Supercritical CO2‐assisted synthesis of polystyrene/clay nanocomposites via in situ intercalative polymerization

Cyclodextrins can form inclusion complexes with different molecules with the aid of their special chemical (molecular) structures. Physical and chemical properties of molecules can change after the formation of complex. This special feature enables the usage of dextrins in different industry areas. In this study, applicability of cylcodextrins in textile dyeing and washing processes was investigated. With this aim, β‐cyclodextrin was used in direct dyeing of cellulosic fabrics and in rinsing processes of direct dyed fabrics. Retarder/leveling effect of β‐cyclodextrin in dyeing process has been studied and the results were compared with that of a commercial product. In general, cyclodextrins were used in washing processes to remove the absorbed surfactants. It has been investigated whether this effect was the same for washing of dyed fabrics. Eight different direct dyes, for which the chemical structures are known, were used in dyeing and washing processes, and effect of β‐cyclodextrin on different chemical structures was investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 208–218, 2006     

Equalizing effect of β‐cyclodextrin on dyeing of polyamide 6,6 woven fabrics with acid dyes

Cyclodextrins (CD) are produced from starch by the action of cyclodextrin glycosyltransferase (CGTase) enzyme. Structurally, cyclodextrins consist of 6, 7, or 8 (α, β, and γ cyclodextrins, respectively) D‐glucopyranosyl units connected by α‐(1,4) glycosidic linkages. Having polar and hydrophilic outer sides and hydrophobic cavitation gives cyclodextrins a chance to form inclusion complexes with dyes in hydrophilic mediums. In this research, the equalizing effect of β‐cyclodextrins in dyeing of polyamide 6,6 woven fabrics with 6 different acid dyes were investigated. From the experimental results, it was determined that the β‐cyclodextrin shows a retarding and equalizing effect in dyeings carried out with the dyes that show interaction with β‐CD. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2660–2668, 2007     

Use of β‐cyclodextrin in an antimigration coating for polyester fabric

When β‐cyclodextrin was adopted as a dye catcher, the degree of dye migration onto adjacent fabrics as well as onto the coated surface was greatly reduced, while other physical properties, such as waterproofness and breathability, remained unaffected. When acetylation of β‐cyclodextrin was carried out, its solubility in an organic solvent, including methyl ethyl ketone and toluene, was greatly improved. Hence, it provided a smoother coated surface and an excellent antimigration effect in a direct‐coating system. These results confirm that β‐cyclodextrin is an effective dye catcher in a polyurethane‐based coating system, in which it prevents the migration of the dyes from coated polyester fabrics onto adjacent surfaces. The solubility of cyclodextrin can be optimised by a chemical modification of its cyclodextrin‐hydroxyl groups. Hence, this host–guest interaction demonstrates a universal and effective platform for antimigration coating systems.     

Application of rare earth as mordant for the dyeing of ramie fabrics with natural dyes

Selecting appropriate metallic compounds as mordants is essential for dyeing with natural dyes. This paper presents the application of rare earth compounds as mordant for the dyeing of ramie fabrics with four kinds of natural dyes. The influences of pre-mordanting, simultaneous mordanting, and post-mordanting on the dyeing effect were explored. The post-mordanting was proved to give rise to the highest dye uptake. The effects of dyeing conditions including dyeing temperature and time, dyeing bath pH and the concentration of rare earth on the dye uptake were investigated systematically. The fabrics dyed with natural dyes in presence of rare earth as mordant exhibited high color shade stability in the baths with pH varying from being acidic to neutral and alkaline. Employing rare earth as mordant apparently raised the color fastness to washing, rubbing and light of the ramie fabrics dyed with the natural extracts. In comparison with the commonly used metallic salts, using rare earth chlorides as mordants can greatly reduce the ionic concentration employed in natural dyeing. This study proved that rare earth would be a kind or promising environmentally friendly mordant in natural dyeing.     

