Bis‐Imidazole Derivative as Latent Curing Agent for One‐Component Epoxy Resin System with Excellent Comprehensive Performance

Abstract One‐component epoxy resins (OCERs) are widely used for simplified processing, prolonged stability, and enhanced performance. This study synthesizes a novel bis‐imidazole latent curing agent (PBMM) via addition reaction of 2‐formylimidazole and m‐phenylenediamine, structurally confirmed by FT‐IR and NMR. The PBMM/E‐51 system demonstrated optimal curing performance at a mass ratio of 15:100 (curing agent to resin), as determined via dynamic gel time analysis. Differential scanning calorimetry (DSC) was employed to reveal the curing parameters. The optimal curing conditions for PBMM/E‐51 comprise a gelation temperature of 125.6 °C, a curing temperature of 148.2 °C, and a post‐curing temperature of 151.8 °C. Kissinger and Flynn–Wall–Ozawa models established a first‐order kinetic equation. Thermal and mechanical performance testing showed that the cured material possesses a tensile strength of 45.74 MPa, an elastic modulus of 684.64 MPa, an elongation at break of 2.15%, a thermal decomposition temperature of 388 °C, a maximum loss factor (tanδ) of 0.49, a glass transition temperature of 178 °C, a storage modulus (E) of 310.46 MPa, and a cross‐linking density of 25857.49 mol/m 3 . The system maintained 9‐day latency at room temperature, resolving the reactivity‐stability trade‐off in latent curing agents. These findings advance high‐performance OCERs design through balanced processability and thermomechanical properties.