Yarn Twist Research Articles

Large-torque and fast-response electrothermal-motivated liquid crystal elastomer twisted yarn actuators

Analogous to biological muscles, twisted yarns with the capacity to output torsional torque and reversible rotation are of significant value in the development of soft robotic systems. However, how to achieve large torque while efficiently integrating electrical control elements to the soft actuators remains scientific and engineering challenges. Here, by concentric twisting a flexible silver-plated polyamide strand (SPS) with multi-layer liquid crystal elastomer fibers (LCEFs), a twisted yarn actuator with the skin-core structure that exhibits outstanding rotational motion under the electrical current control is fabricated. It has been proved that this multi-layered twisting structure efficiently improves the actuating performance. The yarn actuator can produce a peak torque of 33.4 N m kg−1 which outperforms reported commercial rotating motors and a specific power density of 21.2 W kg−1 that is comparable to the human skeletal muscle. As conceptual applications, electrical soft rotors and a novel flexible lifter have been successfully constructed based on the twisted yarn actuator, demonstrating precise torque responsiveness and controllability. Furthermore, a smart crawling fabric embedded with the twisted yarn actuators has been weaving fabricated which can crawl forward continuously and achieve the crawling stroke of 19.9 mm in 55 s and a maximum speed of 1.1 mm s−1. The research provides insights for designing soft robots employing fabric structures.

Structure-Mechanical Property Relationships in Carbon Nanotube Yarns

Carbon nanotube (CNT) is an innovative material with significant potential for a wide range of applications, including but not limited to the development of lightweight composite materials or superconductors. A single CNT demonstrates an exceptional degree of tensile strength. CNTs are commonly employed in a structure of yarn, wherein several CNT strands are arranged and aligned together. CNT yarns, on the other hand, have a lower tensile strength than individual CNTs due to the different parameters of the yarn. This study aimed to investigate the effect of different structural parameters on the mechanical properties of CNT yarn. Sixty CNT yarn models with different structures were simulated with the molecular dynamic (MD) simulation. The varied parameters are the chirality of the CNTs, CNTs’ inner diameter, number of walls, crosslink density, and yarn twist angle. Tensile strength results from the simulations were compared concerning the varied parameters, and their influence on the nominal tensile strength of the CNT yarn was studied. It was found that the parameters for the CNT yarn that yields a higher tensile strength are the armchair type CNT with a small diameter, a large number of walls, crosslink density higher than approximately 1%, and a low twist angle.

An eco-friendly droplet-wet spinning technology for producing high-quality hemp/cotton blend yarn

In recent years, hemp textiles have gained attention as a sustainable alternative to cotton. However, the uneven fineness and length of hemp fibers, along with their stiffness, adversely affect spinnability and exacerbate yarn evenness and hairiness, particularly due to short fibers. This study introduces a modified sustainable droplet-wet spinning technology aimed at enhancing hemp yarn quality, with a primary focus on reducing yarn hairiness. Implemented on a ring spinning machine, the technology utilizes a syringe connected to an adjustable-speed pump, delivering water onto the front top roller. This innovative approach enhances hemp yarn in two ways: firstly, the cohesive force of water promotes the consolidation of short fibers on both sides of the fiber bundle towards the center, thereby condensing the spinning triangle. Consequently, the fibers on both sides of the fiber bundle are more readily drawn into the spinning triangle and twisted to form yarn; secondly, wet hemp fibers possess a lower modulus, rendering them softer and more deformable, facilitating their embedding into the yarn, thereby enhancing yarn tenacity and reducing yarn hairiness. The study systematically investigates the relationship between droplet-wet spinning parameters (water droplet rate, hemp fiber content of the roving, and yarn twist multiplier) and hemp yarn quality. Experimental results reveals that optimal droplet-wet spinning lead to a 22% increase in yarn tenacity and about 50% reduction in hairiness. A higher hemp fiber content in the roving contributes to better performance of droplet-wet spinning technology in enhancing yarn quality. Moreover, droplet-wet spinning enables the production of high-quality hemp yarn at lower twist multipliers, thereby reducing electricity consumption during yarn production. Subsequently, the performance of knitted fabrics made from conventional ring-spun yarn and droplet-wet spun yarn was compared and analyzed. The results indicate that fabric made from droplet-wet spun yarn exhibits an approximately 8% increase in bursting strength and a one-level improvement in pilling resistance. This research highlights the potential of droplet-wet spinning technology to enhance hemp yarn quality and promote sustainable textile production.

