Elastic Yarns Research Articles

Fabrication of Anti-Fatigue Double-Wrapped Yarns with Excellent Mechanical Properties for Generating Compression Fabrics.

Elastic yarns are the key component of high-performance compression garments. However, it remains a challenge to fabricate anti-fatigue yarns with high mechanical force and long elongation for generating compression garments with prolonged wear. In this paper, we report the development of anti-fatigue double-wrapped yarns with excellent mechanical properties by wrapping high-denier Spandex with nylon filaments in opposite twists. In particular, high-denier (560 D) Spandex as the core was untwisted, which can maximally reduce the interaction between the core and wrapping filaments, enabling high elongation of double-wrapped yarns. In addition, we chose 70 D nylon filaments with a tensile force of 3.87 ± 0.09 N as the wrapping materials to provide sufficient force for double-wrapped yarns. Notably, opposite twists were induced for the inner and outer wrapping filaments to achieve a balanced stable yarn structure. By systematically optimizing manufacturing parameters, including inner wrapping density, outer wrapping density, take-up ratio, and drafting ratio, we obtained double-wrapped yarn with excellent tensile stress (32.59 ± 0.82 MPa) and tensile strain (357.28% ± 9.10%). Notably, the stress decay rate of optimized yarns was only 12.0% ± 2.2%. In addition, the optimized yarn was used as the weft-lining yarn for generating weft-lined fabrics. The elastic recovery rate of the obtained fabric was decreased by only 2.6% after five cyclic stretches, much lower than the control fabric. Our design of anti-fatigue double-wrapped yarns could be widely used for fabricating high-performance compression garments.

Investigate the effect of elastic yarn ratios and cotton spinning techniques using different structures on functional and mechanical properties of compression bandages

Investigate the effect of elastic yarn ratios and cotton spinning techniques using different structures on functional and mechanical properties of compression bandages

Cut-resistance of elastic high-performance composite yarn

Soft and lightweight personal protective equipment for civil or military use that is made of cut-resistant textiles is usually rigid and heavy, less elastic or flexible. Insertion of elastane fiber during the fabrication of rigid textiles seems to be working, but actually is not. Therefore, it presents a severe challenge in achieving an appropriate balance among elasticity, flexibility, and protection. To address this issue, an elastic cut-resistant composite yarn is fabricated by single wrapping ultra-high molecular weight polyethylene around elastic Spandex. The effects of wrapping parameters (including the twist, spindle speed, and yarn combination) on yarn elasticity and coverage are investigated to achieve a perfect wrapping, and the cut-resistance of the composite yarn is evaluated by using a self-improved AUTOGRAPH universal testing machine. It demonstrates that the cutting process of the composite yarn consists of four stages, the cut modulus and yarn elasticity are highly correlated with yarn structure and wrapping process parameters. The optimizing coverage and cut-resistance are achieved when the twist is 750 t/m, which is also with a high elastic recovery rate (79.79%) and low plastic deformation rate (10.11%). Groups of parallelized composite yarns with varying densities are fabricated by self-improved sample holders to simulate the cut-resistant weaving fabrics with different weaving densities, of which the cut-resistance is evaluated. The resistance against cutting varies significantly among different groups, which is directly proportional to their densities. Finally, two types of elastic cut-resistant fabrics with different structures are woven from fabricated elastic cut-resistant composite yarns practically. Both weft-backed weave and the double-layer weave fabrics have good flexibility and protection, of which the cut-resistance is level 1 and level 2, respectively. Thus, the composite yarn has an excellent elasticity and maintained cut-resistance, which is an ideal material for the production of highly elastic protective textiles.

