Fracture behaviour of epoxy nanocomposites modified with triblock copolymers and carbon nanotubes

The effect of the addition of a combination of rigid nanofillers and soft rubber nanoparticles on the fracture toughness of epoxy resins was studied. Carbon nanotubes (CNTs), as rigid nanofillers, and polystyrene-polybutadiene-poly(methyl metacrylate) (SBM) triblock copolymers, as rubber nanoparticles that self-assemble in the epoxy matrix, were used. Fracture tests according to ESIS TC4 protocol were performed on neat epoxy, epoxy reinforced with CNTs, epoxy nanostructured with SBM triblock copolymers and, finally, epoxy with CNTs and SBM triblock together. Finally, it was found that both fracture toughness and critical energy release rate increased significantly with the addition of rubber and rigid particles. The analysis of the fracture surfaces revealed the toughening micromechanisms.