A prediction method and its application for twist of slub yarn based on micro-element yarn

A prediction method and its application for twist of slub yarn based on micro-element yarn

Study on the relationship between blending uniformity and yarn performance of blended yarn

The performance of blended yarns is affected by the distribution of component fibers within blended yarn and the blending uniformity. However, there is a lack of comprehensive and quantitative investigations on the relationship between them. In this paper, various specifications for two-component blended yarns were prepared, and the main factors affecting blending uniformity were analyzed. Then the yarn blending irregularity and yarn performance, including tenacity, tenacity coefficient of variation, extension and yarn unevenness were tested. Finally, Pearson correlation analysis and linear regression were performed between blending irregularity and each yarn performance to characterize the influence of blending uniformity on yarn performance quantitatively. The results show that the blending irregularity is effectively improved by uniform feeding of slivers, and increasing the passage of sliver blending. The blending irregularity has no significant influence on the relationship between twist factor and yarn performance. The blending irregularity has the most positive and highest effect on tenacity coefficient of variation, followed by tenacity and unevenness in third place, and the Pearson correlation coefficient ( P) were all above 0.5, and the linear regression coefficient was above 10−3, but the breaking extension was weakest and negatively correlated with blending irregularity. Except for breaking extension, the effect of blending irregularities on yarn performance becomes more obvious when there are large differences in fiber linear density and fiber length. This paper reveals the relationship between blending uniformity and yarn performance, to provide a basis for theoretical research on the properties of blended yarns.

Switchable Pseudo‐Triaxial Structure Enabled Mechanosensory Textiles with Ultra‐Wide Detection Range for Flexible E‐Wearables

AbstractFlexible sensors hold significant promise for wearable monitoring and rehabilitation training applications. However, current flexible strain sensors struggle to compatible their sensing performance and fabrication with textile substrate and weaving technologies, which limits the practical applications of flexible sensors in commercial markets for electronic wearables. Differing from traditional strategies that rely on sophisticated construction of functional materials, leveraging industrial braiding, and weaving technologies, an all‐textile‐based pseudo‐triaxial mechanosensory textile (PTMT) is designed by engineering the wrapping pattern, yarn twist, and fabric architecture. The switchable hierarchically‐structured morphing of the PTMT enables an ultra‐wide strain detection range (up to 140%) along with desirable sensitivity. Moreover, the PTMT shows outstanding air permeability (1915 mm s−1), moisture permeability (1922 g m−2 h−1), high washability, and electromagnetic interference shielding (20.25 dB). The potential applications of PTMT are also demonstrated, such as in simulating fetal‐movement in pregnant women, proving its effectiveness in fetal‐movement health monitoring. Furthermore, by integrating the PTMT into shoe vamps and combining it with machine learning algorithms (CNN, RF, and PSO‐SVM), it is proved that PSO‐SVM outperformed CNN and RF in accuracy and stability, achieving a combined recognition accuracy of 95.42%.

Dry gel spinning of fungal hydrogels for the development of renewable yarns from food waste

BackgroundRenewable materials made using environmentally friendly processes are in high demand as a solution to reduce the pollution created by the fashion industry. In recent years, there has been a growing trend in research on renewable materials focused on bio-based materials derived from fungi.ResultsRecently, fungal cell wall material of a chitosan producing fungus has been wet spun to monofilaments. This paper presents a modification for the fungal monofilament spinning process, by the development of a benign method, dry gel spinning, to produce continuous monofilaments and twisted multifilament yarns, from fungal cell wall, that can be used in textile applications. The fungal biomass of Rhizopus delemar, grown using bread waste as a substrate, was subjected to alkali treatment with a dilute sodium hydroxide solution to isolate alkali-insoluble material (AIM), which mainly consists of the fungal cell wall. The treatment of AIM with dilute lactic acid resulted in hydrogel formation. The morphology of the hydrogels was pH dependent, and they exhibited shear thinning viscoelastic behavior. Dry gel spinning of the fungal hydrogels was first conducted using a simple lab-scale syringe pump to inject the hydrogels through a needle to form a monofilament, which was directly placed on a rotating receiver and left to dry at room temperature. The resulting monofilament was used to make twisted multifilament yarns. The process was then improved by incorporating a heated chamber for the quicker drying of the monofilaments (at 30⁰C). Finally, the spinning process was scaled up using a twin-screw microcompounder instead of the syringe pump. The monofilaments were several meters long and reached a tensile strength of 63 MPa with a % elongation at break of 14. When spinning was performed in the heated chamber, the tensile strength increased to 80 MPa and further increased to 103 MPa when a micro-compounder was used for spinning.ConclusionThe developed dry gel spinning method shows promising results in scalability and demonstrates the potential for renewable material production using fungi. This novel approach produces materials with mechanical properties comparable to those of conventional textile fibers.

