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A range of conductive knitted fabric reinforced polypropylene composites have been developed and their electromagnetic shielding effectiveness (EMSE), electrostatic discharge (ESD) and impact properties have been investigated. Carbon and aramid fibers are used as the reinforcement phase in the composites, while copper and stainless steel wires are...
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... yarns were fabricated into weft knitted fabrics using a 5G semi-automatic flat knitting machine. Eight kinds of knit structure, namely double plain, double plain inlaid one, two ends as shown in Fig. 1, were produced [11]. The uncommingled yarns were used as knitting yarns and also as inlaying yarns. The row of knit loops in the width direction is called 'course' and the row of the loops in the longitudinal direction of the fabric is called 'wale'. Knitted fabric nomenclatures A0, A1, A2 with wale densities of 28, 20, and 20 loops ...
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... ESD voltage of composites increases with increasing conductive filler loading at 12 kV ESD voltage. From the above results, it is clear that the amount of copper, stainless steel, and carbon fiber plays an important role in determining the EMSE and ESD of the knitted composites. Inlaying additional yarns into the double plain inlaid structure ( Fig. 1(b)) may increase the conductive filler loading. In other words, by using an inlaying technique, the EMSE and ESD of knitted fabric composite laminates can be tailored. It may be noted that the knitted inlaid fabrics are non-crimped fabrics and thus contribute to the greater dimensional stability of the ...
Citations
... The inlay knitting technique can be used to apply elastic yarns to the openings of knitted socks and gloves to provide stretchability for donning and holding in position. High-performance materials such as aramid, fibreglass, basalt, carbon, etc. have been used as inlaid yarns in the fabrication of composites to improve mechanical behaviour [21][22][23]. Previously, we developed a novel spacer fabric with silicone tubes inlaid into the connective layer [24,25]. The fabric has a significantly higher compression resistance and increased ability to absorb impact forces. ...
Spacer fabrics are good for impact force absorption and have the potential for vibration isolation. Inlay knitting of additional material to the spacer fabrics can give reinforcement to the structure. This study aims to investigate the vibration isolation properties of three-layer sandwich fabrics with silicone inlay. The effect of the presence of the inlay, inlay patterns and materials on the fabric geometry, vibration transmissibility and compression behaviour were evaluated. The results showed that the silicone inlay increases the unevenness of the fabric surface. The fabric using polyamide monofilament as the spacer yarn in the middle layer creates more internal resonance than that using polyester monofilament. Silicone hollow tubes inlay increases the magnitude of damping vibration isolation, whereas inlaid silicone foam tubes have the opposite effect. Spacer fabric with silicone hollow tubes inlaid by tuck stitches has not only high compression stiffness but also becomes dynamic, showing several resonance frequencies within the tested frequency range. The findings show the possibility of the silicone inlaid spacer fabric and provide a reference for developing vibration isolation materials with knitted structure and textiles materials.
... Örtlek et al. [24] examined the EMSE of pique, plain (E28), and double-knit structures (E18) with the shielded box shielding efficiency measurement method (30 MHz -9.93 GHz). Apart from the studies performed with the free space measurement technique [11][12][13][14][15][16][17][18][19][20] and the shielded box shielding efficiency measurement technique [21][22][23][24], there are also studies on EMSE of knitted fabrics performed with the coaxial transmission line technique [11,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. Knitted fabrics give different EMSE values for each frequency when measured with different measurement techniques and / or different polarizations [11]. ...
The aim of this study is to investigate the influence of knitting structure and metal wire amount on the electromagnetic shielding effectiveness (EMSE) of knitted fabrics comparatively. Single jersey, single pique, weft locknit, and cross miss fabrics involving stainless steel or copper wires were produced on a flat knitting machine. A free space measurement technique was used for the EMSE measurements in an anechoic chamber. The variance analysis results of the EMSE values reveal that the effect of knitting structure, metal wire type, metal wire amount, and incident wave frequency is highly significant. It was observed that fabrics with tuck and miss loop structures had higher EMSE values than single jersey fabrics. It was found that single pique fabrics had higher EMSE values than single jersey fabrics that contain twice as much metal wire. It indicates that changing the knitting structure is more effective than changing the metal wire amount.
