Thermo-formable hybrid carbon fibre laminates by composite recycling

Hybrid carbon fibre-reinforced (CFR) laminates have been manufactured by combining an innovative recycling process with compression moulding. Waste CFR laminates are thermo-mechanically disassembled in single thermoset (TS) plies by heating and bending in a roll-forming machine. The recovered TS layers are re-assembled by interposing a thermoplastic (TP) interlayer. In this study, waste nylon bags from composite manufacturing have been used to produce polyamide interlayers, with different nominal thickness (from 50 to 140 μm). Therefore, final hybrid laminates are 100% recycled. An extensive experimental campaign has been carried out to optimize the compression moulding process of hybrid laminates and to evaluate the effect of the TP-TS hybridization. Calorimetry, dynamic mechanical analyses, microscopy and bending tests have been performed. The optimal processing conditions were found thanks to the results from adhesion tests. In the best case, the hybrid CFR laminate showed the bending strength of 386 MPa and the bending modulus of 34.3 GPa, 47% and 54% of the virgin laminate, respectively. Moreover, the hybrid laminate has unique properties such as higher toughness, an increased damping and the ability to be thermo-formed.