Highly Soft, Abrasion-Resistant, and Moisture-Absorbent Wool/PA56 Blended Yarns for Seating Fabrics.

Biobased nylon (PA56) not only has the same physical properties as nylon (PA6/PA66) but its production method is also more environmentally friendly. PA56 fabric has the advantages of moisture absorption, perspiration, high-temperature resistance, and flexibility, which have been widely studied by scientific researchers. Wool has the advantages of beauty, environmental protection, and anti-wrinkle. However, pure wool fabrics have low strength and are easy to shrink when washed, which has always been a problem. Hence, this work adopted the ring spinning method to prepare wool/PA56 blended yarn with wool content of 0, 10, 30, 50, 70, and 100 wt%. Thus, to examine the effects of different blending ratios and twists on yarn performance, PA56 was blended with wool. The results showed that findings indicate that yarn performance is influenced by both yarn twist and blending ratio. The yarn thickens and takes on more linear density as the blending ratio and yarn twist increase. As the wool ratio increases, the yarn's breaking stress and breaking strain decrease. It is obvious that the strength and elongation at break of pure PA56 yarn are 2.09 cN/Dtex and 33.92%, respectively. When the wool content was 100 wt%, the strength and elongation at break of the blended yarn were 0.66 cN/Dtex and 21.15%, respectively. With the amount of wool blending, the yarn hairiness index's H-value initially rises and subsequently falls. The percentage of blended wool reaches 50% at 2.14; less blending might exacerbate the yarn's stem, resulting in neps and unevenness features. The quality of the yarn improves as the blending percentage rises. The yarn has the advantages of resource saving, biodegradability, and environmental friendliness and has a broad application prospect in the automotive interior field.

High-Energy–Density Fiber Supercapacitors Based on Transition Metal Oxide Nanoribbon Yarns for Comprehensive Wearable Electronics

AbstractFiber supercapacitors (FSs) based on transition metal oxides (TMOs) have garnered considerable attention as energy storage solutions for wearable electronics owing to their exceptional characteristics, including superior comfortability and low weights. These materials are known to exhibit high energy densities, high specific capacitances, and fast redox reactions. However, current fabrication methods for these structures primarily rely on chemical deposition, often resulting in undesirable material structures and necessitating the use of additives, which can degrade the electrochemical performance of such structures. Herein, physically deposited TMO nanoribbon yarns generated via delamination engineering of nanopatterned TMO/metal/TMO trilayer arrays are proposed as potential high-performance FSs. To prepare these arrays, the target materials were initially deposited using a nanoline mold, and subsequently, the nanoribbon was suspended through selective plasma etching to obtain the desired twisted yarn structures. Because of the direct formation of TMOs on Ni electrodes, a high energy/power density and excellent electrochemical stability were achieved in asymmetric FS devices incorporating CoNixOy nanoribbon yarns and graphene fibers. Furthermore, a triboelectric nanogenerator, pressure sensor, and flexible light-emitting diode were synergistically combined with the FS. The integration of wearable electronic components, encompassing energy harvesting, energy storage, and powering sensing/display devices, is promising for the development of future smart textiles. Graphical Abstract

Modeling of mechanical behavior of Agave sisalana fiber's yarn using the design of experiments method