Ion gradient induced self-powered flexible strain sensor

To cope with energy hazards and reduce frequent battery replacement of strain sensors, various self-powered flexible strain sensors (including piezoelectric, triboelectric and electrochemical types) have developed recent years. However, the piezoelectric and triboelectric strain sensors cannot monitor static strain, and electrochemical strain sensors face the problem of performance degradation. Herein, inspired by ion gradient generators, a self-powered flexible strain sensor based on strain regulated ion gradient strategy is constructed. The sensor consists of elastic yarn coated with carbon nanotubes (CNTs), LiCl-filter paper (FP) and latex tube encapsulation. LiCl-FP with excellent water molecules absorption performance is wrapped on one side of the elastic yarn, forming a high humidity region in the sensor. The part of the elastic yarn that is not covered by LiCl-FP has weak water molecules absorption performance, forming a low humidity region in the sensor. The ions in the sensor move directionally from the high humidity region to the low humidity region, forming an ion gradient and generating voltage/current. The test results indicate that the sensor exhibits a wide strain detection range (0.5%–100%) and good repeatability (1000 times). The strain sensing mechanism can be attributed to the strain regulated ion gradient and the resistance strain effect. In addition, the strain sensing function of the sensor is verified by monitoring respiration. This work opens a new avenue for development of self-powered strain sensor using strain regulated ion gradient.

Study on a smart knee sleeve based on piezoresistive strain sensing for stride estimation

PurposeDevices for step estimation are body-worn devices used to compute steps taken and/or distance covered by the user. Even though textiles or clothing are foremost to come to mind in terms of articles meant to be worn, their prominence among devices and systems meant for cadence is overshadowed by electronic products such as accelerometers, wristbands and smart phones. Athletes and sports enthusiasts using knee sleeves should be able to track their performances and monitor workout progress without the need to carry other devices with no direct sport utility, such as wristbands and wearable accelerometers. The purpose of this study thus is to contribute to the broad area of wearable devices for cadence application by developing a cheap but effective and efficient stride measurement system based on a knee sleeve.Design/methodology/approachA textile strain sensor is designed by weft knitting silver-plated nylon yarn together with nylon DTY and covered elastic yarn using a 1 × 1 rib structure. The area occupied by the silver-plated yarn within the structure served as the strain sensor. It worked such that, upon being subjected to stress, the electrical resistance of the sensor increases and in turn, is restored when the stress is removed. The strip with the sensor is knitted separately and subsequently sewn to the knee sleeve. The knee sleeve is then connected to a custom-made signal acquisition and processing system. A volunteer was employed for a wearer trial.FindingsExperimental results establish that the number of strides taken by the wearer can easily be correlated to the knee flexion and extension cycles of the wearer. The number of peaks computed by the signal acquisition and processing system is therefore counted to represent stride per minute. Therefore, the sensor is able to effectively count the number of strides taken by the user per minute. The coefficient of variation of over-ground test results yielded 0.03%, and stair climbing also obtained 0.14%, an indication of very high sensor repeatability.Research limitations/implicationsThe study was conducted using limited number of volunteers for the wearer trials.Practical implicationsBy embedding textile piezoresistive sensors in some specific garments and or accessories, physical activity such as gait and its related data can be effectively measured.Originality/valueTo the best of our knowledge, this is the first application of piezoresistive sensing in the knee sleeve for stride estimation. Also, this study establishes that it is possible to attach (sew) already-knit textile strain sensors to apparel to effectuate smart functionality.

Development of sustainable dual core-spun yarns using several filaments and recycled cotton sourced from pre-consumer fabric waste

Textile industries are now focusing on sustainable issues in manufacturing operations to save the environment. The study focuses on the use of cotton fibers (recycled) sourced from fabric (knitted) waste (pre-consumer) to manufacture elastic yarn (dual-core) for denim fabric. The study involves the production of yarns (dual-core) using a redesigned ring spinning method with different elastomeric components, including T400® (Polyethylene terephthalate)/Polytrimethylene terephthalate), Polybutylene terephthalate (PBT), Polyester (PES), Lycra® (elastane), virgin cotton and cotton (recycled) fiber. The study investigates various yarn (Ne 18/1) characteristics such as strength, IPI (imperfection index), elongation %, unevenness %, and hairiness. It is noticed that the elongation and strength of recycled yarn (double core) are lower and IPI (Imperfection index), unevenness %, and hairiness values are higher than 100 % cotton (virgin) yarn (double core). One-way ANOVA (statistical analysis) is employed to assess the significance of differences among yarns manufactured from various core materials and found significant variation for all characteristics. Additionally, the article introduces the MOORA (multi-objective optimization based on ratio analysis) technique as a decision-making tool to determine the best yarn among three alternatives (PES yarn, PBT yarn, and T400 yarn) based on their properties, considering attributes and finding T400 filament containing yarn as the best option. The study introduces a sustainable approach using recycled cotton in yarn (double core) production and employs decision-making tools to assess and rank the performance of different yarn alternatives.

