Bleaching Of Wool Research Articles

Use of Vegetable Waste for New Ecological Methods in Wool Fibre Treatments

In this current research, various amino acids (lysine, betaine, and cysteine) and peptides (oxidised or reduced glutathione) were considered as potential environmentally friendly alternatives to wool bleaching. A greener methodology was also applied to dyeing. Different agro-wastes (red cabbage, peppercorns, and red and yellow onion peels) served as raw pigment materials. The process’s efficiency was characterised by the whiteness degree, colour strength, and fastness to accelerated washing and perspiration. A higher whiteness index value was observed in the cysteine-based formulations. The onion peel exhibited significant tinctorial properties due to the presence of some natural mordants. All the proposed treatments were designed with a primary focus on environmental sustainability. These treatments offer a sustainable and environmentally friendly alternative to traditional bleaching and dyeing methods for wool. They reduce costs and energy consumption while creating added value by valorising waste.

Improvement of the process of dying of wool with natural dyes

This article describes the process of dyeing bleached wool fibers with natural dyes using aluminum, iron and copper salts as a mordant (the coloristic features of the cinnabar dyeing process are studied). The staining process was carried out in three different sequences: pre-treatment with mordants, then staining in a natural dye solution (I); one-bath dyeing in a solution of dye and mordant (II); dyeing in a solution of natural dye, followed by treatment with mordants (III). The influence of the staining sequence on the quality of staining was evaluated by data determined under standard illumination D65 on a laboratory colorimeter. The article shows the dependence of the processes of dyeing wool with natural dyes Madder (Rubia tinctorum L.), Turmeric (Cúrcuma lónga) and Carmine (Minium - cinnabar) on the presence and place of pickling salts in the technological wiring. Madder dye itself gives a golden color, and in the presence of copper sulfate and iron gives a pale brown color, and potassium dichromate gives a bright saturated red color. When dyeing wool with Carmine dye in the presence of iron and copper salts as mordants, carmine wool gives 1.5-2.5 times more intense dark red colors, depending on the dyeing method, than when dyed without salts. The dependence of the color intensity on the pH of the medium has been studied, taking into account the fact that the pH of the dyeing process affects the strength and color parameters of the colors obtained on wool fiber with natural dyes. An IR spectral analysis of samples dyed with the studied dyes was carried out in comparison with undyed wool fiber to identify the nature of the occurrence of bonds between wool fiber and natural dyes.

Effect of various transition metal ions on mordanting stage of yak wool bleaching process

Yak wool is a smooth, warm, and durable natural protein-structured fiber that could compete with cashmere and other high-end protein-structured fibers on the market. However, it suffers from drawing consumers’ attention due to the lack of color due to the shortfall of the yak wool bleaching technology. Herein, we studied the applicability of various transition metals, i.e., copper (II), cobalt (II), iron (II), and nickel (II) salts, as a mordanting reagent based on their effect on the hydrogen peroxide decomposition reaction and the morphological and mechanical properties of the bleached yak wool with the presence of these transition metal. Our study suggested that the iron (II) ion was the most efficient reagent for the mordant bleaching since it provided less fiber damage, relatively high strength, and elongation to the bleached yak wool with good whiteness, while the Cu (II) was the least favorable agent for the yak wool bleaching process.

Wastewater effluents analysis from sustainable algae-based blue dyeing with phycocyanin

