Enhanced Mechanical, Barrier, and Cross‐Linking Characteristics of Epoxy/Reduced Graphene Oxide/Multi‐Walled Carbon Nanotube/ Fe 2 O 3

ABSTRACT Epoxy nanocomposites reinforced with conducting and magnetic nanoparticles have attracted considerable attention as promising multifunctional materials because of their superior electrical, thermal, mechanical, and barrier properties. In this work, graphene oxide was synthesized from graphite and then used to prepare a hybrid nanofiller composed of reduced graphene oxide, multiwalled carbon nanotubes, and iron oxide nanoparticles (RGO/CNT/Fe 2 O 3 ). Epoxy nanocomposites with varying filler concentrations were fabricated by incorporating the hybrid nanofiller into the epoxy matrix to investigate the effects on mechanical, barrier, and cross‐linking properties. The hybrid epoxy nanocomposite exhibited remarkable improvements of 66%, 188%, and 99% in tensile, impact, and flexural strengths, respectively, even with the addition of only 0.25 phr hybrid filler. Fracture toughness increased by 214% at 0.5 phr filler loading. Dynamic mechanical analysis further revealed substantial improvements in storage modulus and apparent cross‐link density. At 0.5 phr filler loading, the hybrid nanocomposites exhibited 56%, 43%, and 58% reductions in solvent absorption in aqueous, acidic, and alkaline media, respectively, demonstrating superior resistance to corrosive environments relative to neat epoxy. Evaluation of cross‐link density using the equilibrium swelling method indicates the formation of a densely packed cross‐linked network in the hybrid nanocomposites. The interconnected network improved stress transfer, restricted polymer chain mobility, and created tortuous diffusion pathways in the epoxy matrix. The enhanced mechanical, barrier, and cross‐linking characteristics demonstrate the potential of Epoxy/RGO/CNT/Fe 2 O 3 nanocomposites for advanced structural, protective‐coating, and engineering applications that require a combination of mechanical robustness and environmental durability.