Impact fracture behavior and morphology of polypropylene/graphene nanoplatelets composites

The influence of the size and content of graphene nanoplatelets (GNPs) on impact fracture toughness of reinforced polypropylene (PP) composites were investigated by means of a pendulum impact instrument at room temperature. The results showed that the Izod V‐notched and non‐notched impact strength and Charpy V‐notched impact strength increased when GNPs weight fraction was <0.4 wt%, and then decreased with increasing GNPs weight fraction. Moreover, the effect of the GNPs size on the impact fracture toughness was relatively significant; the GNPs with large layer number and flake thickness were beneficial to improve the Izod V‐notched impact fracture toughness, large particle lateral dimension was beneficial to improve the Izod non‐notched impact fracture toughness; while the GNPs with large specific surface area and flake thickness were beneficial to improve the Charpy V‐notched impact fracture toughness. Finally, the mechanisms of the toughened and reinforced effects of the GNPs on the PP/composites were discussed. POLYM. COMPOS., 40:E511–E516, 2019. © 2018 Society of Plastics Engineers