The limiting irregularity of single wool fibers

Fiber irregularity affects fiber mechanical properties. This study has, for the first time, introduced the concept of limiting irregularity to single wool fibers. The limiting irregularity is the minimum variation in fiber cross sectional area that can be expected of a single wool fiber, assuming a random length-wise distribution of its constituent cortical cells. Cortical cells were extracted from merino wool fibers and their dimensions were measured from SEM images to calculate their cross sectional area variations both between cortical cells and within cortical cells, and to work out the average number of cortical cells in the cross section of wool fibers of a given diameter. Single wool fibers were also measured at 5 μm interval along length for fiber diameter variations. These variations were found to be larger than that based on fiber limiting irregularity.     

Influence of chitosan on the effects of proteases on wool fibers

Textile processes generally produce a large amount of wastewater and cause a negative environmental impact. The use of proteases in wool finishing could be an appropriate alternative to classical finishing methods. However, the enzymatic treatment could cause excessive fiber damage. The application of biopolymer chitosan on wool fabrics prior to proteases treatment in attempt to overcome the damage promoted by the enzymes has been studied. The treatments based on chitosan application followed by enzymatic treatment reduce felting shrinkage, enhance whiteness degree, and improve dyeability of wool. Moreover, it plays an important role in minimizing the wool fiber damage.     

Effect of enzymatic treatment on the dyeing properties of protein wool fibers

Two proteolytic enzymes were used as auxiliaries in the dyeing of wool fabrics with acid dyes. The effect of the enzymes on dye exhaustion (%E) and dye uptake (K/S) was studied at 70, 85, and 98 °C and compared to the corresponding values obtained for the control samples which were dyed without enzymes under the same conditions. Two commercially available dyeing auxiliaries commonly used for the dyeing of wool at low temperatures were also used under the same conditions and compared with the dyeings made with and without enzymes. Treatment with transglutaminase was done in order to compensate the damaging effects of protease. The study shows that the enzymes could be used as auxiliaries in the dyeing of wool at lower temperatures.     

Effects of lipase on poly(lactic acid) fibers

Two types of lipases, L3126 and Lipex 100L, were used to modify the surface of poly(lactic acid) (PLA) fiber by measuring weight loss percentage and wettability of the fiber in this work. The influence factors were discussed and optimized based on single-factor experiments. The optimal conditions for the modification of poly(lactic acid) fiber with lipases were determined as follows: incubation with lipase L3126 of 0.5 g/l at 45 °C and pH 8.5 for 8 hours and incubation with lipase of 10 ml/l at 40 °C and pH 7.5 for 10 hours. Lipase L3126 showed higher biodegradation ability to poly(lactic acid) fiber than lipase Lipex 100L. The scanning electron microscopy confirmed that both of the two lipases could lead to the formation of etching characters on treated poly(lactic acid) fibers in comparison with the blank samples. Furthermore, the wettability of the fibers treated with the lipases was evidently improved, especially Lipase L3126.     

Frictional and tensile properties of conducting polymer coated wool and alpaca fibers

Wool and alpaca fibers were coated with polypyrrole by vapor-phase polymerisation method. The changes in frictional and tensile properties of the single fibers upon coating with the conductive polymer are presented. Coating a thin layer of polypyrrole on the alpaca and wool fibers results in a significant reduction in the fiber coefficient of friction, as the conducting polymer layer smooths the protruding edges of the fiber scales. It also reduces the directional friction effect of the fibers. Depending on the type of fiber, the coating may slightly enhance the tensile properties of the coated fibers.     

Study on the influence of scouring on the wettability of keratin fibers before plasma treatment

The present paper studies the wetting behavior and shrink-resistance of keratin fibers prepared by solvent extraction or by industrial-like surfactant washing as well as their response to plasma treatments. The results obtained reveal that keratin fibers can be prepared by surfactant washing instead of using solvents, which will allow carrying out research studies in closer conditions to the industrial reality, and indeed in a much economic and environmentally friendly way.     

