Development of a new hybrid yarn construction from recycled carbon fibers (rCF) for high-performance composites. Part-II: Influence of yarn parameters on tensile properties of composites

Abstract

This article reports the successful manufacturing of hybrid yarns from virgin staple CF (40 or 60 mm) or recycled staple CF (rCF) by mixing with polyamide 6 (PA 6) fibers of defined length. The hybrid yarns are produced using an optimized process route of carding, drawing, and flyer machine. Furthermore, the influence of CF length, CF type (i.e. virgin or rCF), CF volume content, and twist of the yarn are also investigated regarding the tensile properties of unidirectionally laid (UD) thermoplastic composites. The results show that CF length, yarn twist, and CF content of composites play a big role on the tensile properties of thermoplastic composites. From the comparison of tensile strength of UD composites produced from 40 and 60 mm virgin staple CF, it can be seen that the increase of yarn twist decreases the tensile strength. However, the effect of twist on the tensile properties of UD composites manufactured from 40 mm virgin staple CF is insignificant. The tensile strength of UD thermoplastic composites manufactured from the hybrid yarn with 40 and 60 mm virgin staple CF and rCF is found to be 771 ± 100, 838 ± 81, and 801 ± 53.4 MPa, respectively, in the case of 87 T/m containing 50 volume% CF.

Recent developments in the processing of waste carbon fibre for thermoplastic composites – A review

“…The impact of the fibre volume fraction on the mechanical properties of composites based on hybrid yarn was reported in Hengstermann et al. 71 In this study, composites were developed with 30%, 50% and 70% fibre volume fraction, and the mechanical properties of these composite were evaluated. The results highlighted that thermoplastic composites with a 50% fibre volume fraction offer excellent tensile strength.…”

“…Results suggest that a thermoplastic composite prepared from Type-I fibres provides slightly enhanced mechanical properties compared to a composite containing Type-III waste fibre. 71…”

Development and validation of recycled carbon fiber-based binder tapes for automated tape laying processes

“…29 In the case of wovens and NCF, respectively, yarns have to be manufactured as intermediate product first. [30][31][32][33][34] Staple fiber organic sheets made of rCF have been developed based on rCF yarns, providing comparable but not yet equal material properties as virgin CF organic sheets. 35 In Longana et al, 36 the high performance discontinuous fiber process was applied in order to align rCF for the production of epoxy-based prepregs which also provide close to vCF values in terms of mechanical performance.…”

“…Fiber length: A minimum fiber length of at least 3 mm must be preserved by processing rCF according to Flemming et al 43 Literature also indicates that a further increase of strength and stiffness of composites can be achieved by preserving fiber lengths beyond 50 mm. 32 In contrast, insufficient fiber lengths severely affect the mechanical performance of the composite and thus disadvantage the recycling. Composites reinforced with short rCF are considered to be a down-cycling of the material.…”

Deep drawing of organic sheets made of hybrid recycled carbon and thermoplastic polyamide 6 staple fiber yarns

“…This fact is taken into consideration in current research projects. 18,20,21,[40][41][42][43] In addition to developments on rCF yarns, efforts are also being made to process the fibers into oriented slivers and tapes. [44][45][46] Pickering et al, 7 Allen, 8 Turner et al, 9 Palmer et al, 10 Hofmann et al, 11 and Pickering et al 12 Low to medium Low to medium Automotive semistructures, equipment housings, and aircraft interiors Compression molding of aligned nonwovens, veils, and mats Geiger, 13 Turner et al, 14 Howarth et al, 15 Wong et al, 16 and Pickering et al 17 Medium Medium Automotive noncritical structures, aircraft interiors, and wind turbine noncritical structures Compression molding of wovens, NCF Hengstermann et al, 18,19 Abdkader et al, 20 and Goergen et al 21 Medium to high Medium to high Automotive structures NCF: non-crimp fabrics; rCF: recycled carbon fiber.…”