Use of β‐cyclodextrin in the dyeing of polyester with low environmental impact

In this paper, the effect of β‐cyclodextrin as an additive in the dyeing of polyester with disperse dyes, as a substitute for a commercial surfactant commonly used, was explored with the aim of reducing the environmental impact of the exhausted baths. Using a chemometric approach, a small group of dyes was selected as a ‘training set’ to be representative of a larger series of dyes with a similar structure. The selected dyes were synthesised and applied to the dyeing of polyester fibres under various conditions. The technological properties of the dyed samples were measured. The results showed that β‐cyclodextrin can satisfactorarily be used as an additive in dyebaths for polyester without the addition of other auxiliaries, with a positive environmental impact. Solubility isotherms evidenced dye–β‐cyclodextrin interactions. The formation of inclusion complexes did not produce negative effects on the dyeing performance. Light fastness values were modelled as a function of the structure by the chemometric partial least squares method and the established model was used to predict the fastness of dyes of analogous structure, not yet explored.     

Effect of enzyme treatment and dyeing on the mechanical properties of linen

In this paper, different concentrations of cellulase enzyme were used for treating linen fabrics. The pretreated linen fabrics were dyed using a bifunctional reactive dye at various concentrations. The effect of enzyme treatment, together with the dyeing process on the low‐stress mechanical properties of the linen fabric, was then investigated. The low‐stress mechanical properties were assessed quantitatively, including the tensile, shearing, bending, compression and surface properties of the enzyme‐treated and dyed linen fabrics. The results revealed that the enzyme treatment with subsequent dyeing could alter these properties to a greater extent, depending predominantly on the concentration of enzyme used.     

Reactive dyeing of silk using commercial acid dyes based on a three‐component Mannich‐type reaction

Acid dyes are employed for commercially dyeing silk, which results in ionic bonds between the silk fibroin and the dye. This generally leads to low wet fastness properties for dyed silk fabrics. In this work, three commercial acid dyes with aromatic primary amine structures were selected to dye silk using a Mannich‐type reaction, resulting in improved wet fastness of dyed silk by forming covalent bonds between silk fibroin and dye. The Mannich‐type reactive dyeing was applied to silk fabrics at both 30 and 90°C in trials. Dyeing at 90°C can shorten the dyeing time compared with dyeing at 30°C, even although dye exhaustion and relative fixation at 90°C were a little lower. The dyeing process was optimised when the dyeing temperature was 90°C, dyebath pH 4, dye‐to‐formaldehyde ratio 1:30 and holding dyeing time 60 minutes. The results showed that the dye exhaustion on silk fabrics for the three aromatic primary amine‐containing acid dyes exceeded 94% and their relative fixation was over 80%. Their washing and rubbing fastness reached grade 4 or higher. Hence, the colour fastness properties of dyed silk fabrics using the Mannich‐type reactive dyeing method is superior to the conventional acid dyeing method using the same aromatic primary amine‐containing acid dyes. The Mannich‐type reactive dyeing for silk fabrics at 90°C can be developed into a novel and rapid reactive dyeing method, promising an effective dyeing process with excellent colour fastness.     

Pretreatment of cotton fabrics with polyamino carboxylic acids for salt‐free dyeing of cotton with reactive dyes

In this study, polyamino carboxylic acids have been used to improve the dyeability of cotton in a salt‐free reactive dyeing process. These polyamino carboxylic acids were prepared by partial carboxylation of polyvinylamine. Cotton fabric was pretreated with polyamino carboxylic acids and dyed with reactive dyes. The colour strengths of the dyed fabrics were evaluated by measuring the K/S values. The fastness properties (washing, rubbing and light fastness) of the dyed cotton fabrics were also measured. The pretreatment of cotton with polyamino carboxylic acids creates positive charges on the fabric surface. In this way, salt‐free reactive dyeing of cotton or dyeing with only a small amount of electrolyte is possible.     

Topping of naturally dyed wool fabrics with different natural dye sources

Wool fabrics can be dyed with synthetic dyes and even with natural dyes. To present a different aspect to the coloration of wool, the current study was focused on a topping process (ie, the dyeing of wool that was already dyed) with different natural dye sources. For this purpose, the fabrics that were already dyed with a natural dye source were once again dyed with two different natural dyes. In bottom dyeing (bottoming), fabrics were dyed with hops (Humulus lupulus L.) in the presence of different mordanting agents. Then the dyed, washed and dried samples were once again dyed (topping) with two different natural dye sources. For topping, powdered madder and acorn were tested in direct dyeing of wool samples. Finally, the colour changes were analysed with the use of a spectrophotometer. The study demonstrates that such a process (ie, bottoming with hops in the presence of different mordanting agents and then topping with madder or acorn) can be a way of obtaining different shades and colours with sufficient/good fastness values by natural dyeing.     

