Wool Finishing Research Articles

Conjugation of chitosan oligosaccharide to papain for controllable anti-felting finishing of wool textiles

The application of protease as a biocatalyst for the anti-felting finishing of wool has been widely explored. However, commercial proteases tend to hydrolyze the non-keratinized proteins in the cell membrane complex (CMC) layer while removing wool scales, resulting in excessive hydrolysis and unacceptable fiber damage. Herein, chitosan oligosaccharide (COS) was covalently grafted to papain using carbodiimide/N-hydroxysuccinimide (EDC/NHS) to prepare a less-destructive modified protease of Pap-COS. Subsequently, one-bath anti-felting finishing of wool was carried out using reducing agent and Pap-COS, aiming at achieving low shrinkage and reduced strength loss. The results reveal that Pap-COS achieved a larger particle size than native papain, accompanied by a prolongation of its half-life and a decrease in the thermal inactivation rate, demonstrating improved stability. Under the same incubation conditions, the felting shrinkage of wool fabrics treated with papain and Pap-COS was similar (approximately 5 %). In contrast, native papain caused a 20.82 % decrease in fabric strength, while Pap-COS resulted in a substantially lower decrease (8.10 %), meeting the requirements of commercial woolen products. Furthermore, the dyeing performance and wearability of the Pap-COS-treated wool fabrics were also dramatically improved. The present work provides an alternative for eco-friendly shrink-resistant finishing of woolen textiles in wool industry.

Analyzing the effect of polydopamine cross-linked serine protease on anti-shrinkage finishing of wool using response surface methodology design

The polydopamine-cross-linked serine protease anti-felting process of wool fibers was optimized by response surface methodology to prepare wool fabrics with a low tendency to shrink and high strength. The effects of dopamine substrate concentration, serine protease substrate concentration, and reaction time on the physical properties and surface color of wool were investigated. The experimental data were fitted and analyzed by the polynomial regression model, and the predicted area shrinkage and breaking strength response of wool fabric were obtained. The results were analyzed by variance analysis to determine the important parameters for optimization. Wool fabrics were prepared under the conditions of dopamine substrate concentration of 0.834 g/l, serine protease substrate concentration of 2.5 g/l, and reaction world of 127 min. Scanning electron microscopy images showed that the surface of wool fibers was covered with a large amount of polydopamine and some edge scales were passivated. After 20 cycles of washing, the shrinkage area of wool fabric is from 1.49–7.25%, with good durability. In addition, X-ray photoelectron spectroscopy, and X-ray diffraction analysis results showed that the behavior of polydopamine-coated fibers prevented the excessive hydrolysis of scales by serine protease, and the crystallization index and solubility in alkaline solution increased.

Eco-friendly shrink-resist finishing of wool through synergistic effect of disulfide bond reducing agent and papain

The environmental benefits of utilizing protease as a biocatalyst for wool shrink-resist finishing have been widely recognized. However, the efficacy of individual protease treatment is unsatisfactory due to its incapability towards the outermost cuticle layer of wool fibers that contains hydrophobic fatty acids. In order to weaken the structural integrity of the highly cross-linked scales and promote the enzymatic anti-felting, sodium sulfite and tris (2-carboxyethyl) phosphine hydrochloride (TCEP) were employed in combination with papain, respectively, aiming at obtaining a low shrinkage without unacceptable fiber damages. Based on the synergistic effect of papain and TCEP, the edges of wool scales were slightly destroyed by the reduction of disulfide bonds, accompanied by enzymatic hydrolysis of the keratin component. Through the controlled reduction and hydrolysis of wool scales, satisfactory anti-felting result was achieved without causing severe damage to the fiber interiors. In the presence of 0.25 g/L TCEP and 25 U/mL papain, the area shrinkage of wool fabric decreased to approximately 6 %, with a low strength loss of less than 8 %. Meanwhile, the dyeing behavior of the wool fabric under low-temperature conditions was dramatically improved, leading to decreased energy consumption during production. The present work provides an alternative for eco-friendly finishing of wool fabrics, which can be applied commercially.

Effect of liquid ammonia and protease on surface modification and shrink resistance of wool

In order to improve the surface properties of wool fiber, the wool fabric was treated with liquid ammonia and protease treatments successively. The results showed that liquid ammonia pretreatment could cause certain damage to the surface structure and disulfide bonds in keratin, which enhanced the action of protease on wool surface and catalytic hydrolysis of the cuticle. The joint treatment of liquid ammonia and protease changed the secondary structure of wool. The content of α‐helix and random crimp increased, while the content of β‐sheet decreased. In addition, the shrink resistance of wool fabric was significantly improved without obvious losses in tensile strength and elongation. The combination of liquid ammonia and protease treatments provides a potential new method for the surface modification and eco‐friendly shrink‐resistant finishing of wool and further widens the application of liquid ammonia in textile industry.

