Multifilament Yarns Research Articles

Influence of yarn geometry on electrical properties of silver-coated nylon filaments for e-textiles: a fundamental study

Conductive fibrous assemblies and yarns play a crucial role in wearable electronic textiles (e-textiles), through their use in flexible sensors and interconnects. This study investigated the influence of yarn twist and geometrical parameters on the electrical properties of silver-coated nylon multifilament yarns, ranging from 1-ply to 4-ply, with twist levels of 30 twists per meter (TPM) and up to 600 TPM. Increase in twist level resulted in decreasing yarn linear resistance, with a plateau at 300 TPM, along with limiting values for yarn specific volume (1.6-1.9 cc/g), and fibre orientation angle (12-18°). The increase in yarn conductivity with higher twist was explained by greater contact between the fibrous assembly, that bridges electrically conductive pathways in the yarn structure. Twisted yarns (2-ply) were fabricated into electrode structures via embroidery, and a progressive increase in contact impedance was observed, followed by a stabilization and plateau within the range of measured impedance from 210 to 300 TPM. This observation was attributed to the decrease in the yarn specific volume, and subsequently the longitudinal diameter with increasing twist level, which decreased the contact area between the skin and electrode interface. The electrodes fabricated from varying yarn twist levels were used for electrocardiogram (ECG) measurement, and demonstrated comparable signal quality to standard gel electrodes. This experimental and theoretical work forms the basis in defining relationships between established yarn twist mechanics and geometrical properties with electrical properties. This can guide materials and design parameter selection of suitable conductive yarns for e-textiles used in biopotential monitoring applications.

Dissolution of viscose rayon multifilament yarn in the ionic liquid 1-ethyl-3-methylimidazolium acetate studied using time–temperature superposition

AbstractWide-angle X-ray diffraction (WAXS) and mechanical testing techniques are used to track the dissolution of a viscose rayon multifilament yarn in the ionic liquid 1-ethyl-3-methyl-imidazolium acetate [C2mim]+ [OAc]− for different times and temperatures. In the dissolution process, the oriented cellulose II crystals in the regenerated cellulose fibres dissolve and then reform into randomly oriented crystals to form a matrix phase, and this change in orientation enables us to follow the dissolution process using WAXS, and hence determine the dissolved matrix volume fraction $${v}_{m}$$ v m . The change in the average molecular orientation $${P}_{2}$$ P 2 determined from an azimuthal $$(\alpha$$ ( α ) X-ray scan, allows the growth of the matrix volume fraction $${v}_{m}$$ v m to be calculated with time and temperature. The growth of $${v}_{m}$$ v m was found to follow time temperature superposition, with an Arrhenius behaviour, giving a value for the activation energy of Ea = 149 ± 4 kJ/mol. Young’s modulus was measured on all the resulting processed composites. The fall of Young’s modulus with dissolution time and temperature was also found to follow time–temperature superposition, with an Arrhenius behaviour giving a value for Ea = 198 ± 29 kJ/mol. The Young’s Modulus results plotted against $${v}_{m}$$ v m determined from the WAXS measurements fitted well to the Voigt upper bound parallel Rule of Mixtures $$.$$ .

The Effect of Accelerated Aging on the Molecular Weight and Thermal and Mechanical Properties of Polyester Yarns Containing Ceramic Particles

The accelerated aging of polyethylene terephthalate (PET) multifilament yarns containing nano or microparticles of titanium dioxide (TiO2), silicon carbide (SiC), or fluorite (CaF2) at a maximum percentage of 2% has been studied. For this, the yarn samples were introduced into a climatic chamber at 50 °C, 50% relative humidity, and an ultraviolet A (UVA) irradiance of 1.4 W/m2. They were then removed from the chamber after periods of between 21 and 170 days of exposure. Subsequently, the variation in weight average molecular weight, number molecular weight, and polydispersity was evaluated by gel permeation chromatography (GPC), the surface appearance was evaluated using scanning electron microscopy (SEM), the thermal properties were evaluated using differential scanning calorimetry (DSC), and the mechanical properties were evaluated using dynamometry. The results showed that, at the test conditions, there was degradation in all of the exposed substrates, possibly due to the excision of the chains that make up the polymeric matrix, which resulted in the variation in the mechanical and thermal properties depending on the type and size of the particle used. This study provides insight into the evolution of the properties of PET-based nano- and microcomposites and might be helpful when selecting materials for specific applications, which is of great interest from an industrial point of view.

