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. (c) 2006 Elsevier B.V. All rights reserved.