ABSTRACT
ABSTRACT: Fuels are complex mixtures containing different compounds of various substance classes. Depending on the composition, particularly on the content of aromatic hydrocarbons, fuels show different swelling behavior towards elastomers. Therefore, understanding and quantitatively describing diffusion processes are essential requirements to prevent malfunctions as swelling can change material properties.
To get better insight in diffusion processes, model liquids containing different amounts of dodecane and m–xylene, which represent aliphatic and aromatic fuel fractions, were used to perform sorption experiments on Acrylonitrile Butadiene Rubber (NBR). The mass uptake of each compound was traced simultaneously and time resolved by extraction and subsequent Gas Chromatography/Mass Spectrometry (GC/MS).
Swelling potential of mixtures containing m–xylene and dodecane increases with higher aromatics content, which is indicated by higher equilibrium mass uptake and diffusion rate. This work provides an experimental approach to investigate interactions of fuel components and elastomers on a molecular level by quantifying diffusion processes of individual mixtures’ components by GC/MS. The results allow understanding the diffusion behavior of single components in mixtures, and may be applied to compatibilityand lifetime predictions of sealing materials and in–service aviation fuels.