... It has been observed that limited studies have been conducted to determine the mechanical properties of these composites. 26,33,34 Hybrid fabric consisting of hybrid yarn produced by twisting acrylic yarn with stainless steel wire was used. This fabric was produced in our previous study 28 and the mechanical properties of hybrid yarn and the EM shielding effectiveness of fabric were investigated. ...
Hybrid composite specimens were produced with stainless steel-acrylic (SSA) and carbon fiber reinforcement in order to achieve ductile behavior compared to CF reinforced epoxy composites. Laminated composites containing CF and SSA fabrics in with different ply configurations were manufactured using vacuum infusion method. In addition, CF fabric was used in two different ply orientations (0–45°). In both the flexural and tensile test results, composites having CF oriented at 0° showed higher strength and modulus but lower strain than composites having CF oriented at 45°. When the number of carbon fiber layers increased, the composites showed high strength and modulus, but low strain. Increasing the number of SSA significantly increased the flexural and tensile strains of laminated composites. After the mechanical tests, the fracture surfaces of the specimens were examined with an optical microscope and matrix cracks, fiber breakage, fiber pull-out and delamination failures were observed.
... Therefore, researchers are trying to develop such materials that combat these radiations by absorption while maintaining intrinsic properties of textile surfaces though the importance of reflective textile surfaces cannot be neglected completely in certain cases such as absorptive surfaces can be used in transformers, motors, generators, etc. [66]. Skeletons made of all sort of fibers including natural (cotton, bamboo, etc.), regenerated (lyocell), synthetic (polyester, nylon, etc.) and high-performance fibers (carbon, Kevlar, etc.) have been modified physically and chemically to develop textiles capable of protecting against destructive EM waves [67][68][69][70][71]. ...
... However, shielding from the electric component is satisfactory for some applications [76]. For attenuation of waves, conductive metal fibers/filaments are used solely or mixed with natural/synthetic fibers (both conventional and elite fibers like carbon, Kevlar etc.) [68,69], nonconductive fibers are coated with conductive materials including metals and intrinsically conducting polymers. These yarns are used to make fabrics suitable for EM shielding purposes. ...
... EMSE was found to be increased with frequency as tested over 350-3000 MHz. Carbon and copper were proved to be suitable for shielding at low frequency range while for higher frequency ranges steel was proposed to be suited [68]. ...
The rapid proliferation of electronic devices and their operation at high frequencies has raised the contamination of artificial electromagnetic radiations in the atmosphere to an unprecedented level that is responsible for catastrophe for ecology and electronic devices. Therefore, the lightweight and flexible electromagnetic interference (EMI) shielding materials are of vital importance for controlling the pollution generated by such high-frequency EM radiations for protecting ecology and human health as well as the other nearby devices. In this regard, polymeric textile-based shielding composites have been proved to be the best due to their unique properties such as lightweight, excellent flexibility, low density, ease of processability and ease of handling. Moreover, such composites cover range of applications from everyday use to high-tech applications. Various polymeric textiles such as fibers, yarn, woven, nonwoven, knitted, as well as their hybrid composites have been extensively manipulated physically and/or chemically to act as shielding against such harmful radiations. This review encompasses from basic concept of EMI shielding for beginner to the latest research in polymeric-based textile materials synthesis for experts, covering detailed mechanisms with schematic illustration. The review also covers the gap of materials synthesis and their application on polymeric textiles which could be used for EMI shielding applications. Furthermore, recent research regarding rendering EMI shielding properties at various stages of polymeric textile development is provided for readers with critical analysis. Lastly, the applications along with environmental compliance have also been presented for better understanding.
... Core-wrapping technique is also a hybrid yarn manufacturing technique by wrapping softer and lower strength fibres around high performance fibres to protect them during textile preforming processes such as weaving, knitting and braiding [34][35][36]. The literature indicates that core-wrapping technique is mostly used to wrap natural fibres with thermoplastic fibres to produce thermoplastic composite laminates [37][38][39]. ...
