Mechanical properties of wool fiber in the stretch breaking process

Short wool fibers obtained by the stretch breaking process can be blended with cotton fibers and processed in a cotton spinning system, which has a high production rate. For the structural property of the wool fiber after stretch breaking, the diameter and length of the wool fiber were measured as a function of time. The diameter of the broken fibers was finer than the diameter of untreated fibers. The fiber diameter at the break point was the finest and was more irregular than the original fiber. The broken fiber showed mechanical properties of increased modulus, decreased breaking strain, and increased breaking strength.     

热处理对椰子水过氧化物酶和多酚氧化酶活力及色泽变化的影响

研究热处理对新鲜椰子水过氧化物酶(Peroxidase,简称POD)和多酚氧化酶(Polyphenol oxidase,简称PPO)相对酶活力和色泽变化影响,探讨椰子水酶活力与其色泽的相关性。结果表明,随着热处理温度升高或时间的延长,椰子水的POD和PPO相对酶活力均随之降低,其中90℃和95℃热处理4 min后,可分别使POD和PPO的活力降低90%以上。随着热处理温度的升高,椰子水的色泽随之加深;椰子水的PPO和POD相对酶活力与色泽加深程度呈负相关关系,且具有一定的显著性。该结果可为后续研究椰子水色变控制技术提供一定的理论基础。     

Application of silver nanoparticles as an antibacterial mordant in wool natural dyeing: Synthesis,antibacterial activity,and color characteristics

Madder is a natural colorant which is commonly applied with metal salts as a mordant to improve its affinity to fibers and color fastness. Madder produces an insoluble complex or lake in the presence of metal ions on mordanted fabric. In this study, wool fabric was pretreated with AgNPs (silver nanoparticles) as a mordant, then dyed with madder. The wool fabric samples were examined by scanning electron microscopy (SEM) and their colorimetric characteristics were evaluated. The formation of spherical silver nanoparticle was confirmed using UV-Visible spectroscopy, SEM images, and elemental analysis. The average size of synthesized silver nanoparticles on the surface of wool fibers is around 73 nm. The dyed wool samples were pretreated with different concentration of Ag⁺ ions or AgNPs, which showed higher color strength value compared to untreated dyed wool fabric. This pretreatment also presented good antibacterial activity.     

Study on the dyeing of wool fabrics with Phytolacca berry natural dyes

Dyeing of wool fabrics with natural dyes from Phytolacca berries has been studied. The effect of dye concentration, dye bath pH, dyeing time and temperature were discussed. The influence of chitosan application on the dyeing properties of wool fabrics was investigated. The SEM photographs of chitosan treated wool fabrics clearly depict the deposition of chitosan on the fibers. The effect of chitosan concentration, dye bath pH, dyeing time and temperature has been studied by orthogonal experiment. It has been proved that the dyed wool samples pretreated by chitosan have higher color fastness, faster dyeing rate, and better antibacterial properties compared with untreated ones.     

Union dyeing of the photografted PET/wool blend fabrics with dimethylaminopropyl methacrylamide

Dimethylaminopropyl methacrylamide (DMAPMA) was grafted onto PET/wool blend fabrics by continuous UV irradiation. Union dyeing of the photografted fabrics was investigated using three reactive dyes of α-bromoacrylamide reactive groups. The influence of grafting yield, DMAPMA concentration, NaCl amount, pH value, and dyeing temperature on the dyeability was evaluated. The dyeability of both PET and wool components was improved significantly by the DMAPMA photografting and successive reactive dyeing. Although the dyeability of the PET component in the blend substantially was improved with higher grafting, equal dyeability between PET and wool was difficult to achieve due to more facile grafting and higher reactivity of the wool component compared with the modified PET component. However, the color fastness of the PET/wool blend fabric was excellent for all three colors. This study may offer a way to achieve union dyeing of PET/wool blend fabrics.     

Dyeing behavior of low temperature plasma treated wool

In this paper, the effects of low temperature plasma (LTP) treatment on the dyeing properties of the wool fiber were studied. The wool fibers were treated with oxygen plasma and three types of dye that commonly used for wool dyeing, namely: (i) acid dye, (ii) chrome dye and (iii) reactive dye, were used in the dyeing process. For acid dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased but the final dyeing exhaustion equilibrium did not show any significant change. For chrome dyeing, the dyeing rate of the LTP-treated wool fiber was also increased but the final dyeing exhaustion equilibrium was only increased to a small extent. In addition, the rate of afterchroming process was similar to the chrome dyeing process. For the reactive dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased and also the final dyeing exhaustion equilibrium was increased significantly. As a result, it could conclude that the LTP treatment could improve the dyeing behavior of wool fiber in different dyeing systems.     