Dyeing properties of textiles by Turkish hazelnut (Corylus colurna): leaves,coat, shell and dice

Turkey has a great number of hazelnut trees that possess nutritious components. However, only the inside part of the hazelnut is used as a nutrient, while the rest of it is waste. This study suggests that the waste parts of the Turkish hazelnut could be used as a natural dye for dyeing textile fabrics. The dyeing properties of the leaves, coat, shell and dice of the hazelnut were studied on wool, cotton and viscose fabric by using three different mordants: copper sulphate, iron sulphate and aluminium sulphate. The selected dyed fibre sample surfaces were observed using a scanning electron microscope. The colour strength (K/S), light, washing, rubbing, and perspiration fastness levels of the dyed fabrics were investigated. The experimental natural dyeing results indicate that waste hazelnut‐based products can be used as a natural dye for textile coloration.     

锦纶织物原位矿化染色新技术

应用Erionyl系列弱酸性染料,分别采用传统工艺和原位矿化工艺对锦纶织物进行染色加工。对比了采用不同染色工艺的耗水量、排放残液的化学需氧量(CODC)r、染品色牢度及各项物理性能指标,结果表明:与传统工艺相比,采用原位矿化工艺对锦纶织物进行染色加工,染色节水率高达80%;排放染色废水中CODCr显著降低;不同工艺的染色织物颜色深度和各项色牢度基本一致;采用原位矿化工艺染色的织物断裂强力及断裂伸长率略优于传统工艺。     

Grafting of cotton with β‐cyclodextrin via poly(carboxylic acid)

Cyclodextrins are cyclic oligosaccharides. Cyclodextrin molecules can form inclusion complexes with a large number of organic molecules. The properties of cyclodextrins enable them to be used in a variety of different textile applications. Cyclodextrins can act as auxiliaries in washing and dyeing processes, and they can also be fixed onto different fiber surfaces. Because of the complexing abilities of cyclodextrins, textiles with new functional properties can be prepared. Poly(carboxylic acid)s such as 1,2,3,4‐butane tetracarboxylic acid (BTCA) are well‐known non‐formaldehyde crosslinking reagents. BTCA has four carboxylic acid groups, which can react with hydroxyl groups of cellulose and form stable ester bonds. We crosslinked β‐cyclodextrin molecules on hydroxyl groups of cellulose via BTCA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1323–1328, 2005     

An innovative approach to the preparation of coloured and multifunctional silk material with the natural extracts from chestnut shell and black rice bran

In order to reutilise the byproducts of foods and crops to benefit the environment and economise on resources, the natural extracts from chestnut shell and black rice bran were applied in the simultaneous dyeing and multifunctionalisation of silk fabrics. In this work, the influence of pH value on dyeing properties was studied. The effects of the ratio of chestnut shell and black rice bran extracts and the application of mordants (aluminium potassium sulphate and ferrous sulphate) on the dyeing performance as well as anti-ultraviolet and antioxidant properties of treated silk were also discussed. The results showed that deep-coloured silk fabrics can be obtained when dyed with the two natural extracts as the pH value of the dyebath approached 3. The ratio of the two natural extracts and the use of the mordants have significant effects on colour depth, colour hue, colour fastness, and the functionalities of dyed silk fabrics. Combination dyeing and mordanting are able to enrich the colour hues of dyed fabrics. The washing, rubbing, and light fastness of the dyed fabrics after mordanting can be rated higher than grade 4. Moreover, the silk after combination dyeing has good UV protection performance (UPF > 30) and antioxidant activity. In addition, the functionalities of treated fabrics showed excellent washing fastness. This study reveals that chestnut shell and black rice bran extracts are suitable as natural colourants and multifunctional finishing agents for the preparation of coloured and multifunctional silk materials.     