Characterization of viscoelastic properties of yarn materials: Dynamic mechanical analysis in the transversal direction

Abstract Warp knitting creates very challenging dynamics due to its high production speeds. On the one hand, this makes it method of choice for many products in various fields. On the other hand, not all materials are suitable for such high productivity. With the current generation of machines being limited to only achieve their maximum speed of around 4,400 min−1 with highly elastic yarns, it is desired to gain a deeper insight into yarn behavior in such highly dynamic environments. Among other influences, resonance effects gain high significance as they may result in high loads on the used materials; therefore, yarn breakages interrupt the production and decrease the quality of the product. To extend the material choice, especially high-performance fibers, for high productivity, a deep understanding of the intrinsic properties of the yarn is required. In particular, the viscoelastic properties are of importance. This study proposes a method to determine these characteristics using the dynamic mechanical analysis method. For the purpose of finding the damping in the transversal direction to the yarn axis, the variant of free oscillation is chosen. For the trials, a high-speed camera is suspended above a testing rig. On this rig, a yarn sample is clamped and then displaced from its rest position. The resulting oscillation is recorded and later extracted from the video. From the decrement of the maxima of the amplitude and corresponding time intervals, the damping factor is determined. It decreases with higher initial deflection. Summarised the developed trial setup proved suitable for the determination of the viscoelastic properties in transversal direction.

Strength of cotton dual-core elastane yarn splice

Cotton/elastane yarns are composite yarns composed of a blend of elastane core covered with cotton fibres. An increase in the demand for sports and leisure garments with high comfort and elasticity has led to more significant usage of elastane filaments. New yarn using two elastane filaments with a high ratio of elastane are introduced. An experimental study was established to define the most appropriate parameters for spliced cotton dual-core elastane yarn strength. The splice strength was enhanced when binding air pressure, joining air duration, and preparation duration were raised. Increased preparation air pressure does not affect the strength of the splice.

Influence of Undergarments on the Comfort Level of Scoliosis Brace Wearers.

Bracing has proven to be an effective method for the conventional treatment of scoliosis in young people. A brace, a therapeutic device, covers the upper body and promotes healing by applying pressure to specific areas. However, wearing a scoliosis brace negatively affects the user's thermo-physiological well-being and often leads to discomfort. In this study, we investigated the influence of T-shirts as an undergarment on the thermo-physiological well-being of the brace wearer. For this purpose, we performed a comparative analysis of six T-shirts made from different special knitted fabrics. We carried out wearing tests in a computer-controlled climate chamber according to a predetermined protocol. The test subject wore the orthopedic brace over the different T-shirts at three different temperatures. The results indicate that the knitted fabrics of undergarments and environmental conditions considerably impact the wearer's thermo-physiological comfort. In the tests, the T-shirts made from the selected functional fabrics performed very well. The T-shirt made from the classic cotton fabric containing elastane yarn also performed well and was the most environmentally friendly. Currently, due to its lower price and easier availability, this cotton T-shirt can be recommended for wearing under a scoliosis brace.

Calotropis gigantea Fiber-Based Sensitivity-Tunable Strain Sensors with Insensitive Response to Wearable Microclimate Changes

Wearable tensile strain sensors have attracted substantial research interest due to their great potential in applications for the real-time detection of human motion and health through the construction of body-sensing networks. Conventional devices, however, are constantly demonstrated in non-real world scenarios, where changes in body temperature and humidity are ignored, which results in questionable sensing accuracy and reliability in practical applications. In this work, a fabric-like strain sensor is developed by fabricating graphene-modified Calotropis gigantea yarn and elastic yarn (i.e. Spandex) into an independently crossed structure, enabling the sensor with tunable sensitivity by directly altering the sensor width. The sensor possesses excellent breathability, allowing water vapor generated by body skin to be discharged into the environment (the water evaporation rate is approximately 2.03 kg m−2 h−1) and creating a pleasing microenvironment between the sensor and the skin by avoiding the hindering of perspiration release. More importantly, the sensor is shown to have a sensing stability towards changes in temperature and humidity, implementing sensing reliability against complex and changeable wearable microclimate. By wearing the sensor at various locations of the human body, a full-range body area sensing network for monitoring various body movements and vital signs, such as speaking, coughing, breathing and walking, is successfully demonstrated. It provides a new route for achieving wearing-comfortable, high-performance and sensing-reliable strain sensors.Graphical