Micro-warpping of sub-scale fibre bundles with thermoplastic fibres has been explored for improved intra-tow
hybridisation in comparison to traditional commingling process. This paper investigates matrix toughening of
thermoset composites with thermoplastic fibres delivered through textile preforming and hence does not adversely effect resin viscosity during the infusion process. Tow-scale thermoplastic fibres appear to diffuse cracks
from inter-laminar to intra-tow due to relatively weak interface, and at the same time protect the reinforcing fibres by acting as elastic foundations during impact loading. In this paper, two hybridisation methods, traditional
commingling and novel micro-wrapping, have been compared for assessing the impact damage performance of
thermoset composite laminates. It appears that micro-wrapped laminates exhibit better impact and damage tolerance performance than the commingled composite laminates due to the smaller impact induced damage areas
and better PP fibre distribution. Improved thermoplastic fibre distribution in micro-wrapped tow architechture
has been shown to improve impact damage tolerance through mechanisms of fibre cushioning and intra-tow
crack dispersion.
... Recently, fabrics have received increasing attention when compared to other reinforcement materials like particles, fibers, and so on. Although the fibers are applied for three-dimensional (3D) or two-dimensional (2D) structures [1,2], the architectures are also used through textile fabric (such as woven, nonwoven, knitted, and braided) [3][4][5][6][7][8][9]. In 3D fabrics, the fibers are intermeshed lengthwise, thickness-wise, and crosswise, while 2D woven fabrics are made of two sets of yarn (one is lengthwise 0°and the other is crosswise in a 90°direction) through conventional weaving technology. ...
Fabric-based laminated composites are used considerably for multifaceted applications in the automotive, transportation, defense, and structural construction sectors. The fabrics used for composite materials production possess some outstanding features including being lighter weight, higher strength, and lower cost, which helps explain the rising interest in these fabrics among researchers. However, the fabrics used for laminations are of different types such as knit, woven, and nonwoven. Compared to knitted and nonwoven fabrics, woven fabrics are widely used reinforcement materials. Composites made from fabric depend on different properties such as fiber types, origin, compositions, and polymeric matrixes. Finite element analysis is also further facilitating the efficient prediction of final composite properties. As the fabric materials are widely available throughout the world, the production of laminated composites from different fabric is also feasible and cost-effective. This review discusses the fabrication, thermo-mechanical, and morphological performances of different woven, knit, and nonwoven fabric-based composites.
... For engineering and industrial applications, PP materials should exhibit increased heat resistance, improved impact toughness and stiffness; and low molding shrinkage [2][3][4][5][6]. Some studies have showed that PP properties are improved when combined with clays [7][8][9], wood [10][11][12] and glass fibers [13,14], carbon derivatives [15][16][17][18], among other fillers. ...
This work reports the easy production of hybrid organoclays composed of Cloisite 20A and modified graphene oxide (r-mGO) at different proportions, and their effect on PP composites properties. In this way, it is proposed to evaluate both, the effect of the amount of r-mGO in the hybrid organoclay, and the effect of the amount of the hybrid organoclay on the PP composites. Morphological and structural details of PP composites were followed by scanning electron microscopy and X-ray diffraction, respectively. The thermal stability of the composites was analyzed by thermogravimetric analysis and differential scanning calorimetry, tensile mechanical properties were also tested. The results show that the obtained laminated hybrid material exhibited homogeneous intercalation of Cloisite 20A and r-mGO. The interactions among the clay intercalant molecules and graphene oxide grafting makes them remain united even in a polymeric matrix, acting as a good reinforcer and resulting in a rigid polymeric composite with improved mechanical properties at low content of the filler, mainly when having small amounts of r-mGO.
... Various researchers and industrial companies have shown keen interest in providing solutions to overcome this problem. Among the various solutions offered, textile products and textile-based composite materials have caught the attention of researchers [8,9]. In recent years, conductive fabrics have been considered for electromagnetic shielding and anti-electrostatic purposes in various applications for the defense, electrical, and electronic industries. ...
