Demonstration and testing of a process chain for the realignment of discontinuous random-oriented recycled carbon fibers into a unidirectional tape

This study introduces a process chain for the realignment of discontinuous, randomly oriented recycled carbon fibers (rCF) into a unidirectional tape, to achieve higher mechanical values compared to nowovens rCF materials. The first step involves carding for sliver production, followed by a lab-scale alignment unit to reorient the rCF, with the final step being a laminating machine to achieve the tape structure. For this study two different tapes were produced, to evaluation of the process chain for thermoset and thermoplastic applications. The materials used are pyrolyzed carbon fibers (Tenax HTA 40) with a fiber length of 60-100 mm and two different Polyamides (K140 and P301). The first set of tapes consists of 90-wt% rCF content and 10-wt% Co-Polyamide (K140). This material was wet pressed with the use of a thermoset matrix (Araldite LY3585/ Aradur AD3475). The second set of tapes will comprise 50-wt% rCF content and 50-wt% Polyamide-6 (P301), processed in a variothermal mold. The combination of carding, alignment unit and a laminating machine allows a continuous production of rCF-tapes for thermoplastic or thermoset systems/processes. As a result, the mechanical properties of the tapes reach up to 57 GPa bending modulus and 690 MPa bending strength in fiber orientation.