Effect of clay surface modification and concentration on the tensile performance of clay/epoxy nanocomposites

In this study, the effect of montmorillonite (MMT) clay modification and concentration on the tensile behavior of MMT/epoxy nanocomposite was investigated. MMT was surface-modified using 3-aminopropyltriethoxysilane. MMT/epoxy nanocomposite samples were fabricated by mixing the unmodified and the surface-modified MMT of 2, 6, and 10 wt%, respectively, with epoxy resin. XRD analysis was performed to determine the increase of spacing between layers, after the modification. Tensile tests were performed on the MMT/epoxy nanocomposite specimens with and without the MMT modification. The results showed that the d-spacing between layers increased by more than 55% with the 3-aminopropyltriethoxysilane modification of MMT. For unmodified MMT/epoxy nanocomposite, as the concentration of clay increased the elastic modulus increased, but the tensile strength was not affected significantly. For surface-modified MMT/epoxy nanocomposite, both the elastic modulus and the tensile strength increased as the concentration of clay increased. Tensile strength and elastic modulus of surface-modified MMT/epoxy nanocomposite were larger than those of unmodified MMT/epoxy nanocomposite, and the modification effect increased with clay concentration. This occurred due to the increased exfoliation of clays along with the improved interfacial strength by the surface modification.