Impact of 2-Phenylimidazole on the Toughness of Cured Epoxy Resins Abstract: Epoxy resins are widely employed in structural adhesive, coating, and composite material applications due to their excellent mechanical strength, chemical resistance, and adhesion properties. However, their inherent brittleness often limits their broader application scope. This study investigates the influence of 2-phenylimidazole (2-PI), a widely...