Higher Color Yield Research Articles

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.

Naphthoquinone disperse dyes and their dyeing application to polyethylene terephthalate fabrics

Examination of natural quinone dyes and their dyeing properties exist in the literature. However, disperse dyeing of synthetic quinone dyes on textile materials and examination of these properties are quite rare. In this study, the derivatives of new N-,O-heteroatom-substituted-1,4-naphthoquinone dyes were synthesized with the reactions between 2,3-dichloro-1,4-naphthoquinone with some aromatic and aliphatic N-nucleophiles according to Michael addition mechanism and the exact structure of dyes were specified by using various spectroscopic methods (FT-IR, 1H NMR, 13C NMR, MS, and UV/Vis.) and microanalyses. In the second step of this work, the polyethylene terephthalate fabrics were dyed with these newly synthesized disperse dyes. Dyeing performances such as dye exhaustion (%), color, and color fastness (to washing, alkaline perspiration, acidic perspiration, water, seawater, wet rub, dry rub, sublimation, and light fastness) properties of these dyes on PET fiber fabrics were investigated and compared. The highest color yield (K/S) by 12.33 was obtained with dye compound 10 at a dyeing depth of 3% owf and displayed better dyeing performance than the other dyes studied. In conclusion, PET fibers dyed with dye 2-4-(4-Chlorofenoxyaniline)-3-chloro-1,4-naphthoquinone (dye compound 10) displayed the highest dye exhaustion (%) values, the highest color yields, and excellent washing, perspiration (alkaline and acidic), water and seawater and rub (dry and wet) fastness values with no staining whatsoever.

Green Application of Isolated Colorant from Neem Bark for Mordant-Coated Wool: Optimization of Dyeing and Mordanting for Shade Development

This study aimed to assess the effectiveness of utilizing a tannin-based natural brown colorant from neem bark for dyeing wool under microwave treatment, specifically evaluating its coloring efficiency. The colorant was extracted in a methanol solution that had been acidified both before and after being subjected to microwave treatment for up to 6 min. The dyeing variables were optimized to create new shades of dye with desirable fastness properties, and sustainable chemical and bio-mordants ranging from 1 to 10 g/100 mL were employed. Through experimentation, it was determined that when an unirradiated acidic methanolic extract (AME) with a salt concentration of 3 g/100 mL was applied onto wool fabric (RWF) and subjected to microwave treatment for 4 min, it resulted in a high color yield. This was achieved by heating the solution to 65 °C and allowing it to remain in contact with the fabric for a duration of 65 min. Favorable color characteristics were achieved when utilizing a pre-chemical mordant of 5% Fe and a post-chemical mordant of 5% Fe. In contrast, the utilization of 7% henna as a pre-bio-mordant in combination with 3% turmeric extract as a meta-bio-mordant resulted in favorable color characteristics. The study concludes that microwave treatment exhibits outstanding sustainable efficacy in isolating colorants from neem bark powder for wool dyeing. Incorporating bio-mordants further enhanced the process’s sustainability and eco-friendliness.

Alternative Eco-friendly Treatment of Hollow Cellulosic Fiber-Based Hybrid Composites for Remarkable Reactive Dyeing

Egyptian Chorisia hollow fibers have been blended with cotton waste, polyester waste, and raw bamboo at various ratios and weft counts using open-end spinning. The blended fabrics of hybrid composites were subjected to atmospheric plasma, pectinase, and lipase enzyme treatments, as well as the substitution of all hazardous chemicals, as sustainable alternatives to traditional alkaline scouring. The impacts of the treatments on the hollow-based fabrics' hydrophilicity, surface morphology, and color performance have been discussed. Pretreatment is associated with considerable weight loss (~ 12%) and a wetting time of less than 5 s which represents adequate absorbency of the composite. The enzymatic treatment contributed to looser arrangement of the fibrils which indicates an effective elimination of lignin and hemicellulose. The crystalline sections were greatly influenced by enzymatic treatment, providing effective decrease of cellulose crystallinity by about 30–40% as revealed by X-ray diffraction (XRD) measurements. Compared to conventional scouring, bio-scouring discharges significantly less effluent. The treated composite using either enzyme or plasma pretreatment method produced about at least 300% higher color yield (K/S) and 100% enhanced dye fixation (% F) than the untreated fabric. The lipase pretreatment without subsequent to atmospheric plasma treatment could be enough to achieve the highest hydrophilicity and color performance level under the experimental conditions.

