Synthesis of imidazolated graphitic carbon nitride and its effect on the thermal properties of epoxy compositions

Abstract

Epoxy resins are widely used in various industrial applications owing to their exceptional mechanical properties and durability. This study investigates the incorporation of imidazolated graphitic carbon nitride (IM-g-C₃N₄) to epoxy formulations, where it serves as a catalyst as well as a filler. Surface modifications of g-C₃N₄ were confirmed through Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The catalytic effect was validated by calculating the activation energy using the Kissinger equation, derived from differential scanning calorimetry data. Thermal stability was evaluated using thermogravimetric analysis, which indicated improved thermal stability based on the residuals. Additionally, assessments with a micro-combustion calorimeter showed a reduction in total heat release from 30.7 kJ/g to 22.8 kJ/g, confirming the flame-retardant effect of the modified epoxy system. Mechanical properties, measured through single-lap shear strength tests, yielded results from 19 to 25 MPa, depending on the IM-g-C₃N₄ content. Overall, imidazolized g-C₃N₄ functions as both a catalyst and filler in epoxy resins, enhancing their thermal stability and performance.