Stretchable Woven Fabric-Based Triboelectric Nanogenerator for Energy Harvesting and Self-Powered Sensing

With the triboelectric nanogenerator developing in recent years, it has gradually become a promising alternative to fossil energy and batteries. Its rapid advancements also promote the combination of triboelectric nanogenerators and textiles. However, the limited stretchability of fabric-based triboelectric nanogenerators hindered their development in wearable electronic devices. Here, in combination with the polyamide (PA) conductive yarn, polyester multifilament, and polyurethane yarn, a highly stretchable woven fabric-based triboelectric nanogenerator (SWF-TENG) with the three elementary weaves is developed. Different from the normal woven fabric without elasticity, the loom tension of the elastic warp yarn is much larger than non-elastic warp yarn in the weaving process, which results in the high elasticity of the woven fabric coming from the loom. Based on the unique and creative woven method, SWF-TENGs are qualified with excellent stretchability (up to 300%), flexibility, comfortability, and excellent mechanical stability. It also exhibits good sensitivity and fast responsibility to the external tensile strain, which can be used as a bend-stretch sensor to detect and identify human gait. Its collected power under pressure mode is capable of lighting up 34 light-emitting diodes (LEDs) by only hand-tapping the fabric. SWF-TENG can be mass-manufactured by using the weaving machine, which decreases fabricating costs and accelerates industrialization. Based on these merits, this work provides a promising direction toward stretchable fabric-based TENGs with wide applications in wearable electronics, including energy harvesting and self-powered sensing.

Prediction of air permeability and effective thermal conductivity of multifilament polyester yarn by finite element analysis

The effective thermal conductivity and air permeability of a multifilament polyester yarn used in sports T-shirts was investigated by computer modeling using finite element analysis. It has been shown that the number of fibers, the porosity of the yarn and the proportion of fibers in the volume fraction of the yarn have a direct effect on the effective thermal conductivity and air permeability of the multifilament yarn. It was found that with the increase in the number of fibers, the porosity of the yarn decreases linearly, while the volume fraction of the fibers increases, and thus the effective thermal conductivity increases. In addition, air permeability decreases exponentially.

Low-bagging (growth) stretch denim yarn production by spinning optimization of cotton-wrapped dual-core elastane and T400 multifilament

Cotton-wrapped elastane core yarns have been widely used in producing stretch denim fabrics due to their comfortable stretching and recovery, but they suffer from undesirable fabric growth under prolonged or repeated stress. To reduce that problem, an additional semi-elastic multifilament has been incorporated with the elastane core, called dual-core yarn. Herein, it was intended to produce well-engineered dual-core yarns possessing high elasticity with low bagging. Twenty types of cotton-wrapped elastane/T400 multifilament dual-core yarns with different combinations of elastane and T400 tension draft were produced on industrial scale in a spinning mill. Structural parameters, tensile properties and elastic recovery behavior under cyclic loading of the yarns were thoroughly studied. For an optimum combination of elastane/T400 draft, the dual-core yarn attained excellent tenacity and elongation with significantly low evenness, imperfections and hairiness values. More importantly, the results of the cyclic loading study explicitly revealed a remarkable reduction in plastic deformation and stress decay indicating low growth and high resilience of yarn after deformation. The dual-core yarn containing high strength, high elongation and low growth obtained here can have durable stretch jeans with high body movement comfort and long-lasting shape retention.

