Dyeing Polyester Fabrics Research Articles

One-Step Polyester Dyeing and Antibacterial Treatment Using Innovative Thiazole Azo Dyes in Supercritical Carbon Dioxide

AbstractA novel approach in the field, a range of new azothiazole dyes substituted with different hydrophobic groups, was utilized as colorants for dyeing polyester fabrics in a supercritical carbon dioxide environment. The innovative dyes were analyzed using standard spectroscopy techniques and elemental analysis. The dyeing process was assessed for its dyeing ability, color strength, and color fastness for twelve different dyes. The polyester fabrics dyed with these dyes appeared in various shades, between red and magenta. Using the AATCC method, the antibacterial assessment revealed that some dyes exhibited significant antibacterial properties against both positive and negative bacteria. All 12 dyes showed outstanding resistance to washing, rubbing, and light, with staining and color change ratings of 4–5. The results indicate that the synthesized dyes could be employed for large-scale, energy-efficient, and environmentally friendly polyester fabric dyeing utilizing supercritical carbon dioxide. Graphical abstract

Utilization of Tea Polyphenols as Color Developers in Reversible Thermochromic Dyes for Thermosensitive Color Change and Enhanced Functionality of Polyester Fabrics

Thermochromic textiles possess the capability to indicate ambient temperature through color changes, enabling real-time temperature monitoring and providing temperature warnings for body heat management. In this study, three thermochromic dyes—blue, red, and yellow—were synthesized using crystalline violet lactone (CVL), 6′-(diethylamino)-1′,3′-dimethyl-fluoran (DDF), and 3′,6′-dimethoxyfluoran (DOF) as leuco dyes, respectively, with biomass tea polyphenol serving as the color developer and tetradecanol as the phase change material. The chemical structures of these dyes were characterized using UV spectroscopy, infrared spectroscopy, Raman spectroscopy and 1H NMR. The thermochromic mechanisms were investigated, revealing that the binding bonds between the leuco dyes and the color developer broke and reorganized with temperature changes, imparting reversible thermochromic property. Polyester fabrics were dyed using an impregnation method to produce three reversible thermochromic fabrics in blue, red, and yellow. The structure and properties of these fabrics were analyzed, showing a significant increase in the UPF value from 26.3 to approximately 100, indicating enhanced UV resistance. Water contact angle measurements revealed that the contact angle of undyed polyester fabrics was 139°, while that of dyed polyester fabrics decreased by about 40°, indicating improved hydrophilicity. Additionally, the fabric inductive static tester showed that the static voltage half-life of dyed polyester fabric was less than 1 s, demonstrating a significant antistatic effect. Infrared thermal imaging results indicated that during the warming and cooling process, the thermochromic polyester fabric exhibited specific energy storage and insulation effects at 38 °C, close to the human body temperature. This study presented a novel approach to developing smart color-changing textiles using biomass-derived thermochromic dyes, offering diverse materials for personal thermal management, and intelligent insulation applications.

A novel quaternary ammonium triethanolamine modified polyester polyether for rapid wetting and penetration pretreatment for digital inkjet dyeing of polyester fabric

Green environmental protection and digitisation are vital for the future development of the textile printing and dyeing industry. Dispersed dye digital inkjet dyeing, as a new technology, enables on-demand low-liquor dyeing and controllable segment dyeing of polyester fabric. This facilitates the transformation, upgrading and sustainable development of the printing and dyeing industry. Due to its inherent hydrophobicity, polyester fabric poses challenges in terms of quick wetting and penetration of ink droplets. To enhance its moisture absorption and rapid wettability, a novel pre-treatment agent, i.e. cationic polyester polyether (CPP), was synthesised via the triethanolamine quaternisation modification of polyester polyether. The wetting and penetration behaviours of ink droplets on the CPP-pre-treated fabric were studied, and the colour performance of CPP-pre-treated dyed fabric was investigated. Results showed that the optimal conditions for CPP synthesis were a DMT to PEG molar ratio of 3:1, a molecular weight of PEG 2000 and a PEG to NAB molar ratio of 1:0.2. At a CPP concentration of 0.3 %o.w.f., the CPP-pre-treated fabric exhibited excellent moisture absorption and rapid wetting with water spreading time of 4 s, wicking height of 9.5 cm/5 min and ink droplet spreading time of 960 ms. Compared with the original inkjet-dyed fabric, the front K/S value of CPP-pre-treated dyed fabric decreased to 17.1 and the back K/S value increased to 16.0. The colour penetration was 93.3 %, which was 13 % higher than that of the original fabric. Thus, CPP pre-treatment of polyester fabric can facilitate complete dyeing of the fabric even within the interior of yarns.

