Curing characteristics and mechanical and aging properties of ethylene propylene diene monomer/calcium carbonate/bentonite hybrid composites

Ethylene propylene diene monomer (EPDM)/calcium carbonate/bentonite (Bt) hybrid composites were prepared via a laboratory size two-roll mill. In this work, loading ratio of calcium carbonate to Bt was varied, that is, 30/0, 5/25, 15/15, 25/5 and 0/30 parts per hundred rubber. The effect of partial replacement of calcium carbonate with Bt on the curing characteristics, tear properties, morphology, aging and fatigue life of the hybrid composites was studied. On increasing Bt loading, cure time, scorch time and maximum torque of EPDM/calcium carbonate (CaCO ₃ )/Bt composites decreased, whereas minimum torque increased. The tear strength and fatigue life of EPDM/CaCO ₃ /Bt hybrid composites showed improvement with increasing Bt loading. The results also showed that the retention of aging of EPDM/CaCO ₃ /Bt hybrid composites decreased with increasing Bt loading.