PROPERTIES OF PARACHUTE FABRICS FROM POLYAMIDE AND POLYESTER MATERIALS

Traditional parachute fabrics are composed from PA 66 (nylon type) multifilament yarns. They are resistant against high frequency repeat deformation but they are able to absorb water which is not optimal for use in different climatic conditions. Challenge is to create parachute fabrics made of PES multifilament yarns which are more versatile. Main aim of this work is to investigate influence of parachute fabric composition and construction characteristics on real end use properties. The relationships based on the prediction of bulk densities were used to calculate the volume porosity. The morphology of the parachute fabrics was evaluated using scanning electron microscopy. Mechanical and dynamic mechanical properties of parachute fabric Ortex made from multifilament PA 66 and PES yarns by Sky Paragliders company are compared.

C2C12 HÜCRELERİ KULLANILARAK MİYOKARDİYAL DOKU MÜHENDİSLİĞİ İÇİN ÖRME HAVLU KUMAŞ İSKELENİN IN VITRO DEĞERLENDİRİLMESİ

Pile loop knitted scaffold has attracted attention for being used as a three dimensional (3D) biocompatible material particularly for the application of myocardial tissue engineering. In this research, nonintermingled, textured polyethylene terephthalate (PET) multifilament yarn with a filament count of 48 was used for producing a pile loop knit structure to investigate if structure could provide an appropriate microenvironment for the seeded murine C2C12 myoblasts in case of increasing in filament diameter (20.7 micron versus 9.1 micron from the previous study). The resulting structure had a pore network mainly consisting of macropores of 100-200 µm that were well interconnected with micropores (<90 µm). Furthermore, the mean values of the Young’s modulus of the structures at 20% strain were 240.67 kPa in the warp direction, and 85.73 kPa in the weft direction, which can be claimed not to be far from those declared in the literature for the human heart muscle. In addition, the cyclic loading-unloading test revealed no creep in the fabric after 100 cycles. According to the results of the WST-1 assay, the 48 filament-based scaffold was non-cytotoxic for C2C12 cells that were able to proliferate properly on the scaffold, which was visualized by SEM and confocal images. In this respect, pile loop knit structures keep promising results for being used as a cardiac patch.

Automatic Modeller of Textile Yarns at Fibre Level.

This paper presents a geometrical modelling principle for the modelling of yarns at the fibre level. The woven and the knitted textile structures are built of yarns, which on the other side, are fibrous assemblies. In many yarn and fabric modelling works, yarns are considered as a single line element; however, most yarns are composed of a number of staple or filament fibres. It is then very important to understand the yarn at the micro level for a better understanding, production and application of the above structures. The current paper aims to present the modelling and implementation of yarn structures at the fibre level using the algorithmic geometrical modelling principle. The research work uses basic assumptions for the building of the models and various implementation issues, connected with the proper representation of the single multi-filament yarns, plied yarns and finally the staple fibre yarns. Except for visualization, the generated yarn models are prepared as a basis for mechanical, thermal, fluid flow and other simulations of textile structures using FEM, CFD and other numerical tools.

Effect of Colorants and Process Parameters on the Properties of Dope-Dyed Polylactic Acid Multifilament Yarns.

The color of textile fibers is typically imparted by submersion in a high-temperature dye bath. However, the treatment of the effluent is challenging and the textile industry is therefore a major source of water pollution. Current fashion trends favor biobased polymers such as polylactic acid (PLA) but exhaust dyeing at high temperatures causes hydrolytic degradation, reducing the crystallinity and tenacity of the yarn. To preserve the mechanical properties of PLA-based textiles, an alternative to exhaust dyeing called dope dyeing can be used, wherein colorants are incorporated into the polymer matrix during melt spinning. We evaluated this process by dope dyeing PLA with several colorants, then testing the thermal, physical, and mechanical properties of the yarn and the physical properties of circular-knitted fabrics. Although the colorants affected the crystallization behavior at lower cooling rates, during the melt-spinning process, the drawing speed had a greater effect on the crystallinity and mechanical properties of the dyed yarn. Scanning electron microscopy revealed that the colorants were well dispersed in the PLA matrix. We found that the colorants did not affect the physical properties of the knitted fabric. Our results can be used to develop more environmentally beneficial dope-dyed PLA yarn with improved mechanical properties.

