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    Determining the Permeability and Handle Properties of Wool, Yak and Cashmere Hand-knitted Fabrics
    (Taylor & Francis Inc, 2023) Unal, Pelin Gurkan; Atav, Riza; Ergunay, Ugur
    Luxury fibers are used for their tactile properties, comfortable feeling for the users, and sometimes for status in society. These fibers are all protein-based and have always been compared to the properties of wool. Cashmere is known for its incredibly soft and warm yet lightweight and breathable qualities, making it a must-have fabric for any fall and winter closet. Besides labored and time-wasting cashmere production makes the fiber very expensive. Yak fiber is an alternative to expensive cashmere with similar properties, which costs only a quarter of cashmere. In this study, air and water vapor permeability properties, which are important for consumer comfort were investigated in addition to handle properties of the fabrics compared with the properties of the fabrics made of wool fibers. It was found that yarns made of wool fibers were easy to spin in fine yarn counts whereas yarns made of yak fibers were the coarsest. Hand-knitted fabrics made of cashmere fibers had the softest feeling even if the fabrics were produced with similar technical specifications. The permeability results of the fabrics were different, especially the porosity of the fabrics had a higher impact on the permeability of the fabrics.
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    Dyeing of polyacrylonitrile knitted fabric using liposomes
    (Taylor & Francis Ltd, 2024) Atav, Riza; Koyluoglu, Selin Guler; Haji, Aminoddin; Ergunay, Ugur
    In this study, it was aimed to analyze the effects of liposomes on the dyeing of polyacrylonitrile fabrics. For this purpose, firstly liposome synthesis was carried out, and then liposome production was confirmed by Fourier transform infrared spectroscopy analysis. Additionally, zeta potential measurements were carried out to see whether stable structures were formed. Then, a selected basic dye was encapsulated with a liposome and the possibilities of using these capsules as alternative to retarders in the dyeing of polyacrylonitrile fabrics were examined. According to results obtained, it can be said that the 1% solution of synthesized liposomes creates a more stable suspension with a polydispersity index of 0.472 and the average particle size of 165.2 nm. On the other hand, it has been revealed that if 1% liposome is used in dyeing, a kind of retarder effect can be achieved in the dyeing of polyacrylonitrile fabrics. Moreover, it can be said that the decrease in color efficiency, that is, the loss of yield, caused by the use of liposome at the end of dyeing is lower compared to the retarder. This is also a very important issue, because a good retarder is expected to slow down the dye uptake, but not reduce the dye intake too much at the end of the dyeing. Dyeing levelness (%) was found to be 96.1, 97.4, and 97.1 for dyeings without auxiliary, with 1% cationic retarder and with 1% liposome, respectively. Beyond this, no significant difference was observed in terms of fastness of dyeing.
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    Effect of chromophore type on efficiency of reactive dye removal using polyamidoamine dendrimer
    (Wiley, 2024) Atav, Riza; Akkus, Eray; Cifci, Deniz Izlen; Ergunay, Ugur; Gunes, Yalcin; Gunes, Elcin
    In this study, by selecting a sample of dyes from a wide variety of chromophores used in the production of reactive dyes (monoazo, bisazo, metal azo, phthalocyanine, anthraquinone, copper formazan and triphendioxazine), the colour removal performance of polyamidoamine (PAMAM) dendrimer in reactive dyes was statistically evaluated depending on the dye chromophore groups (and accordingly molecular weight and number of sulfo groups of the dye), dendrimer concentration and centrifugation time. When all the results were examined, it was observed that the colour removal efficiency was significantly lower in metalazo and copper formazan-based reactive dyes, whereas colour removals ranging from 93% to 98% could be obtained in bisazo, triphendioxazine, monoazo, anthraquinone and phthalocyanine dyes. With the use of dendrimer, the best colour removal efficiencies occurred at pH 3. However, it was found that the centrifugation time of 15 min is sufficient for all dyes, and a longer centrifugation does not provide any additional benefit in terms of colour removal.
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    Enzymatic coloration of wool fabrics and its comparison with conventional dyeing
    (Wiley, 2024) Atav, Riza; Karagoz, Gokmen; Ergunay, Ugur
    The search for a more ecological alternative to dyeing processes, which is the most polluting textile process, has become one of the most studied topics today. In this respect, enzymatic colouring with the use of laccases offer important opportunities, but studies on enzymatic colouring are still very limited. However, in order for enzymatic dyeing to find industrial-scale use, the colour variety must be wide. Within the scope of this study, it is an important output that this study has brought to the literature, that the variety of colours that have been obtained in the literature in enzymatic dyeing has been increased so far by working with a wide variety of precursors and their mixtures, including those that have not been tested on wool before. At the same time, the reaction mechanism of the enzymatic dye synthesis and the chemical structures of the dyes were elucidated by Fourier-transform infrared spectroscopy. Beyond that, as it is known, when a new dyeing process is developed, its technical, economic and ecological advantages and disadvantages compared to the currently accepted conventional dyeing should be revealed. In this study, the colours obtained by enzymatic dyeing were matched with 1:2 metal complex dyes and then two fabrics dyed with the same colour, one enzymatic and the other with conventional method, were compared in terms of technical (colour, fastness), economic (water, energy and chemical consumption) and ecological (biological oxygen demand of wastewater, chemical oxygen demand, etc.) aspects.
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    Investigation of the dyeability and various performance properties of fabrics produced from flax and hemp fibres and their blends with cotton in comparison with cotton
    (Wiley, 2024) Atav, Riza; Dilden, Durul Busra; Keskin, Seda; Ergunay, Ugur
    In this study, it is aimed to provide alternative fibres to cotton with enhanced comfort level, environmentally friendly and colour-enriched in the cellulosic knitted fabric field. For this purpose, in addition to 100% cotton, 100% linen, 100% hemp yarns, knitted fabrics were produced from 70% cotton/30% linen and 70% cotton/30% hemp yarns. First of all, the properties of yarns such as tenacity, elongation at break, yarn unevenness, thin places, thick places and neps were examined comparatively. Then, pique fabrics were produced from these yarns and dyed with a reactive dye to a selected colour. Afterwards, physical (weight, wale/course density), mechanical (bursting strength, pilling, abrasion resistance) and comfort (air permeability and water vapour permeability) properties of all fabric samples, both in raw form and after dyeing and finishing processes, were compared. Furthermore, dyeing properties (colour, dye-uptake, dyeing levelness, fastness) of fabric samples were also investigated. The dye uptake (%) values of the yarns decrease in the order of cotton > cotton/hemp > cotton/linen > hemp > linen. However, fastness values of dyed fabrics were nearly identical. Physical and mechanical properties of fabrics were very similar, while the air permeability of the fabrics decrease in the order of hemp > linen > cotton/hemp > cotton/linen > cotton. As a result of the study, it has been possible to produce knitted fabrics with superior performance characteristics (dyeability, comfort, etc.) from yarns produced via blending natural cellulosic fibres (flax and hemp) with certain proportions of cotton fibres, which contribute to sustainable production.