Erratum: Coloration and Functional Finishing of Wool via Prangos ferulacea Plant Colorants and Bioactive Agents: Colorimetric, Fastness, Antibacterial, and Antioxidant Studies

Erratum: Coloration and Functional Finishing of Wool via Prangos ferulacea Plant Colorants and Bioactive Agents: Colorimetric, Fastness, Antibacterial, and Antioxidant Studies

Simultaneous dyeing and finishing of wool and natural silk fabrics using Azolla pinnata extract

Simultaneous dyeing and finishing of wool and natural silk fabrics using Azolla pinnata extract

Coloration and Functional Finishing of Wool via Prangos ferulacea Plant Colorants and Bioactive Agents: Colorimetric, Fastness, Antibacterial, and Antioxidant Studies

Coloration and Functional Finishing of Wool via Prangos ferulacea Plant Colorants and Bioactive Agents: Colorimetric, Fastness, Antibacterial, and Antioxidant Studies

Valorization of flavonoid-rich invasive weed-Eupatorium adenophorum in the cleaner production of coloristic and functional wool fabric with a research focus on photofading mechanism

The ecological destructions and economic losses caused by the invasion of Eupatorium adenophorum have been perplexing researchers and governments. The resource utilization of invasive weeds provides an emerging direction for the control and management of Eupatorium adenophorum. The objective of this study is to utilize Eupatorium adenophorum as a cost-effective source of flavonoid compounds for the cleaner production of coloristic and functional wool. First, the extraction, purification, and identification of Eupatorium adenophorum flavonoids (EAFs) were investigated. The crude extraction of EAFs was implemented by using ethanol/water and the highest total flavonoid content of 37.8 mg rutin equivalent/g was obtained. The crude EAFs extract was further purified by using macroporous adsorption resin. The main components of purified EAFs were patuletin and myricetin, identified by FT-IR and liquid chromatography-mass spectrometry (LC-MS). Afterward, the adsorption mechanism and dyeing performance of EAFs on the pre-mordanted wool were studied. Results stated that the adsorption between them belonged to mono-layer adsorption driven by coordination bond, electrovalent bond, and hydrogen bond, which endowed the dyed wool with a good color fastness of rubbing and washing. The building-up property of EAFs on wool fabric was quite acceptable, implying the feasibility of large-scale production. In addition, the dyed wool showed a ultraviolet protection factor value of 345 and a half-life period of 0.89 s (at 65% relative humidity), demonstrating excellent UV-shielding and antistatic properties, respectively. The improved functionalities of dyed wool were owing to the good UV absorption capacity and hygroscopicity of flavonoids. However, such dyed wool suffered from photofading due to the inferior photostability of EAFs. For exploring the photofading mechanism of dyed wool, the photo-degradation pathway of EAFs on the fabric was speculated based on the detection of the photo-degradation products of EAFs by LC-MS. The founding of some colorless hydroxybenzoic acids in the photo-degradation products suggested the occurrence of oxidation and ring-opening of pyranone structure in flavonoids. In general, our work made an attempt to valorize invasive weed in the green dyeing and finishing of wool and provided theoretical support for the development of the light resistance of flavonoid-treated wool.

Extraction and characterization of natural colorant from Melia azedarach bark and its utilization in dyeing and finishing of wool

Melia azedarach has a long history of use in furniture production in China. However, its by-product Melia azedarach bark (MAB) and its application as a natural colorant for textiles have not been fully exploited. Increasing awareness of environmental protection and health has led to an increase in the utilization of natural dyes from agricultural and forestry bio-products. This paper focuses on the extraction and application of MAB as a novel natural functional colorant for wool fabrics. Three different solvents (ethanol/water, water with acid or alkali, and ethanol/water with alkali) were used. The chemical composition of the different MAB extracts, the color characteristics, colorfastness, and functional properties of MAB dyed wool fabrics by different dyeing methods were investigated in this work. The extraction solvent of 40% ethanol/water with alkali gave the maximum crude yield of 18.9%. Wool fabrics dyed directly or pre-mordanted with Al3+ and Fe2+ salts showed various hues with acceptable colorfastness to laundering, crocking, and light, as well as functional properties such as UV protection, fluorescence, and anti-moth. MAB extracts proved to be a desirable natural colorant and the dyed wool fabrics proved to be high value-added.

