Effects of carbon filler on sorption and diffusion of gases through rubbery materials

Abstract

AbstractEffects of carbon filler on the sorption and diffusion of carbon dioxide in natural rubber and in styrene‐butadiene rubber have been studied. Sorption isotherms conform to Henry's law in unfilled rubber and to Langmuir's law in carbon black. The isotherms in filled rubber exhibit a combination of the two sorption modes. The Henry's law solubility parameter kD increases with carbon filler content; the Langmuir saturation constant C′A initially is constant with filler level, but then decreases abruptly when carbon particles begin to aggregate. The diffusion coefficient decreases with increasing filler content, presumably owing to geometric effects and to polymer chain immobilization in the interfacial regions.