Seidlitzia rosmarinus as a multipurpose environmentally friendly alkali in simultaneous dyeing and nanofinishing of polyester fabric: ZnO-NPs synthesis, carrier-free dyeing, and reduction clearing

A multipurpose product could be produced by synthesizing metal oxides and dyeing the fabric. However, to achieve better, cleaner results while consuming less energy, it is ideal to shorten the time and reduce costs by simultaneously creating nanoparticles and dyeing. This work facilitates carrier-free dyeing of polyester fabric and the synthesis of ZnO-NPs using Kelyab as a green alkali. The remarkable results demonstrated reduced bending length, i.e., a softer handle, higher air permeability, and tensile strength, longer resistance in alkaline conditions, and comparable color strength and fastness. Moreover, the after-treatment, the last treatment step on the finished or dyed fabric, pertains to the reduction clearing. It is essential for dyed PET fabric, given its significance in colorimetric characteristics and other fastness attributes, particularly washing. Thus, it is necessary to develop innovative techniques to achieve these objectives without using harmful chemicals. Kelyab, as an environmentally safe reducing agent, produced comparable results to those of the conventional method, especially in color strength. In addition, air plasma was applied as a surface activation and green pre-treatment, resulting in the highest color and tensile strength. The prepared samples were examined using FT-IR, XRD, and FESEM, among other tests. Using fewer chemicals (50% lower) in the reduction clearing, saving time and energy for preparing reduction solution, and lowering the requirement for waste-water treatment in the simultaneous nanosynthesis and dyeing are the novelties of the introduced processing that can replace conventional method in dyeing, post-dyeing, and nanofinishing treatments.

Methyl Red-loaded halloysite nanotubes-based silica coatings for durable dyeing of polyester fabrics

Since unmodified polyester fibres have no reactive groups like those in cellulose and protein fibres, they do not show an affinity for water-soluble acid, basic and direct dyestuffs. Only disperse dyestuff, a non-ionic dyestuff class with low molar mass molecules, proved to be useful for dyeing this man-made fibre following a solid–solid interaction; disperse dyestuffs do not form primary chemical bonds with polymer chains rather the dye colour is retained by H-bonds and Van der Waals forces. Herein, a new strategy for dyeing polyester fabrics with a direct dyestuff in a two-step strategy was designed and realized, using an organic–inorganic composite coating based on methyl red-loaded sol-gel modified halloysite nanotubes. In the first step two distinct reaction methods were compared to functionalize halloysite nanotubes with (3-Glycidyloxypropyl)trimethoxysilane, as a covalent crosslinker between the halloysite nanotubes and fibres, (i) in water and (ii) in ethanol, using BF3O(C2H5) and chloridric acid (HCl) as catalysts, respectively.In the second step, methyl red loaded GPTMS modified halloysite sols were applied onto polyester fabrics by impregnation. The amount of methyl red dyestuff was evaluated to be superior for the complex realized in ethanol than in water, thus promoting homogeneous nanocomposite coatings on treated polyester samples. Methyl red loaded sol-gel modified halloysite complex, as well as treated and untreated samples, were investigated to characterize their properties and morphology. NMR investigation confirmed the structure of the new complex, validating the successful dyestuff coordination reaction at GPTMS.The influence of treatments on the morphology of fibres surfaces was demonstrated by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), and Atomic Force Microscopy (AFM) analyses, highlighting the influence of GPTMS-based composites on the microstructure of functionalized polyester fibres. To further confirm if the suggested approach offers a stable dyestuff loading on PE, diffuse reflectance spectroscopic studies, X-ray Photoelectron Spectroscopy (XPS) and colour fastness to rubbing and washing tests were carried out on the coated polyester.All findings make sol-gel based modification of halloysite a reliable and promising method for eco-friendly dyeing processes of polyester fabrics.

