Textile Yarn Research Articles

The Study of Chemical and Thermal Influences of the Environment on the Degradation of Mechanical Properties of Carbon Composite with Epoxy Resin.

The present research deals with the investigation of the influence of aqueous solutions of chemical substances in combination with temperature on the change of material properties of polymer composites based on epoxy resins reinforced with carbon fibers. The aim of the research was to investigate and evaluate the impact of degradation processes due to the influence of chemical environments of different temperatures and time of their action on changes in the material properties and macrostructure of carbon composite with epoxy resin. The chemical and thermal influence of the environment on the experimental material was evaluated by monitoring changes in mechanical properties, glass transition temperature, and material surface macrostructure. The achieved results show different behavior of the experimental composite material in different environments, while it was demonstrated that the degradation effect of chemical and thermal influences on changes in material properties increase with increasing temperature. Among the investigated environments (NaCl, NaOH, and H2SO4), exposure to 10% NaOH, and 15% H2SO4 had the greatest degradation influence on the polymer composite, and exposure to 20% NaCl had the smallest influence, which is also confirmed by invisible changes in material surface macrostructure and decrease of tensile strength by about 20%. Exposure to 10% NaOH resulted in significant surface roughening of the epoxy resin, white deposit creation on the surface, and a decrease of tensile strength by 35%. Opposite that, exposure to 15% H2SO4 resulted in the highlighting of the fiber yarns of the carbon fiber fabric, yellowing of the surface, surface pore occurrence, and a decrease of tensile strength by 35%.

Heat release and wear comfort characteristics of the ceramic imbedded fabrics for cold weather protective clothing

This paper examined the heat release and wear comfort characteristics of clothing made of aluminium oxide (Al2O3)/graphite imbedded yarn fabrics for cold weather protective clothing. The wear comfort of the clothing was compared and discussed in terms of the moisture vapor resistance of the fabric, which was verified by far-infrared and light heat emission experiments. The maximum surface temperature of the Al2O3/graphite-imbedded sheath/core yarn fabric was 3.4°C higher than that of the regular one, which was attributed to heat release by the far-infrared radiation emitted from the Al2O3/graphite imbedded in the yarns. The moisture vapor resistance of the Al2O3/graphite-imbedded sheath/core yarn clothing, as measured by a sweating thermal manikin test, was 3.6% lower than that of the regular PET one. In addition, the clothing microclimate temperature of the Al2O3/graphite sheath/core yarn fabric measured by wearer trials was approximately 1°C higher than that of the regular PET fabric, which revealed the superior thermal insulation of the Al2O3/graphite sheath/core yarn clothing compared to the regular PET one. Finally, the superior breathability with thermal insulation of the Al2O3/graphite-imbedded sheath/core yarn fabric were revealed due to its good heat release and storage properties, which support the possible applications for cold weather protective clothing.

Mechanical response of sisal/glass fabrics reinforced polyester – polyethylene terephthalate foam core sandwich panels

The object of this study is to investigate the influence of different fabrics’ configurations, of faced polyester-sisal fiber composites, on the mechanical behavior of a vacuum infused polyethylene terephthalate-foam core sandwich panel. Sisal-unidirectional (yarn and combed yarn fabrics) and plain weave fabrics were fabricated and the sandwiches’ performances were compared to faced polyester-unidirectional glass fabric. Comparisons about the morphological aspects and relations with mechanical behavior (flatwise and edgewise compression and 3-point bending) were performed. Different face sheets’ thickness was used for this purpose, aiming to correlate the results found for those sisal and glass sandwich panels. The main results showed that faced sisal fabrics/polyester present competitive performance and sometimes higher than those glass/polyester, due to differences on failure mechanisms of the panels.

Experimental Techniques to Obtain the Cross-Sectional Images of Textile Yarns.

In the fabric industry, textile yarns are the fundamental building blocks. Hence, visualizing and studying yarn structure is essential to understand the structure and behavior of the fibers. Obtaining the yarn’s cross-section images is crucial in the calculations of yarn’s porosity; furthermore, a more precise expansion for the fiber’s migration can be concluded from the cross-sectional images. In this paper, three different methods (microtome, micro-computed tomography, and epoxy grinding–polishing methods) to image and visualize the yarn’s cross-section are presented. The experimental techniques are compared in terms of result useability, time of preparation, and overall outcome of the cross-sectional image. The images can be used for fiber distribution, air gap calculation, and twist analysis as well. The fiber diameter distribution of polyester yarn was measured based on the images obtained by the three different methods; the average fiber diameter measured based on the combined data from the three different methods was found to be 10.90 ± 0.30 µm.