The aim of this study is to propose a model for predicting the mechanical properties of natural sisal yarn based on mechanical strength of used fibers, unit twist of yarn and its density. To achieve this, a complete factorial design modelling method was used, based on a design of experiments approach, which is recommended today because of the ease it offers in taking into account the most complex phenomena. It was developed on the basis of laboratory tests. The model obtained predicts mechanical strength and elasticity modulus of sisal yarn, based on control parameters such as fiber strength, unit twist and yarn mass. This model is currently one of the most accurate tools for predicting and optimising the mechanical properties of sisal yarns. The iso-surface curves represented by this model, can be used to obtain the strength and elasticity modulus of sisal yarn during manufacture, by varying the optimum control parameters. This model is an original tool that can be recommended to the spinning and sisal fiber composite manufacturing industries and others, as it saves time and materials and ensures precision in the manufacture of yarns according to the field of application, thereby contributing to safety in use.

Twisting process of basalt fibers in water: The effects of water on microscopic structure and spinning property

Basalt fibers (BFs) are eco-friendly and natural high-performance fibers, specifically engineered for use in protective clothing, offering significant benefits. However, the inherent brittleness of this inorganic fabric not only poses challenges in processing but also renders it uncomfortable for wear. Consequently, there is an urgent need to modify BFs to enhance their torsional property and skin compatibility. Herein, we immersed BFs in water and twist them into yarn to investigate the effects of water erosion on BFs, specifically focusing on its impact on fiber structure and spinning performance. Under water's erosion, the BFs experienced ion-exchange reactions that compromised the silica framework, leading to a significant rise in both static and dynamic friction coefficients 162.5 % and 233.3 %, respectively, and a 1.53-fold improvement in torsional performance. The process of twisting in a water bath facilitated better fiber bundling, yielding a more compact yarn structure. This compaction reduced the occurrence of burrs following friction and enhanced both tensile and loop strength. At the fiber level, we utilized a simple water erosion method to enhance the twisting performance of basalt filament. This approach circumvents the disadvantages of large etching modification damage and poor sizing fastness, offering a novel method for the preparation of basalt twisted yarn.

Mechanical Properties of Twisted Cellulose Nanofiber-Reinforced Silk Yarns.

Silk has recently attracted considerable interest owing to its versatile properties as a natural fiber, especially in the medical sector. However, the mechanical properties of silk limit its potential applications. In our earlier work, the mechanical performance of silk filaments was enhanced owing to the insertion of cellulose nanofibers (CNFs). Nevertheless, silk filaments must be assembled and twisted to form a continuous yarn. In this study, the mechanical properties of CNF-reinforced silk yarns were evaluated to determine the optimal yarn structure. The evolution of the Young's modulus, ultimate tensile strength, toughness, and elongation at break was assessed as a function of the twist level in comparison with regular silk. The results demonstrated that the most favorable compromise of the mechanical properties was obtained at 1000 twists per meter.

Flexible Mechanical Sensors Fabricated with Graphene Oxide-Coated Commercial Silk.

Many studies on flexible strain and pressure sensors have been reported due to growing interest in wearable devices for healthcare purposes. Here, we present flexible pressure and strain (motion) sensors prepared with only graphene oxide (GO) and commercial silk fabrics and yarns. The pressure sensors were fabricated by simply dipping the silk fabric into GO solution followed by applying a thermal treatment at 400 °C to obtain reduced GO (rGO). The pressure sensors were made from rGO-coated fabrics, which were stacked in three, five, and seven layers. A super-sensitivity of 2.58 × 103 kPa-1 at low pressure was observed in the seven-layer pressure sensor. The strain sensors were obtained from rGO-coated twisted silk yarns whose gauge factor was 0.307. Although this value is small or comparable to the values for other sensors, it is appropriate for motion sensing. The results of this study show a cost-effective and simple method for the fabrication of pressure and motion sensors with commercial silk and GO.

