Knitted Structures Research Articles

Shielding properties of hybrid knitted fabrics: reflection and absorption

Last decade a lot of research was done in the development and investigation of textile-based shielding materials against electromagnetic radiation. Still, there is a gap in understanding the effect of knitted structure (i.e., stitch type and shape) on shielding effectiveness by different shielding mechanisms: reflection and absorption. Seven knitted fabrics were produced on 8-gauge flat knitting machines, using 0.12 mm diameter stainless steel (SS) wire and 30 x 2 tex cotton yarn. The fabrics differ by the method of incorporation of conductive element (SS wire) into the knitted structure: separately and simultaneously with cotton yarn and used interloopings. The effect of stitch type (loop, float, or tuck) was studied as well. It was found that both the method of SS wire incorporation and the shape of its positioning in the knitted structure affect the EMR shielding effectiveness while only the method of SS wire incorporation determines the shielding mechanism: absorption or reflection. The half Milano rib knitted structures demonstrate the best shielding efficiency due to the additional floats behind held loops.

Research of Warp Structure Modelling for Calculation of Two Guidebars Warp Knitted Fabric Parameters

Abstract. Warp knitted fabrics were known as rather complicated structures. Until now, only geometrical models for general warp knitted structures were presented. Calculation of two guidebars warp knitted fabric parameters using geometrical models was limited. This paper presented an extension of available geometrical models for simulation warp knitted structures parameters such as fabric thickness, looplength, warp and weft density, fabric area porosity, fabric mass density. The theorical parameters were compared to experimental parameters to verify the built fabric model during the calculation of the geometrical form warp knitted structures. The proposed geometrical model was applied for two types of tricot-tricot fabric knitted from polyamide and polyurethane with different yarn counts. The results showed the differences between theorical parameters calculated by the model and the experimental parameters were 1% - 4% for fabric area mass, up to 9% for the fabric warp and weft density and about 90 % difference in fabric area porosity, which recommended the built model could be applied to calculate the fabric parameters and need to continue developing for of the physico-mechanical warp knitted properties.

Unraveling electromagnetic shielding potential: exploring carbon and stainless-steel Weft knitted fabrics

To address the growing concern of electromagnetic radiation from electronic devices, we developed advanced textile solutions for protection and comfort. Carbon and stainless steel were tested as shielding materials, with carbon nano powder and stainless-steel nano powder embedded into polyester fibers. We also created carbon-embedded and stainless steel-embedded polyester yarns. A total of 12 distinct samples with varying knitted structures and yarn compositions were produced to explore shielding performance and comfort. Testing showed a direct correlation between fabric thickness and the electromagnetic shielding efficiency of stainless steel-polyester fibers. Thicker fabrics provided superior thermal resistance, improving wearer warmth by reducing heat loss, while maintaining relatively high electromagnetic shielding efficiency (EMSE). Our findings highlight the balance between shielding effectiveness and comfort, including air permeability, water vapor permeability, and thermal resistance. These insights are crucial for optimizing textile structures for electromagnetic protection, especially for vulnerable populations like pregnant women.

Flattening behaviour of weft-knitted spacer fabrics

Weft-knitted spacer fabrics are thick 3D knitted structures prized for their cushioning properties which have gathered increasing attention in the last decade. The thickness of a spacer fabric is one of its most influential parameters and strongly impacts its cushioning properties, wearability, thermal insulation or permeability. However, the fabric's natural undulation and high deformability make its thickness measurement uneasy. The current standard measurement methods require to measure the fabric thickness after compressing it until a fixed threshold stress value is reached to flatten it. The diversity of these threshold values is confusing, and each of them is unsuitable to variety of fabric rigidity. In this article, a standard for thickness evaluation was proposed and used to measure the thickness of 20 samples knitted with 5 independent parameters. The measured thickness was compared to the thickness measured at a threshold value of 1 kPa and to a theoretical thickness. The proposed measurement standard was proved reproducible and efficient for all fabrics when the threshold measures showed large errors on the softer and stiffer samples. The flattening stress of the fabrics ranged from 86 to 5262 Pa and could not be approximated by a single standard value. The theoretical thickness was more accurate, predicting the thickness with an average error of 3.8%.