Assessment of uniformity of fibre coloration in Tencel woven fabrics dyed using reactive dyes

Weave structure and fabric density has an influence on dye penetration. The uniformity of dyeing, expressed as the uniformity of fibre coloration, of Tencel woven fabrics comprised of different weave structures, was assessed. The fabrics were dyed by exhaust and continuous dyeing methods using selected reactive dyes. Cross‐sectional images were captured and then given a rating 1–5 with respect to the depth of the fibre filaments of the yarn of the woven fabric. The images were assessed both subjectively and objectively. The uniformity of fibre coloration was expressed in terms of the standard deviation, mean value and histogram analysis such as dispersion and bandwidth. Objective assessment of uniformity of fibre coloration is a more accurate and quicker method than visual assessment and can be used to assess the uniformity of fibre coloration of woven and knitted fabrics dyed by any class of dyes. Improvement of the uniformity of fibre coloration of Tencel fabrics of various weave structures by causticisation of the fabrics and by modification to the padding process was investigated.     

Dyeability improvement of proteinic and polyamide fabrics pretreated with saccharin sodium salt: A kinetic approach

Improvement of the dyeability of wool, silk, and polyamide fabrics with cationic dye was achieved by their pretreatments with saccharin sodium salt. The acquired color values of the dyed materials were significantly enhanced by the aforementioned treatment. Kinetic investigations of the dyeing process were performed by determining the half dyeing time, specific dyeing rate constant, and diffusion coefficient. Fastness properties to crocking (dry and wet) and washing of the pretreated dyed fabrics were significantly improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Colour of flax fibres in regard to different pretreatment and dyeing processes

The main objective of this work was to compare the colour of different pretreated (alkaline, acidic and enzymatic) and dyed (conventional and ultrasonic-assisted) flax fibres, to establish the impact of various parameters on dyeing kinetics. Flax fibres were dyed using two direct dyes of different chemical structures and molecular mass. Diffusion profiles were established by the application of Fick's Law and dyeing behaviour was studied by means of online spectrophotometry. Finally, the dyed samples were colorimetrically evaluated and colour differences and colour strengths were subsequently calculated. The results provided evidence that a dye molecule's size has a greater influence on the exhaustion degree, migration and diffusion than individual pretreatment processes. The determined diffusion coefficients indicated superior dye mobility and faster diffusion into the fibres when ultrasonic power was used in comparison with conventional process. Nevertheless, the colour depth obtained was found to be low after ultrasonic dyeing using a larger dye molecule, implying part degradation of CI Direct Red 80 (and total degradation of small-size dyestuff, CI Direct Red 81).     

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.     

Dyeing of cotton and jute with tea as a natural dye

Cotton and jute fabrics were dyed with an aqueous extract of tea, containing tannins as the main colorant species. The dyeing was carried out with and without metal salts as mordants, using three different dyeing methods: pre-mordanting, meta-mordanting and post-mordanting. The resulting wash and light fastnesses of the dyed fabrics were good to excellent. The colour of the fabrics was investigated on computer colour matching system in terms of K/S , and CIELAB colour-difference values. Deep shades ( K/S = 3.9) were obtained for jute in acidic media, while cotton fabrics could be dyed in medium depths ( K/S = 2.0) under identical conditions of dyeing.     

槐米染色棉织物工艺及其抗紫外性能研究

为实现槐米染料的工业化应用及提高棉织物的功能性,分析了使用壳聚糖、Al3+、Fe2+媒染剂预媒染色法对棉织物染色效果的影响,重点研究了铝预媒染方法染色温度、染色时间、pH值等工艺参数对染色棉织物K/S值的影响,并测试了槐米染色棉织物的抗紫外性能。结果表明:直接使用槐米染色的效果较差;壳聚糖媒染对上染效果影响不大,使用铝、铁媒染剂,可得到不同颜色的棉织物;铝媒染剂染色棉织物为鲜艳的黄色,为较好的媒染方法;铝预媒染染色方法染色优化条件为:温度为80℃,染色时间120分钟,染浴pH值为6.8;铝预媒染染色棉织物具有较好的抗紫外性能。     

Determining the dependence of colour values on yarn structure

The colour values of knitted cotton fabrics made from single and plied ring and compact yarns were investigated before and after dyeing. The fabric samples were knitted under the same constructional properties and then dyed with direct and reactive dyes. It was found that fabrics with ring yarns had high lightness and low chroma and colour strength values compared with fabrics with compact yarns. Also colour strength and colour difference values of dyed fabrics were assessed after increasing abrasion cycles (2500, 5000, 7500 and 10 000). The main changes in colour strength values were observed at 2500 abrasion cycles. The effect of abrasion on colour difference values of fabrics having ring yarns was more obvious than fabrics having compact yarns.