The mechanical and thermal properties of graphitic carbon nitride (g‐C3N4)‐based epoxy composites

Numerous ways to reinforce epoxy resin and improve its thermomechanical properties have been attempted using organic and inorganic nanoparticles. In this paper, graphitic carbon nitride (g‐C3N4) nanoparticles were synthesized and used to improve the mechanical properties and thermal stability of epoxy composites. The g‐C3N4 was synthesized from cheap melamine powder using a simple one‐step thermal treatment, then was used to reinforce the resin at different weight percentages (wt%). X‐ray diffraction, scanning electron microscopy (SEM), and Fourier infrared spectroscopy were used to characterize the g‐C3N4 and ensure its successful synthesis by studying the changes in its crystal structure, morphology, and chemical structure. The filler was dispersed in the resin using a combination of ultrasonication and high shear mixing. The results showed that the mechanical properties were optimum when 0.5 wt% g‐C3N4 was used. The tensile strength and fracture toughness of the resulting epoxy composite improved by 21.8% and 77.3%, respectively. SEM was used to investigate the morphologies of cracks formed in epoxy composite specimens after the tensile testing. The SEM micrographs of the fracture surface showed a transition from a brittle to a rough morphology, signifying the enhancement in the composites' toughness. Thermogravimetric analysis showed a good improvement in degradation temperature of up to 8.86% while dynamic mechanical analysis showed that the incorporation of g‐C3N4 did not affect the material's glass transition temperature. Graphitic carbon nitride (g‐C3N4), synthesized from melamine, was incorporated into epoxy resin at different weight percentages. The optimum filler content achieved the maximum fracture toughness due to reduced filler agglomeration and enhanced interfacial bonding with the matrix.