Design of Hybrid Yarn with the Combination of Fiber and Filaments and Its Effect on the Denim Fabric Performance

Abstract Consumer choice and behavior are changing and focusing on comfortable clothing along with fitting. Elastic yarn or fabric is necessary to achieve this comfortableness. By making elastic yarn and using elastic material in fabric production, elastic cloths are produced with proper stretchability and recovery. For that, core-spun yarn was used, but due to a lack of recovery performance, dual core-spun yarn has been developed. Different elastane ratios, linear density, and filaments were used in the dual core-spun yarn according to achieve desired stretchability. In this study, denim fabric performances were evaluated by designing different composite/hybrid dual core-spun yarn with a combination of cotton fiber and filaments. Different elastane linear densities with different filaments, PET/PTT, PTT, and PET, were used, and it was found that using finer elastane in dual core-spun yarn, strength, and unevenness are increased, and elongation decreased. Using PET/PTT filament increases hairiness, and using PTT filament increases elongation. For fabrics, coarser elastane in the dual core-spun yarns has higher stiffness, elasticity, and shrinkage. Fabric with PTT showed higher weight change and stiffness, whereas PET filament-based fabric samples have good strength and low stiffness. In addition, a multiple regression analysis was carried out for yarn and fabric properties, and mathematical models were developed.

Mass-Produced Flexible Strain Sensors Based on Dip-Coating and Water Bath for Human–Computer Interaction

Flexible strain sensors play a key role in the field of human–machine interaction because of their ability to sense deformation. To meet the needs of mass production of wearable electronic devices, it is very necessary to develop a strain sensor with excellent sensing performance and low-cost mass fabrication. In this article, a fabrication process of a flexible resistive strain sensor, which is perfectly matched by the combined method with dip-coating and water bath, is proposed. A layer of conductive polymers containing carbon black/multiwall carbon nanotubes/thermoplastic polyurethane (CB/MWCNTs/TPU) was quickly and evenly wrapped on the surface of the core-spun elastic yarn. Combining the synergistic conductive effect of the filler and the high elasticity of the yarn matrix, the designed flexible strain sensor has high sensitivity (gauge factor (GF) to 68), low detection limit, wide strain range, fast response time, fast recovery time, and high stability. The designed strain sensor exhibits outstanding sensing performance and wearability, which can be used for real-time monitoring of human joint bending and breathing state. Furthermore, a wireless operating system based on wearable data gloves has been developed to realize the remote synchronous movement of the human hand/the bionic manipulator. The results indicate that the proposed strain sensor has great potential in human–machine interaction and its fabrication technology provides guidance for the sensor in mass production.

Effect of using alternate elastic and non-elastic yarns in warp on shrinkage and stretch behavior of bi-stretch woven fabrics

Stretch woven fabrics are known for their elastic and recovery properties. To date, they found many interesting applications from simple jeans to complex fabric structures with functional properties for example bi-stretch auxetic woven fabrics, compressions garments and stretchable textile carriers for healthcare applications. Many studies have been carried out on the physical, mechanical and comfort properties of stretchable knitted and woven fabrics. However, to identify combination of yarns with different stretch properties and other design parameters required to meet multiple objectives in the production and usage of bi-stretch woven fabrics is an area that has been taken up by fabric scientists recently. This study compared the effect of using elastic yarns and alternate elastic and non-elastic yarns in warp on the properties of bi-stretch woven fabrics while using elastic yarns in weft direction. It was found that shrinkage of the fabrics made of elastic yarns was higher along the warp direction as compared to that in weft direction due to shrinkage balancing effect; however, in case of fabrics made of alternate elastic and non-elastic yarns in warp the shrinkage behavior was exact opposite. The comparison of shrinkage for different weave patterns revealed that satin had the highest shrinkage followed by twill and plain, due to least number of interlacements in satin among these three patterns.