Evaluation of Cellulosic and Protein Fibers for Coloring and Functional Finishing Properties Using Simultaneous Method with Eucalyptus Bark Extract as a Natural Dye

Aqueous extract of Eucalyptus globulus L. bark is used for simultaneous dyeing and finishing of cotton, silk, wool, and eri silk fabrics in the absence of inorganic salts or mordants for producing value-added environment-friendly products. All the fabrics have an affinity towards the colorants obtained from this bark. The phytochemical studies reveal the presence of bioactive compounds, i.e. saponin, phenols, tannin, flavonoids, terpenoids, and glycosides in the bark. The protein fabrics dyed with this extract exhibit improved color fastness to washing and light as compared to cotton. A positive value of both a* and b* indicates the color of all the fabrics dyed with this bark is reddish-yellow. K/S values of all the dyed fabrics are improved with the increase in dye bath concentration from 100 g/l to 200 g/l for all the fabrics dyed with these colorants. The calculated average particle size and zeta potential value of the aqueous extract is ∼535 nm and −22.4 mV, respectively. All the dyed fabrics show an excellent result in terms of resistance against S. aureus and E. coli at 200 g/l dye concentration. Eucalyptus bark at 200 g/l dye bath concentration results in maximum UPF value for cotton, eri silk, and wool fabrics.

Investigating the usage of eucalyptus leaves in antibacterial finishing of textiles against Gram-positive and Gram-negative bacteria

Recently, people are sensitive about healthy living and preferring healthy products in all areas including the textile goods. So it is thought that antibacterial textile products will be in demand in this context. For this aim different chemicals can be consumed in the textile industry. But different studies on the use of some different industrial crops have exhibited exciting results. In this study, beyond the known industrial crops and herbal wastes, dried and ground eucalyptus leaves were extracted and used in finishing of wool to color and gain an antibacterial activity. In the finishing process, the liquor ratio was chosen as 1:40 and experiments were carried out with and without mordants. After finishing processes, the samples were evaluated in terms of obtained colors (CIE L*a*b* values) and antibacterial activities against Staphylococcus aureus and Escherichia coli bacteria. Meanwhile, FT-IR and ICP-MS analysis, color fastness, and SEM images of the finished samples were also examined. As a result of these processes, it has been determined that wool fibers can gain antibacterial activities by using eucalyptus leaves and can be colored with this herbal waste. By the addition of mordants, the colors have differed and fabrics gained antibacterial activity against E. coli as well.

Environmental friendly bioactive finishing of wool textiles using the tannin-rich extracts of Chinese tallow (Sapium sebiferum L.) waste/fallen leaves

Recently, there has been an increasing interest towards the fabrication/finishing of bioactive materials using natural plant extracts, which can achieve a wide range of functional properties and environmental benefits. This study presents an environmentally benign bioactive finishing of wool fabric via the use of unexplored tannin-rich waste/fallen leaves extract of Chinese tallow/Sapium sebiferum L. through simple adsorption technique. Simple aqueous extraction followed by the evaluations of build-up properties on wool fabric using Chinese Tallow (CT) leaves extract were studied in due course of this study. Optimization of extraction and dyeing variables/conditions such as pH, temperature, CT concentration, and time were conducted using UV–Visible and reflectance spectral method. The nature of functional groups of the extracted dye were investigated through FT-IR spectral analysis with further in depth thermal analyses using TG and DSC measurements. Additionally, the extracted dye was subjected to quantitative analytical tests to check the relative amounts of total phenolics and flavonoid with respect to gallic acid and catechin equivalents, respectively. Build-up properties and fastness characteristics were studied in the presence and absence of mordants (two metal and one biomordant) under corresponding ISO standards. Results showed that wool fabric treated with CT leaves extract exhibit excellent antioxidant activity, good UV protection and high antibacterial activities against E. coli and S. aureus. The use of biomordant to alter the functional properties provide an eco-friendly method for wool finishing. In general, the treated wool fabric in this work has shown a promising future for the preparation of health and hygiene-related textile materials.

