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Composites based on e.g. randomly oriented nonwovens and injection moulded structures from discontinuous carbon fibre (CF), which are processed industrially exhibit low tensile strengths of 200–300 MPa and 400 MPa, respectively. In contrast, composites based on twisted hybrid yarns from discontinuous CF and thermoplastic fibre show higher tensile strengths such as 1150 MPa. Reasons are improved fibre orientation and higher fibre volume content. However, tensile strength is still lower than that of uni-directional carbon fibre reinforced composites (CFRP) based on continuous filament yarn, which is around 1560 MPa. The reason is a low fibre orientation due to yarn twisting and high fibre shortening, which occurs throughout the yarn manufacturing process. As mechanical properties of composites largely depend on fibre orientation and length, there is a high potential to achieve higher mechanical properties in CFRP by ensuring gentle processing of CF and reducing yarn twist. However, due to brittleness and smooth surface of CF, spinning of yarns with low twist (<60 T/m (twist per meter)) is challenging. In order to exhaust the potential of hybrid yarns, a semi-industrial process chain to produce hybrid yarns while ensuring gentle processing of discontinuous CF (fibre length 100 mm) and polyamide 6 fibres (fibre length 80 mm) at significantly low level of twist 20 T/m is reported in this paper. Carbon fibre reinforced composite manufactured from these hybrid yarns show high tensile strength (1453 ± 27 MPa), Young's modulus (94 ± 6 GPa), flexural strength (1090 ± 41 MPa) and flexural modulus (98 ± 5 GPa). [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the thermophysiological comfort behavior of fabrics based on copper wire that can be used for electro-textile applications. For this purpose, hybrid folding yarns were produced by twisting cotton/polyester yarn with copper wire. These electrically conductive hybrid yarns were then used to produce upholstery fabrics with different weave types as plain, 2/1 twill and sateen weave in three different density levels as tight, medium and loose. Thermophysiological comfort properties such as air permeability, thermal and water vapor properties of the hybrid fabrics were measured. In addition, the heat transfer properties of the fabrics were investigated with thermal camera videos, and porosity values were determined from microscope images. In this way, the main thermophysiological comfort properties of the basic electro-textile structures were revealed. According to the results obtained, it was found that the use of conductive wire in the fabric structure did not negatively affect the thermophysiological comfort properties of the fabrics, and fabric density was a determining parameter in relation to the thermophysiological comfort properties of the fabrics. The obtained results of this study may be used to improve the design of electro-textile structures taking into account the thermophysiological comfort. [ABSTRACT FROM AUTHOR]

Processing carbon fiber reinforced thermoplastic parts includes heating to form the thermoplastic matrix. The needed heat can be applied externally or internally to the preform. One possibility to generate intrinsic heat involves the use of carbon fibers as a resistive element to induce joule heat. So far, most research efforts have been based on contacting continuous carbon fibers on both ends to melt the thermoplastic matrix of a pre-impregnated preform. The objective of this project is to use a dry hybrid yarn textile in a one-step process to impregnate and rapidly consolidate the dry textile in less than a minute. The desired molding process is based on joule heating of carbon fibers due to an applied current in the transverse fiber direction. This article focuses on the detection of the involved macroscopic parameters. The first composites produced by means of this new method exhibit a high potential with heating times of 15 s, a void fraction below 1%, and flexural properties comparable to the state of the art. [ABSTRACT FROM AUTHOR]

Processing carbon fiber reinforced thermoplastic parts includes heating to form the thermoplastic matrix. The needed heat can be applied externally or internally to the preform. One possibility to generate intrinsic heat involves the use of carbon fibers as a resistive element to induce joule heat. So far, most research efforts have been based on contacting continuous carbon fibers on both ends to melt the thermoplastic matrix of a pre-impregnated preform. The objective of this project is to use a dry hybrid yarn textile in a one-step process to impregnate and rapidly consolidate the dry textile in less than a minute. The desired molding process is based on joule heating of carbon fibers due to an applied current in the transverse fiber direction. This article focuses on the detection of the involved macroscopic parameters. The first composites produced by means of this new method exhibit a high potential with heating times of 15 s, a void fraction below 1%, and flexural properties comparable to the state of the art. [ABSTRACT FROM AUTHOR]

In this study, an innovative method consisting of electrospinning and conventional textile production techniques was built up to produce hybrid yarns enabling the production of functional textile products. The principle of the developed method is to open the twist of spun yarn, make this fibre bundle conductive for use as a collector, collect the electrospun nanofibres onto the conductive opened fibre bundle and finally twist this structure to produce hybrid yarn. To determine the feasibility of the developed method, surface morphology, chemical composition, coating features and tensile properties of the hybrid yarns were compared with that of the pure yarn and nanofibre-coated yarns produced without untwisting and retwisting processes. Test results demonstrated that untwisting process in hybrid production method provided the application of nanofibres interior structure of the spun yarn while retwisting process made integration of classical textile fibres and nanofibres together and hence locking the obtained yarn structure effectively. Thanks to the integrated structure, it was successful to get the yarn have the required tensile properties for weaving, knitting and other processes. Three minutes was determined as the optimum coating time for the effective nanofibre deposition and tensile properties. Summing up the results, it was believed that the method helps to benefit from the special properties of nanofibres for the functional yarn production together with durability and higher tensile properties of the spun yarns for larger usage areas. The presented findings could encourage the researchers to commercialize the method in order to get nanofibre-coated functional yarns. [ABSTRACT FROM AUTHOR]