Microwave-assisted santalin extraction from Pterocarpus santalinus for mordanted woolen yarn dyeing

Natural dyes have attracted the world because of its ayurvedic and biological functioning characteristics. In this research, the functional bio-actives santalin from red sandal wood (RSW) powder has been isolated and exposed to MW treatment for up to 5 min. The extracts and fabrics were stimulated and used to dye at a given condition. The results revealed that 50 mL of red sandal wood extract (RSWE) at 4 pH containing 2g/100 mL of salt was employed at 65 °C for 65 min. After 4 min, MW treatment has given the highest color yield. The surface morphology of the fiber shows that the yarn surface has been modified without any chemical changes. Mordanting with chemical and biological extract at low amounts has improved shade fastness with new tints. It can be calculated that MW ray has the potential to explore colorant from crude powder in a suitable solvent under mild conditions but also reducing dyeing conditions and mordant, revealing that this green tool is cost, energy and time effective.

Coloring efficacy of Nyctanthes Arbortristis based yellow natural dye for surface-modified wool

Sustainable products particular plant pigments as colorants have gained a worldwide fame due to their ayurvedic and eco-friendly nature. In this research, improvement in colorfastness of Coral Jasmine ( Nyctanthes Arbortristis ) based yellow natural pigment has been investigated using eco-friendly shade developers (mordants) after being separated from crude mixture in aqueous medium and applied before and after dyeing of wool at given conditions in microwave radiation (MW). It has been found that 35 mL of yellow water extract (6 pH) of Coral Jasmine after irradiation upto 4 min, has given high colour yield onto MW-irradiated wool when used to dye wool at 85 °C for 35 min in presence of 2 g/100 mL of salt. Before dyeing 0.5% of tannic acid and 0.5 % of orange peel , 2 % of acacia and 1.5 % of pomegranate extract has developed colourfast shades of high strength. Similarly after dyeing, 2.5 % of tannic acid, 2 % of orange peel, 2.5 % of acacia and 1.5 % of pomegranate extract has developed colourfast shades of high strength also. It is inferred that eco-friendly mordants has played promising role in improving bio-colouring behaviour of wool with Nyctanthes Arbortristis but also addition of MW-rays to get high yield has made process more sustainable and valuable. • The microwave-assisted extraction of Nyctanthes dye was investigated. • Bio-mordanting were used as a replace of metal mordant. • Bio-dyeing of wool shown excellent fastness properties. • Nyctanthes Arbortristis based yellow natural dye can be an alternative of synthetic dyes.

Sustainable exploration of coffee extracts (coffea arabica l.) for dyeing of microwave-treated bio-mordanted cotton fabric

PurposeThis study aims to observe the coloring efficacy of coffee-based natural brown colorant for cotton dyeing under microwave (MW) treatment.Design/methodology/approachThe colorant extracted in particular (neutral and acidic) media was stimulated by MW treatment up to 6 min. Dyeing variables were optimized and 2–10 g/100 mL of sustainable anchors (mordants) have been used to get colorfast shades.FindingsIt has been found that un-irradiated acidic extract (RE) containing 5% of table salt at 80 °C for 50 min has given high color yield onto MW-irradiated cotton fabric (RC = 2 min). The utilization of 2% of Fe, 10% of tannic acid and 10% of sodium potassium tartrate before bio-coloration, whereas 4% of Fe, 10% of tannic acid and 6% of sodium potassium tartrate after bio-coloration has given good color characteristics. In comparison the application of 6% of pomegranate and turmeric extracts before bio-coloration and 6% of pomegranate and 10% of turmeric extracts after bio-coloration have given good color characteristics. New bio-mordants can be added to get more new colorfast shades.Research limitations/implicationsThere is no research limitation for this work. New bio-mordants can be added to get more new colorfast shades.Practical implicationsThis work has practical application for artisans, textile industry and handicrafts. It is concluded that colorant from coffee beans can be possible alternative of synthetic brown dyes and inclusion of MW rays for extraction and plant molecules as shade developers can make process more green.Social implicationsSocially, it has good impact on eco-system and global community because the effluent load is not carcinogenic in nature.Originality/valueThe work is original and contains value-added product for textiles and other allied fields.

