The synergistic effect of carbon nanotubes and clay on the toughness of epoxy nanocomposites

The diglycidyl ether of bisphenol A (DGEBA) epoxy resin containing different shape nanofillers, such as multi-wall carbon nanotubes (MWCNTs), clay and clay-MWCNTs composites, were prepared separately, and diaminodiphenyl sulfone (DDS) hardener was used as curing agent. The nanocomposites were processed by shear mixing and speed mixture at different clay concentrations (2 and 5 wt%) and varied MWCNTs concentrations (from 0.1 to 0.5 wt%). Investigation by X-ray diffraction (XRD) revealed that an exfoliated nanocomposite structure was formed in which the clay layers were randomly dispersed in the matrix. Morphologies of the fracture surfaces of nanocomposites were characterized by field emission scanning electron microscopy (SEM). The fracture toughness test results show that clay-MWCNT exhibits a synergistic effect on toughening epoxy resin.