Sustainability in the textile industry is a challenge with an imminent need to be tackled. One approach can be focused on replacing fossil-based dyes with renewable and less polluting alternatives. In this sense, this study focuses on validating the suitability of an innovative natural-based blue dye, phycocyanin, sourced from Spirulina platensis microalgae. The laboratory-based experimental approach envisages the exhaustion dyeing of pre-mordanted cotton and bleached wool with phycocyanin-rich extract, representing the sustainable blue dye. The color characterization of naturally blue-dyed fabrics was performed via CIE Lab coordinates, depth of color by color stregth valures ( K/S), values of dye exhaustion, and colorfastness to laundering and light. The results indicate suitable dyeability with the natural blue dye, with process improvements a possibility. The main environmental character of this process was analyzed from the dyeing effluent characterization perspective. Measurements of chemical oxygen demand, biochemical oxygen demand, and metal content were performed on effluents resulting from dyeing processes with variable parameters, to analyze the influence of mordant use, process temperature, time, and pH. Findings indicate that the application of optimum dyeing process conditions results in the lowest oxygen demand values, suitable for further wastewater reuse, according to international industrial effluent limitations. The biological fungi wastewater treatment resulted in the reduction of biochemical oxygen demand and chemical oxygen demand values by around 80%, comparable with the industrial process, validating the sustainable character of using algae-based phycocyanin in the bath exhaustion dyeing process.

Optimization of Mordant Bleaching of Yak Wool with Hydrogen Peroxide at Low Temperature

Protein-based materials like wool and cashmere are highly valued renewable natural resources. The total world consumption of products made of such materials has risen steadily in the past fifty yea...

Effects of Liposome-Assisted Peroxide Bleaching on Woolen Fabric Properties

The effect of liposomes, constituted from soy lecithin and cholesterol, on hydrogen peroxide bleaching of wool fabrics was investigated. A thin lipid layer method was used for liposome production. Use of commercial liposomes was also investigated. Whiteness index (Stensby), breaking strength, solubility in alkali, and several instrumental analysis methods for determining morphology were carried out. Bleached samples were dyed with a 1:2 metal complex dye and color strength values were analyzed. The effect of liposome type on hydrogen peroxide consumption in the bleaching bath was also analyzed using UV-Vis spectroscopy. Elemental analysis was carried out to determine the ratio of elements in the bleached wool samples. Liposomes acted as a stabilizer in the bleaching bath and improved the physical, bleaching, and dyeing properties of wool.

The First Knowledge Economy: Human Capital and the European Economy, 1750–1850 by Margaret C. Jacob

The First Knowledge Economy: Human Capital and European Economy, 1750-1850, by Margaret C. Jacob. Cambridge, Cambridge University Press, 2014. ix, 257 pp. $108.95 Cdn (cloth), $39.95 Cdn (paper). Margaret C. Jacob provides a coherent account of reasons behind industrialization of four Western European countries with expert clarity, brevity, and instructiveness. Jacob argues that Britain was a pioneer in Industrial Revolution because for first time in history a productive combination of knowledge translation, human capital, and cultural ethos worked. The author rightly maintains that deployment of knowledge wielded by semi-literate tinkerers, (2) self-educated industrial innovators, and gentlemen-scientists was critical for establishment in Great Britain of first knowledge economy. In Jacob's words, Both lofty and mundane lay at heart of early industrial (126). This line of reasoning was partly inspired by Musson and Robinson's Science and Technology in Industrial Revolution (Toronto, 1969), which suggested that eighteenth-century Industrial Revolution in Britain was a result of both uneducated empiricism and intellectual movement characteristic of Enlightenment with its scientific spirit percolating top-down and its empirical knowledge diffusing bottom-up. Jacob significantly extends Musson and Robinson's considerations on development of steam engines in Birmingham (from Savery and Newcomen to Boulton and Watt) and technical processes of bleaching and dyeing of fabrics, manufacturing linen and wool in Leeds, and industrial-scope cotton making in Manchester. Determinedly brushing aside economic arguments in favour of social and material basis for Industrial Revolution, Jacob insists on crucial role of human capital in triggering rapid industrialization in Britain. However, outright dismissal of argument about role of abundance of easily extractable coal in Britain somewhat diminishes weight of Jacob's argument. The above-mentioned Musson and Robinson discuss approximate number of steam engines that helped to propel Industrial Revolution, particularly in proportion to water power (71-72). Consider as well that availability of easily accessible coal deposits, as German historian Rolf P. Sieferle argues in The Subterranean Forest: Energy Systems and Industrial Revolution (Munchen, 1982, transl. Cambridge, 2001), enabled people to turn increasingly to manufacture-oriented activities: by substituting wood for coal in burning, thus saving wood for construction, and increasing efficiency of smelting. Moreover, shift in land-use structure occurred because woodland was converted into pasture for sheep on which manufacturing of wool-cloth depended. Therefore, Jacob's argument suffers from underestimation of socio-economic factors and exaggeration of the growing pool of mechanically knowledgeable entrepreneurs and civil engineers (55) at end of eighteenth century. …