Eco-dyeing and functional finishing of wool fabric based on Portulaca oleracea L. as colorant and Musa basjoo as natural mordant

Biomass energy is the most acknowledged renewable resource due to its universality, richness, and renewability. This study utilized a Portulaca oleracea L. plant as a natural colorant for wool fabric dyeing with a high color yield at optimum extraction and dyeing conditions. To evaluate the dyeing mechanism and feasibility of the extracted dyes, we analyzed and characterized the molecular structure and nano-level particle size. The dyeing kinetics and the morphology of dyed fabrics were integratedly explored; the adsorption process of wool fabric on natural colorant molecules was increasingly in line with the pseudo-second-order kinetic adsorption model. Further, the dyeing effects of wool fabrics were compared to that of Musa basjoo mordant and synthetic dyes to confirm the superior color depth (K/S value 23.53), biological function as anti-ultraviolet (UPF value 253.47), and anti-bacterial activity (antibacterial rate of Staphylococcus aureus/Escherichia coli was 71.3%/37%). Our findings provide a feasible scheme for providing deep color and biological activity to wool fabrics. This has broad application prospects in the field of eco-friendly textile materials.

Impact of MW rays on extraction and application of Ficus religiosa bark based natural colourant for cotton dyeing

The present study aims to extract a natural brown colourant from Ficus religiosa for cotton dyeing using the microwave radiation process. The colourant was isolated in aqueous and acidic media before and after microwave treatment (MW) for up to 6 min. The dye variables have been optimised for the development of new shades with good fastness characteristics, 1–5 g/100 mL of sustainable chemical and bio-mordants have been used. It has been found that irradiated aqueous extract (RE) containing 3 g/100 mL of salt at 55°C for 45 min has given high colour yield onto cotton fabric (RS) after microwave treatment for 4 min. The utilization of 2% of Al, 2% of Fe, 3% of tannic acid (T.A.) as pre chemical mordant whereas 4% of Al, 5% of Fe, 2% of tannic acid as post chemical mordant has given good colour characteristics. In comparison 3% of acacia and 4% pomegranate while 4% of Acacia and 2% of pomegranate extracts as post-bio-mordant have given excellent colour characteristics. It is concluded that MW treatment has an excellent sustainable efficacy to isolate colourant from Ficus Religiosa bark powder for cotton dyeing, whereas the inclusion of bio-mordants has made the process more sustainable and environmental friendly.

Dyeing and Color Fastness Properties of Natural Dyed Actual Size Hanji

After manufacturing the natural dyed actual size Hanji using 11 kinds of plant natural dyeing materials and 2 kinds of animal natural dyeing materials, the color characteristics and color change and color fastness after post-mordanting were compared and discussed. The hues of 13 types of natural dyed Hanji were black, PB, and RP, each with 1 type, YP with 3 types, and Y with 7 types. Among the natural dyeing materials, Chinese ink, indigo and Lac showed high color yield and color difference, and violet-root cromwell and gardenia seeds showed low color yield. The color fastness of Hanji dyed with turpentine diluted Ottchil, Pagoda tree seeds, Chinese ink and indigo was excellent, while that of gardenia seeds and violet-root cromwell were very poor. After post-mordanting of natural dyed Hanji with Al, Cu, and Fe mordants, the hue changes were show up the Alnus firma, clove, lac and cochineal. In addition, the color difference was very diverse and was overall the most biggest due to Fe mordant. After 72 hr. of UV irradiation on post-mordanting natural dyed Hanji, hue change was observed in 3 types and color fastness was improved in 8 types by post-mordanting. The Hue and color fastness are significantly different depending on the type of natural dying materials and post-mordants. Therefore, when dyeing Hanji with natural dyes, it is necessary to dye with sufficient knowledges and informations about the desired color and fastness.

