On the influence of CB loading on the creep and relaxation behavior of SBR and NBR rubber vulcanizates

It is well known that the time dependence behavior (creep and relaxation) of crosslinked rubber systems are influenced by the incorporation of particulate fillers. The influence of carbon black (CB) loading on the creep and relaxation behavior of styrene butadiene rubber (SBR) and nitrile-butadiene rubber (NBR) has been studied. Creep test is carried out at 3 different stress levels while the relaxation test is carried out at 100% strain. The obtained results of five different compositions for SBR and NBR with 0, 20, 30, 50 and 70 phr of CB were compared. It can be found that creep resistance increases as CB loading increases and stress level decreases, while as CB loading increases the relative modulus (E(t)/E(0)) and initial relaxation speed decrease.