Dynamic Behavior of Twisted UHMWPE Yarns

Twisting is an effective method to reduce defects during fabric weaving and improve the impact resistance of the armor material. This study examined the dynamic behavior of twisted ultra-high molecular weight polyethylene (UHMWPE) yarns. Material characterization was conducted using three-dimensional X-ray tomography and scanning electron microscopy (SEM). Dynamic mechanical experiments were carried out on the twisted yarns using a Kolsky bar, with the yarn's failure process captured in real time through high-speed imaging. Additionally, the digital imaging correlation (DIC) technique was used to calibrate the strain measured by the Kolsky bar. Post-fracture analysis was performed using SEM. The effects of twisting extent, strain rate, and gauge length on the dynamic behavior of twisted yarns were studied. It was observed that all twisted yarns underwent elongation, shrinkage, fiber breakage, untwisting, and yarn rupture. Furthermore, as the twisting degree and strain rate increased, and the gauge length decreased, the fracture area became more concentrated. The tensile strength peaked at a twisting degree of 250 t/m and decreased thereafter. Moreover, twisting was found to alter the sensitivity of the yarns' stress–strain curves and tensile properties to the strain rate and gauge length.

An Investigation on the morphology, chemical, and physical properties of singed and singed-mercerized twisted cotton yarn

An Investigation on the morphology, chemical, and physical properties of singed and singed-mercerized twisted cotton yarn

Comparison of constant spindle speed twisting technology and constant tension twisting technology of E‐glass yarn

AbstractThe rapid advancement of the electronics industry has continuously increased demands for the E‐glass yarn's quality and production capacity. The twisting and winding process stands out as a crucial step in E‐glass yarn production. Twisted bobbin yarns are produced separately using constant spindle speed technology and constant tension technology in order to address issues such as high yarn breakage rates and excessive yarn hairiness during twisting. By comparing the twisting tension, yarn breakage rates, and yarn hairiness between these two technologies, this study delves into the impact of twisting technology on E‐glass yarn quality and production capacity. The results indicate that, in comparison with constant spindle speed technology, constant tension technology reduces the unevenness ratio of twisting tension from 8.94% to 0.55%, decreases yarn breakage rates from 3.05% to 2.03%, reduces long hairiness by 20.3%, and reduces short hairiness by 25.1%. By reducing the spindle speed when the bobbin yarn's diameter increases, constant tension twisting technology reduces the unevenness ratio of twisting tension, yarn breakage rate, and yarn hairiness. These research findings lay the foundation for the development of high‐end E‐glass yarn products and carry significant practical value in improving yarn quality, enhancing production capacity, and reducing E‐glass yarn losses.Highlights The twisting and winding principle of E‐glass yarn is revealed. The relationship among four tensions in the twisting and winding process is clarified. The parameters for the constant tension twisting technology are developed. The measurement method for the twisting tension is improved.

Jute textiles with enhanced interfacial bonding as reinforcement for cementitious composites

In fabric-cement composites, the limited impregnation of cementitious matrix products due to thick and twisted yarns leads to premature failure due to poor bonding strength. In addition, cellulosic textile reinforcements have many challenges about durability, appearance of voids at mortar-fiber interface, and rise of microcracks. Textile performances were evaluated in different conditions: coated with micro-silica powder, pretreated, and without any treatment. This study also assessed how textile weave structure and yarn geometry configuration affect the interactions of two different jute textiles (Close Weave Jute Fabric – CJF and Open Weave Jute Fabric - OJT) when used as reinforcement in mortar matrix. Textile characterization and composite analysis (by four-point bending tests, SEM/EDS, and physical tests) were conducted to assess the different textile reinforcements, the mechanical behavior of produced composites, and visual and chemical compounds analysis of the interfacial transition zone between textile and mortar matrix after silica coating. Micro silica powder coating was deemed necessary to address limited impregnation and to avoid telescope pull-off. Weave structure determined the difference between jute fabrics to reinforce mortar matrix, being only OJF (larger interstices in the weave structure) with micro silica coating allowed a better matrix interaction and stood out from the other textiles and achieved the best specific energy of all samples, (4.28 ± 0.91) kJ.m-2. Calcium and silicon inside the yarn interstices and textile-matrix interface indicate the formation of strong bonds by calcium-silicate-hydrate products. The silica coating treatment enhanced formation of strong bonds, which demonstrated future promise for natural fiber application.

Dual-Responsive MXene-Functionalized Wool Yarn Artificial Muscles.

