Morphology, tensile and fracture characteristics of epoxy-alumina nanocomposites

The paper presents studies of the morphology, mechanical properties and fracture behavior of epoxy-alumina nanocomposites; the influences of alumina particle's shapes and sizes are discussed. Alumina particles (pre-treated with surface modifier) of platelet- and rod-shapes ranging from 10-40 nm in size are introduced into epoxy resin. It is found that the dispersion of the nano-sized alumina particle within the epoxy matrix mainly depends on the geometry of the particle. Mechanical characterization and fracture mechanics tests show that the tensile modulus, tensile strength and fracture toughness are affected by the geometry of the particles. The fracture surface investigation shows that several toughening mechanisms, including particles pull-out, crack pinning, plastic yielding and deformation are the main factors for the increments of the fracture toughness of the epoxy-Alumina nanocomposites.