Chemical modification of marigold (Tagetes erecta) dye via diazo-coupling reaction for enhanced dyeing on polyester: A sustainable approach

Plant-derived natural extracts contain large amounts of polyphenolic compounds, presenting opportunities for chemical modification. The present study deals with the extraction of dye from Marigold (Tagetes erecta), a widely cultivated and commercially utilised flower, using water as an extraction medium followed by its chemical modification for sustainable synthesis of yellow dye and dyeing of polyester fabric. Phytochemical analysis and FTIR spectroscopy of the natural dye extract from Marigold flowers indicated the presence of polyphenolic flavonoids. The water-extracted natural dye was subsequently chemically modified with aniline, a primary aryl amine, via diazotisation and coupling reactions to yield a semi-synthetic natural dye with a 1.2 ± 0.3 g yield. The major constituents in the marigold natural extract and the Modified Marigold Extract (MME) dye were characterised using High-Resolution Liquid Chromatography-Mass Spectrometry (LC-HRMS). The marigold water extract contained a high concentration of Gossypetin 8-Glucoside, a yellow-coloured flavonoid compound with a mass-to-charge ratio (m/z) of 480.0904. LC-HRMS analysis further confirmed the presence of a constituent (m/z 424.0485) in the MME dye, corresponding to the predicted mass of chemically modified Gossypetin 8-Glucoside. The MME dye was subsequently employed for dyeing polyester fabric, exhibiting maximum colour strength at 10 % shade under acidic condition. The dyeing performances of the MME-dyed fabrics were evaluated in terms of fastness and post-dyeing strength. This study demonstrates a unique and novel approach to develop a yellow semi-synthetic natural dye, emphasising its potential utility for polyester dyeing.

Performance Enhancement of Novel and Sustainable Foam Dyeing of Polyester Fabrics Using Disperse Dyes

Performance Enhancement of Novel and Sustainable Foam Dyeing of Polyester Fabrics Using Disperse Dyes

Organofluorosilicon Modified Polyacrylate with the Unidirectional Migration Promotion of Disperse Dyes toward Polyester Fabric for Wash-Free Digital Inkjet Dyeing.

The printing and dyeing industry is currently accelerating toward a direction of high efficiency, energy conservation, environmental protection, and integration with digitalization. Disperse dye wash-free digital inkjet dyeing is a revolutionary breakthrough for cleaning and coloring polyester fabric. Based on the solubility parameters and the hot-melt dyeing characteristics of disperse dyes, soft, hard, and functional monomers of acrylate were used as the main body. Moreover, single-vinyl fluorinated polysiloxane and divinyl polysiloxane with low solubility parameters were used as modified monomers. A modified polyacrylate (PFSMA) adhesive containing silicon in the main chain and fluorine silicon in the side chain was prepared via miniemulsion polymerization. Using disperse digital inkjet dyeing of polyester fabric without washing can realize energy saving, emission reduction, and carbon reduction. Results showed that the optimum preparation conditions of PFSMA were as follows: DVFS molecular weight of 957 g/mol and DVFS content of 2.5 wt %. Compared with that of polyacrylate (PA), the glass-transition temperature of PFSMA film decreased, and its water resistance, toughness, and adhesion enhanced. When the PFSMA content in the wash-free disperse red ink was 8 wt %, the color yields of the front and back of the PFSMA jet-dyed polyester fabric were 18.86 and 13.28, respectively. Moreover, the color yield of the front of PFSMA jet-dyed polyester fabric was 39.9% higher than that of the pure liquid disperse red jet-dyed fabric. The simulated fixation rate was 87.9%, approximately 2.9 times higher than that of the PA wash-free jet-dyed fabric. The color fastness to dry rubbing reached level 4 and the color fastness to wet rubbing reached level 3-4, which was one level higher than that of pure liquid disperse red jet-dyed fabrics. The color fastness to soaping reached grade 5 and the color fastness to heat compression reached grades 4-5 and above. The fabric was a little firmer but smoother. The color properties, color fastness, and hand feeling of the PFSMA wash-free jet-dyed polyester fabric exceeded the levels of commercially available adhesives.

