Transport properties of crosslinked acrylonitrile butadiene rubber/poly(ethylene-co-vinyl acetate) blends

The diffusion and transport of organic solvents through crosslinked nitrile rubber/poly(ethylene-co-vinyl acetate) (NBR/EVA) blends have been studied. The diffusion of cyclohexanone through these blends was studied with speci al reference to blend composition, crosslinking systems, fillers, filler lo ading, and temperature. At room temperature the mechanism of diffusion was found to be Fickian for cyclohexanone-NBR/EVA blend systems. However, a dev iation from the Fickian mode of diffusion is observed at higher temperature . The transport coefficients, namely, intrinsic diffusion coefficient (D*), sorption coefficient (S), and permeation coefficient (P) increase with the increase in NBR content. The sorption data have been used to estimate the activation energies for permeation and diffusion. The van't Hoff relationsh ip was used to determine the thermodynamic parameters. The affine and phant om models for chemical crosslinks were used to predict the nature of crossl inks. The experimental results were compared with the theoretical predictio ns. The influence of penetrants transport was studied using dichloromethane , chloroform, and carbon tetrachloride. (C) 1999 John Wiley & Sons, Inc.