In this study, electromagnetic shielding and solar properties of woven fabrics which were produced barium titanate/polyester bicomponent yarns were investigated. 1, 2 and 3% additive ratios of barium titanate and three different fabric structures (1/1 plain, sateen and special weave) were used in the experiments. The effect of additive ratio and the fabric structure on electromagnetic shielding properties were evaluated. Electromagnetic Shielding Effectiveness (EMSE) of the woven fabrics was determined according to the ASTM D4935-10 standard by using coaxial transmission line measurement technique in the frequency range of 15–3000 MHz. The fabric with the highest content of the barium titanate (3%) and special weave showed the highest shielding effectiveness, reaching 13.96 dB at 15 MHz. The solar properties were measured according to EN14500 using a UV/VIS/NIR spectrophotometer and results were calculated according to EN 410 standard. The reflectance values of barium titanate added polyester fabrics increased and the transmittance values decreased.
... In addition, they have advantages due to their flexibility and comfort, 2 protection against radio frequency interference, coordination of thermal expansion, and, at the same time, has low weight. 3 Textile materials that are used for protection against EMR require screening performance depending on the scope of their use: 4 professional protection or general use (see Table 1). The first class includes medical equipment, quarantine material, professional security uniform for electronic manufacturer, electronic kit, or other newest applications. ...
... Some of the development is devoted to the creation of knitted screen materials by introducing metal wires in the form of weft threads into the knitted structure. 3,18,19 Test results show that such weft-knitted structures have 10-40 dB shielding effectiveness (SE) under the frequency of 500 MHz. 19 On the contrary, such materials lose flexibility in the direction of wire filling, which reduces the consumption properties of the materials and limits their use scope. ...
Today we can’t imagine our life without electricity and technology, transport and television. In the information age, computers, the Internet, cell phones, and smartphones are helpers for everyday needs. However, our environment and comfortable living in it can be detrimental to our health. It is hard to realize the fact that such a global technical breakthrough has hit human health. Exposure to electromagnetic radiation could lead to changes in the structure of nerve cells and blood formulas, deformation of the circulatory system, pathology of the endocrine system, decreased immunity, and so on. Nowadays the development of innovative textiles with electromagnetic radiation shielding is a relevant topic that promotes the creation of a flexible protective screen for the human being and various electronic devices. Textiles themselves do not protect against electromagnetic radiation; however, the textiles can be successfully converted into protective material after changing the raw material composition, creating a new production process, or adapting technologies that can make them electrically conductive. Basic methods of textile producing such as weaving, knitting, non-weaving, or their combination can be used to make electromagnetic shielding fabric. In this study, the knitting on 8-gauge flat-bed machine has been chosen as main technology. The metal wire (stainless steel: 0.12 mm) is used separately or together with 10 × 2 tex cotton yarn. Two sets of samples with different interloopings are produced which differ by steel percentages and positioning in the structures. Electromagnetic shielding effectiveness of textile samples (dB) was measured according to ASTM 4935-10 on frequency range 30 MHz–1.5 GHz. It is concluded that the positioning of the metal components in the knitted structure is the main factor determining the shielding ability. The half Milano rib knitted structure demonstrates the highest shielding efficiency.
... The lack of the free electrons reduces dramatically the electrical conductivity of the polymer. There are several method to increase the electrical conductivity of the polymers, each one with certain benefits and drawbacks [1], [2], [3], [4]. The higher conductivity can be achieved through the use of: a. Inherent conductive polymers. ...
The textile fibers are almost ideal isolators with extreme low electrical conductivity. However in certain applications it is necessary to use electrically conductive textile materials. The electrical conductivity of the textile products is important in heating applications, where the electrical current flows through the mass of the fabric and results in the heat dissipation due to the Joule effects. The electrical conductivity of the textile materials is also useful in the electromagnetic shielding applications. The conductive textile materials can be used to create a Faraday shield effect. The present study examines the attenuation of the conductive textile yarns in the radio frequency of the GHz range. The materials combine textile and electrical characteristics and they allow the development of new protective multifunctional structures. The experiments give an exact idea of the behaviour of these multifunctional materials in the important Super High Frequencies range of the electromagnetic spectrum.
