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In this paper, the swelling effect of ionic liquid reverse micelle system on cotton fabric in supercritical CO2, and the influence of swelling on the dyeing of cotton fabric were studied. The results indicate that the ionic liquid reverse micelle system can cause swelling of cotton fabric. In the process of alkali free dyeing, swelling has a significant effect on the dyeing properties of cotton. With the extension of reaction time, both the crystallinity and XRD diffraction intensity of cotton fabric decreased, and the dyeing depth (K/S value) of cotton fabric increased. The temperature and molar ratio of ionic liquid to surfactant have a significant impact on the swelling of cotton fabrics. At higher temperature (90 °C), the crystallinity index of cellulose in cotton fabric significantly decreases, which affected the K/S values of dyed cotton fabric. Adding a certain amount of DMSO can promote the swelling of cotton fiber, greatly reduce crystallinity, and improve the dyeing performance of cotton fabric. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to solve the problems of dyeing difficulty and serious pollution of traditional water-based dyeing of para-aramid, supercritical CO2 fluid was employed as a dyeing solvent to dye para-aramid yarn (temperatures 80–120 °C, pressures 16–24 MPa, dyeing time 15–90 min, and dye concentration 1 %–7 % o.m.f.). The K/S values reached 2.07 and 1.91 at 120 °C, 24 MPa, 60 min, 5 % o.m.f., and a CO2 flow of 20 g/min with C. I. Disperse Red 54 and C. I. Disperse Blue 79, respectively. The results proved that para-aramid yarn could be dyed in supercritical CO2 fluid. Moreover, the thermal and mechanical properties of dyed para-aramid yarns in supercritical CO2 showed a slightly increasing trend. The washing, rubbing, and the light color fastness of the dyed samples were rated above 4–5, and the color fastness durability of the dyed para-aramid was also presented good. [ABSTRACT FROM AUTHOR]

Traditional water-based flame-retardant finishing causes serious pollution due to the use of a large number of chemicals, and color change is easily generated since the flame-retardant finishing takes place after the cotton dyeing. An eco-friendly flame-retardant finishing of dyed cotton was explored using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 2,2′-oxybis-(5,5-dimethyl-1,3,2,-dioxaphosphorinane-2,2′-disulfide) (5060), SiO2, DOPO/SiO2 (1:1), 5060/SiO2 (1:1) and DOPO/5060 (1:1) in supercritical CO2. The effects of finishing time and pressure as well as temperature on the flame-retarding properties of the cotton were discussed. As expected, samples with the higher weight gain rates exhibit a lower after-flame time as well as after-glow time. In different flame-retardant systems, cotton fabric finished with DOPO presents the lowest after-flame time of 20.6 s and after-glow time of 0 s at 130°C, 22 MPa and 120 min due to its biphenyl ring and O=P-O bond. Moreover, tiny fluctuations of L *, a *, b * and K / S values occurred from 32.10 to 34.24, 5.78 to 6.05, –37.89 to –37.64 and 10.59 to 10.81 when the cotton samples were treated with DOPO, 5060, SiO2, DOPO/SiO2 (1:1), 5060/SiO2 (1:1) and DOPO/5060 (1:1), proving that no significant negative role in the color property of the samples occurs after supercritical CO2 finishing. [ABSTRACT FROM AUTHOR]

Supercritical CO2 (SC-CO2) scouring and bleaching of flax roves was developed by using enzymes instead of chemical additives. Effect of dosage of enzyme, enzyme ratio, temperature, pressure, time and CO2 flowrate on the scouring and bleaching properties of flax roves was investigated. The results showed that the whiteness and residual gum content were significantly improved under appropriate conditions. Scouring and bleaching of flax roves by SC-CO2 in combination with compound enzymes consisting of cellulose, xylanase and glucose oxidase could increase whiteness and reduce residual gum content. Moreover, glucose oxidase catalyzes the oxidation of β-d-glucose to produce H2O2, leading to the bleaching of fibers. An optimized scouring and bleaching of flax roves in SC-CO2 was recommended at 50 °C and 15 MPa for 60 min with a dosage of enzyme of 3% (% weight of flax roves), an enzyme ratio (in mass) of 1:2:1 (cellulase: xylanase: glucose oxidase) and a CO2 flowrate of 30 g/min. SEM displays more vertical grooves and bulges appeared on the fiber surface. The breaking strength and elongation at break of the samples were improved with the variation of scouring and bleaching conditions in comparison with the original flax roves. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modified curcumin, which has the advantages of low toxicity, high solubility, and little color change after modification, is very suitable for nonaqueous supercritical carbon dioxide cotton dyeing. However, the existing curcumin modification technology focuses on improving its solubility. Modified curcumin is directly adsorbed onto cotton fabrics, and the main interaction forces are van der Waals forces, which causes the poor fastness of modified curcumin to dyed cotton fabrics. In this study, reactive groups (hydroxyalkyls) were introduced into curcumin to enhance its fastness to cotton fabrics. The results showed that, similar to alkyl groups, hydroxyalkyl groups can enhance the color depth of dyed cotton fabrics by elevating the solubility of modified curcumin in supercritical carbon dioxide. The higher the solubility of modified curcumin in supercritical carbon dioxide was, the higher the K/S value of the dyed cotton fabric. Furthermore, the hydroxyl groups on the modified curcumin could form ether bonds with the hydroxyl groups on cotton fabrics. Therefore, the washing and rubbing fastness of hydroxyalkyl-curcumin-dyed cotton fabric was better than that of alkyl-curcumin-dyed cotton fabric. [ABSTRACT FROM AUTHOR]