Improving the photostability of bleached wool without increasing its yellowness

Bleached wool is rapidly yellowed by exposure to the UV radiation present in sunlight. The conventional application of a water‐soluble hydroxyphenyl benzotriazole UV absorber (such as UVFast W) to bleached wool reduces its rate of photoyellowing but has a negative impact on the whiteness of the bleached wool, largely cancelling out the improvements in whiteness achieved during bleaching. However, if the UV absorber is applied to peroxide‐bleached wool from a reductive bleach bath, white wool with improved photostability to sunlight and UV radiation can be obtained.

Microwave-Assisted Bleaching of Wool Fabrics

Microwave irradiation was used to reduce consumption of energy and time during bleaching of wool fabrics with hydrogen peroxide. The effect of some reaction conditions; viz. hydrogen peroxide concentration, treatment time, presence of stabilizer, on degree of whiteness imparted to bleached wool, was studied systematically. Comparative study between bleaching of wool using microwave irradiation and conventional heating was undergone. The effect of bleaching of wool on its morphological structure was assigned by scanning electron microscopy. The change in some chemical and physicomechanical characteristics of bleached wool was monitored; namely whiteness index, alkali solubility, wettability, critical surface area, tensile strength, and elongation at break, of the treated as well as untreated fabrics were measured. The microwave-assisted bleaching of wool resulted in improved degree of whiteness comparable to that is obtained using conventional heating method. However, the microwave-assisted bleached wool shows lower degree of deterioration than that of conventionally bleached wool. The COD and BOD of the wool bleaching effluents were determined.

The effects of bleaching on the photostability of white fleece wools

The photostability of Merino fleece wools shows moderate heritability and therefore could be improved by selection. However, wool used for bright whites and pastel shades is always bleached with hydrogen peroxide during processing to improve its colour, and bleaching is known to reduce photostability. This paper describes the effects of peroxide bleaching on two groups of Merino fleece wools having the same range of initial yellowness but differing photostabilities. After peroxide bleaching, there was no significant difference in photostability between the two groups, suggesting that genetic selection of sheep for higher photostability would only offer a commercial benefit for production of bright white and pastel shades if yellowness is reduced to such an extent that peroxide bleaching is unnecessary. A more viable short-term approach would be to use a water-soluble UV absorber to reduce the rate of photoyellowing, if a means of applying the UV absorber to bleached wool without reducing its whiteness could be achieved.

Photo bleaching of wool using nano TiO2 under daylight irradiation

Wool bleaching is usually carried out on raw wool through treatment with oxidizing or reducing agents. Here, nano TiO2 as a photocatalyst was applied on raw wool fabric to decompose the naturally occurred pigments under daylight irradiation. To enhance nano particles adsorption on the fabric, it was first treated with protease and then treated with nano TiO2 along with citric acid. The whiteness and yellowness indexes and hydrophilicity features of the treated wool fabrics indicated a reasonable whiteness with a significant improved hydrophilicity. This new wool bleaching approach was named as “nano photo bleaching” as a most successful bleaching application.