Fiber-based artificial muscles are promising for smart textiles capable of sensing, interacting, and adapting to environmental stimuli. However, the application of current artificial muscle-based textiles in wearable and engineering fields has largely remained a constraint due to the limited deformation, restrictive stimulation, and uncomfortable. Here, dual-responsive yarn muscles with high contractile actuation force are fabricated by incorporating a very small fraction (<1wt.%) of Ti3C2Tx MXene/cellulose nanofibers (CNF) composites into self-plied and twisted wool yarns. They can lift and lower a load exceeding 3400 times their own weight when stimulated by moisture and photothermal. Furthermore, the yarn muscles are coiled homochirally or heterochirally to produce spring-like muscles, which generated over 550% elongation or 83% contraction under the photothermal stimulation. The actuation mechanism, involving photothermal/moisture-mechanical energy conversion, is clarified by a combination of experiments and finite element simulations. Specifically, MXene/CNF composites serve as both photothermal and hygroscopic agents to accelerate water evaporation under near-infrared (NIR) light and moisture absorption from ambient air. Due to their low-cost facile fabrication, large scalable dimensions, and robust strength coupled with dual responsiveness, these soft actuators are attractive for intelligent textiles and devices such as self-adaptive textiles, soft robotics, and wearable information encryption.

Active‐Textile Yarns and Embroidery Enabled by Wet‐Spun Liquid Crystalline Elastomer Filaments

AbstractLiquid crystal elastomers (LCEs) are promising candidates for creating adaptive textile‐based devices that can actively and reversibly respond to the environment for sensing and communication. Despite recent advances in scalable manufacturing of LCE filaments for textile engineering, the actuation modes of various LCE filaments focus on contractual deformations. In this study, manufacture of polydomain LCE filaments with potential scalability by wet‐spinning is studied, followed by mechanical exploitation to program liquid crystal mesogen alignments, demonstrating both contractual and twisting actuation profiles. By plying these LCE filaments into yarns with different twist concentrations, yarn actuation, and mechanical performance is tuned. Yarns plied at 4 twists per cm can generate up to a seven‐fold increase in elastic modulus while maintaining 90% of actuation strain performance from their native filament. The contractual and twisting LCE filaments are then embroidered with varying stitch types to spatially program complex 2D‐to‐3D transformations in “inactive” fabrics. It is shown that a running stitch can actuate up to 15% in strain and create angular displacements in fabric with twisted mesogen alignments. It is envisioned that the wet‐spun polydomain LCE filaments for diverse plied yarn production together with textile engineering will open new opportunities to design smart textiles and soft robotics.

&lt;i&gt;In Situ&lt;/i&gt; Measurement of Twist Propagation and Yarn Tension with Superconducting Magnetic Bearing Twisting Element for Ring Spinning Process

The twisting of yarn in one of the most widely used conventional ring spinning processes is based on the ring/traveler system. The existing limitation of productivity in the ring spinning process lies on the prevailing force relation between ring, traveler and yarn as well as the frictional heat between traveler and ring, principally in the ring traveler system. Recently, a frictional free twisting element based on a superconducting magnetic bearing (SMB) was developed to increase the productivity of ring spinning drastically, which was patented by ITM and Leibniz IFW Dresden. This SMB consists of a circular superconductor and a permanent magnet (PM) ring. In the superconducting state, the PM ring levitates and can freely rotate even up to an angular speed of 50.000 rpm. It is connected with the spindle via the yarn through a guide attached to the PM ring to impart yarn twist. Through the rotation of the PM ring, the twist propagates to the nip point of the delivery rollers. The twist propagation rate depends on different parameters, e.g., spindle speed, balloon geometry, and friction between yarn and yarn guides. A change in the level of twist affects the process, yarn tension, yarn breakage rate, and yarn properties. Hence, it is important to investigate the twist distribution to derive effective measures for improving the twist propagation especially at higher angular spindle speeds and thus eliminate weak points to increase process stability and yarn quality. The aim of these measurements is to analyze the twist distribution along the yarn path to understand the causes of yarn breakages. In this study, the yarn path was traced at different regions by in-situ measuring the helix angle of twisted yarn using a high-speed camera. From the recorded images, the number of twists per unit length was determined using the image processing software ‘Image J’. Thus, the measurement method allows a new insight into the problem of yarn breakages originating from twist propagation in order to take optimized measures at higher angular spindle speeds.