Impact of graphite nanoflakes and gamma radiation on the mechanical, electrical, and thermal properties of EPDM/modified BaTiO3 composites

Abstract

The effect of graphite nanoflakes (GNFs)/modified barium titanate (MBT) hybrid fillers on the mechanical, electrical, and thermal properties of ethylene-propylene-diene monomer (EPDM) was extensively investigated in the current study. Moreover, the effect of gamma irradiation on the different properties of the prepared nanocomposites was investigated. To accomplish this goal, EPDM/MBT composites with various GNFs contents (0, 2, 4, 6, and 8 phr) were fabricated using a conventional roll mill. Graphite was expanded by heating and subsequently modified using tween 80 surfactant, resulting in the formation of GNFs. The presence of various functional groups on the surface of the modified BaTiO3 particles was verified by Fourier transform infrared spectroscopy (FTIR). The scanning electron microscopy (SEM) analysis revealed a uniform dispersion of GNFs in EPDM/MBT composites, with a concentration up to 6 phr. The study revealed that the mechanical properties of the nanocomposites were reinforced by the inclusion of GNFs up to 6 phr. The irradiated EPDM/MBT/6 phr GNFs nanocomposite exhibited the maximum elastic modulus value of 4.8 MPa, which was approximately 32 % higher than that of the corresponding unirradiated nanocomposite. The thermal conductivity of the irradiated EPDM/MBT/8 phr GNFs nanocomposite increased from 0.213 W/m.K to 0.260 W/m.K (22 %), while the dielectric constant increased from 4.475 to 5.551 (24 % increase) at 103 Hz as compared to the pure EPDM/MBT composite. The enhanced electric and thermal performance of GNFs can be attributed to the mobility of their π-electrons.