Fracture performance of clay/epoxy nanocomposites with clay surface-modified using 3-aminopropyltriethoxysilane

It is known that the mechanical properties of clay-reinforced nanocomposites are significantly affected by the dispersion of clay particles in the matrix. This study investigated the clay concentration's effect on the fracture behavior of surface-modified MMT/epoxy nanocomposites. For this purpose, fracture tests were performed using samples with four different clay concentration levels. After the fracture tests, scanning electron microscopy analysis was performed on the fracture surfaces to examine the fracture mechanism depending on the clay concentration level. The analysis found that MMT modification using 3-aminopropyltriethoxysilane produces good dispersion of MMT in the epoxy and increases the intercalation effect. Fracture toughness decreased up to 4 wt% of MMT and increased at 6 wt%, followed by another decrease at 10 wt%. This occurs due to the nanocomposite's increased brittleness and increased debondings between MMT and epoxy, as well as voids.