Transfer of liquid and water vapour through knitted materials

Active sportswear has certain functions that should meet the expected properties and improve the performance of athletes. In addition to functionality, an important aspect of sportswear is thermal and physiological comfort. By choosing the right clothing for athletes, the dynamic and thermal load can be significantly reduced because sports require unhindered mobility, and clothing must be adapted to the body and absorb sweat. Proper vapour and liquid flow in textile materials are important from a comfort point of view. Therefore, in this research, seven representative samples were selected that are used for clothing intended for sport and leisure. Using an infrared thermal camera, the transfer of liquid on the surface of the material was precisely monitored, until the final stage when the material is completely dry. The obtained results show that fabric made of 100 % polyester has the shortest drying time, while the highest vapour permeability was exhibited by fabric made of viscose and elastane yarn. Those fabrics should be considered as the most suitable for sportswear because they do not cause discomfort when worn. Infrared thermography is a very useful method in research because it provides reliable data, especially when it comes to the drying time of the material.

Tolerance of cotton to certain biotic factors and fiber quality parameters of the ridges created by simple and complex hybridization

Among the strains derived from simple hybrids studied in the experiments, T-3 T-9, T-18 and strains T-43, T-53, T-57 and 60 from strains derived from complex hybrids were resistant to gommosis and wilt diseases. As a result of several years of research, it was found that the ridges obtained from complex hybrids were less affected by gommosis and wilt diseases than the ridges obtained as a result of simple hybridization. It was found that wilt disease was 3-4 times more resistant in the ridges created as a result of simple and complex hybridization compared to the model seed. Lines T-155, T-158, T-163, T-167, T-188 and T-208 from simple hybrids of cotton and lines T-212, T-215, T-220 and T-222 from complex hybrids are other It was determined that the quality of the fiber meets the requirements of the world standards in relation to the ridges and pattern type. In the studied samples, the families of ridges that do not have positive quality indicators such as fiber micronaire, yarn elasticity coefficient, fiber length, relative tensile strength and fiber uniformity are discarded, and experiments are carried out in the following years in order to incorporate new ridges that meet the requirements of the world standard with other economically valuable characteristics detached to continue.

Distribution of Connective Tissue Fibres in the Feline Ovary and Uterus

Connective tissue is significant because it is one of the supporting tissues, it connects organs and keeps them in place, it contains inflammatory response components, and it provides the environment in which metabolic exchange occurs between cells. Collagen fibres are the most common type of connective tissue component. Type 3 collagen, glycoproteins, and proteoglycans make up reticular fibres. They allow the uterus and ovaries to contract and stretch since they are situated in between the muscles and collagen fibres in these organs. According to the requirements of the microenvironment in which they are found, elastic fibers have persistent changeable functionalities and are resistant to tensile forces. After regular histological tissue follow-up after washing, tissues removed from the ovaries and uterus of cats were fixed in 10% formaldehyde and blocked in the paraplast. Sections from the prepared blocks were cut at a thickness of 5–6 µm. The distribution and structure of these yarns were studied using the methods of Orsein for the structure of elastic yarns derived from connective tissue yarns, Van Gieson's for the structure of collagen yarns, and Gordon and Sweet's dyeing process for the structure of reticulum yarns. It was determined that the ovary and uterus had increased collagen fiber dispersion. Less dispersion was observed in reticulum and elastic fibres. The collagen fibres in the elastic and reticulum fibres, which were arranged in thick bundles between the follicles in the ovary, were found to have a thinner structure. It was noted that the collagen fibres were more thickly distributed in the lamina propria of the uterine endometrium, where the elastic and reticulum fibres were formed from thin filaments.