Effect of color changes of naturally colored organic cotton fibers on human sensory perception

This study aims to investigate the color changes of Naturally Colored Organic Cotton (NaCOC) fibers after scouring, and to evaluate the human sensory perception for the fibers. Furthermore, it tries to observe the relationship between the color coordinates and the sensory perception. Three colors (ivory, coyote-brown, green) of NaCOC fibers were scoured under four different treatments (boiling water, enzyme, sodium carbonate, sodium hydroxide). The color coordinates (L, a, b) were measured in CIELAB using spectrophotometer (SP62, X-Rite), and color differences (ΔL, Δa, Δb, ΔE) were calculated. Human sensory perception for the NaCOCs was evaluated by 27 female participants. The questionnaire consisted of nine pairs of bipolar visual sensory adjectives using the SDS. The values of L and b fell, while the value of a arose after scouring in general. The value of ΔE was the highest when treated with alkali solutions among all treatments. Human sensory perception such as brightness, clearness, lightness and freshness generally decreased, while vividness and strength increased. The meaningful color factors to predict brightness, lightness were L and ΔL, and those to predict vividness and strength sensory were ΔL.     

A novel eco-friendly colorant and dyeing method for poly(ethylene terephthalate) substrate

Although madder (Rubia tinctorum) has been used as a well-known natural textile dye source for dyeing of natural fibers such as wool, silk and cotton, 100 % polyester dyeing with madder is not common. In this study, polyester samples were dyed with madder at different dyeing temperatures, from 60 °C to 130 °C, in company with 7 chemical and 5 natural mordants. Color properties and rub, light and wash fastness performances were investigated. Different shades of orange, brown, pink and reddish green colors were obtained. Dyeing at 130 °C exhibited the highest color yield, the highest chroma and the lowest lightness values. Overall, chemical mordants exhibited higher color yields than natural mordants. High wash fatness, moderate light and rub fastness levels were observed. The potassium bitartrate and gallnut, a natural mordant, exhibited the best results. The madder dyeing of polyester should be carried out at hot temperature conditions, 130 °C, in order to obtain the highest achievable color yield and chroma with the highest light and wash fastness properties.     

A bio-antifelting agent based on waterborne polyurethane and keratin polypeptides extracted by protease from waste wool

A bio-composite made from keratin polypeptides and waterborne polyurethane was firstly employed as a bioantifelting agent for wool fabric. The keratin polypeptides, extracted from the waste wool fibers with the protease Esperase8.0L, possessed 5271 weight-average molecular weight. The bio-composites containing different contents of keratin polypeptides were applied for wool anti-felting treatment by a pad-dry-cure process. The results indicated that with increasing content of keratin polypeptides from 0 to 6 wt.%, the area-shrinking rate of the treated wool fabrics was decreased from 4.55 % to 0.47 %, respectively. The warp and weft tensile strength at break of the fabric was increased by 8 % and 12 %, respectively and reduced by about 55 % consumption of waterborne polyurethane. The film of bio-composites had more excellent thermal stability, higher mechanical property in elasticity, and better cytocompatibility compared with the pure waterborne polyurethane film.     

Coloration of ultra high molecular weight polyethylene fibers using alkyl-substituted anthraquinoid blue dyes

UHMWPE fibers were dyed with a series of anthrquinoid blue dyes having different length of alkyl substituents at general dyeing condition. The dyeability was investigated at various conditions and fastness of the dyeings was examined. As the length of alkyl substituents increased, the dyeability toward UHMWPE fibers tends to be improved gradually. Color strength of the fabrics was increased with the increase of dyeing temperature from 100 to 130 °C. From the dyeing rate, equilibrium dyeing at 130°C was achieved at 2–3 h. The tensile strength of UHMWPE fibers after dyeing at 130 °C for 1 h was maintained at a level of 95 % of untreated fiber. However, at prolonged dyeing time at 130 °C, the tensile strength was significantly decreased to a practically unacceptable level. The color fastnesses to washing, rubbing and light of the dyeings were very good showing higher than 4 ratings.     