This research describes the structural and tensile properties of glass/polyester hybrid yarns produced by co-wrapped and side-by-side technologies. Based on co-wrapping technology, the hybrid yarn is composed of polyester and glass fibers as shell and core structure, respectively. In order to produce this type of yarn, a new machine was designed and manufactured to investigate the influence of linear densities (16, 50.67, and 67.11 tex) and wrapping densities (115, 180, and 230 turns/m) of polyester fibers. It was found that the linear and wrapping densities have a significant effect on the structural and tensile properties of the final hybrid yarn. In order to compare, another type of hybrid yarn was also been investigated by hybridization of glass and polyester fibers (16, 50.67, and 67.11 tex) via side-by-side method. In comparison with the side-by-side and single glass yarns, the co-wrapped yarns have higher breaking load and tenacity due to the lateral compression force of the wrapped filament. The results show a 62% increase in breaking load of co-wrapped hybrid yarns in comparison with the side-by-side and single glass yarns. [ABSTRACT FROM AUTHOR]

This paper involves a comprehensive evaluation of electromagnetic shielding characteristics of woven fabrics. The conductive fabrics produced by using cotton/copper-wrapped and cotton/stainless steel-wrapped hybrid yarns in plain and twill weaves were tested in single and double layer structures to determine the electromagnetic shielding effectiveness (EMSE), absorption and reflection values over an incident frequency of 0–3000 MHz. In addition, the shielding effectiveness (EMSE) of these conductive fabric layers was tested under pure cotton fabric. The results indicated that fabrics including copper-wrapped hybrid yarns exhibited EMSE values that increase with increasing incident frequency then decline after a peak value is reached. On the other hand, fabrics including stainless steel-wrapped hybrid yarns showed no sharp peak values, instead; slight peaks were observed. The differences between the EMSE values of plain and twill weave fabric samples were found to be statistically insignificant. The use of fabrics including stainless steel-wrapped hybrid yarns in the layered structures resulted in better shielding effectiveness in a wider incident frequency range when compared to the fabrics including copper-wrapped hybrid yarns. Finally, it was found that the use of conductive fabrics under pure cotton fabric did not interrupt the shielding effectiveness of the conductive fabrics, which can lead to consider the use of layered structures for garments requiring special protective capabilities. [ABSTRACT FROM AUTHOR]

In this study, the application of carbon filament yarn (CFY)-based conductive hybrid yarn as the heating element in a textile-reinforced concrete structure is reported. For this purpose, a hybrid yarn having a core-sheath structure (the core is made of carbon filament yarn and the sheath consists of a mixture of short glass and polypropylene fibres) is manufactured by DREF-2000 spinning technique and integrated into textile structure by tailored fibre placement method. Heat can be generated in the concrete structure by passing electric current through the conductive carbon filament yarn core of the hybrid yarn using the principle of resistive heating, where the sheath acts as the protection and isolation layer. From the initial investigations made on a small concrete specimen, important information is gathered and a large concrete slab with integrated conductive hybrid yarn is manufactured. The heat ability and the comfort level of the manufactured concrete slab are measured. The investigations have revealed the potential of using such hybrid yarn for a pointwise heating of the concrete surface for possible appliance in outdoor furniture. [ABSTRACT FROM PUBLISHER]

A prospective method for manufacturing thermoplastic composites involves commingling to produce hybrid yarn consisting of two components: reinforcement fibres and thermoplastic matrix. In this work, various types of commingled hybrid yarns were developed to improve blend uniformity and achieve homogeneous filament distribution in two-component hybrid yarns. An experiment was carried out to examine the distribution of filaments in a series of glass/polypropylene commingled hybrid yarns. The influence of changes in process parameters such as the degree of overfeeding, production speed, and air pressure on the filament distribution in the cross-section of commingled hybrid yarns was investigated. In this study, new technological approaches to achieve blend uniformity in commingled hybrid yarns are developed. The radial distribution index and a new blending coefficient were used to evaluate the blending uniformity of the yarns. [ABSTRACT FROM PUBLISHER]

With the growing popularity of hybrid yarn techniques, the micro-braided yarn is becoming a good choice as one kind of intermediate materials for thermoplastic biocomposites, by presenting favorable morphology during the preform process and lowering the resin flow distance during the thermo-compression process. In this article, different flax/polypropylene (PP) based multi-core micro-braided hybrid yarns with the similar total number of flax core fibers were manufactured, by varying the parameters: multi-core configuration and braiding angle; both dry-and thermo- states tensile tests on yarns were carried out, since it is necessary to simulate the deforming behavior of a single hybrid yarn during the thermoforming process. The objective is to determine the cover factor especially for multi-core micro-braided yarn as a comprehensive textile indicator; and to study the influence of the cover factor parameters on mechanical tensile properties at the yarn scale. It has been observed that the cover factor parameters contributed the braider effect (friction and compression) on flax cores in the dry-state and lubricant effect (distribution and viscosity) in the thermo-state; further influenced the characterizations. Increasing multi-core configuration and braiding angle can both increase the tensile strength; larger cover factor results in greater tensile stiffness both in dry-and thermo-states. [ABSTRACT FROM AUTHOR]