Electrical and thermal properties of a thermoplastic elastomer nanocomposite based on polypropylene/ethylene propylene diene monomer/graphene

The effect of multilayer graphene (MLG) and few layer graphene (FLG) on electrical, thermal, and morphological properties of polypropylene (PP)/ethylene propylene diene monomer (EPDM) blends prepared by the melt mixing process is reflected in this work. The electrical conductivity test indicates a pronounced increase in electrical conductivity from an insulator to almost a semiconductor with increasing graphene content. The electrical percolation threshold of the prepared nanocomposites was found to be sensitive to the PP/EPDM ratio and type of graphene. The percolation threshold was realized in the concentration range of 0.5–1 wt% of FLG for PP/EPDM (60/40). The power-law model was used to describe the behavior of electrical conductivity of the prepared nanocomposites based on graphene. In this model, the t parameter is dependent on the aspect ratio and dispersion state of graphene. The morphology of the samples was characterized by wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) which reveal that the electrical and thermal properties of prepared nanocomposites depend on the aspect ratio, dispersion state of graphene layers, and size of the dispersed phase (EPDM). Thermogravimetric analysis (TGA) of the nanocomposites demonstrates that the maximum thermal degradation and onset thermal degradation were shifted to higher temperatures with the introduction of graphene. The thermal conductivity of the nanocomposites is also remarkably improved with the addition of FLG compared with the nanocomposites based on MLG.