Investigation of Dyeing Properties of Red Cabbage to Cotton Fabrics in Different pH and Mordanting Conditions

In this study, dyeing properties of cotton fabrics with red cabbage extract as a natural colorant and by mordanting materials like potassium aluminumsulphate and tannic acid were investigated. Pre-mordanting, simultaneous mordanting and post-mordanting methods were used for mordanting of cotton fabric and natural dyeing process was carried out by exhaustion method. Moreover, since it is known that red cabbage presents different colors in different pH values due to its indicator property, the trials were renewed for three pH conditions as acidic, basic and neutral. After dyeing processes, color measurement, washing and rubbing fastness tests were applied to the samples. As a result of the study, it was observed that red cabbage extract can be used to dye cotton fabrics and the most permanent colors can be obtained in neutral pH conditions. When mordanting methods and mordanting materials were compared to each other, it was determined that various color shades were provided according to the mordanting materials and methods. In terms of general, it was concluded that uniform dyeings with high color yield can be obtained by tannic acid mordant and pre-mordanting method and high mordant concentration should be used to get dark color shades. In addition, washing and rubbing fastness values were determined to be in acceptable limits for natural dyeing.

Waterborne polyurethane‐based dye with covalently bonded to Disperse blue 60

ABSTRACTA series of sulfonated waterborne polyurethane‐based dyes (DB60‐SWPUs) with covalently bonded to different proportions of Disperse blue 60 (DB60) were prepared by a modified acetone process. The expected structures of DB60‐SWPUs are characterized by Fourier transform infrared spectroscopy and 1H‐NMR spectra. The obtained DB60‐SWPUs show high viscosity and intriguing storage stability. The fluorescent performances, thermal properties, and mechanical properties of DB60‐SWPUs were characterized. Compared with DB60, the UV–vis spectra of DB60‐WPUs have obvious hypochromic shift, and the fluorescence intensities are obviously enhanced. The migration rates of DB60‐SWPUs are much lower than that of DB60. DB60‐SWPUs have thermal migration resistance and excellent color fastness. The polyester fiber dyed by DB60‐SWPUs has not only high color yield, good fracture strength, excellent breaking strength retention, but also good permeability and wrinkle resistance. Moreover, DB60‐SWPUs are polymeric dyes with water as a solvent, which are especially suitable for environmental protection. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48862.

Effect of pH Condition on Natural Indigo (Indigofera tinctoria) Reduction by Yeast (Saccharomyces cerevisiae)

Ultimate goal of this research is to develop an efficient microbial system for indigo reduction by using yeast (Saccharomyces cerevisiae). For this purpose, we investigated the effect of pH condition on natural indigo (Indigofera tinctoria) reduction by yeast. We also checked the viability of yeast at high pH condition by observing yeast cell in the indigo reduction bath with an optical microscope. The pH of indigo reduction bath was initially set from 10.2 to 12.0 with the buffer solution. The pH value dropped drastically up to 5.5–6.5 at the initial stage of reduction. After adjusting pH once within 1–2 days, we measured some parameters related to reducing power such as the color yield (K/S value) of ramie fabric dyed with the supernatant of bath, the oxidation/reduction potential (ORP), and the pH values changed. When the initial pH was set at lower than 11 (10.2, 10.7), the baths adjusted to pH 11 showed better reducing power than the baths of pH other than 11. And also, when the initial pH was set higher than 11 (11.3 and 12.0), the baths adjusted to pH 11 showed better reducing power than the baths of pH other than 11. It took 5–11 days to reach the maximum dye uptake after the initiation of reduction, and, during the corresponding time, the ORP was from -563 to -599 mV. All the initial and the adjusted pH values were not maintained but decreased continuously, and the maximum dye uptake reached at pH 9.17-9.43. The initial and the adjusted pH greatly affected the indigo reducing power, and the highest color yield was obtained with indigo reduction bath of initial pH 10.7. When the pH of the bath was adjusted to pH 11.0, the maximum reducing power was obtained most efficiently. Also, for the pH adjustment, use of sodium hydroxide showed higher reducing power than use of calcium hydroxide.

The effect of O2 plasma treatment and PA 6 coating on digital ink-jet printing of PET non-woven fabric