Enhancing color brilliance and fastness of polyester dyeing with antipyrine-derived disperse dyes

Disperse azo dyes are important colorants for dyeing polyester fabrics, but developing optimized disperse azo dyes remains a challenge. This work details the synthesis of seven new disperse azo dyes 3a-g derived from the coupling reaction of 4-aminoantipyrine diazonium salt with various phenolic precursors including phenol (3a), salicylic acid (3b), salicylaldehyde (3c), cresols (3d-f), and resorcinol (3g). The dyes were characterized by spectroscopic techniques. Their UV–visible absorption spectra were studied, revealing bathochromic shifts for 3d-g containing electron-donating methyl and hydroxyl substituents compared to parent dye 3a while dyes 3b-c showed hypsochromic shifts. The impact of acid and base on the absorption spectra indicates azo-hydrazone tautomerism for 3f-g but predominant azo form for 3a-e. The dyes showed excellent dyeing on polyester fabrics with up to 97.86 % dye exhaustion. High wash, light and perspiration fastness was exhibited while fastness to respiration varied. The strongest color yield on polyester was achieved with 3g derived from resorcinol coupler. Density functional theory calculations were performed to elucidate relationships between substituent effects and spectral attributes. Lower energy gaps were computed for 3f-g, consistent with enhanced reactivity. This work expands disperse azo dye precursors while offering fundamental structure-performance insight to guide future design. The potent polyester coloration and good fastness properties warrant ongoing investigation of these dyes.

Novel Disperse Dyes Based on Enaminones: Synthesis, Dyeing Performance on Polyester Fabrics, and Potential Biological Activities.

1-(3-aryl)-3-(dimethylamino)prop-2-en-1-one (enaminones) derivatives and the diazonium salt of para-chloroaniline were used to synthesize several novel disperse azo dyes with high yield and the use of an environmentally friendly approach. At 100 and 130 °C, we dyed polyester fabrics using the new synthesized disperse dyes. At various temperatures, the dyed fabrics' color intensity was assessed. The results we obtained showed that dyeing utilizing a high temperature method at 130 °C was enhanced than dyeing utilizing a low temperature method at 100 °C. Reusing dye baths once or twice was a way to achieve two goals at the same time. The first was obtaining a dyed product at no cost, and the second was a way to treat the wastewater of dyeing bath effluents and reuse it again. Good results were obtained for the fastness characteristics of polyester dyed with disperse dyes. When the disperse dyes were tested against certain types of microbes and cancer cells, they demonstrated good and encouraging findings for the potential to be used as antioxidants and antimicrobial agents.

Supercritical fluid dyeing of polyester fabrics using polymeric nanofibers loaded with disperse dye