Investigating the Impact of Air Permeability and Thermal Properties on Rib Knit Structures

Factors influencing the comfort and performance of knitted fabrics can be investigated to enhance the understanding and development of functional accessories. Issues related to the thermal regulation and moisture management of these materials are systematically explored in this research. Additionally, the effects of fibre type, yarn properties, fabric variables, and finishing methods are examined through the evaluation of physical properties relevant to the comfort of rib knit structures, particularly in sportswear design. 1x1 Rib knit 1structures were created using polyester spun, cotton spun, polyester filament, and viscose filament yarns with varying linear densities employing a KH-323N computerized flatbed knitting machine. Evaluations of physical properties, thermal characteristics, air permeability, antibacterial efficiency, and hydrophilic finish were conducted following ASTM standards and specific testing methods to thoroughly assess the quality and performance of the fabric. Significant insights into the physical and comfort properties of the fabrics were provided by the results. Varying thermal and air permeability characteristics were demonstrated by polyester-cotton and viscose-cotton fabrics. Thermal resistance and conductivity are influenced by filament denier, loop length, and knit structure, while these same factors affect air permeability. Air permeability is also impacted by finishing treatments, thereby highlighting the complex interplay between fabric properties and comfort. Advanced finishing techniques and novel fibre blends could be explored in future research to further optimize fabric comfort properties.

Computer numerical control knitting of high-resolution mosquito bite blocking textiles

Mosquitoes and other biting arthropods transmit diseases worldwide, causing over 700,000 deaths each year, and costing about 3 billion USD annually for Aedes species alone. Insect vectored diseases also pose a considerable threat to agricultural animals. While clothing could provide a simple solution to vector-borne diseases, modern textiles do not effectively block mosquito bites. Here we have designed three micro-resolution knitted structures, with five adjustable parameters that can block mosquito bites. These designs, which exhibit significant bite reduction were integrated into a computer numerical control knitting robot for mass production of bite-blocking garments with minimal human labor. We then quantified the comfort of blocking garments. Our knits enable individuals to protect themselves from insects amidst their day-to-day activities without impacting the environment.

Enhanced thermoregulation performance of knitted fabrics using phase change material incorporated thermoplastic polyurethane and cellulose acetate nanofibers

AbstractNanofibers act as carriers in systems containing functional materials produced via electrospinning method. By this way, it is possible to transport functional materials with polymer nanofibers, besides having a large surface area compared to their volume, the encapsulation process, which includes complex preparation processes, is eliminated here, and functional materials such as phase‐change materials (PCMs) can be conveniently integrated directly into the carrier material by electrospinning method. The resulting nanofiber membrane can also be used in combination with textile fabrics. This study aims to develop PCM containing nanofibrous membrane coated knitted fabric structures with heat regulation capabilities. Two types of PCMs, hexadecane and octadecane loaded into thermoplastic polyurethane (TPU) and cellulose acetate (CA) nanofibers, directly electrospun on cotton (CO), cotton/polyester (CO/PES), cotton/acrylic (CO/PAC) knitted fabrics for thermoregulation. These nanofiber‐coated fabrics were characterized by scanning electron microscopy (SEM) and differential scanning colorimetry (DSC), and their comfort properties were evaluated by water vapor and air permeability tests and compared with a commercial microcapsule impregnated fabric. According to DSC results, PCM incorporated CA nanofibers had better heat storage capacity than TPU nanofibers and microcapsule applied fabrics. Although PCM‐loaded CA nanofibers may not block airflow as effectively as TPU nanofibers, when a proper coating is achieved air permeability can be decreased to 21.70 L/m2/s, along with a heat storage capacity of 26.38 J/g and still having permeability to water vapor (%40).Highlights Phase change materials were integrated directly to the carrier material by electrospinning PCM integrated nanofiber coating reduced air permeability PCM integrated nanofiber coating did not block water vapor permeability Electrspun cellulose acetate +PCM coating had better heat storage capacity

Study on the promotion multiple of blood flow velocity on human epidermal microcirculation of volcanic rock polymer fiber seamless knitted fabric

