Aromatic liquid transport through filled EPDM/NBR blends

The sorption and diffusion characteristics of 70/30 ethylene propylene diene monomer rubber (EPDM)/acrylonitrile butadiene rubber (NBR) blends loaded with black fillers such as ISAF (intermediate super-abrasion furnace), HAF (high abrasion furnace) and SRF (semi-reinforcing furnace) have been investigated. The penetrants used were benzene, toluene and xylene. Filled samples have been found to show a reduced solvent uptake compared to the unfilled sample for the given blend ratio. The observations have been correlated with the morphology of the systems. Blends loaded with ISAF exhibited the lowest liquid uptake among black filled systems which has been attributed to the better filler reinforcement and enhanced crosslink density of the matrix. The extent of particulate filler reinforcement has been studied by using Kraus theory. The unfilled and filled systems have been found to exhibit non-Fickian transport behaviour. The effect of fillers on the cure and mechanical properties of the blends have also been investigated. Among the black filler loaded systems used, the ISAF mix showed the highest maximum torque value. The improvement in the cure and mechanical properties has been observed to be the highest for ISAF filled samples followed by HAF and SRF filled systems, which is in compliance with the observation from the sorption studies.