Effect of carbon black on rate constant and activation energy of vulcanization in EPDM/BR and EPDM/NR blends

Soon at the beginning of the last century after it was discovered that carbon black is an active filler in rubbers, it became one of the most important components in manufacturing of rubber products. In this work, the effect of carbon black's type and loading and the structure of rubbers on rate constant and activation energy of the vulcanization were studied by the rheometer. The rubbers for this purpose are ethylene propylene diene monomer (EPDM), with natural rubber (NR), and butadiene rubber (BR). The overall rate of vulcanization is calculated from the kinetic expression of first order vulcanization. The results have showed that carbon black reduces activation energy in all rubbers and increases overall rate of vulcanization. In this case N330 reduces the activation energy and increases the overall rate of vulcanization rather than N660. On the other hand, this research showed that vulcanization rate of EPDM/BR is less than EPDM/NR. This is as the same trend as the number of allylic hydrogens in the repeat unit of these rubber chains.