Effectively improve the mechanical properties of carbon fabric/epoxy composites by oxidized carbon nitride.

In this work, carbon nitride (C3N4) powder was oxidized by the Hummers oxidation method, and oxidized carbon nitride (O‐C3N4) was obtained. Epoxy (EP) was modified with O‐C3N4, and then carbon fiber fabric/epoxy (CF/EP) composites were prepared by hand‐pasting molding. The O‐C3N4 greatly improves the wettability of EP resin, enhances the interface properties of CF/EP composites, and makes the composites have better mechanical properties. The interlaminar shear strength (ILSS) is increased from 51.75 to 59.68 MPa, the tensile strength is increased from 564.54 to 635.39 MPa, the bending strength is increased from 809.64 to 938.81 MPa, and the impact strength is increased from 73.48 to 84.84 kJ/m2. Meanwhile, the dynamic mechanical properties of composites are also significantly improved. The energy storage modulus is increased from 14.9 to 21.4 GPa, with an increase of 43.6%. Highlights: Developing carbon fiber composites is conducive to industrial applications.O‐C3N4 effectively improves the mechanical properties of the composite.O‐C3N4 has the advantages of simple synthesis, low costs, and light color.O‐C3N4 is rich in oxygen‐containing functional groups. [ABSTRACT FROM AUTHOR]