Reinforcing effect of amine-functionalized and carboxylated porous graphene on toughness, thermal stability, and electrical conductivity of epoxy-based nanocomposites

Epoxy-based nanocomposites reinforced with nonfunctionalized porous graphene (NPG), carboxylated porous graphene (CNPG), and amine-functionalized porous graphene (ANPG) were investigated with regard to mechanical properties, thermal stability, and electrical conductivity. Nanomaterials were added to the epoxy matrix in varying contents of 0.5, 1, and 2 wt %. Generally, mechanical properties were improved as a result of introducing nanomaterials into the epoxy resin. However, the amelioration of toughness was only observed in functionalized NPGs/epoxy nanocomposites. Field emission scanning electron microscopy images showed that functionalized nanomaterials induced a rougher fracture surface compared to the neat epoxy. Dynamic mechanical analysis along with differential scanning calorimetry confirmed an increment in the glass-transition temperature (T-g) of the reinforced nanocomposites. Also, they proved that functionalization made the epoxy network tougher and more flexible. The electrical conductivity and thermal stability of the epoxy resin were also improved when loaded with nanomaterials. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47475.