Comparative study of radiation effect on rubber–carbon black compounds

Acrylonitrile butadiene rubber (NBR) and ethylene–propylene diene monomer (EPDM) rubber compounds have been prepared without and with 50 phr contents of high abrasion furnace carbon black (HAF). Cure characteristics, namely, minimum (Ml) and maximum torque (Mh), scorch time (ts2), the optimum cure time (tc90) and the cure rate index (CRI) have been investigated. Prepared compounds have been subjected to gamma radiation doses up to 200 kGy to induce radiation crosslinking and degradation process under atmospheric conditions. Mechanical and physical properties, namely, tensile strength (TS), elongation at break (Eb), hardness (Sh-A), Flory–Huggins parameter (χ), the crosslink density (ν  ) and the molecular weight of the rubber between two crosslinks (M‾c) have been followed up as a function of irradiation dose. The morphology investigations of prepared compounds were carried out using SEM micrograph. The results obtained indicate that improvement to irradiation has been attained in different properties of carbon black reinforced NBR and EPDM rubber compounds with respect to unloaded ones.