Nano TiO2as a New Tool for Mothproofing of Wool: Protection of Wool againstAnthrenus verbasci

Wool protection against moths is an important concept in wool finishing that can obtained through application of various chemicals with different mechanisms of actions. In this paper, a novel mothproofing method is introduced through treatment of wool fabric with nano titanium dioxide (NTO) and citric acid (CA). Citric acid (CA) helps to enhance the washing durability, antifelting, and antibacterial properties of the NTO treated wool. Mothproofing was assessed through the study of damages on the wool surface by the larvae of the carpet beetle, Anthrenus verbasci, feeding on protein fibers. The damage intensity of wool fabric and TiO2 nanoparticles on the fabric surface were confirmed with scanning electron microscopy images and energy-dispersive spectrometry. X-ray diffraction (XRD) of NTO treated fabrics indicated the crystal structure of NTO on the wool surface. Overall, the wool fabrics treated with CA and NTO indicated the highest protection against moths compared with raw and bleached wool fabrics.

Application of liposomes in the textile industry

The results of the research of the role of liposomes in bleaching, dyeing, and finishing of wool and cotton, as well as sorption of dyes are discussed.

Ultrasound-assisted wool bleaching

Bleaching is a finishing process to whiten the gray fabrics. During this process it is important to ensure the demanded results with minimum fiber damage by considering environmental aspects. As a result of this, the study focused on the wool bleaching which is also an important process for the quality of wool products. It was managed with and without ultrasound and it was found that via ultrasound better bleaching results can be obtained in addition to improvement in contact angles related to the hydrophilicity. It is expected that with the addition of ultrasound to bleaching process, same results obtained with conventional bleaching will be reached with lower treatment temperatures or lower treatment time which is now essential for the protection of environment.

Treatment of Bleached Wool with Trans-Glutaminases to Enhance Tensile Strength, Whiteness, and Alkali Resistance

Trans-glutaminases is known as a cross-linking enzyme for proteins. Wool is a proteinous fiber conventionally is treated through several processes to obtain the desirable characteristics. Bleaching is also one of the most important processes usually carried out by using an oxidizing agent in a conventional method. The tensile strength of wool yarns was reduced as a consequence of oxidative bleaching. Here, with the help of microbial trans-glutaminases (m-TGases), a novel bleaching process was disclosed in a way to obtain a bleached wool yarn with no significant reduction in the tensile strength. The results confirmed that the bleached wool yarns with H(2)O(2) could be modified by m-TGases post-treatment. The m-TGases treatment on the bleached wool yarns improved the tensile strength and whiteness along with the higher alkali resistance.

Bleaching of Wool with Sodium Borohydride

An untreated wool fabric was bleached both with sodium borohydride (SBH) in the presence of sodium bisulphite (SBS) solution and with a commercial H2O2 bleaching method. The concentration effects of SBH and SBS, bleaching time, pH and temperature on SBH bleaching process were investigated. Whiteness, yellowness and alkali solubility results were assessed for both bleaching methods. The results showed that whiteness degrees obtained with SBH bleaching was comparable with that of H2O2 bleaching method; whereas the alkali solubility values of the SBH bleaching was superior to the H2O2 bleaching.

Keratin Coatings for Wool: Shrinkproofing and Nanoparticle Delivery

AbstractSummary: Wool fabrics were treated with keratin hydrolysate in isolated systems, in systems incorporating a cross‐linking enzyme, and in systems with nanoparticle silver. The dimensions of wool fabric were controlled after keratin applications and the strength of bleached wool fabric was improved. Keratin applications imparted these improved properties when applied alone and when applied with the enzyme. The enzyme was effective for in‐situ, solid‐state cross‐linking of wool fabric, cross‐linking keratin‐to‐keratin, and cross‐linking keratin‐to‐fabric. To further improve the properties of wool, nanoparticle silver was produced in various shapes. Transmission electron microscopy (TEM) micrographs of these particles showed discrete and isolated particles of size 8‐100 nm, dependent on the preparation. A combination of TEM and UV‐VIS spectroscopy was used to characterize these particles and scanning electron microscopy running in backscattered electron mode confirmed their placement on wool fibers. The application of nanoparticle silver to wool when co‐added with keratin may both improve dimensional stability and impart antimicrobial efficacy.