In the absence of pre-processing, polyethylene terephthalate (PET) non-woven have strong hydrophobicity. Therefore, patterns printed with pigment ink-jet printing have poor color yield and low resolution. In this study, the surface properties of PET non-woven fabric were modified by plasma treatment, and a coating solution made by waste polyamide 6 (PA 6) filament, methanol, and CaCl2 to prepare 3.5% and 6.8% PA 6 concentration. After that, plasma-treated sample, coated sample, and plasma treatment plus PA 6 coated sample results on pigment ink-jet printing were investigated to prepare good printing PET non-woven packaging fabric. Scanning electron microscopic image indicated that plasma makes etching on the fabric surface, hence increase the hydrophilic property of the fabric, which helps slight increase in the color yield and resolution. The contact angle shows PA 6 coating also achieved hydrophilic on the surface of PET non-woven fabric and facilitated the ink absorption in pigment ink-jet printing, which helped the printed fabric have higher color yield and clear resolution. However, for significant results it was very important to increase the absorption of coating solution. Plasma makes it easier for the fabric to absorb more coating solution containing dissolved waste PA 6 filament in both concentrations from 11.97% to 19.92% and 5.68% to 10.50%. This ultimately provides the capacities for the fabric to capture more ink and penetration of more colorant particles into the fabric. Therefore, plasma treatment first plus PA 6 coating can help prepare better-patterned PET non-woven fabric packing through pigment ink-jet printing, even though the plasma treatment and coating caused a little negative influence in whiteness and handle.

One-Bath Pretreatment for Enhancing the Color Yield and Anti-Static Properties of Inkjet Printed Polyester Using Disperse Inks.

This paper presents a simple and economical method for preparing durable anti-static functionalized inkjet prints by using P[St-BA-F6]—novel antistatic agents synthesized by an oxidative polymerization of styrene, butyl acrylate, and allyl alcohol polyether F6. The P[St-BA-F6] was characterized by gel permeation chromatography and Fourier transformation infrared spectroscopy. One bath pretreatment solution containing P[St-BA-F6] and pentaerythritol tetraacrylate (PETA) were applied to polyester fabrics before inkjet printing, in order to enhance the color yield and the anti-static properties. The pretreatment conditions, including the concentrations of P[St-BA-F6], curing temperature, and time, were optimized based on inkjet printed polyester fabrics. SEM (scanning electron microscope), XPS (X-ray photoelectron spectroscopy), XRD (X-ray diffractometer), TG (thermogravimetric), and DSC (differential scanning calorimetry) examined the fabrics. The results showed that the treated PET fabrics exhibited good applied performances, such as higher color yield, better dry rubbing fastness, lower electrostatic voltage, and durable anti-static properties, even after washing 10 times. These results can be attributed to alcohol polythene group (F6) and allyl group (PETA). PETA can be cross-linked with P[St-BA-F6] and PET fiber. The thermal stability of the treated fabric was lower than that of the untreated fabric, owing to the presence of resin film on the fiber surface.

A photochromic waterborne polyurethane-based dye with chemically fixed azobenzene groups

A photochromic waterborne polyurethane-based dye with azobenzene groups WPU-DDB-3BF was prepared by incorporating Disperse Diazo Black 3BF (DDB-3BF, CAS: 6232-57-1) into the polyurethane chain according to a modified acetone process. The expected structure of WPU-DDB-3BF was characterized by FT-IR, Raman and UV–Vis spectra. Containing the well-known dye of azobenzene groups, WPU-DDB-3BF exhibits a slow photochromic process. Compared with DDB-3BF, the isomerization time of WPU-DDB-3BF has obviously grown longer. The improved thermal stability of WPU-DDB-3BF is ascribed to the attachment of azobenzene units to polyurethane backbone chains. The polyester fibers dyed with WPU-DDB-3BF show high color yield (K/S), outstanding breaking strength retention, excellent breathability and strong wrinkle resistance. From the experimental results, WPU-DDB-3BF possesses outstanding photochromism and dyeing performance.

A waterborne polyurethane-based polymeric dye with covalently linked disperse red 11

A red fluorescent sulfonated waterborne polyurethane-based dye WPU-DR11 was synthesized by conjugating Disperse Red 11 (DR11) into polyurethane backbones. The expected structure of WPU-DR11 was characterized by FT-IR and UV–vis spectra. Containing the well-known dye of anthraquinone chromophores, WPU-DR11 exhibits intriguing optical behaviors. Compared with DR11, WPU-DR11 shows an obvious bathochromic shift in absorption spectra, whereas a evident hypsochromic shift in emission spectra. The fluorescence intensity of WPU-DR11 is dramatically enhanced compared with that of DR11. The fluorescence intensity of WPU-DR11 increases with the temperature, which is different from that of ordinary fluorescent materials. It is found that the fluorescence intensity of WPU-DR11 gradually increase with the increase of concentration, and then decrease. Migration rate of WPU-DR11 are only 2.0–4.0%, which is well below migration rate of DR11. The polyester fibers dyed with WPU-DR11 show high color yield, excellent breaking strength retention, good air permeability and anti-wrinkle resistance. According to the experimental results, WPU-DR11 exhibits excellent fluorescent and dyeing performance.

