Mechanisms for enhanced impact strength of epoxy based nanocomposites reinforced with silicate platelets

This research investigates the effect of reinforcing organically modified nano-clay on the mechanical properties of epoxy-clay based nanocomposites. Tensile strength, tensile modulus, strain at break, micro-hardness, and impact strength were evaluated. Nano-clay content was varied in the range of 0–4 wt%. Nano-clay was dispersed using ultrasonication and homogenization. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed intercalated clay morphology for all the nanocomposites, thereby ratifying that the processing methodology was effective in dispersing nano-clay in the epoxy matrix. Tensile strength, impact strength, and micro-hardness values for nanocomposites were maximum at 1.5 wt% nano-clay with improvement of 48%, 22%, and 44.5% respectively over the neat epoxy. Mechanical testing results correlated well with SEM and FEG-SEM micrograph analysis of fractured impact test specimens. The novelty of the present work lies in identifying the underlying mechanisms resulting in improved impact performance of nanocomposites. Nanocomposites displayed superior mechanical properties due to the presence of energy absorbing mechanisms like crack deflection, crack pinning, and crack arresting.