Recycled carbon fiber reinforced composites: Enhancing mechanical properties through co-functionalization of carbon nanotube-bonded microfibrillated cellulose

[Display omitted] •The functionalization of the rCFs is effectively done by electrophoresis deposition.•CNT and MFC are chemically grafted to the surface of the carbon fibers.•Epoxy-based composite is fabricated via vacuum infusion technique.•The tensile and flexural strength of the composites significantly improved. The imperative challenge of repurposing recycled carbon fiber (rCF) in composite structures, due to its cost-effectiveness and eco-friendly attributes, has spurred innovative research. This study introduces a scalable processing technique, integrating carbon nanotube (CNT)-bonded microfibrillated cellulose (MFC) onto randomly oriented rCF mats, focusing on enhancing mechanical properties. Employing electrophoretic deposition (EPD), rCF surfaces are effectively functionalized with CNT/MFC, probed through X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Modified fiber surfaces exhibit reduced contact angles, indicating improved wettability. Epoxy-based composites, fabricated via vacuum infusion, show up to 32% and 27% improvements in tensile and flexural strength. Dynamic mechanical analysis (DMA) confirms elevated storage modulus and energy dissipation capability. SEM analysis of fracture surfaces illustrates robust adhesion between coated fibers and the matrix, supporting the proposed approach's efficacy. This study unveils an innovative pathway to enhance recycled carbon fiber composite properties, extending their application potential in diverse engineering domains.