Effects of graphene network formation and its correlation with microstructure and mechanical properties in dynamically vulcanized PP/EPDM composites reinforced with few‐layer graphene

Abstract

In this study, the effects of graphene network formation on stress–strain behavior and different mechanical properties in PP/EPDM nanocomposites were investigated. TEM observation clarified that up to the optimum content of nanoparticles, the efficient networks of graphene formed which heightened the nanocomposites tolerance against different mechanical loads. The efficiency of graphene networks in arresting crack along with the mechanisms through which they dissipate energy were extensively examined. SEM observations from the fracture surface of impact test indicated that as a result of these networks, the cracks perpendicular to the load directions were formed which efficiently assisted the nanocomposite in dissipating energy and/or hindering further development of cracks and the premature failure in PP/EPDM samples. The stress–strain behavior of resultant nanocomposites was also studied by Arruda–Boyce hyperelastic model which can predict the behavior of nanocomposites with a high degree of accuracy that is rooted in the increased interaction between graphene and polymer matrix by graphene network formation. Exceeding the optimum content, the agglomerations form and results in deviation of experimental results with the model predictions. The findings of this model also substantiated the efficiency of graphene networks in developing a load‐resistant the microstructure of PP/EPDM nanocomposites.