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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]

Antibacterial textiles have attracted much attention in recent years. The stability of the antibacterial effect is one of the most important properties of antibacterial textiles. Integrating antibacterial nanofibers into cotton yarn is a green and efficient method to produce antibacterial textiles. However, due to the loose yarn structure of traditional rotor spinning, the functional nanofibers are easily detached from the blended yarns, resulting in reduced antibacterial effect. Herein, we modified the rotor spinning unit by adding an extra air supply channel for tighter yarn structure. The airflow field of the modified rotor spinning unit was simulated using computational fluid dynamics to determine the best setting angle of the extra air supply channel. Then, the antibacterial blended yarn was produced by trans-scale electrospinning and followed by air-assisted rotor spinning. At the same yarn density, the mean diameter of modified rotor spinning hybrid yarn was smaller than that of conventional rotor spinning hybrid yarn, demonstrating that the structure of modified rotor spinning hybrid yarn was tighter. The overall qualities of modified rotor spinning hybrid yarn were much better than those of conventional rotor spinning hybrid yarn. The fluorescent tracer technique was carried out to show that more nanofibers can be preserved in modified rotor spinning hybrid yarn than in conventional rotor spinning hybrid yarn, especially after 10 washing cycles. The antibacterial properties of modified rotor spinning hybrid yarn-based fabric against Escherichia coli and Staphylococcus aureus can reach as high as 80.5% and 82% even after 50 times of washing, indicating the high antibacterial durability. Our new technology provides a method to prepare super stable antibacterial functional yarn, and is expected to be used to prepare other durable functional textiles. [ABSTRACT FROM AUTHOR]

Carbon fibres (CF) are used in CF reinforced plastic (CFRP) components. However, waste from CF yarn trim, CFRP and the end of life (EOL) CFRP structures will cause a recycling challenge in the next decades because of strict environmental regulations. Currently, recycling is carried out almost entirely by the use of pyrolysis to regain CF as a valuable resource. This high temperature process is energy consuming, and the resulting fibres are brittle. Hence, they are not suitable for processing of textiles into yarns or new reinforcement structures. To enable grave to cradle processing, a new approach based on a solvolysis recovery of CF and subsequent yarn spinning to obtain hybrid yarns suitable for textile processing, especially by weft knitting, was the focus of the international research project IGF/CORNET 256EBR. For the first time, it was possible to process hybrid yarns made of rCF on a weft knitting machine to produce biaxial reinforced structures to form CFRP from recycled carbon fibres. Therefore, various modifications were done on the textile machinery. In this way, it was possible to process the rCF and to get out a reproducible textile structure for the production of 3D recycled CFRP (rCFRP) parts. [ABSTRACT FROM AUTHOR]

The aim of this paper is to highlight recent developments in the processing of waste carbon fibre for thermoplastic composites. Initially, injection moulding and nonwoven technologies have been used to integrate waste carbon fibres into fibre-reinforced thermoplastic composites. Recently, tape and hybrid yarn spinning technologies have been developed to produce tape and hybrid yarn structures from waste carbon fibre, which are then used to manufacture recycled carbon fibre-reinforced thermoplastics with much higher efficiency. The hybrid yarn spinning technologies enable the development of various fibrous structures with higher fibre orientation, compactness and fibre volume fraction. Therefore, thermoplastic composites manufactured from hybrid yarns possess a good potential for use in load-bearing structural applications. In this paper, a comprehensive review on novel and existing technologies employed for the processing of waste carbon fibre in addition to different quality aspects of waste carbon fibre is presented. [ABSTRACT FROM AUTHOR]

• Set of Friction Spun Yarn (FSY) and Thermally Bonded Roving (TBR) have been produced. • Composites with different architectures have been fabricated using FSY and TBR. • Mechanical properties of all composites increase with increasing flax content. • TBR composites show better mechanical properties than FSY composites. The main objective of this work is to study the effect of composite architecture on the mechanical properties of flax reinforced polypropylene (PP) composites. In this context, two different hybrid yarn structures using flax and polypropylene (PP) fibres have been produced; one, through the friction spinning method and the other through thermal bonding of blended roving. The friction spun yarn (FSY) has a core-sheath type of yarn structure, whereas the thermally bonded roving (TBR) has a blended flax/ PP distribution in its structure. The flax content in both yarn structures is varied at 40 wt. %, 50 wt. % and 60 wt. %, respectively. Further, these hybrid yarns are consolidated to fabricate unidirectional composite samples and the resultant composites are tested accordingly. It is observed that the tensile and flexural strengths of all composite specimens increase with increasing flax content. While the impact strength of FSY-compressed composite decreases with increasing flax content and in case of TBR-compressed composite, it increases with increasing flax content. At constant flax content, the TBR-compressed composites demonstrate better tensile, flexural and impact properties than FSY-compressed composites. [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 article reports the results of investigations carried out to produce yarns consisting of staple carbon fiber (CF) obtained from process waste for the manufacturing of composites suitable especially for thermoset applications. For this purpose, a comparative analysis is done on processability between 100% staple CF and 60 weight% staple CF mixed with 40 weight% PVA fibers in carding, drawing and spinning process. The hybrid yarns are produced by varying twist level. The PVA fibers of the hybrid yarn are then dissolved using hot water treatment. The mechanical properties of yarns consisting of 100% staple CF and hybrid yarns consisting of staple CF and PVA before and after hot water treatment are investigated. Furthermore, test specimen is also prepared by impregnating 100% staple CF yarn and the hybrid yarns (after the dissolving of PVA) with epoxy resin. The results of the tensile test of the yarns in consolidated state reveals that the hybrid yarn produced with 80 T/m after hot water treatment exhibits approximately 75% of the tensile strength of virgin filament tow, and it is expected that the hybrid yarns can be applied for the manufacturing of thermoset based composites for load bearing structures. [ABSTRACT FROM AUTHOR]

Clothing is among the basic needs of human and this has led to tremendous growth in the textile sector. However, huge amounts of hazardous chemicals used in the clothing industry have raised concern in recent years. Due to the increasing awareness in regards to environmental pollution and personal health, particularly in the textile manufacturing, there has been a need for sustainable manufacture of clothing with reduced exposure to the toxic chemical. This research presents a new domain of core-spun yarn (hybrid structure), developed to improve fabric handle, comfort and thermal properties without the application of softening chemicals. Fabrics made up of spun over spun hybrid yarns (SSHY) exhibited remarkable reduction in fabric stiffness. There was approximately 50% reduction in fabric bending rigidity in the case of SSHY fabric in comparison with ring-spun conventional yarn (RSCY) fabric. Notably, there were improvements in the fabric tear strength and other physical parameters. [ABSTRACT FROM AUTHOR]