Electronic textiles for electrocardiogram monitoring: A review on the structure–property and performance evaluation from fiber to fabric

The development of electronic textiles used for wearable devices and systems for healthcare monitoring applications has experienced rapid growth in the last decade. Knowledge and understanding of the textile structural hierarchy, as well as the ability to define properties from the fiber and yarn to the fabric level are crucial to the selection of materials and design and performance of wearable systems. However, few studies have approached the selection of optimal e-textile structures with respect to material, electrical, and signal performance properties of sensors used for long-term biological signal monitoring. In this work, a review of e-textile structural properties (fiber, yarn, and fabric) for electrocardiogram (ECG) electrodes is presented, along with their relationship to performance properties including electrical, material, ECG signal quality, fabric hand (sensory perception and quality), and physiological comfort. Considerations and insights into the textile fiber and yarn morphology, electrode structure, design, and construction are outlined. In addition, relevant and upcoming standards for e-textile testing and performance evaluation are summarized. This work serves to organize requirements for ECG textile electrodes into a general reference framework from a bottom-up approach, which can better guide the material selection and design of ECG textile electrodes for wearable applications.

Structural and compressibility properties of weft-knitted rib fabrics from glass yarn

The structural and compressibility properties of the weft-knitted glass yarn fabrics from 1x1, 2x2, English, and fisherman rib architectures were investigated in this study. Due to their tight structures; 2x2 and fisherman rib fabric architectures exhibited higher loop density, and shorter loop length than 1x1 and English rib fabric architectures. English and fisherman rib fabric architectures displayed higher fiber volume fraction than 1x1 and 2x2 rib architectures in multi-layer compaction and recovery tests where the pressure was varied between 2 and 200 kPa. Number of layer increased the fiber content that pointed the nesting between the fabric layers. As a result of lack of complete recovery from compression; the fabrics exhibited lower thicknesses (i.e. higher fiber volume fractions) during the recovery periods than they did during the compression periods. A second order polynomial regression model with 0,89 R2 (coefficient of determination) was developed to estimate the fiber volume fraction by means of knit architecture, number of fabric layers, pressure, and measurement period.

Yarn porosity and its relationship with the dyeing behavior

PurposePorosity is one of the most important properties of the textile substrate. It can influence the comfort of a garment by affecting its breathability and thermal conductivity. During the process of dyeing, the dye liquor comes in contact with the substrate; the absorption of the dye liquor into the substrate will be dependent on its porosity. The concept of porosity between the yarns of fabric is a common phenomenon; however, the porosity between the fibres in the yarn can also influence the dyeing behaviour of the fabric.Design/methodology/approachIn this research, ring and rotor yarns of 25/s and 30/s counts are considered as textile substrates. The porosity of yarns was determined theoretically and experimentally using the image analysis method.FindingsIt was found that theoretical porosity is independent of the yarn manufacturing method. In addition, 30/s yarn was more porous as compared with 25/s yarn having a higher pore area. Rotor yarns had higher porosity, dye fixation and K/S as compared with ring yarns. Dyeing behaviour was also dependent on the count of yarn. Specifically, 30/s yarns have higher dye fixation as compared with 25/s yarns. However, 25/s yarns were dyed with deeper shades showing higher K/S values. Also, 25/s yarns are coarser than 30/s yarns having higher diameters and cross-sectional area, thus resulting in deeper shades and higher K/S values.Originality/valueThis novel technique is based on the comparative study of the porosity of various types of yarns using the image analysis technique. This investigation shows that the porosity between the fibres in the yarn can also influence the dyeing behaviour of the yarn.

Simulation of Mechanical Behaviour of Woven Fabrics at the Scale of Yarns under Multi-Loading

The mechanical behaviour of textile structures is one of their most important characteristics as far as their end use is concerned. Textile structures, fabrics, or yarns are often considered as continuous mediums apart from the fact that they are composed of some discrete elements, individual fibres composing yarns and yarns composing fabrics. This is known as the transition scale, a very important lock to be considered, to evaluate the real structure behaviour. In this context, this work presents some simulations of the mechanical behaviour of a fabric where the yarn is a continuum material. Particular attention was paid to simultaneous loading in uniaxial or biaxial extension and shear loadings. The results of numerical simulations, which show the deformed fabric unit cell under multi-load conditions, are coherent with experimental observations and encourage the authors to continue the present work with parametrical and inverse case studies.

