Electro-mechanical Behavior of Graphene–Polystyrene Composites Under Dynamic Loading

An experimental investigation was conducted to understand the electro-mechanical response of graphene reinforced polystyrene (PS) composites under static and dynamic loading. Graphene/PS composites were fabricated using a solution mixing approach followed by hot-pressing. Absolute resistance values were measured with a high-resolution four-point probe method for both quasi-static and dynamic loading. A modified split Hopkinson (Kolsky) pressure bar apparatus, capable of simultaneous mechanical and electrical characterization, was developed and implemented to investigate the dynamic electro-mechanical response of the composites. In addition to measuring the change in electrical resistance as well as the dynamic constitutive behavior, real-time surface damage and global deformation was captured using high-speed photography. The real-time damage was correlated to both stress–strain and percent change in resistance profiles. The experimental findings indicate that the bulk resistance of the composite increased significantly due to the brittle nature of the PS matrix and the presence of relative agglomerations of graphene platelets which resulted in micro-crack formations. Scanning electron microscopy imaging gives further insight into the various damage mechanisms that occur within the composites subjected to a static or dynamic load. The results show that the change in transport properties can provide further insight into the micro-structural evolution of composite materials during loading.