Enhancing Multifunctional Properties of Recycled Carbon Fiber Composites Through Graphene Nanoplatelet Integration

The growing demand for lightweight, high‐strength materials in advanced engineering sectors had led to an increased use of the carbon fiber reinforced polymer (CFRP) composites; however, their end‐of‐life disposal posed significant environmental and economic challenges. This study presented the upcycling of the recycled carbon fiber (rCF) waste into multifunctional composites by integrating the graphene nanoplatelets (GNPs). Comprehensive characterization was carried out using mechanical testing, single fiber fragmentation test (SFFT), electromagnetic interference (EMI) shielding, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The results showed that 0.3 wt% GNPs optimized the composite's performance, with improvements in tensile strength (535 MPa, +30%), flexural strength (708 MPa, +46%), and interfacial shear strength (+31%). EMI shielding effectiveness increased from 20 dB (pristine) to 32 dB at 0.5 wt% GNP, and damping capacity improved by +51%, all without compromising thermal stability or glass transition temperature ( T g ). These results demonstrated that GNP‐modified rCF composites could match virgin CFRP in performance, providing a sustainable solution for high‐value industrial applications.