Experimental and numerical investigations on flexural and thermal properties of nanoclay–epoxy nanocomposites

The prime aim of this investigation is to study the effect of montmorillonite nanoclay on mechanical and thermal properties and to develop a non-linear damage model to describe the stress–strain relationship of epoxy resin system. Neat and nanocomposites with 1–3 wt.% clay loading were fabricated. Dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA) and three-point bend tests were carried out to evaluate thermo-mechanical and mechanical properties. Results demonstrated optimum enhancement in 2 wt.% doped system in both thermal and mechanical properties when compared to the neat system. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results indicated mixed intercalation and exfoliation of clay platelets in 2 wt.% system. Scanning electron micrographs (SEM) of 2 wt.% samples showed rougher fracture surface in comparison to neat epoxy samples. Based on the experimental results, a non-linear damage model using flexural modulus and Weibull parameters was established to describe the stress–strain relationship. These simulated strain–strain relationship coordinated well with the experimental results and show that the Weibull scale parameter, σ0, increased whereas the Weibull shape parameter, β, remained insensitive with increasing clay content.