In this work, the mechanical and fracture performance of epoxy nanocomposites consisting of epoxide and imidazole functionalized silica nanoparticles has been studied. The post-synthesis grafting method was utilized to functionalized SiO2 nanoparticles with GPTMS (GGS) and used them as reinforcement (0–2 wt%) in epoxy resin. The cure behavior of nanocomposites demonstrated that the composite has excellent cure capability at 0.5 wt% of GGS. The composite containing 0.5 wt% of GGS exhibited significant improvement in tensile strength (~65 %) and modulus of toughness (~272 %), respectively. Additionally, the flexural strength, flexural modulus, and work of flexural were enhanced by ~48, ~50, and ~48%, respectively. Interestingly, the GGS showed its tremendous potential to improve the fracture toughness (K1C) and the fracture energy (G1C) of the nanocomposite by ~97 and ~292 %, which is also evident by the study of cure behavior. The fractography analysis endorsed the enhancement of material properties due to the use of GGS in the epoxy matrix. Failure investigation examined under FESEM elucidated forced the crack to move around the poles of the nanoparticles due to better interfacial adhesion. Hence, GGS nanoparticle has the potential to use as an excellent cost-effective reinforcement for the epoxy matrix to mitigate the brittle failure in epoxy composites.
