric black dye. Analysis of the thermal stability and penetration ability of the polymeric black dye showed that the polymeric dye has high stability in the application and a uniform distributution in the cotton fabric.     

A method for dyeing cotton fabric with anthocyanin dyes extracted from mulberry (Morus rubra) fruits

For the first time, the natural anthocyanin dyes (mainly consisting of cyanidine 3‐glycoside) extracted from mulberry (Morus rubra) fruits has been successfully used to dye cotton fabric, with a dyeing property performance good enough for potential commercial applications. In this study, succinic acid was firstly incorporated into cotton fabrics by esterification to the hydroxyl groups of cellulose, forming an anionic site for the dyes. The performance of the modified material was characterised by Fourier transform infrared spectroscopy and tensile strength. Results showed that the tensile strength of cotton fabrics was mostly retained after modification. The anthocyanin extracts from mulberry fruits were used to study the dyeability of the control and modified cotton fabrics. Red and deep purple (aubergine) are two main shades of cotton fabrics dyed with mulberry fruit extracts. Most importantly, aubergine shade is rare in cotton fabrics dyed with natural dyes. Modification with succinic acid clearly increased the colour strength of the dyed cotton fabric. The colour strength of dyed cotton fabric was improved from 2.7 to 5.3 in the case of dyeing without mordants, and from 3.2 to 6.9 in the case of dyeing with tin mordanting. Meanwhile, the colour fastness was improved by 0.5–2 grades with increasing succinic acid concentration in the finish solution. The colour fastness to perspiration, crocking, light, and washing of fabric dyed with simultaneous tin mordanting and modified with 30 g l^?1 of succinic acid was found to be acceptable, with a grey scale grade of at least 3. As for home laundering, neutral soapy solution was more acceptable than alkaline soapy solution.