Structural and friction characteristics of g-C₃N₄/PVDF composites

Highlights: • The graphite-like carbon nitride (g-C₃N₄) was first used as filler to fill in polymer matrix for the modification of polymer. • The structure, morphology, and thermal properties of g-C₃N₄/PVDF composites were studied by XRD, FT-IR, SEM, TGA. • The friction characteristics of g-C₃N₄/PVDF composites were studied under dry sliding conditions. - Abstract: This paper introduced the preparation, structural, and friction characteristics of graphite-like carbon nitride (g-C₃N₄)/poly(vinylidene difluoride) (PVDF) composites. The g-C₃N₄/PVDF composites with different g-C₃N₄ contents were prepared via wet mixing and hot press molding technique. The structure, morphology, thermal properties, and friction characteristics were studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA), and universal micro-tribotester under dry sliding conditions. The XRD and FT-IR studies confirmed the incorporation of g-C₃N₄ into the PVDF matrix. The SEM results showed good dispersion of g-C₃N₄ in PVDF matrix. The "onset" temperature T_o of the composites increased with increasing the content of g-C₃N₄ filler, which confirmed the enhancement of thermal stability of the composites. The friction characteristics results indicated that small amount of g-C₃N₄ filler was not beneficial to reduce friction coefficient of the composite while large amount of filler had little effect on it. In addition, the g-C₃N₄ filler was beneficial to reduce wear loss of the composite, and the wear loss decreased with increasing the content of g-C₃N₄ filler