Synergistic strengthening and toughening of CF/EP composites via a tri-alternant carbon nanofillers–fiber–matrix hierarchy

Official URL: https://dx.doi.org/10.1016/j.compositesa.2026.109604

This study delivers an industrially scalable pathway for high-performance multiscale CF/EP composites designed for use in demanding sectors. A multiscale interphase is tailored by bonding a zwitterionic aminosilane agent, 3-((2-aminoethyl)(3-(trimethoxysilyl)propyl)ammonium)propane-1-sulfonate (SEPPS), onto ozonated 1D (SWCNTs, MWCNTs) and 2D (GO) carbon nano-structures to enhance interfacial interactions between carbon fibers (CFs) and epoxy resin. The system is deposited onto CF fabrics using ultrasonic spraying with thoroughly optimized parameters. The surface modification and spray deposition are thoroughly optimized by using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis (TGA) for the characterization of carbon nanostructures and modified CF fabrics. Prepregs are produced by impregnating neat and nano-enhanced CF fabrics with hot-melt resin using hot pressing, followed by autoclave curing to manufacture the final composite laminates. Comparative performance analysis across composite samples with different types of carbon nanostructures showed that SEPPS-functionalized SWCNTs deliver the best results overall, effectively mitigating common failure modes and demonstrating improvements both in-plane and through thickness. This strategy resulted in a 30% increase in tensile strength, 10% improvement in modulus, 87% enhancement in tensile toughness, and 45% increase in elongation at break, along with a notable rise in interlaminar shear strength (ILSS).