Amineborane: a unique reductive bleaching agent that protects cystine disulphide bonds in keratins

This paper reports a new application for amineboranes in the bleaching of wool, a typical example of keratin fibre. It has been found in this investigation that amineboranes are unique reductive bleaching agents that do not attack cystine disulphide bonds in wool keratin and do not impart permanent set to the fibre during bleaching. Selected amineborane compounds can be used in conjunction with oxidative agents such as hydrogen peroxide in aqueous media to further enhance the whitening effect and prevent disulphide bond disruption in keratins. The results of this study have suggested that the researched technology outperforms existing bleaching methods on a number of levels and may be an important step towards a new commercial bleaching technology.

Determination of Photo‐oxidation Products Within Photoyellowed Bleached Wool Proteins

Photo-oxidative processes occurring in wool can lead to significant photoyellowing of the fiber. In particular, wool that has been chemically bleached photoyellows more rapidly and to a greater degree than untreated wool. Direct identification of the chromophores responsible for such yellow discoloration in irradiated wool has proven to be elusive for many years. This article describes the characterization and location of yellow photo-oxidation products within the proteins of photoyellowed bleached wool fabric, using advanced protein chemistry techniques. The discolored fabric was enzymatically digested and chromatographed by high-pressure liquid chromatography, with monitoring at 400 nm, to select out fractions containing yellow chromophoric species. Thorough tandem mass spectrometric analysis was then used to sequence peptides and, in turn, to characterize modifications to key amino acid residues that had resulted in yellow chromophore formation. In total, 11 separate yellow chromophoric species were identified, ten derived from tryptophan residues and one from tyrosine. The tryptophan-derived modifications characterized included hydroxytryptophan, N-formylkynurenine, hydroxyformylkynurenine, kynurenine, hydroxykynurenine, carbolines, tryptophandiones and nitrotryptophan. The tyrosine-derived modification of tyrosine to dopa was also identified. The range of photomodifications we observed provides insight into the photo-oxidation pathways occurring within irradiated fibrous proteins leading to the formation of yellow chromophores.

Activated Peroxide for Enzymatic Control of Wool Shrinkage Part I: Elucidation

The ARS process combines activated peroxide for pretreatment and enzyme for subsequent treatment to provide bleached, biopolished, and shrinkage-resistant wool. The pretreatment step is of particular interest because it combines dicyandiamide (DD) with alkaline peroxide to form peroxycarboximidic acid, a stable and powerful bleaching agent that is stabilized by gluconic acid (GA) when applied at pH 11.5 for 30 minutes at 30 ° C. Analytical methods of analysis provided information showing that the active bleaching component, peroxycarboximidic acid, is formed immediately upon the combination of DD with alkaline H2O2 and that cyanamide forms concomitantly as a co-product. The peroxide pretreatment bath was stable at room temperature for up to 4.5 hours with only 10% peroxide consumed. It should therefore be possible to reconstitute the bleaching bath for further utilization. The eventual alkaline hydrolysis of cyanamide to form urea and the recombination of urea with peroxycarboximidic acid formed the end-product, guanylurea, shown by high performance liquid chromatography associated with electron impact mass spectrometry (LC/EI-MS), Fourier transforminfrared (FT-IR), and 13C NMR. Differential scanning calorimetry and peroxide titration of pretreatment baths provided evidence that GA stabilizes the activated peroxide. Activated DD peroxide pretreatment is essential to the ARS process for it provides a high level of whiteness without loss in fabric properties and it prepares the wool fiber for enzymatic treatment designed to selectively modify the scales of wool to biopolish the fabric surface and provide itch-free, machine-washable wool.