Functional modification of wool fabric by thiol-epoxy click chemistry

The paper reports modification and characterization of wool fabrics achieved through thiol-epoxy click chemistry. A pretreatment with tris (2-carboxyethyl) phosphine (TCEP) as an effective reducing agent was carried out to produce thiol groups on wool surface. Glycidyl trimethyl ammonium chloride (GTAC) was later covalently bonded with wool fibers via thiol-epoxy reaction. The reaction was confirmed by SEM, FTIR, Raman and TG analysis. Antibacterial activity, antistatic property, hydrophilicity and dyeability of treated wool fabric were assessed. The results demonstrated that TCEP-GTAC treatment can endow wool fabric good antibacterial and antistatic properties as well as improved hydrophilicity. Tensile strength studies indicated fiber strength loss of ~12 % on modification.     

Transglutaminase treatment for improving wool fabric properties

The microbial transglutaminase (mTGase) is used as a bio-catalyst to repair the wool damages caused by chemical or enzymatic treatments. In this paper, the effect of mTGase on the degree of yarn strength, area shrinkage, wettability, and the dyeing properties of wool was investigated. Through mTGase treatment, the yarn strength was improved about 22.2 %. The knitted wool fabrics treated with mTGase after pretreatment of H₂O₂ and protease displayed 7.5 % of area shrinkage and about 22.3 % recovery in tensile strength when compared with those treated without mTGase. Also, mTGase treatment could improve the wettability and dyeing properties of wool fabrics. With the increase of mTGase concentration, the initial dye exhaustion increased significantly and the time to reach the dyeing equilibrium was shortened. It was evident that the improvement of dyeing properties was closely related to the improvement of wettability performance of wool fabric by using transglutaminase.     

Atmospheric plasma advantages for mohair fibers in textile applications

In this study, mohair fibers were treated by air and argon plasma for modifying some properties of fibers. The fibers were evaluated in terms of their hydrophilicity, grease content, fiber to fiber friction, shrinkage, dyeing, and color fastness properties. The surface morphology was characterized by SEM images. The results showed that the atmospheric plasma has an etching effect and increases the functionality of a wool surface, which is evident from SEM and FTIR-ATR analysis. The hydrophilicity, dyeability, fiber friction coefficient, and shrinkage properties of mohair fibers were improved by atmospheric plasma treatment.     

Coating superfine down powder on polypropylene for the production of dyeable fibers

To develop dyeable isotactic polypropylene (iPP) fibers, superfine down powder (SDP) was coated on the surface of iPP fibers post melt-spinning. Optical micrographs showed that the surface of powder-coated iPP fibers was roughness, and the amount and dispersion of coated SDP were found entirely dependent on melt-spinning temperature. With the increase in coated SDP content, the moisture and water absorption of powder-coated iPP fibers increased. Powder-coated iPP fibers could be, respectively, dyed by reactive red dye and acid red dye, and the observed enhancement of color strength (K/S) and red value (a*) of powder-coated iPP fibers could be attributed to SDP coated on iPP fibers. It was worth noting that the removal of coated SDP affected the wet-washing fastness of powder-coated iPP fibers largely. In addition, the powder-coated iPP fibers were produced in a few minutes with lower cost and could have potential applications in textile industry.     

An effective and simple process for obtaining high strength silkworm (Bombyx mori) silk fiber

This article describes a new process for strengthening natural silk fibers. This process is simple yet effective for mass production of high strength silk fibers, enabled by drawing at a lower temperature and immediately heat setting at a higher temperature. The processing conditions were investigated and optimized to improve the strength. Silk fibers drawn to the maximum ratio at room temperature and then heat set at 200 °C show best tensile properties. Some salient features of the resulting fibers are tensile strength at break reaching 533±10.2 MPa and Young’s modulus attaining 12.9±0.57 GPa. These values are significantly higher than those of natural silk fibers (tensile strength increased by 44 % and Young’s modulus by 135 %). Wide-angle X-ray diffraction and FTIR confirm the transformation of silk I to silk II crystalline structure for the fiber obtained from this process. DSC and TGA data also provide support for the structural change of the silk fiber.     