This study explores the efficacy of electrospun polyvinyl alcohol (PVA) nanofibers loaded with C.I. Disperse Red 60 (DR60) as dyeing agents for polyethylene terephthalate (PET) fabrics in a supercritical carbon dioxide environment. The fabrication of DR60-loaded PVA nanofibers (DR60/NF-1) involved a spinning solution containing water and dimethyl sulfoxide. Analysis revealed that PET fabrics treated with DR60/NF-1 exhibited significantly higher K/S values (8.51) compared to those treated with DR60 powder (3.19), resulting in visibly distinct coloration among dyed fabrics (ΔEab: 17.77). Additionally, DR60/NF-1 demonstrated superior dye uptake by PET fabrics (15.07 mg/g) at a dosage of 3% (o.w.f.) compared to DR60 powder (13.19 mg/g) at a dosage of 4% (o.w.f.). These findings underscore the potential of DR60-loaded PVA nanofibers to enhance coloration and dye uptake in PET fabric dyeing processes conducted under supercritical carbon dioxide conditions, offering promising avenues for advancing efficiency and sustainability in textile manufacturing.

Divinyl polysiloxane modified polyacrylate for promoting the directional migration of disperse dyes in digital jet dyeing of polyester fabric without washing

Future developments in the printing and dyeing industry will involve greenisation and personalisation. Less/no water digital technology has drawn much attention over traditional printing and dyeing for reducing carbon and emissions. Based on the solubility parameter difference between disperse dyes and monomers, divinyl polysiloxane modified polyacrylate (PSMA) with the directional migration effect for disperse dyes was prepared herein via mini-emulsion polymerisation. PSMA was used as wash-free polymer additive in the digital jet dyeing of polyester fabrics with disperse dyes, which yielded wash-free dyed fabrics with high color yield and color fastness. The results showed that PSMA achieved the optimum overall performance at a molar ratio of octamethylcyclotetrasiloxane to 1,3-divinyltetramethyldisiloxane 44:1 and divinyl polysiloxane dosage of 4 wt%. PSMA had the best tensile properties, good flexibility, certain hydrophobicity and high directional migration of disperse dyes. When the PSMA dosage was 9 wt% in the wash-free ink, the front and back color yield of the wash-free dyed fabric were 18.23 and 13.56, respectively. Compared with the fabric dyed with pure liquid disperse red, the front color yield of the wash-free dyed fabric increased by about 35.2 % and the back color yield had a little change. Its color fastness to dry/wet rubbing were improved from grade 3 to 4 and from grade 2–3 to 3, respectively. The handle of the wash-free dyed fabric basically maintained the level of original fabric.

Design, Synthesis, Characterization, and Antimicrobial Properties of New Azo Disperse Dyes Incorporating Quinazolinone-Pyrazolone Moieties and Their Applications for Dyeing of Polyester Fabrics

The current study outlines a straightforward and efficient method for creating new quinazolinone disperse dyes based on pyrazolone moieties, starting with quinazolinone and a variety of substituted pyrazolone as couplers. The synthesized dyes were characterized using a variety of spectroscopic and analytical methods. The synthesized dyes' ultraviolet–visible spectra showed bands brought on by several molecular transitions. We investigated in detail the multifunctional characteristics such color representation, dyeing duration, concentration, pH, buildup, and fastness properties of the dyed samples. Fastness properties and colorimetric data showed satisfactory results, demonstrating the effectiveness of these dyes in dyeing polyester fabrics. A pH of 5 and a dyeing temperature of 130 °C were the ideal conditions for dyeing polyester fabrics. Additionally, an ultraviolet protection factor test was performed on the dyed fabrics, and the results showed that these dyes provide the best UV protection. These dyes are suitable for industrial dyeing applications since they are easy to manufacture and scale up. Additionally, in-vitro testing was done to determine the dyes' antibacterial effectiveness against various bacteria and fungi. The antibacterial activity of the dyes was moderate to very good against both Gram-positive and Gram-negative bacteria, as well as fungi.