Color difference of yarn-dyed fabrics woven from warp and weft yarns in different color depths

PurposeThis paper aims to determine the most practically applicable color-difference formula for yarn-dyed fabrics woven from warp and weft yarns in different color depths and to establish color-difference tolerance for perceptibility by evaluating yarn-dyed fabrics visually and instrumentally.Design/methodology/approachA total of 108 sample pairs were evaluated by a panel of 13 observers with perceptibility method under three typical light sources (A, D65 and cool white fluorescent). The data sets were statistically analyzed by the homogeneity of variance test (F-test), analysis of variance, standardized residual sum of squares and performance factor/3.FindingsLight sources had a slight influence on the visual assessments of yarn-dyed fabrics. Among the eight color-difference formulae for measurements of yarn-dyed fabrics, CIEDE2000(2:1:1) outperformed all other tested formulae, and the color tolerance for the perceptibility of CIEDE2000(2:1:1) was 0.62. When the homochromy index (K) of warp and weft yarns of yarn-dyed fabric was lower than 1.25, the color difference based on ΔE*00(2:1:1) between the two samples was acceptable in terms of the color tolerance for perceptibility (i.e. 0.62).Practical implicationsThe warp and weft yarns in different color depths could be woven in fabric with a relatively uniform color appearance.Originality/valueThis study could contribute to cost savings by reusing disqualified dyed yarns during the weaving manufacturing process.

Fabrication of a Flexible Aqueous Textile Zinc-Ion Battery in a Single Fabric Layer

Zinc-ion batteries (ZIB), with various manganese oxide-based cathodes, provide a promising solution for textile-based flexible energy storage devices. This paper demonstrates, for the first time, a flexible aqueous ZIB with manganese-based cathode fabricated in a single woven polyester cotton textile. The textile was functionalized with a flexible polymer membrane layer that fills the gaps between textile yarns, enabling fine control over the depth of penetration of the spray deposited manganese oxide cathode and zinc anode. This leaves an uncoated region in the textile-polymer network that acts as the battery’s separator. The textile battery cell was vacuum impregnated with the aqueous electrolyte, achieving good wettability of the electrodes with the electrolyte. Additionally, the choice of cathodic material and its influence over the electrochemical performance of the zinc ion battery was investigated with commercially available Manganese (IV) oxide and Manganese (II, III) oxide. The textile ZIB with Manganese (II, III) oxide cathode (10.9 mAh g−1 or 35.6 µA h.cm−2) achieved better performance than the textile ZIB with Manganese (IV) oxide (8.95 mAh g−1 or 24.2 µAh cm−2) at 1 mA cm−2 (0.3 A g−1). This work presents a novel all-textile battery architecture and demonstrates the capability of using manganese oxides as cathodes for a full textile-based flexible aqueous ZIB.

Science and Business Developments

Science and Business Developments

The matching relation analysis of yarn pre-tension in weaving 3D bi-directional angle-interlock fabrics

Yarn pre-tension is an important technological parameter in the weaving process and significantly affects the geometry and properties of woven composites. 3D bi-directional angle-interlock (3DBA) fabrics have the same yarn crimp in the warp and weft directions, which requires a special matching relationship between the warp and weft yarn tensions applied in the weaving process. This study focused on obtaining the pre-tension matching relationship that applied between the warp and weft yarns in the weaving of 3DBA fabrics. A quasi-static mechanical model of yarn interactions in the weaving of 3DBA fabrics was developed based on the 2D woven fabric yarn interaction model. The weaving process of 3DBA fabrics could be divided into two interweaves as one cycle. In a given interweaving of a single group of yarns, the pre-tension applied to the warp yarns tends to increase irregularly with the position of the interweaving point and varies linearly with the weft pre-tension. The weft crimps distribution of 3DBA fabrics was compared when yarns were applied to the different proportions of pre-tension in the weaving process. The experiment result shows that the sample with the best uniform distribution of yarn geometry is the one to which the yarn pre-tension calculated by the model is applied in the weaving process. The result provides theoretical support for warp and weft pre-tension applied in the 3DBA fabrics weaving process.

Fabric-Reinforced Cementitious Matrix (FRCM) Carbon Yarns with Different Surface Treatments Embedded in a Cementitious Mortar: Mechanical and Durability Studies.