Environmentally benign scouring of wool fibers using mesophile acidic lipase

Surfaces of raw wool fibers possess high amounts of greasy substances that need to be removed prior to further processing. Acidic lipases using Bacillus licheniformis (MTCC 2618) were produced with the optimum activity levels closer to the room temperature. Scouring of wool fibers using mesophile acidic lipase has been attempted, in the present work, as an alternative to the existing alkaline treatment and the samples were assessed in terms of weight loss, moisture regain, tenacity, elongation, surface appearance, and friction of the fibers. The lipase scoured wool fibers showed moisture regain and weight loss values comparable to that of alkaline treatment, with lower static and dynamic frictional coefficients. Higher tenacity and elongation values were observed in the lipase scoured fibers compared to the alkaline scoured samples and clear appearance of the surface, compared to the raw wool fibers, was also observed in the lipase scoured samples.     

Effectiveness of flavourzyme treatment on polyamide fabric

We characterized the effectiveness of Flavourzyme treatment in the hydrolysis of amide bonds in polyamide fabric by quantitating the ionic groups released into the treatment liquid and those formed on the fabric surface. On the basis of hydrolytic activity, we demonstrated that Flavourzyme effectively hydrolyzed amide bonds in polyamide (PA) fabric. The optimal treatment conditions were found to be pH 7.0, temperature 40 °C, treatment time 120 min, and Flavourzyme concentration 10 % based on weight of fiber. PA fabric treated with Flavourzyme exhibited increased numbers of amino and carboxyl groups, as evaluated by zeta potential and color strength. As the amounts of ionic groups formed by Flavourzyme hydrolysis increased, the water contact angle and water absorbency time decreased.     

One-Bath Union Dyeing of Wool/Acrylic Blend Fabric with Cationic Reactive Dyes Based on Azobenzene

Three unreported cationic reactive dyes based on azobenzene were synthesized using a novel synthetic route. Synthesized dyestuffs containing three primary color dyes were characterized by FTIR, H-NMR, LC-MS, Element Analysis and UV-vis spectroscopic techniques. The absorption spectra of dyes were measured in three solvents with different polarities. The dyeing and color fastness properties of three cationic reactive dyes on wool, acrylic and wool/acrylic blend fabrics were determined. The optimum pH for wool and acrylic fabrics were 6 and 5, respectively. Effect of temperature, time on dyeing properties and color fastness properties on wool fabric showed the same tendency with acrylic fabric. The K/S value of wool fabric dyed with three dyes was similar to that of acrylic fabric when both fabrics were dyed simultaneously in the same dyebath using low dye concentration. Wool/acrylic blend fabric dyed with three cationic reactive dyes using onebath one-step method achieved good union dyeing property and excellent color fastness.     

Dyeing of synthetic fabrics in water using azoic dyes based on boronic acid derivatives

Development of water-soluble dyes for the dyeing of different textile fabrics is essential for the textile industry due to ecological and economical reasons. In this study, a series of new azoic dyes were prepared by diazotization reaction between the phenyl boronic acid and different aniline derivatives, and their dyeing capacity in aqueous solution was evaluated. The synthesized boronic azo dyes present good water solubility and can dye polyamide (nylon), wool, silk, and cellulose acetate fabrics. The effect of factors such as concentration of dye, dyeing temperature, and pH on the level of color strength (K/S) was studied. The dyeing results showed that higher color strength K/S (about 16) and fastness properties (about 4/5) with boronic acid dyes were achieved at higher temperatures avoiding the use of surface agents, mordants, and other polluting chemical additives.     

Surface Modification of Wool Fabric with POSS® Nanomaterial

Wool fabrics, without any surface treatment, can undergo undesirable and irreversible structural changes of wool fiber during washing under heat and mechanical agitation, leading to high shrinkage of wool garments. The traditional method based on polyamide resin can prevent felting and/or shrinkage of wool textiles, but adversely affect the surface hydrophobicity. In the present study, a treatment solution was developed based on TriSilanolIsooctyl POSS® and 3- mercaptopropyl trimethoxysilane, which created wool surface with increased hydrophobicity and highly resistant to shrinkage or felting, as measured after 3×5A wash cycles (equivalent to 24 domestic washes). After the treatment, the wool fabric appeared to be superhydrophobic with a water contact angle of above 150°, compared to the untreated fabric. The treatment has marginal effect on mechanical performance as observed in tensile properties. Scanning electron microscopic images revealed a coating of POSS® on the wool surface. The dyeing of untreated and treated fabrics appeared to be uniform to the naked eye, though spectrophotometric analysis indicated a difference in the extent of dyeing performance. This research showed that POSS®-based treatment is a potentially effective approach for developing shrink-resistant wool textiles with enhanced surface hydrophobicity, in contrast to traditional chlorine/polyamide resin treatment.