Compatibilizer/graphene/carboxylated acrylonitrile butadiene rubber (XNBR)/ethylenepropylenediene monomer (EPDM) nanocomposites: Morphology, compatibility, rheology and mechanical properties

In this study, nanocomposites based on different blends of XNBR/EPDM with 0, 0.1, 0.3, 0.5, 0.7, and 1 phr graphene were prepared on a two-roll mill. The role of EPDM-grafted maleic anhydride compatibilizer (EPDM-g-MAH) and the effect of graphene on morphology, curing characteristics, and mechanical properties were investigated. The curing behavior of the nanocomposites was studied using a rubber curing rheometer. Also, microstructure of the nanocomposites was observed by transmission electron microscopy and scanning electron microscopy. With increasing the graphene content in the composite, in addition to the torque, the curing time and scorch time were increased. Fracture surface morphological studies indicated that the presence of EPDM-g-MAH improved the graphene dispersion within the XNBR/EPDM matrix and a uniform dispersion with a small amount of aggregation was observed. On the other hand, the presence of graphene in the matrix created a rough fracture surface. In addition, with adding EPDM-g-MAH compatibilizer and increasing the graphene, the dispersed phase size of EPDM in the XNBR matrix became smaller and a uniform dispersion was obtained. Also, hardness, tensile strength, fatigue, modulus, and elongation-at-break of XNBR/EPDM nanocomposite showed a significant increase by the addition of compatibilizer and increasing the graphene content.