Abstract: | Epoxy nanocomposites modified with multiwalled carbon nanotubes (MWNTs), rubber nanoparticles (RNPs), and the combinations of MWNTs and RNPs were prepared. The effects of multiphase reinforcements on mechanical and fracture properties of epoxy resin were investigated. With combined use of RNPs and MWNTs, the ternary nanocomposites exhibit simultaneous enhancement in stiffness, strength and fracture toughness. Maximum increase of 101% in KIC and 294% in GIC of the ternary composites were achieved in this study. A modified model was developed to predict the modulus of the ternary composites based on the Halpin‐Tsai equation, which was proved to match the experimental results exactly. DSC, TEM, SEM, and AFM studies were carried out to evaluate the composition and microstructure of the binary and ternary composites. POLYM. COMPOS., 36:2147–2156, 2015. © 2014 Society of Plastics Engineers |