Diffusion and Transport of Aromatic Solvents through Prevulcanised Natural Rubber/Styrene Butadiene Rubber Latex Blends

Abstract

Molecular transport of aromatic hydrocarbons through crosslinked NR/SBR blends prepared by latex blending has been studied in the temperature range of 28–60°C. NR/SBR blends were vulcanised by conventional and more efficient vulcanising systems. The more efficient system showed higher uptakes than the conventional system. This is due to the difference in crosslink density. The sorption behaviour of the blends was analysed in three different solvents i.e., benzene, toluene and xylene. The effects of various parameters (blend composition, vulcanising systems, temperature and penetrant size) on the sorption parameters were studied. The mechanism of diffusion showed an anomalous behaviour. The entropy, enthalpy and first order kinetic rate constant have been evaluated. Theoretical and experimental results were correlated. The molecular weight between crosslinks ( $\overline{\text{M}}$ _c) was calculated from the diffusion data. The experimentally calculated $\overline{\text{M}}$ _c values were very close to the affine model. The mechanical properties of the swollen samples were evaluated and found to be lower than those for the unswollen state.