Thermoforming, characterization, and in-house recycling of multi-layered laminated composites made with polyamide 6/recycled carbon fibers hybrid yarns-based plain weave fabrics

Carbon fiber reinforced plastics (CFRPs) in the form of laminated composites are widely used in various sectors, such as aeronautics and clean energy fields, due to their superior mechanical properties compared to traditional homogeneous composites. In this study, the authors developed a manufacturing process based on thermoforming a 7-layer stack of plain weave fabrics made from hybrid yarns (polyamide 6/recycled carbon fibers) to introduce a new method for reusing end-of-life (EoL) CFRPs and avoid landfilling. Several attempts were made to determine the optimal combination of process parameters, including forming temperature, forming pressure, and holding time. The manufactured multi-layered laminated composites underwent in-depth mechanical and thermal characterization tests to obtain information on their physical properties and identify potential applications for market exploitation. The developed materials exhibit very interesting mechanical properties, which are comparable to or greater than those of commercial carbon or glass fiber-reinforced polymers. Morphological analysis revealed good wettability of PA6 on rCFs and a very low degree of porosity. Finally, the re-use of yarn scraps and fabric remnants generated during the manufacturing process, as well as the recyclability of the manufactured composites once they reach the status of EoL materials, were studied through an in-house recycling process based on comminution and hot pressing of materials.