High-Performance Multifunctional rPA6/rCFRP/rGraphite Hybrid Composites from Recycled Industrial Waste

High Resolution Image Download MS PowerPoint Slide Environmental concerns and the global shift toward a more sustainable and circular economy have increased the demand for economically viable materials derived from industrial waste. In this study, high-value engineering materials discarded from different industries were repurposed to develop new multifunctional hybrid composites. The selected postindustrial waste included polyamide 6 (rPA6) from automotive plastic washers, recycled graphite (rGra), and recycled carbon fiber reinforced polymer (rCFRP) epoxy-based composites originating from the aerospace sector. These materials were separately ground using a knife mill and subsequently compounded via extrusion. The fillers (rGra and rCFRP) were incorporated individually and as hybrids (rCFRP:rGra, 1:1 wt %) at total loadings of 5, 10, and 20 wt % in the rPA6 matrix. The composites were characterized in terms of morphology, rheology, mechanical performance (tensile test), thermal behavior (differential scanning calorimetry─DSC), electrical conductivity, and electromagnetic properties. The mechanical results revealed a notably high ultimate tensile strength of 126 MPa and an elastic modulus of 4.8 GPa for the rPA6/rCFRP (20 wt %) composition, suggesting strong interfacial adhesion promoted by secondary interactions between the epoxy resin coating on the rCFRP and the rPA6 matrix. Electrical conductivity measurements on composite films showed values from 10 –5 to 10 –1 S.cm –1 for the hybrid and rCFRP-filled compositions, indicating their potential for antistatic (anti-ESD) applications. Although rGra exhibited lower mechanical and electrical performance than rCFRP at the evaluated contents, it was less detrimental to processability, making the hybrid formulations more balanced candidates for real-world applications. Overall, this study demonstrates a promising strategy for upcycling industrial waste into high-value, multifunctional composites, thereby contributing to resource efficiency and waste minimization across various industrial sectors.