Halogen free flame retardant finishing of wool and wool rich fabrics for aircraft seats

Wool and wool/nylon blended yarns were knitted and treated by a phosphorus sulphur based agent by padding. The flammability hazard was evaluated considering parameters such as; the spread of flame, heat release and smoke emission. The flame spread of fabrics was measured according to the FAR/CS 25.853 12 Second Vertical Bunsen Burner test procedure. Regardless of the blend ratio, the fabrics treated by the flame retardant (90% add-on) could comply with the vertical flammability requirements for aircraft materials. Important flammability parameters such as heat release rate and peak heat release rate ware measured by the cone calorimeter. The FR treatment of fabrics was found to be effective in reducing heat release and thus risks associated with fire. The smoke generated by the materials during flaming combustion was evaluated by both cone calorimeter and NBS smoke density chamber.

Grafting of chitosan-acrylamide hybrid on the wool: Characterization, reactive dyeing, antioxidant and antibacterial studies

This study presents a new approach to enhance reactive dye uptake and functional finishing of wool yarns via simple grafting with synthesized chitosan-acrylamide (Ch-Ac) hybrid. To this, Ch-Ac was synthesized and characterized with fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Then, Ch-Ac was grafted on wool, characterized with FTIR, SEM, and weight gain analysis and dyeability with two commercial reactive dyes. Results showed that Ch-Ac treated wool could be dyed at lower temperatures (ca. 40 °C), times (ca. 30 min), and amount of reactive dye (2% owf) as compared to raw wool. Also, deeper shades not obtainable in conventional dyeing could be attained using Ch-Ac treated wool. In addition, Ch-Ac treatment imparted very good radical scavenging and excellent antibacterial activity against gram-negative (E. coli) and gram-positive (S. aureus) bacteria. Color fastness results confirmed that Ch-Ac treatment had no adverse effect on durability of dyes against washing, light, rubbing and perspiration. The results of this study clearly indicated that Ch-Ac can be used in eco-friendly functional finishing of wool with enhanced reactive dye uptake, minimized residual dye in wastewater, saving in consumption of chemicals, energy, and time of dyeing.

Chitosan-cyanuric chloride hybrid as an efficient novel bio-mordant for improvement of cochineal natural dye absorption on wool yarns

This study presents an ecological and economical method for dyeing and durable antibacterial finishing of wool with cochineal natural dye. Wool yarn was treated with prepared chitosan-cyanuric chloride hybrid (Ch-Cy), was checked for its capability to covalently react with wool, and its dyeing, color fastness, as well as antibacterial properties were also investigated. The influences of key factors such as Ch-Cy concentration, dye concentration, pH, time, and temperature of dyeing were investigated and optimized. Results showed that Ch-Cy (15% on weight of fiber ) treatment of wool had several beneficial effects which brought about remarkable improvement in dye uptake, decrease in optimum dyeing time and temperature, elimination of metal mordant from dyeing process due to bio-mordant role of Ch-Cy, and development of antibacterial finish against pathogenic gram negative Escherichia coli and gram positive Staphylococcus aureus bacteria which was durable up to 20 washing cycles. Color fastness properties of treated wool were all satisfactory and in acceptable range. It was concluded that the simple Ch-Cy treatment of wool can considerably assist to reduce energy consumption, chemicals, and dyeing costs which makes the process cost effective and eco-friendlier over conventional processes.

Extraction, Dyeing, and Antibacterial Properties of Crataegus Elbursensis Fruit Natural Dye on Wool Yarn

Fruits obtained from shrubs of the Crataegus elbursensis (C. elbursensis) plant demonstrate significant antioxidant and antibacterial properties. In this study, natural dye was sono-extracted from fresh and dried fruits and applied in dyeing and antibacterial finishing of wool. The maximum sono-extraction yield was obtained when optimal conditions of ethanol/ water (4/1 v/v) as extracting solvent, time 30 min, pH 4, temperature 50 oC, and C. elbursensis concentration 10 g/l were used. When wool yarns were dyed with the extracted natural dye, the maximum dye uptake was achieved using dye concentration 75 % owf, and dyeing condition of 100 oC, 60 min, pH 4, and LR 100:1. Different metal salts like aluminum sulfate, copper sulfate, and tin chloride were applied on wool by pre-mordanting method and their effects on dye uptake, color variation, and color fastness were examined. Results showed that the natural dye itself had relatively high uptake and good color fastness on un-mordanted wool. Further, each mordant had different effect on dye uptake, color variation, and color fastness properties depending on its coordination ability with dye molecules and wool chains. Moreover, dyed yarns showed good antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria.