New washing-free printing binder based on organosilicon-modified polyacrylate for polyester fabric printing of disperse dyes

Based on the disperse dye washing-free printing technology, a new washing-free printing binder was prepared through organosilicon modification of polyacrylate (PA) by mini-emulsion polymerization to achieve high color yield and color fastness of the printed fabric. The washing-free printing properties, structure, thermal behaviours, and surface characteristics of organosilicon-modified polyacrylate (PDMEMA) were intensively investigated. The migration-diffusion-fixation mechanisms of disperse dyes (DD) from PDMEMA film to polyester fiber (PET) were tentatively explored. Results showed that using PDMEMA with vinyl terminated polysiloxane 4313 g/mol at 4 wt %, the washing-free printed polyester fabric obtained the best washing-free printing properties. The color yield, color fastness and handle of PDMEMA surpassed those of commercial printing binders. The organosilicon modification of PA widened the differences of solubility parameters between DD and PDMEMA, contributing to the migration-diffusion of DD from PDMEMA film to PET and the fixation into PET. The decrease of the glass transition temperature of PDMEMA accelerated the migration-diffusion process of DD towards PET. Meanwhile, the organosilicon chain-segments of PDMEMA shifted onto the film surface in baking, which realized the directional transfer of DD from film to PET.

Breathable and Colorful Cellulose Acetate-Based Nanofibrous Membranes for Directional Moisture Transport.

Textiles with excellent moisture transport characteristics play key role in regulating comfort of the body, and use of color in textiles helps in developing aesthetically pleasing apparels. Herein, we report an aesthetically pleasing and breathable dual-layer cellulose acetate (CA) based nanofibrous membranes with exceptional directional moisture transport performance. The outer layer was synthesized by subjecting CA nanofibers to hydrolysis and reactive dyeing processes, which converted moderately hydrophobic CA nanofibers into uniformly colored superhydrophilic CA nanofibers with an excellent wettability. In addition to excellent wettability and superhydrophilic nature, dyed CA (DCA) nanofibers also offered high color yield and dye fixation as well as considerable colorfastness performance against washing and light, thus, were used as the outer layer. However, pristine CA nanofibers were chosen as the inner layer for their moderate hydrophobicity. The subsequent CA/DCA nanofiber membrane produced a high wettability gradient, which facilitated directional moisture transport from CA to DCA layers. The resultant dual-layer nanofiber membranes offered a high color yield of 16.33 with ∼82% dye fixation, excellent accumulative one-way transport capacity (919%), remarkable overall moisture management capacity (0.89), and reasonably high water vapor transport rate (12.11 kg d-1 m-2), suggesting them to be a potential substrate for fast sweat-release applications.

Dyeing performance of the azo dyes containing trifluoromethyl group for polyester fabrics and its single crystal structure

The structures of disperse dyes and their intermolecular interactions have important impacts on dyeing and printing performances for polyester fabrics. The fluorine dyes show some unique molecular stability and photochemical properties. The dyeing property of the azo dye containing trifluoromethyl group for polyester fabrics, 4'-(N-acetoxyethyl-Nethyl)- amino-2-bromine-4-nitro-6-trifluoromethylazo- benzene (D1), was investigated and compared with the similar structure disperse dye. The results show that the high color yield and good exhaustion of the dyed PET fabrics could be obtained. The polyester fabrics dyed with D1 had excellent light fastness. Its single crystal was prepared and the supramolecular interactions were solved by X-ray diffraction. Dye D1 formed triclinic crystals in a trimeric packing mode. The C-F bond distances of CF3 are 1.2730 A, 1.2240 A and 1.2900 A, respectively. The two benzene rings linked azo unit (-N=N-) are obviously twist. The dihedral angle of the two benzene rings is 50.23 o. There are six weak hydrogen bonds around trifluoromethyl group in the intramolecule and intermolecule. The excellent light stability of the dye should be attributed to its unique supramolecular structure.