The Production and Physical Characterization of Polybutylene Succinate Multifilament Yarns

There are significant problems in the production, use and waste management of petroleum-based polymers due to the increasing plastic waste problem, exceeding limit of the greenhouse gas emissions and decreasing fossil resources. The textile sector is the second sector that causes the plastic waste problem after the packaging sector. About 65% of the total yarn produced in the textile industry consists of yarns obtained from petroleum-based polymers. Biopolymers come to the fore in studies carried out within the scope of sustainability philosophies such as using of renewable raw materials, recycling at the end of their life and decomposition without harming the nature. In this study, it is aimed to produce biobased and biodegradable polybutylene succinate (PBS) polymer into multifilament yarn by melt spinning method and examine the effect of different winder speeds on the textile values of PBS yarns. In this context, multifilament yarns with round cross-sections were produced at 4 various winder speeds. The linear density, elongation (at Fmax) and tenacity of the produced yarns were obtained by performing analyzes, and also cross-sectional images of the filaments were also taken. The results suggested that the elongation (at Fmax) and dtex values decrease, and the tenacity value increases due to increasing winder speed. Additionally, the cross-section properties of the PBS multifilament yarn are smooth round sections and that the filaments in a yarn have similar diameters to each other.

Thermal Resistance of Gray Modal and Micromodal Socks

Abstract Men's socks were produced on a Lonati circular knitting machine in 18 different combinations in multi-plated plain jersey from basic modal and basic micro modal yarn with the addition of cotton or PA multifilament yarn and elastane yarn in the sock cuff. The modal and micromodal yarns were ring-spun, rotor-spun and air-spun; they consist of 38 mm long staple fibres with a fineness of 1.3 and 1.0 dtex respectively. Thermal resistance was determined by use of the thermal foot. The thermal resistance values for all socks samples range from 0.0091 to 0.01586 m2 °C W−1. The highest thermal resistance per groups of basic modal fibres was obtained in the samples made of air-jet spun yarn of 0.0132 m2 °C W−1 and the lowest in samples of rotor yarn of 0.0109 m2 °C W−1. The highest thermal resistance in all groups of basic micromodal samples made of ring yarn (0.0132 m2 °C W−1) and the lowest in the samples made of air-spun yarn (0.0099 m2 °C W−1). At low levels of thermal resistance, as the thickness of the sample of basic modal and micro modal fibres of ring and rotor yarns increases, the thermal resistance of socks increases with a correlation coefficient of 0.711. The tested sock samples have low thermal resistance, i.e. they can conduct heat better than the sock leg, thus achieving cooling and comfort, which is important for wearing socks in warm weather.

Influence of polyester fabric with infrared emissive additives on cell metabolism

