Thermoforming Process Effect on Performances of Thermoplastic/Recycled Carbon Fiber Composites

The reuse of recycled carbon fibers (rCF) is a response to growing environmental concerns associated with the composites industry. Recycling and reusing carbon fibers represents a more sustainable alternative by reducing waste at the end of the life cycle of composite materials and decreasing dependency on virgin raw materials. This study investigates the influence of process parameters on two different non-woven mats made by carding rCF and blending with thermoplastic filaments: Carbiso TM-PA6/60 and Carbiso TM-MAPP/60. Two processing methods have been examined: one-shot process (Method 1) and lamination (Method 2) to fabricate multilayer coupons. Results indicate that the two-layer panels produced using Method 2 exhibited lower porosity (9.9% for PA6/60 and 4.1 for MAPP/60) and superior mechanical performance, with a storage modulus of 15.2 GPa for PA6/60, respect to 10.0 GPa for 2LM1, and 16.7 GPa for MAPP/60 2LM2 compared to 10.8 GPa for 2LM1. However, the differences in performance between the two methods diminished as the number of layers increased. Concerning matrix-fibre compatibility, MAPP/60 has shown the best results, due to the fibre's roughness, the presence of matrix particles on the fibres, and the incorporation of maleic anhydride in polypropylene (PP), which significantly enhanced adhesion.