Improving certain properties of wool fibers by applying chitosan nanoparticles and atmospheric plasma treatment

The nanochitosan particles were prepared by ionic gelation method using sodium tripolyphosphate (TPP) as anionic chemical agent. Structural and morphological properties of the nanoparticles were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) analyses. The results showed that nanoparticles were spherical with a diameter range of 17-105 nm. After nanochitosan synthesis, the effects of chitosan and nanochitosan concentrations on the dyeability, fastness properties, shrink-proofing, tensile strengths, and surface friction coefficients of untreated and plasma treated wool fabrics were investigated. The studies revealed that nanochitosan treated wool fabric possesses better dyeing and shrink-proofing properties in comparison with conventional chitosan treated fabrics.     

Environmentally benign alternatives: Plasma and enzymes to improve moisture management properties of knitted PET fabrics

Effects of enzymatic and atmospheric plasma treatments individually and their combinations on knitted PET fabrics were investigated in terms of hydrophilicity, surface modification and moisture management properties. Cutinase from Humicola Insolens, lipase from Candida SP and atmospheric plasma with air and argon gases were applied to PET fabrics. To evaluate results, moisture management tester (MMT) and scanning electron microscopy (SEM) were utilized. Wicking heights of samples were measured by wicking test method. Improved moisture management properties were observed with environmentally benign processes compared to the untreated ones. Especially combined treatments have given the same or slightly better results than those of conventional alkaline treatments. Fabrics treated with plasma and then followed by enzymatic incubations have significantly improved the wetting time, absorption rates and spreading speed results.     

Identification of wool, cashmere, yak, and angora rabbit fibers and quantitative determination of wool and cashmere in blend: a near infrared spectroscopy study

Near infrared spectroscopy coupled with chemiometric analysis was investigated as a fast and non destructive method for the identification of wool, cashmere, yak, and angora rabbit fibers in the raw and combed sliver state and for the quantitative determination of cashmere in cashmere/wool blends. The main differences among spectra of different animal hair arise from physical charateristics rather than chemical characteristics (mainly pigmentation and mean diameter) of animal fibers. The Soft Independent Modelling by Class Analogy method allows the classification of distinct fibers into separate groups with interclass distances ranging from 12.64 for the nearest classes (white cashmere and wool) to above 1000 for the most distant classes of white and pigmented fibers. Percentages of recognition and rejection of 100 % were found with the exception of a yak sample that was not rejected from the pigmented cashmere class (98 % of rejection). The prediction capacity of the model was also evaluated. Quantitative analysis was carried out using samples obtained by carefully mixing known amounts of wool and white cashmere. A standard error of the estimate of 8.5, a standard error of prediction of 13.10 and a coefficient of determination of 0.95 were calculated. From the results obtained, it can be concluded that near infrared spectroscopy can be used as a tool for an initial and rapid screening of unknown animal fiber samples in the raw and combed sliver states and for a fast and coarse estimate of the amount of cashmere in wool/cashmere blends.     

Dual-mode adsorption of cochineal natural dye on wool fibers: Kinetic,equilibrium, and thermodynamic studies

The dual-mode adsorption model was used to investigate the adsorption behavior of cochineal natural dye on wool fibers. Kinetic, thermodynamic, and equilibrium characteristics were investigated in terms of the adsorption isotherm, affinity, enthalpy and entropy changes, dyeing rate, diffusion coefficient, and activation energy of dye diffusion. The results revealed the prominent role of dyeing pH in determination of dyeing mechanism and dye adsorption isotherm type. At pH 4, dual Langmuir-Nernst model with the highest correlation coefficient was found as the most appropriate isotherm model to describe the adsorption behavior of cochineal onto wool fibers while at pH 6, the adsorption isotherm was the Nernst type. Cochineal adsorption onto wool was exothermic which resulted in progressive fall in affinity and equilibrium dye up-take values with increasing temperature. Moreover, dyeing rate steadily increased with temperature. At pH 4, affinity, dyeing rate, and diffusion coefficient demonstrated higher values compared to pH 6 whereas enthalpy and entropy changes, and activation energy showed lower values. Additionally, negative value for activation energy was obtained at pH 6. The results are deliberated based on the different possible interactions between cochineal dye and wool fiber.     