Functional fabrics with effects of influencing the metabolism and energy supplying are of great interest and may extensively be applied in wellness and sport apparel. In this work, three different combinations of additives such as silicon oxide doped with 10% of iron oxide III, 10% of graphene and 10% calcium hydroxyapatite were prepared, each combination was compounded separately with polyester, and pellets were extruded with additive weight around 4%. Melt spun multifilament yarns (130D/48f) were produced from the prepared pellets. Further, three knitted fabrics from a yarn with additives and one control fabric from the yarn without additives were developed for comparison and analysis. Infrared emissivity test result showed that fabrics with functional additives have significantly higher effective emissivity (0.997 to 1.006) than the reference fabric (0.909) for wavelength 5-14 µm. Moreover, spectral emissivity of fabrics with additives are relatively high at peak human IR emission wavelength (8-14 µm). As a key signal molecule that is involved in certain physiological pathways, nitric oxide (NO) generation was assessed by co-culturing with human skeletal muscle cells (HMSCs). It is observed that selected additives in the fabric lead to 15%-40% increase of nitrite levels in muscle cells after 24 and 72 hours of exposure and the best among them were graphene containing additives. Besides, it is also discovered that additives in the fabric increase mitochondrial biogenesis, which is proved by the increase of mitochondrial copy number by a factor of 1.25. The mitochondrial biogenesis may be a possible pathway activated by nitric oxide and potentially accelerate the energy expenditure. The observations in the cell study indicated the potential biological effects of the fabric with selected functional additives.

Investigation of deformation properties of textured multifilament PES yarns

In the process of texturing, smooth filaments are formed into crimpy yarns. By combining thermal and mechanical action, thermoplastic fibres acquire a permanent wavy shape. Since textured multifilament yarns, formed from POY PES filaments, produced on machines with high-temperature heaters, are insufficiently studied, this paper analyses the deformation characteristics of yarns produced in industrial conditions using different process parameters (primary heater temperature, yarn speed, yarn stretching, peripheral speed of friction discs). Special attention is paid to the characteristics at the elastic limit, then at the creep limit, yield and breaking of multifilament textured yarns. A method is proposed which can determine the key points of deformation in the process of stretching textured polyester multifilament yarn, as well as the relationship between the values of force and elongation at the limits of elasticity, creep, end of creep zone, yield and break

New insight into the flexural rigidity of multi-filament yarn

Filament yarn is one of the most widely used soft strands in the textile industry; it exhibits excellent flexibility and is capable of being used in various productions, including knitting, weaving, braiding, sewing, and embroidery. The inherent complex interlacement between fibers, including twist, entanglement, and yarn geometry, often exhibits a nonlinear response to external loads. In addition, the interlacement of fibers also introduces difficulties when accurately measuring the flexural property of multi-filament yarn. In particular, the flexural rigidity of the yarn strongly influences the quality of end products when incorporated into novel textile technologies. In this paper, we developed a three-point bending instrument and a method for measuring the flexural rigidity of filament yarn. A representative point obeyed from Coplan’s construction on the bending constitutive curve was determined to obtain pure flexural rigidity. Furthermore, the bending process and deformations across cross-sections of filament yarns were discussed. The research provides new physical insights into the yarn bending property with the consideration of eliminating the sub-deformation variabilities. The work also paves the way for the accurate and quick measurement of the flexural rigidity of high length-to-width ratio soft materials by a three-point bending method.

Investigation of quasi-static punching penetration behavior of Kevlar plain-woven fabric

Punching resistance properties of the fabric are vital for several applications such as slash-resistant clothing. In this paper, the penetration of a puncher through a plain Kevlar woven fabric was analyzed to recognize the process of punching and the mechanism of yarn breakage. The model focused on the study of the difference between fabric that is woven from the continuous multifilament yarn or the spun yarn and the effects of their yarn structure on punching resistance. The relation between the warp and weft yarns and the punching resistance force of the fabric at different punching speeds was investigated. This work focused on the potentiality to use fabric from coarse Kevlar spun yarns instead of continuous filament yarns to enhance the punching resistance. Samples of fabrics were tested on a specially designed set-up to investigate the behaviour of warp and weft yarns under punching load. A basic understanding of the damage to the fabric under punching has been developed. The ANOVA analysis of the specific punching force and energy shows that the fabric types have a significant effect on the specific punching force and energy. The use of the fabrics from spun yarns increased specific punching force by 145% while the specific punching energy was elevated by 210% in comparison to fabrics from continuous filament yarns. The current study opens a new research road to the application of Kevlar spun fabric from spun yarns.