Prediction of colour strength in environmentally‐friendly dyeing of polyester fabric with madder using supercritical carbon dioxide

AbstractThe textile industry is one of the significant reasons for global water pollution, with dyeing processes being particularly environmentally detrimental. Researchers have explored alternative approaches to address this issue, such as using natural dyes, supercritical fluids and so forth. In addition to environment‐friendly approaches, reducing the number of experiments in studies, accurate production straightaway and using artificial intelligence (AI), one of the technologies of the present and the future that will provide significant support. Reaching clearer results with AI technology will not necessarily contribute to environment‐friendly technologies. However, AI techniques, including artificial neural networks (ANNs) and adaptive neuro fuzzy interface system (ANFIS) were employed to predict the colour strength (K/S) of the dyed fabric based on process parameters. A comprehensive experimental design involving pressure, temperature, and time variations was conducted, and the results were analysed using multi‐factor analysis of variance (MANOVA). The study demonstrates that supercritical carbon dioxide (scCO2) dyeing with madder on polyester fabric is a promising and environmentally friendly approach. Additionally, the optimised ANN and ANFIS models, aided by genetic algorithms (GAs), exhibit high predictive accuracy (less than 3%), providing insights into the impact of process parameters on colour strength. This research underscores the potential of AI‐driven automation in textile dyeing, offering solutions for dye formula prediction, colour matching, and defect detection, reducing the need for human intervention in these processes.

A Holistic Review of 3-Dimethylamino-1-Arylpropenones Based Disperse Dyes for Dyeing Polyester Fabrics: Synthesis, Characterization, and Antimicrobial Activities.

The enaminone compounds 3-Dimethylamino-1-arylpropenones produced in this review was synthesized by reacting para-methylacetophenone and para-nitroacetophenone with dimethylformamide dimethyl acetal. In this review article, we discuss how to create novel disperse colors by reacting enaminone derivatives 3a and 3b with phenyldiazonium salt. The highly productive procedure of creating new disperse dyes was followed by the process of dyeing polyester fabrics at temperatures between 70 and 130 °C. As a result, the colours' resistance to light, rubbing, perspiration, and washing fastness was assessed. In an effort to show the additional value of these dyes, the expected biological activity of the synthetic dyes against fungus, yeast, and Gram-positive and Gram-negative bacteria was also assessed. We have applied zinc oxide nanoparticles for polyester fabrics treatment to impact them a self-cleaning quality, increase their light fastness, enhance their antibacterial efficacy, and enhance UV protection as part of our ongoing strategy to obtain polyester fabrics with newly acquired specifications.

Agricultural waste Ipomoea batatas leaves for low-temperature dyeing and functional finishing of polyester fabrics

The increasing focus on eco-friendly textiles and cleaner production manufacturing techniques have made natural pigments for coloring and enhancing the functionality of textiles become a popular trend. This research aimed to extract plant pigment from bio-waste Ipomoea batatas leaves and utilize it for dyeing and functional decoration of polyester fabric at low temperature. The study optimized the parameters for pigment extraction and fabric dyeing and also investigated the stability of the pigment solution. The finding indicated that strong acids and bases, intense light, high temperatures, and oxidants have a greater impact on pigment stability. Observation and analysis using SEM, bio-optical microscope, FTIR, and UV–vis–NIR absorption spectroscopy revealed that chlorophyll pigment entered into the interior of polyester molecular chains through hydrophobic end intercalation and was retained by the physical forces, enabling low-temperature coloring and functional finishing of polyester fabrics. As a result, the polyester fabrics dyed with natural pigment exhibited excellent resistance to rubbing, washing, saliva, and perspiration (rated at level 4 or higher), except for the average light fastness (only grade 4). Additionally, the dyed polyester fabrics demonstrated outstanding UV resistance (UPF of 33.57 for raw polyester and 120.77 for pre-mordant dyed polyester) and antibacterial properties (raw polyester agar plates showed bacterial growth, while the colored polyester agar plates had almost no bacterial growth). Even after 10 wash cycles, the dyed polyester fabrics maintained their UV protection and antibacterial properties. This research is expected to provide a new approach to the valuable utilization of agricultural residues in the textile industry.

Novel Monosulfonated Azo Dyes: Design, Synthesis, and Application as Disperse Dyes on Polyester Fabrics.