The structure of wool fibers grafted with chitosan coated Ag-loading nano-SiO2 antibacterial composites

Wool fiber was grafted with chitosan coated Ag-loading nano-SiO₂ (CCTS-SLS) antibacterial composites under ultraviolet irradiation. The morphologies and structures of CCTS-SLS-wool were characterized by using scanning electronic microscopy, transmission electron microscopy, and Fourier transformation infrared spectrometry. The results show that a uniform and smooth antibacterial layer of 200 nm in thickness was formed on the surface of wool fiber by covalent bonding. The mechanical properties of the antibacterial wool fiber were improved. The antibacterial performance was found to be excellent, with antibacterial effect up to 90 % even after repeated washing. CCTS-SLS-wool possessed soft hand-feeling and good color.     

UV-grafting coloration of cotton and wool fabrics using bismethacrylated quinizarin dye

A novel bifunctional quinizarin dye possessing two photoactive methacrylate groups was synthesized by the reaction of quinizarin with methacryloyl chloride. The synthesized dye, a low substantive dye under the conventional dyeing process, can be photografted onto cotton and wool fabrics at room temperature without neutral salts, which makes it a novel coloration process of excellent environmental friendliness. The concurrent polymerization and grafting of the synthesized dye onto cotton or wool can be assisted by a photoinitiator and acrylic acid in the case of cotton grafting. Moreover, color yields of the grafted fabrics improved significantly with the photografting of the bifunctional dye. The bifunctional dye can be photopolymerized with the increase in UV energy to 25 J/cm² and the oligomeric dye has a degree of polymerization of 5 or more. Furthermore, the color fastness properties of the grafted fabrics were superior to those of the dyed fabrics via exhaustion.     

Bioscouring of cotton fabrics using pectinase enzyme its optimization and comparison with conventional scouring process

The conventional scouring process involving the harsh environment is slowly being replaced with environment friendly approach using enzymes. These enzymes remove the non cellulosic impurities present in the fabric. Such a process would enhance the absorbency of the fabric without appreciable strength loss and also would help in the proper dyeing and finishing of the fabric. In the present work pectinase enzyme was isolated from Fusariumn sp. and was optimized under different cultural conditions. The partially purified pectinase enzyme was used in the scouring of cotton fabric. The efficiency of the bioscoured cotton fabric was compared with that of the conventionally scoured fabric. It was found that the water absorbing character of the bioscoured fabric was found to be considerably higher than that of the conventionally scoured fabric. Also, the tensile strength of the cotton fabric was found to be higher for the sample treated using pectinase enzyme than the sample treated conventionally. The results of FTIR confer that the pectin and wax impurities were removed from the cotton surface in both the conventionally scoured and bioscoured fabrics.     

Modification and properties of polypropylene fibers using aluminosiloxane

Siloxylated polypropylene fibers composed of polypropylene (PP) and aluminosiloxane (AS) were prepared by melt blending followed by spinning. The effects of blend compositions on the thermal behaviors, surface and tensile properties of PP/AS blend fibers were investigated by DSC, WAXD, SEM, static honestometer, etc. The heat of fusion of PP/AS blends decreased with increasing AS contents. In addition, the peak intensity of PP/AS blends in X-ray diffraction patterns decreased with increasing AS contents. It was observed that the silicone molecules exist and well distribute on the surface of siloxylated polypropylene fibers. From the results of the half-life period measurements, the anti-static properties of PP fibers siloxylated with AS was found to be significantly modified.     

Modeling of abrasion resistance of Persian handmade wool carpets using response surface methodology

The effect of knot density, pile height, number of ply in pile yarn and pile yarn twist on abrasion resistance of Persian handmade wool carpets has been studied. The interaction between the process variables has been analyzed by using response surface methodology based on the Box-Behnken design of experiment. Knot density, pile height, interactions between knot density and pile height; pile height and pile yarn twist; as well as squares of the knot density, pile height and number of ply in pile yarn are significant process variables. The minimum abrasion loss occurs at the combination(s) of medium values of knot density (six knots per inch) and number of ply in pile yarn (three ply) as well as lower values of pile height (ten mm) and pile yarn twist (three and a half twists per inch).     