Nowadays, FRCM systems are increasingly used for the strengthening and retrofitting of existing masonry and reinforced concrete structures. Their effectiveness strongly depends on the bond that develops at the interface between multifilament yarns, which constitute the reinforcing fabric, and the inorganic matrix. It is well known that fabric yarns, especially when constituted by dry carbon fibers, have poor chemical-physical compatibility with inorganic matrices. For this reason, many efforts are being concentrated on trying to improve the interface compatibility by using different surface treatments on multifilament yarns. In this paper, three different surface treatments have been considered. The first two involve yarn pre-impregnation with flexible epoxy resin or nano-silica coating, while the third one involves a fiber oxidation process. Uniaxial tensile tests were carried out on single carbon yarns to evaluate tensile strength, elastic modulus and ultimate strain before and after surface treatments, and also after yarn exposure to accelerated artificial aging conditions (1000 h in saline or alkaline solutions at 40 °C), to evaluate their long-term behavior in aggressive environments. Pull-out tests on single carbon yarns embedded in a cementitious mortar were also carried out, under normal environmental conditions and after artificial exposure. Epoxy proved to be the most effective treatment, by increasing the yarn tensile strength of 34% and the pull-out load of 138%, followed by nano-silica (+9%; +40%). All surface treatments were shown to remain effective even after artificial environmental exposures, with a maximum reduction of yarn tensile strength of about 13%.

Experimental Evaluation of Carbon Reinforced TRC with Cement Suspension Matrix at Elevated Temperature.

Textile-reinforced concrete (TRC) is a new composite material comprising high-performance concrete and textile reinforcement from textile yarns with a matrix, usually consisting of epoxy resins (ER). The most significant advantage of ER is the homogenization of all filaments in the yarn and full utilization of its tensile potential. Nevertheless, ER matrix is a critical part of TRC design from the perspective of the fire resistance due to its relatively low resistance at temperatures of approximately 120 °C. This work expands the previously performed mechanical tests at normal temperatures with cement suspension (CS) as a non-combustible material for the yarn matrix. Here, the mechanical properties of CS matrix at elevated temperatures were verified. It was found that the addition of polypropylene fibers into HPC negatively affected the mechanical results of CS matrix specimens. Simultaneously, thermal insulation effect of the covering layers with different thicknesses did not significantly influence the residual bending strength of specimens with CS matrix and achieved similar results as reference specimens. Furthermore, all specimens with ER matrix progressively collapsed. Finally, CS as a textile reinforcement of yarn matrix appears to be a suitable solution for increasing the temperature resistance of TRC structures and for substituting synthetic resins.

Preparation and Characterization of Natural Silk Fibroin Hydrogel for Protein Drug Delivery.

In recent years, hydrogels have been widely used as drug carriers, especially in the area of protein delivery. The natural silk fibroin produced from cocoons of the Bombyx mori silkworm possesses excellent biocompatibility, significant bioactivity, and biodegradability. Therefore, silk fibroin-based hydrogels are arousing widespread interest in biomedical research. In this study, a process for extracting natural silk fibroin from raw silk textile yarns was established, and three aqueous solutions of silk fibroin with different molecular weight distributions were successfully prepared by controlling the degumming time. Silk fibroin was dispersed in the aqueous solution as “spherical” aggregate particles, and the smaller particles continuously accumulated into large particles. Finally, a silk fibroin hydrogel network was formed. A rheological analysis showed that as the concentration of the silk fibroin hydrogel increased its storage modulus increased significantly. The degradation behavior of silk fibroin hydrogel in different media verified its excellent stability, and the prepared silk fibroin hydrogel had good biocompatibility and an excellent drug-loading capacity. After the protein model drug BSA was loaded, the cumulative drug release within 12 h reached 80%. We hope that these investigations will promote the potential utilities of silk fibroin hydrogels in clinical medicine.

Flax Noils as a Source of Cellulose for the Production of Lyocell Fibers

The production of long flax fiber for the subsequent production of textile yarn is accompanied by the formation of a significant amount of waste—noils, which is a mechanical mixture of long and short flax fibers and shives. Comparative studies of the structure and chemical composition of the fibrous fraction of noils and shives were carried out using IR spectroscopy. The solubility of shives and flax noils in N-methylmorpholine-N-oxide (NMMO) was studied, a comparative analysis of the rheological behavior of solutions of flax and wood cellulose was carried out and the optimal temperature–concentration conditions for obtaining flax fibers from noils were determined. It was shown for the first time that using the method of solid-phase activation of the cellulose-solvent system makes it possible to obtain fibers in a short period of time (no more than 10 min). The structure of both the raw material and the resulting fibers was studied by X-ray diffraction analysis. The thermal properties of a new type of cellulose fibers was evaluated. The complex of the conducted studies allows us to consider flax fibers from noils along with flax fibers from long-staple flax, as a real alternative to fibers from wood pulp.

Material and Structural Functionalization of Knitted Fabrics for Sportswear.

