Thermal Decomposition Kinetics and Viscoelastic Properties of Epoxy Nanocomposites: Comparative Study of Graphene, GO , and rGO Nanoparticle Effects

ABSTRACT Graphene‐family nanofillers were dispersed at loadings (≤ 0.60 wt%) into a diglycidyl ether of bisphenol‐A epoxy to elucidate how the sheet chemistry of graphene (Gr), reduced graphene oxide (rGO), and graphene oxide (GO) governs thermal stability and visco‐elastic behavior. Thermogravimetric analysis (TGA) showed that Gr raised the 5% mass‐loss onset temperature by 25.7°C and lowered the peak degradation rate by 18% versus neat epoxy, whereas rGO and GO offered moderate gains. Isoconversional kinetic modeling indicated a 15 to 25 kJ mol ⁻¹ increase in apparent activation energy throughout the conversion range, confirming that Gr creates a more energy‐intensive degradation pathway through tortuous, heat‐shielding barriers. Dynamic mechanical analysis (DMA) revealed a 16.6% enhancement in storage modulus ( E ') at 25°C for the Gr composite while maintaining tan δ = 0.43, evidencing efficient stress transfer without compromising damping. All improvements were realized below the electrical percolation threshold, preserving viscosity and density critical for aerospace and electronic encapsulation. These results establish pristine graphene as the most effective single additive route to simultaneously elevate thermal reliability and mechanical resilience in epoxy matrices, while rGO and GO enable application‐specific tuning of damping or glass transition temperature.