Abstract As a material that can release infrared rays, volcanic rock polymer fibers can be used in textiles to improve human microcirculation, which is helpful to relieve chronic inflammatory diseases such as perishoulder arthritis. In this article, there are two different kinds of exterior yarns. Volcanic rock blended polyester, volcanic rock blended polyamide, polyester and polyamide are chosen as the material type of exterior yarn Ⅰ, whereas the material type of exterior yarn II is conductive polyamide yarn. The exterior yarn feed ratio of exterior yarn Ⅰ and exterior yarn II is designed as 8:0, 7:1 and 6:2 when weft plain stitch, 1 + 1 mock rib and 1 + 3 mock rib are used as the knitted structure of the fabric. According to the three-factor four-level orthogonal experimental design method, the sample protocol was established, and 16 knitted sample fabrics were produced. Then, the promotion multiple of blood flow velocity on human epidermal microcirculation of each sample was tested and analyzed. The results show that the promotion multiple of blood flow velocity on human epidermal microcirculation of the fabrics woven by volcanic rock polymer fibers is better than that of the blank control group, and the difference between fabrics with different volcanic rock polymer fibers is small. The higher the proportion of exterior yarn Ⅰ is, the better the promotion multiple of blood flow velocity on human epidermal microcirculation of fabric will be. The effect of knitted structure on the promotion multiple of blood flow velocity on human epidermal microcirculation of fabrics is not obvious. This study provides reference for the design of medical or health textiles for chronic inflammatory diseases.

A preliminary study of polymer optical fiber’s knittability for smart wear applications

PurposeThe purpose of this research is to ascertain the feasibility of fabricating polymer optical fibers (POFs) based textile structures by knitting with Polymethylmethacrylate (PMMA) based optical fibers for textile sensor application. It has long been established that by using the principles of physics, POFs have the capability to function as sensors, detecting strain, temperature and other variables. However, POF applications such as strain and pressure sensing using knitting techniques has since not been very successful due to a number of reasons. Commercially available PMMA-based optical fibers tend to be fragile and susceptible to breakages when subjected to stress during the knitting processes. Also light transmitted within these fibers is prone to leakage due to the curvature that results when optical fibers are interlaced or interlooped within fabric structures.Design/methodology/approachUsing Stoll’s multi-gauge CMS 350 HP knitting machine, five fabric structures namely, 1 × 4 float knit structure, tunnel inlay knit structure, 3:1 fleece fabric and 2:1 fleece fabric structure respectively were used to knit sensor samples. The samples were subsequently tested for length of illumination and sensitivity relative to applied pressure.FindingsThe results of this preliminary study establish that embedding plastic optical fibers into a knitted structure during the fabric formation process for soft strain sensor application possible. The best illumination performance was recorded for tunnel inlay structure which had an average of 94 cm course length of POF being illuminated. Sensor sensitivity experiments also establish that the relative spectral intensity of the fiber is sensitive to both light and pressure. Problems encountered and recommendations for further research have also been discussed and proffered.Research limitations/implicationsDue to resource limitations, an innovative technique (use of precision weight set) was used to apply pressure to the sensors. Consequently, information regarding the extent of corresponding sensor deformation has not been used in this initial analysis.Practical implicationsBecause the fundamental step toward finding a solution to any engineering problem is the acquisition of reliable data, and considering the fact that most of the popular technologies used for soft textile sensors are still bedeviled with the problem of signal instability and noise, the success of this application thus has the tendency to promote the wide spread adoption of POF sensors for smart apparel applications.Originality/valueAs far as research on soft strain sensors is concerned, to the best of the authors’ knowledge, this is the first study to have attempted to knit deformable sensors using commercially available POFs.

Fibre fragment pollution: source directed intervention through design

This study analyses the difference in fibre fragment pollution generated during the laundering of woven and knit fabrics for clothing and the influence of fabric parameters on the amount of pollution released. 100% polyester single jersey knit and 2/2 twill woven fabrics were created and washed according to AATCC TM212-2021. Results indicated more tightly woven structures released over three times less pollution than looser knit structures, releasing 6.41 mg of fibre fragments per kg of woven fabric (mean ± 1.50 SD, n = 8) compared to 21.21 mg of fibre fragments per kg of knit fabric (mean ± 1.80 SD, n = 8). The first wash for both knit and woven fabrics shed significantly more fibre fragments than subsequent washes. By the fifth wash both fabrics released under a tenth of the amount of pollution released in the first wash. To mitigate fibre fragment pollution that is released by fabrics designed for clothing this work recommends designing out pollution using more tightly constructed fabrics. Furthermore, the implementation of technology in fabric and garment manufacturing processes (e.g. fibre catching devices) should be utilised specifically during first washes allowing pollution to be filtered from the wastewater to stem the flow of contaminants into the environment.