Analysis of Sunnhemp fibers processed using jute spinning system

Sunnhemp is a coarse, strong and stiff bast fiber similar to jute fiber but not considered by textile technologists for the purpose of spinning into yarn, which can be further woven into fabric. The objective of this study was to spin 100% Sunnhemp fibers in to different yarns of same count on a jute spinning system by using different number of passages of carding and drawing to find how the structural changes in the fiber after each stage mechanical processing. To observe structural changes in the fiber, random sampling method was used to collect the fiber samples at various stages of processing and analysis of each fiber was done using microscope. It was found that a lot of changes occur in the fiber structure due to mechanical processing. The structural details about the fiber entity are depicted in the article. Further, correlation was established between various fiber parameters such as fiber length, fiber diameter and fiber number of branches. Finally, an exponential frequency distribution of the fiber lengths for various stages in the spinning process was calculated. This curve explains how the degree of individualization increases as the fiber length decreases and makes the fiber spinnable into better quality yarn.     

Production and characterization of fibroin hydrogel using waste silk fibers

The use of natural resources, especially processing wastes, as low cost and environmentally friendly alternative aiming high value-added applications is a subject of broad interest. Since the Brazilian silk production annually generates a large amount of waste during the silk fibers processing, this work explores the preparation and characterization of silk fibroin hydrogels using spinning waste silk fibers from textile processing and the processed ones. Hydrogels were obtained directly by dialyzing silk fibroin solutions against frequent changes of water until the gelation point and then lyophilized and characterized in terms of their morphology, crystallinity, thermal resistance and secondary structure. X-ray diffraction analysis revealed the presence of β-sheet conformation related to sol-gel transition. FT-IR spectra indicated the coexistence of random coil (silk I) and β-sheet (silk II) structures, with predominance of β-sheet conformation for hydrogels from processed silk fibers. From thermogravimetric analysis the presence of β-sheet secondary conformation was demonstrated by a degradation peak around 292 °C for both hydrogels. Freeze-dried hydrogels presented sheet or leaf like morphology and no significant change was observed among the hydrogels from waste silk fibers and processed ones. These characteristics suggest that silk fibroin hydrogels prepared from spinning waste silk fibers and obtained directly by dialysis can be potential candidates for biomaterials application, such as drug delivery systems and for wound dressings.     

Preparation of chitosan fibers using aqueous ionic liquid as the solvent

In this work, acidic ionic liquid glycine hydrochloride (Gly·HCl) is reported as a new solvent for dissolving chitosan. The regenerated chitosan fibers were fabricated by a wet spinning process and characterized by scanning electronic microscopy, fourier transform infrared spectroscopy, wide-angle X-ray diffraction and thermal gravimetric analysis. The result shows that the regenerated chitosan fibers had the same chemical structure as the raw chitosan flake, however, its thermal stability and crystallinity is a little low. Furthermore, a new mechanism of dissolving chitosan in ionic liquid was proposed. The chitosan fibers had soft feeling, excellent antibacterial property and have huge potential application in biomaterials.     

Measurement of fuzz fibers on fabric surface using image analysis methods

Fuzz on the fabrics, which is the fibers protruded from the fabric surface, is very important in view of appearance quality, since it causes unpleasant appearance on the fabrics and also leads to pilling which makes fabric appearance and softness worse. However, fuzz on fabric surface is measured mostly by subjective methods (human vision) rather than objective methods. Thus, in this study, objective method using image analysis techniques has been developed for the measurement of fuzz on fabric surface. Fuzz on the fabric has also been ranked and rated by experts in order to see the reliability of the results obtained from the fuzz measurement. It was observed that correlation coefficient (r) between rating value and objective measurement value was 0.9 and this correlation coefficient value confirmed the reliability of this method.     

Optimization of dyeing condition for wool/cotton union fabric with direct dye using box-behnken design

Wool/cotton union fabric was dyed with a direct dye in union shade. The dyeing was performed in a single bath in relation to four factors: leveling agent (Lyogen SMKI, 0–1.5 % oww), electrolyte (sodium sulfate, 0–10 %), dyeing temperature (85–95 °C), and dyeing time (15–60 min). The dyeing was characterized by dye bath exhaustion (%), color strength (K/S value), washing fastness, and light fastness of dyed sample. Response surface analysis showed that the exhaustion of direct dye increased with electrolyte, dyeing temperature, and dyeing time while the K/S value followed a linear shape with leveling agent and dyeing temperature. An optimized recipe was formulated based on response surface strategy and numerical optimization solution.