ABSTRACT
This study investigates the diffusion of synthetic fuels, plasticizers and stabilizers in pristine and aged acrylonitrile-butadiene rubber (NBR), spatially-resolved and component-selective. The objective of this study is to describe the influence of aging phenomena on the swelling of NBR in fuels in consideration of its spatial resolution, especially in small dimensions. Carbon black filled NBR with an acrylonitrile content of 18 wt% and a sample geometry of 10 x 10 x 60 mm3 was aged thermo-oxidatively at 100 °C for 14 and 28 days. Hardness measurements show a spacially inhomogeneous aging behavior of the elastomer. Gravimetrical sorption experiments are conducted to describe the macroscopic diffusion behavior of synthetic fuel and the additives in NBR. Gas chromatography/mass spectrometry (GC/MS) was applied to differentiate between sorption of fuels into the elastomer and desorption of the additives out of the elastomer simultaneously and in a spacially-resolved manner. The results show a correlation between the local swelling properties and the local aging status of the elastomer. Spatially-resolved hardness investigations show a local influence of absorbed fuel on the hardness. The swelling mitigates the aging caused hardening. With a better understanding of the swelling behavior of aged elastomers the investigation aims to ensure a safe application of renewable fuels in future aviation.
