Sorption dynamics of synthetic fuels and corresponding model mixtures in aged acrylonitrile-butadiene rubber

The sorption dynamics of synthetic aviation fuels, conventional kerosene, and corresponding model mixtures in thermo-oxidatively aged acrylonitrile-butadiene rubber (NBR) are studied. It is found that the diffusion coefficients and equilibrium mass uptakes of fuels and model mixtures in the elastomers are increased for compositions with high aromatics content and decreased for aged elastomers due to increased crosslink densities and polarity. Gas chromatography/mass spectrometry-assisted experiments are used to quantitatively analyze sorption for individual substances in the model mixture with time resolution. Due to strong interactions between the aromatics and the cyano group, the aromatics strongly swell the elastomer especially at the beginning after immersion. In addition, mechanical properties such as hardness, density, elongation, and stress at break are discussed, considering the chemical composition of the fuel and the aging condition of the elastomer. The aging of NBR affects the sorption dynamics of synthetic and conventional fuels similarly and are explained in detail by the model fuel approach.