Imparting functionality viz color, antioxidant and antibacterial properties to develop multifunctional wool with Tectona grandis leaves extract using reflectance spectroscopy

In recent years, considerable attention has been given to plant colorants for use in dyeing applications because of their newly discovered properties such as insect repellency, deodorizing, antioxidant, sun protection, and antibacterial activity. In view of their better biocompatibility, biodegradability, less-toxicity, natural colorants are gaining worldwide interest for producing elegant hues and highly functional value-added textiles. In the present work, we investigated the coloring and functional finishing of wool with Tectona grandis L. leaves extract with the emphasis on effect of metallic salt mordants on colorimetric potential, fastness, radical scavenging potential, and antibacterial activity in an attempt to develop bioactive fibres for use in health care applications. The pretreatment of wool with ferrous sulfate, potassium aluminium sulfate and stannous chloride provided a significant enhancement in CIELa*b* parameters and fastness properties. Antioxidant tests showed that the control dyed wool had excellent radical scavenging activity than mordanted samples. In addition, metal mordants particularly ferrous sulfate enhanced the durability of antibacterial efficacy to several laundering cycles. It can be concluded that the extract of Tectona grandis may be developed as multifunctional finishing agent to impart simultaneous color, antioxidant and antibacterial properties to wool based fabrics.

Enzymatic coloration and finishing of wool with laccase and polyethylenimine

Enzymes have been widely used in textile wet processing. The precise reaction specificity of an enzyme has been utilized for specific or targeted textile finishing without causing undesirable fiber damage. Laccases are important enzymes for application in textile processing due to their great versatility and capability of catalyzing the oxidation of a broad range of substrates. The investigation of laccase-catalyzed coloration towards either wool or polyethylenimine was carried out. It is understood that amino groups from wool and polyethylenimine are involved in the formation of polymeric color during laccase catalyzation of catechin and gallic acid. The color depth and shrink-resistance of wool can be improved significantly by incorporating a multi-primary amine compound, such as polyethylenimine, and a crosslinking agent, such as glycerol diglycidyl ether, in the enzymatic coloration process of wool. This demonstrated the potential to achieve combined coloration and shrink-resistant finishing for wool fabrics.

Controlled eco-friendly shrink-resist finishing of wool using bromelain

Shrink-resist finishing is imperative to introduce dimensional stability and characteristic handle for wider acceptance of woolen garments. Conventionally used oxidative anti-felting treatments using sodium hypochlorite, gaseous chlorine, dichloroisocyanuric acid etc. release chlorine leading to high concentration of absorbable organic halides in waste water; application of resin results in stiffer handle because of spot welding effect. In contrast, enzymatic processing using protease is a sustainable alternative to substitute eco-hazardous conventional processes though diffusion of protease deep inside the wool in alkaline pH is the major concern for substantial weight as well as tensile loss thus limiting its application on wool. Treatment with bromelain even at very mild alkaline pH around 7.5 in absence of salt results in considerable damage in wool structure with consequence of higher weight and tensile loss due to partial/complete removal of cuticles on the surface. In this work, bromelain, a type of proteolytic enzyme, was used along with salt in acidic pH for controlled superficial hydrolysis of wool. A two-step acidic bromelain treatment was opted first using Box–Behnken design keeping in view minimum area shrinkage succeeded by optimization of the treatment parameters to achieve least area-shrinkage, weight loss, strength loss along with improved subjective softness. Controlled adsorption of bromelain at the outer surface of wool in presence of salt at pH ∼6 was observed yielding desirable anti-felting behaviour with minimum weight and strength loss. In contrast to conventional chlorine based technologies, acidic bromelain may be used in presence of sodium chloride to yield machine washable wool possessing minimum loss in weight and tensile strength both at industrial level.

양모 방축가공에 따른 물리적 성질 변화

In this study, the effect of shrink-resist treatment agent on the wool finishing, specifically anti-felting of wool product was studied. We aimed at providing preliminary data leading to the diversification of high-value added fashionable wool product. Two type of wool fabrics, dense and sheer, were employed. The fabric specimens were treated with solutions of shrink-resist treatment agent with wet pick-up rate 110%, 130%, and 150%, respectively, by using a padding mangle. The solution treated fabric specimens were then dried at room temperature first, at for 15 minutes in a drying oven, and finally cured at for 3 minutes. Cured wool fabric specimens were then subjected to a felting process. The physical and mechanical properties, including shrinkage rate along warp/filling direction, thickness at specified measurement pressure, drape stiffness, and air-permeability, were analyzed. After felting process, the shrinkage rates of wool fabric specimens, treated with shrink-resist treatment agent, were lower than those of control wool fabric specimens. The stiffness values of wool fabric specimens measured by using Flexometer were increased.