Thermal Effusivity Assessment of Sportswear Fabrics in the Dry State: Stacked and Air-Hoop Methods

Abstract In recent years, thermal effusivity, a property that describes the warm or cool touch perception, has gained significant attention in the apparel industry as it contributes to human thermophysiological comfort. The current study aims to explore the thermal effusivity of 27 sportswear fabrics, including woven and knitted structures with various fiber contents, using the stacked method (according to ASTM D7984-21, Standard Test Method for Measurement of Thermal Effusivity of Fabrics Using a Modified Transient Plane Source (MTPS) Instrument) and a modified air-hoop method. The results obtained revealed that the pressure range specified in ASTM D7984-21 (10–50 kPa) may cause fabric compression, resulting in the measurement of a material-based thermal effusivity rather than the fabric thermal effusivity. A pressure of 1 kPa was found to be more appropriate for obtaining accurate measurements of sportswear fabrics without altering their three-dimensional structure. Furthermore, a strong correlation was observed between the stacked and air-hoop methods for fabrics with thicknesses close to or greater than 0.4 mm. The air-hoop method simulates the configuration when the fabric is worn as part of a garment. The new knowledge provided by this research will enhance the accuracy of the thermal effusivity measurement of sportswear fabrics. It will contribute to the development of more comfortable fabrics considering realistic garment use scenarios.

A Highly Durable and UV‐Resistant Graphene‐Based Knitted Textile Sensing Sleeve for Human Joint Angle Monitoring and Gesture Differentiation

Flexible strain sensors based on textiles have attracted extensive attention owing to their light weight, flexibility, and comfort when wearing. However, challenges in integrating textile strain sensors into wearable sensing devices include the need for outstanding sensing performance, long‐term monitoring stability, and fast, convenient integration processes to achieve comprehensive monitoring. The scalable fabrication technique presented here addresses these challenges by incorporating customizable graphene‐based sensing networks into knitted structures, thus creating sensing sleeves for precise motion detection and differentiation. The performance and real‐world application potential of the sensing sleeve are evaluated by its precision in angle estimation and complex joint motion recognition during intra‐ and intersubject studies. For intra‐subject analysis, the sensing sleeve only exhibits a 2.34° angle error in five different knee activities among 20 participants, and the sensing sleeves show up to 94.1% and 96.1% accuracy in the gesture classification of knee and elbow, respectively. For inter‐subject analysis, the sensing sleeve demonstrates a 4.21° angle error, and it shows up to 79.9% and 85.5% accuracy in the gesture classification of knee and elbow, respectively. An activity‐guided user interface compatible with the sensing sleeves for human motion monitoring in home healthcare applications is presented to illustrate the potential applications.

Classification, Structure and Construction of Functional Orthopaedic Compression Knits for Medical Application: A Review

Analysis of functional products for medical textiles indicates that there are plenty of different classifications of this group. Requirements for compression generated by compression garments differ depending on the application area, and even more, sometimes are contradictory and can be fulfilled in very different ways. The effectiveness of such products depends on mechanical and physical properties as well as psychological barriers. Currently, there is no uniform classification of compression classes, furthermore, there is no uniform standard, test method or technic for evaluation of the product’ compression. Knitted compression fabrics are made by knitting together at least two types of yarns: a ground yarn which ensures stiffness and thickness and an elastomeric yarn which generates compression. Knitted compression products can be produced on both flat and circular knitting machines, though parameters and usage of production are different. Additional elements used in the structure of the compression product can significantly change the generated compression. Purposes and number of additional details depend on the application and functionality of the compression support, nevertheless, all rigid elements must be taken into account at the designing stage. Additional functionality like antimicrobial activity or thermal therapy can also be provided for compression knits. It is highly important to ensure the longevity of all functional properties.

