Influence of carbon black filler on the autohesion of polybutadiene rubber

Abstract A study of the autohesion of polybutadiene rubber filled with different amounts of carbon black has been made. When the elastomer is uncrosslinked, the autohesive strength initially rises linearly with square root of contact time and finally shows a time independent course. The initial autohesion at time zero increases almost linearly with increasing carbon black content, while the ultimate strength is markedly influenced only when the filler content exceeds 30%. The time necessary to achieve ultimate strength decreases significantly when small amounts of filler are added. Experiments with slightly crosslinked polybutadiene did not show a characteristic time dependence. The autohesive strength increases strongly up to 30% carbon black content and seems to decrease again on further addition of filler.