Barrier properties of natural rubber/ethylene vinyl acetate/carbon black composites

Composites based on natural rubber (NR), ethylene vinyl acetate (EVA) and carbon black were prepared. Three types of carbon black viz.; semireinforcing furnace (SRF), high-abrasion furnace (HAF) and intermediate superabrasion furnace (ISAF) were used for reinforcement. The barrier properties of these filled samples were examined in an atmosphere of petrol, kerosene and diesel. Blends loaded with ISAF exhibited the lowest liquid uptake which has been attributed to the higher filler reinforcement and crosslink density of the matrix. Among the three vulcanising systems used, viz.; sulphur (S), dicumyl peroxide (DCP) and mixed (S+DCP), DCP crosslinked samples exhibited high barrier properties to the probe molecules. Diesel showed the lowest interaction with the composites compared to petrol and kerosene. The sorption data were used to estimate the enthalpy, entropy and free energy of the transport process.