Comfort is an important quality criterion, especially for sportswear. It influences well-being, performance and efficiency. The necessary dissipation of heat and air flow, at high metabolic rates, must be designed and planned in advance. The influence of structure, density, mass and thickness of fabric were considered as well as yarn material composition, yarn linear density, yarn evenness and yarn hairiness. The influence of the mentioned parameters on thermal properties and air permeability was calculated. From the correlation analysis, it can be concluded that yarn’s linear density, yarn short fibers hairiness, and mass per unit area of knitted fabric has the greatest impact on heat resistance. The yarn linear density, the yarn hairiness of the longer protruding fibers, and the thickness of the knitted fabric have the greatest impact on air permeability. A statistically significant model of multiple linear regression equations was offered to predict the thermal comfort of knitted fabric.

Finite element modelling and experimentation of plain weave glass/epoxy composites under high strain-rate compression loading for estimation of Johnson-Cook model parameters

Split Hopkinson pressure bar (SHPB) is a widely used experimental technique for testing materials at a high strain-rate. SHPB testing of fiber-reinforced polymer (FRP) composite samples have become common in recent decades. Specimen geometry is one of the essential parameters that can ease sample fabrication and help in-situ analysis when altered as per convenience. Further, developing a computationally accurate model would reduce the need for multiple experimental iterations, thus saving cost and time. As part of the current study, high strain-rate tests using a compressive SHPB setup were conducted on glass/epoxy (GE) laminated composite samples of both square prismatic and cylindrical shape along the through-thickness direction experimentally. Negligible differences were observed due to the change in specimen geometry. Further, we know that the woven fabric consists of yarns, which are a bundle of fibers. The strain-rate dependency of the epoxy's material property is well known, but very limited information is available about the strain-rate dependency of yarn's properties. The effect of strain-rate dependency of the yarn was analysed numerically on Abaqus software using a square prismatic shaped yarn-level finite element composite model. The homogenised properties of the yarn were taken to be reflective of a high fiber volume fraction composite. The bulk epoxy's and yarn's material property were defined using the Johnson-Cook (JC) constitutive model, and the failure mechanism was defined using the JC damage model. One of the primary reasons for using this model is its availability and ease of implementation in almost every finite element analysis (FEA) simulation software. Three cases were analysed numerically, first keeping both yarn and bulk matrix property strain-rate dependent, second keeping the strain-rate dependency only in the bulk matrix, and in third case both yarn and matrix were kept strain-rate independent. It was observed that completely strain-rate dependent model showed comparable peak stress and strain values with the experimental result than other models.

Development of Stainless Steel Yarn with Embedded Surface Mounted Light Emitting Diodes.

The integration of electronic components in/onto conductive textile yarns without compromising textile qualities such as flexibility, conformability, heat and moisture transfer, and wash resistance is essential to ensuring acceptance of electronic textiles. One solution is creating flexible and stretchable conductive yarns that contain tiny surface-mounted electronic elements embedded at the fiber level. The purpose of this work was to manufacture and subsequently evaluate the physical features and electromechanical properties of stainless steel yarn with light-emitting surface mounted devices (SMDs) embedded in it. The SMDs were successfully integrated into a conductive stainless steel yarn (SS) by inserting crimp beads and creating a bond through hot air soldering machines, resulting in what we call an E-yarn. The relationship curves between gauge length and electrical resistance, and the relationship curves between conductive yarn elongation and electrical resistance, were explored experimentally. The results of the analysis demonstrated that E-yarn had a lower tensile strength than the original electrically-conductive SS yarn. The effects of the washing cycle on the conductivity of the E-yarn were also investigated and studied. The results showed that E-yarns encapsulated at the solder pad by heat shrink tube still functioned well after ten machine wash cycles, after which they degraded greatly.

Study of the effect of temperature and relaxation time on the force‐strain characteristics of textile yarns upon tensile loading

AbstractThe textile materials can be used in many technical applications in various fields, such as automotive. Depending on the application areas, the textile or fiber‐based materials have to meet certain predetermined requirements. Textile yarns can be used as reinforcing cords in composites in which an elastomeric matrix is used. The basic mechanical tensile test at standard temperature does not provide all the information required for obtaining the material parameters. The tests are also necessary to be performed at reduced temperatures, depending on the following application. Furthermore, it is necessary to consider stress relaxation in specific tests for the practical use. In this work, there is the experimental investigation of the effect of the selected temperatures (20 °C and 120 °C) and the relaxation times (60 s and 120 s) on the mechanical properties of the selected textile yarns from polyamide 6.6 under the uniaxial tensile tests. The results reveal that the relaxation time for the first 20 seconds is interesting because there is a significant decrease in the force while holding the strain. A final method is proposed, and it can be used for any other applications, and it guarantees the repeatability of measurements in the relatively fast measured time.