Investigation of the influence of high molecular weight polyethylene and basalt content used in three-dimensional weft-knitted fabrics on the mechanical risks

This study investigates the resistance of three-dimensional (3D) weft-knitted fabrics to mechanical risks in order to determine the impact of the percentage content of raw materials in the knits on mechanical loads. For this purpose, 3D weft-knitted fabrics, consisting of a front side, binding, and back side layers, were designed and produced on an E20 circular weft-knitting machine using organic multifilament yarns (high molecular weight polyethylene, HMWPE) and inorganic multifilament (basalt, BS) yarns for the front and back side layers and conventional polyamide yarns for the binding layer. The cut, puncture, abrasion, and tear resistance tests were performed to assess the resistance of 3D weft-knitted fabrics to mechanical risks. According to the testing results, basalt in the structure of 3D weft-knitted fabrics significantly increases the cut resistance, even in cases of a small basalt content in the knit. The puncture, abrasion, and tear resistance testing results showed that the highest HMWPE percentage content in the knitted structure provided the highest resistance to these risks, while increasing the basalt content in the knit did not improve the resistance testing results. Based on the testing results and the assessment of the protection levels provided by the knitted fabrics, the conclusion can be made that the use of HMWPE multifilament yarns and basalt multifilament yarns in the structure of 3D weft-knitted fabrics contributes to the achievement of the highest levels of performance. All the designed 3D weft-knitted fabrics provide complex protection against different mechanical risks (cut, puncture, abrasion, tear). The tests performed may be useful for further development of knitted fabrics designed to provide protection against mechanical risks.

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%.

Research of textile logarithmic-aperiodic antennas with a matching circuit for textronics applications

The antenna is the basic element of radio communication systems. Its proper design allows for a sufficiently wide transmission range and quality of data transmission. Most known communication systems operate in a certain frequency range and dipole antennas only work at one frequency of resonance, therefore log-aperiodic antennas are built for covering a wide bandwidth. In a typical configuration, such antennas are made of metal rods; however, in textronics garment applications a flat structure integrated with the textiles is necessary. This article presents the construction and research of a flat antenna entirely made with textile materials and with the use of technologies. Embroidery technology was proposed for the prototyping of antennas for all three communication technologies. Polyester multifilament yarns with a silver top layer were used in the research. A textile impedance matching circuit for the antenna was also built with the use of textile technology. The antennas were designed for the Global System for Mobile Communications, Global Positioning System and WiFi systems, because such wireless technologies have been used in the prototype system for transmitting measurement data of human physiological signals in textronics clothing. Wearable antennas are a part of a device that ensures continuous health monitoring of an elderly person or a patient without hindering his day-to-day activities. The construction of this system was the subject of a project financed by the National Centre for Research and Development in Poland. The design stage was presented along with the method of connecting the antenna with the transmitter. The repeatability of the antenna parameters was also analyzed and a textile impedance matching circuit was presented. In this article, the author focused on checking the quality and repeatability of electrical and geometric parameters of textile antennas for various types of transmission, including connections in constant environmental conditions.

An insight into enhancing the physical properties of poly(lactic acid) (D600) fibers

The most applicable polymer in different applications is poly(lactic acid) (PLA) due its merits. This polymer attracts great interest as an environmentally friendly bioplastic polymer. The main goal of this work is to enhance the different physical properties of PLA. The melt-spun process was used to produce a continuous multifilament yarns of PLA textile fibers. The mechanical properties (tensile properties) of PLA(D600) filaments were studied. The tensile modulus and the maximum tensile strength were 3 and 0.4 GPa, respectively. The effect of the cold-drawing process on some physical properties, such as the melting temperature, glass transition temperature, crystallinity, birefringence, and orientation factor, were measured. The crystallinity values changed as the draw ratio increased, confirming the reorientations and chain packing. From the obtained results of the different physical properties, it was concluded that the drawing process has a great effect on performance of PLA fibers.