Sorption and diffusion of a brake fluid in EPDM elastomers

This article reports on an investigation into how the morphology of four commercially available ethylene propylene diene monomer (EPDM) elastomers was affected by exposure to a brake fluid. The sorption and diffusion coefficients as a function of carbon‐black content as well as the EPDM type were determined at 23°C, 60°C, 100°C and 150°C. It was found that variation in carbon‐black loading showed an effect on the transport characteristics of EPDM elastomers. The sorption data at room temperature were not reported since these took too long a time. The leaching out of the indigenous additives might be due to the paraffin oil migrating to the surface of the specimens. The diffusion of the brake fluid in the EPDM membranes follows non‐Fickian transport. The results of this investigation are discussed in terms of the morphological differences in the EPDM formulations. The diffusion coefficients showed a dependence on the morphology of EPDM, as studied by the glass‐transition temperature of the elastomers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 000–000, 2001