Friction spun yarns with high RCF content for thermoset composites

Abstract

Thermoplastic composites based on hybrid yarn structures consisting of recycled carbon fibre (rCF) and thermoplastic fibres (rCF content approx. 50 weight percentage) achieve high mechanical properties because of a long fiber length, homogeneous mixing and even yarn structure [1]. However, manufacturing of yarns with high rCF content (>90%) required for thermoset composites is still not realizable. Because of the special properties of rCF such as low shear strength, smooth fibre surface and high brittleness, high shortening (≥ 70%) in fibre length of rCF occurs during different processing steps of spinning [2]. The wide distribution of rCF fibre length arising especially during carding of pure rCF is regarded as very critical. In addition to this, lack of crimp in rCF leads to drafting error during drawing and spinning process. As a result, the quality of a yarn with high rCF content is still not acceptable. For this purpose, investigations are carried out in this work to enable gentle processing of rCF to produce slivers consisting solely of rCF. Furthermore, different core sheath yarn structures with rCF content (>90%) have been developed on a DREF-3000 friction spin machine for thermoset composites.