An approach to improve the elasticity of rib fabric through mechanical and chemical finishing

In recent years, the demand for knit fabric has increased significantly due to some of its unique properties like comfortability, stretchability, easy care, excellent wrinkle resistance and a high degree of fashion features. Among the different types of knit fabric, rib fabric is very popular for its elasticity. There is a demand for more elasticity of rib fabric in manufacturing apparel like sportswear. A common practice is to use elastane yarn along with native yarn to increase the knit fabric’s elasticity. Elastane fibres are synthetic fibres which are not comfortable. Elastane yarns are costly and cause a few difficulties during knitting. In this study, a combination of mechanical and chemical finishing processes has been introduced to increase the elasticity of 100% cotton rib fabric. The best possible finishing route was incorporated to maximize the rib fabric elasticity. It was observed that rib fabric elasticity can be increased up to 1.5 times from its native value. The material cost between the new proposed process and the existing elastic fabric manufacturing process was compared. It was found that the new process is much cheaper. This is an approach to finding an easy, industrially applicable and cost-effective method to maximize rib fabric elasticity without using any elastane yarn.

Development and characterization of socks with improved anti-odour, thermo-regulating and handle properties

Due to awareness of the potential threats of spreading diseases, the demand for antimicrobial fabrics in the world market has grown significantly and, is, expected to increase the share of medical textiles in the future world market. The purpose of this study is to develop antibacterial socks with the application of silver particles and to study thermo- physiological properties as well as the evaluation of tactile sensory perceptions of treated socks against untreated socks. Socks, which are a necessary item of clothing, need to be comfortable and affordable. The materials used for this study are cotton and polyester fibre with three different cross-sectional shapes i.e., common Polyester (round shape), Coolmax (Channeled polyester) and Thermolite (Hollow polyester). Blend ratios with percentages of 80/20 Cotton/Polyester, 80/20 Cotton/Coolmax and 80/20 Cotton/Thermolite were used as main yarns in plain crew socks while elastane yarn is used in the same percentage in all developed socks. A comparison between the samples treated with silver particles and the corresponding control samples concerning the selected properties was done. The presence of particles on the treated fibre was confirmed through an SEM study. Testing of untreated and treated fabrics for antibacterial study and odour test was carried out and found significant. The thermo-physiological properties such as air permeability, relative water vapour permeability % and thermal resistance were also studied and found better results as compared to untreated samples. Later tactile sensorial comfort i.e., fabric hand value was compared which is improved for treated samples which makes the wearer comfortable hand feeling. These data present a great interest to socks manufacturers who can make better choices to manufacture, cost-effective anti-odour socks.

Twisted and coiled yarns for energy harvesting and storage, artificial muscles, refrigeration, and sensing

This overview focuses on our teams work on using twisted yarns and highly elastic coiled yarns for artificial muscles, energy harvesting, energy storage, sensing, and refrigeration. Despite the diversity of these applications for coiled carbon nanotube and polymer yarns, similar fabrication methods are applicable and conversion of coiling twist to yarn twist results in yarn elasticity, actuation, twistocaloric cooling, and the capacitance changes used for energy harvesting and sensing. Likewise, the same biscrolling method yields coiled yarns containing up to 95 weight percent of guest powders that provide various new properties. The obtained performance of the coiled polymer and carbon nanotube yarns are remarkable, such as artificial muscles that generate up to 98 times the output mechanical power than the maximum for the same weight human muscle and mechanical energy harvesters providing a higher peak electrical power per weight than prior art material-based mechanical energy harvesters for stretch frequencies between a few Hz and 600 Hz.

Development of Low Hysteresis, Linear Weft-Knitted Strain Sensors for Smart Textile Applications.

In recent years, knitted strain sensors have been developed that aim to achieve reliable sensing and high wearability, but they are associated with difficulties due to high hysteresis and low gauge factor (GF) values. This study investigated the electromechanical performance of the weft-knitted strain sensors with a systematic approach to achieve reliable knitted sensors. For two elastic yarn types, six conductive yarns with different resistivities, the knitting density as well as the number of conductive courses were considered as variables in the study. We focused on the 1 × 1 rib structure and in the sensing areas co-knit the conductive and elastic yarns and observed that positioning the conductive yarns at the inside was crucial for obtaining sensors with low hysteresis values. We show that using this technique and varying the knitting density, linear sensors with a working range up to 40% with low hysteresis can be obtained. In addition, using this technique and varying the knitting density, linear sensors with a working range up to 40% strain, hysteresis values as low as 0.03, and GFs varying between 0 and 1.19 can be achieved.