This study synthesizes and characterizes a series of disperse dyes based on azo Schiff bases, compounds 8-10. Their structures were identified using various analytical techniques, such as FT-IR, 1H/13C NMR, and mass spectrometry. The study's primary objective was to investigate the behavior of disperse dyes 8-10 when used for dyeing polyester fabrics under different conditions, including variations in time, temperature, shade, and pH. The polyester fabric was chosen for this research due to its wide usage and popularity in the textile industry. By examining the effect of temperature and time on the dyeing process, it was observed that increasing the dyeing temperature from low to high (ranging from 90 to 120 °C) and extending the dyeing time from 10 to 30 min resulted in higher K/S values for the polyester samples dyed with disperse dyes. Additionally, dyes 9 and 10 exhibited the most excellent K/S values among the tested dyes. Furthermore, the study found that dye 8 showed the best dyeing performance as the pH of the dye bath increased to 6.

Dyeing of polyester fabrics with eco-friendly modified natural dyes using IR and ultrasonic methods without mordants or dispersion agents

Dyeing of polyester fabrics with eco-friendly modified natural dyes using IR and ultrasonic methods without mordants or dispersion agents

Synthesis, characterization, and application of novel aryldiazenyl disperse dyes on polyester fabrics

Azo dyes are widely used for dyeing polyester fabrics but require optimization of properties like color strength and fastness. Fourteen novel disperse azo dyes were synthesized from 2,3-naphthalenediol and aniline derivatives to examine their potential for polyester dyeing. The dyes were prepared via diazotization and coupling reactions and characterized using FT-IR, UV–Vis, 1H NMR, 13C NMR, and elemental analysis. Furthermore, several techniques were employed to study the azo-hydrazone tautomerism, including UV–Vis spectroscopy, NMR spectroscopy, and computational methods. DFT computations revealed hydrazone tautomers were more stable than azo tautomers. The prepared azo dyes were applied on polyester fabrics at 2% depth using a high temperature pressure technique in water utilizing DYEWELL-002 as a dispersing agent. The color shading of dyed polyester samples ranged from peach amber to apple of my eye, depending on the coupler moieties. The fastness properties, assessed using a grey scale of dyed polyester fabrics, indicated very good to excellent grades for most dyes. Additionally, measurements of color strength (K/S), dye exhaustion (%E), as well as colorimetric colors CILAB of dyed polyester fabrics values, were measured and discussed in terms of the effect of substituents. The findings provide new insights into structure-performance relationships to design optimized disperse dyes for polyester coloration. Overall, the synthesized aryldiazenyl dyes are promising candidates for dyeing polyester fabrics across a spectrum of shades with good fastness properties.

D- π-A azo dyes bearing thiazole-diphenylamine units: Synthesis, photophysical and molecular structure properties, and use for dyeing of polyester fabrics

Herein, six new thiazole-dipehenylamine-based azo dyes containing azo and thiazole bridges and diphenylamine donor with different donor/acceptor groups were synthesized. All the synthesized dyes were characterized by FT-IR, NMR and HRMS analyses. The structure of (E)-N-methyl-4-((thiazol-2-yl)diazenyl)-N-phenylaniline (4) was conclusively confirmed by single crystal X-ray diffraction analysis. Photophysical studies were performed in different solvents with various polarity. Although the three synthesized compounds can be represented as potential azo-hydrazone tautomers only the azo form was observed in all solvents used. UV/vis spectroscopic studies showed that the color changed dramatically when the dyes contain a strong electron accepting nitro substituent. Moreover, after protonation of azo dyes, with the exception of the azo dyes with nitro group, a bathochromic shift was observed. The effects of protonation on the geometry and electronic structure of the compounds were studied, and the NLO properties were also investigated using DFT calculations. In addition, the thermal stability of the azo dyes was investigated using thermal gravimetry (TGA). Dyeing performance was evaluated with these dyes on polyester fabric in an aqueous medium. All dyes except dyes 3 and 6 showed good color fastness properties. Therefore, these compounds can be used as textile dyes for polyester fabrics.