The effect of knit structure on natural dyeing properties of cotton fabric

Natural dyeing of textile materials is gaining popularity all over the world since natural dyes are mostly eco-friendly, less toxic, and less allergenic as compared with synthetic dyes. Although synthetic dyes offer a broad range of color and color fastness and bright hues, they are nonbiodegradable and carcinogenic compounds and cause water pollution as well as waste disposal problems. This study presents the natural dyeing of cotton knitted fabric with three different structures using R. cordifolia root extract as a natural dye. Knitted fabrics with three different structures, interlock (350 g/m2), single jersey (145 g/m2) and rib (135 g/m2), were produced and dyed with madder (Rubia Cordifolia) in the presence of tannic acid as a mordant. The dyed samples were evaluated in terms of color measurement results (CIE L*,a*, b*, C*, h0, DE) and color fastness properties.

Theoretical analysis for the mechanical properties of the knitted structures

Abstract Knitting is a technology that has a thousand-year-old history, and can be normally seen in our daily lives. The knitted structure is constructed by the interwoven yarns that constrained by themselves, exhibiting extreme stretchability. The mechanical properties of the knit fabric also enable their integration with the flexible electronic devices. Nonetheless, it is yet problematic to expose the mechanical behaviors of knitting intrinsically. This paper investigates the mechanical characteristics of knitted structures subjected to uniaxial stretching. The analysis includes a structural assessment of the unit cell, with a focus on half of the cell accounting for symmetry. Mechanical analysis for three distinct scenarios (without elongation and friction, with elongation and no friction, with elongation and friction) is also presented. The stress-strain curve of the knitted structure and the correlation between stiffness and geometric parameters are illustrated. Additionally, simulations are carried out based on finite element analysis, yielding consistent results with the theoretical calculations. Subsequently, a uniaxial stretching experiment is conducted, and the experimental outcomes also verifies the theoretical analysis. Our analysis successfully explains the mechanical behavior of knitted structures, and also provides a reference for studying knitted fabrics with other topologies.

Quantification of Fundamental Textile Properties of Electronic Textiles Fabricated Using Different Techniques

Electronic textiles (E-textiles) have experienced an increase in interest in recent years leading to a variety of new concepts emerging in the field. Despite these technical innovations, there is limited literature relating to the testing of E-textiles for some of the fundamental properties linked to wearer comfort. As such, this research investigates four fundamental properties of E-textiles: air permeability, drape, heat transfer, and moisture transfer. Three different types of E-textiles were explored: an embroidered electrode, a knitted electrode, and a knitted structure with an embedded electronic yarn. All of the E-textiles utilized the same base knitted fabric structure to facilitate a comparative study. The study used established textile testing practices to evaluate the E-textiles to ascertain the suitability of these standards for these materials. The study provides a useful point of reference to those working in the field and highlights some limitations of existing textile testing methodologies when applied to E-textiles.

Influence of duoplasmatron ion source plasma treatment on multi-axial knitted structure reinforced glass fiber composites

The present study investigates the impact of glow discharge cold plasma-induced duoplasmatron ion source on the mechanical properties of multi-axial knitted structure reinforced glass fiber composites. Analysis of failure location and mode in bending tests was conducted using the acoustic emission method. The results reveal that the tensile and bending strength of the multi-axial structure reinforced glass fiber composites treated with oxygen/nitrogen plasma had increased by 21.84% and 37.28%, respectively. In contrast, when treated with oxygen/argon plasma, the corresponding enhancements were 17.47% and 24.16%, respectively. These results indicate that oxygen/nitrogen plasma treatment yields superior mechanical properties to oxygen/argon treatment. The accumulated acoustic emission energy in the multi-axial structure reinforced glass fiber composites subjected to oxygen/nitrogen and oxygen/argon treatments was 25.49% and 62.39% lower than untreated samples, respectively. The failure mode observed in the untreated composites was matrix cracking, whereas the composites treated with dual plasma exhibited interface debonding. The dual plasma modification enhanced fiber wettability and surface roughness, facilitating increased contact area between the fiber and matrix and promoting the overall bonding performance between the two components. Taken together, our findings suggest that duoplasmatron ion source treatment enhanced the interface bonding and mechanical properties of the multi-axial structure reinforced glass fiber composites.

