Epoxy nanocomposites significantly toughened by both poly(sulfone) and graphene oxide

Toughening of brittle epoxy (EP) resins is important to widen their applications. In this work, both polysulfone (PSF) as thermoplastic toughening agent and graphene oxide (GO) as nanofiller toughening agent are employed to toughen diglycidyl ether of bisphenol-A (DEGBA) epoxy resin. PSF and GO are added to EP via melt blending and solvent mixing method, respectively. Pure epoxy resin is brittle with a fracture toughness (K-IC) of ca. 0.99 MPa.m(0.5). Dual toughening by the simultaneous addition of PSF and GO significantly enhances the fracture toughness of the epoxy resin. The GO/PSF/EP ternary nanocomposite with 5 phr PSF and 0.2 phr GO shows the maximum value of ca. 1.88 MPa.m(0.5) with an increase of 89.90% in K-IC compared to that of neat epoxy. Meanwhile, the elongation at break is also greatly enhanced by the addition of PSF and GO. Moreover, the tensile strength, Young's modulus and thermal stability are slightly enhanced and glass transition temperature is maintained after PSF and GO are introduced into EP resin. The current strategy of using both PSF and GO as dual toughening agents is promising for effectively toughening epoxy resins without sacrificing tensile and thermal properties.