Influence of airflow resistance on acoustic behaviour of needle-punched nonwoven structures

Textile materials and structures have gained significant attention in the field of noise reduction due to their porosity, softness, and good acoustic absorption properties. Porous materials are an excellent example of passive materials, which reduces sound energy by dissipating heat energy due to the presence of void structure. In textiles, nonwovens are highly porous and less expensive materials compared to woven and knitted structures. In this research, flax, jute, and polyester nonwovens were used to study the effect of various parameters such as fiber fineness, fiber cross section, areal density, and punch density on the airflow resistivity of the nonwovens and in turn its influence on the sound absorption coefficient. It was observed that the acoustic performance of woven and nonwoven structures is mainly dependent on the porosity or bulk density of the structure which also influences the airflow resistivity of the fabrics. Therefore, the investigation of the airflow resistance of the nonwovens and its correlation with the sound absorption coefficient became an important part of this study. An instrument based on ISO 9053 standard was fabricated to measure the airflow resistivity. It was observed that the increase in the areal density leads to increase in the airflow resistance of the nonwoven. The airflow resistance increases as the mass density increases and porosity decreases. It was observed that the sound absorption coefficient and airflow resistance were directly proportional.

Fermenting Knits: A material-driven exploration of knit-based bacterial cellulose biocomposite textile materials through fibre reassembly

ABSTRACT Environmental concerns surrounding textile production have increased the need and interest in developing material innovations and interdisciplinary approaches to offset this ecological impact. Bacterial cellulose is present in several industries, and its biologically produced form has shown potential use within fashion. Within the emerging field of biodesign, research surrounding bacterial cellulose textiles generally focuses on the initial sheeted growth, while alternative outputs and working methods remain scarce. Here, fibre reassembly is analysed by fully integrating broken down BC fibres with knitted structures. Material selection and working methods take a practice-led approach to experiment formulation in order to observe material behaviour as central to development. This project aims to create biocomposite textiles that enhance the properties of bacterial cellulose and expand its designable characteristics through low-tech working methods accessible from designerly backgrounds. The results are intended to inform further research in footwear design contexts, as basis to develop BC-based components. Experimentation shows BC fibres reassembled around the knitted structures, varying according to yarn choice and fermenting environment alteration. This demonstrates potential for material and methodology development while exploring co-design with living organisms. In the context of future applications, BC-based composite textiles can self-assemble at different growth stages, offering the possibility of material-driven approaches to spaces intersecting biology and design.

Functional System for Temperature and Relative Air Humidity Software Monitoring in Interlayer Clothing Space

Introduction. The study of the parameters of the clothing space is extremely important in the development of seasonal clothing for the military, police, athletes, etc.Problem Statement. The use of “smart” textiles capable of responding to changes in the environment, adapting to it by integrating functional capabilities into the textile structure, deserves attention. Person’s feeling and emotional response are accompanied by electrical, thermal, chemical or other changes in the human body, which can be recorded by electronic devices and used to monitor the comfort of clothing.Purpose. The purpose is to develop a functional system for monitoring the interlayer space of clothing given the temperature and relative humidity and for creating a prototype remote control system for clothing.Materials and Methods. Sensors (a microcontroller with a battery, radio modules, temperature and relative humidity sensors) placed in the knitted structure of the T-shirt, on certain parts of the human body have been used. Atmega328 microcontroller equipped with 18650 batteries has been employed to detect the temperature and the relative humidity in the interlayer space of the clothing with the help of DS18B20 temperature sensors and DHT22 humidity sensors. The HC-12 radio module has been used for transmitting the data from the microcontroller to the target device. The data have been processed by a special program with the use of the Serial, NumPy, Matplotlib, and Drawnow libraries.Results. The system for remotely monitoring changes in the internal microclimate within the airspace between layers of diff erent clothing materials has been developed. The relationship between the average temperature and the relative humidity in the interlayer clothing space has been determined and are equal to ~26 0C and 29.8%, respectively, after exposure to an outdoor temperature of –10 0C.Conclusions. The obtained results can be used to improve existing and to develop new items of clothing with increased comfort.