The Compatibility Study of Aircraft Fuel Tank Elastomers with Synthesized Paraffinic Kerosine and its Blends

The synthetic paraffinic kerosine (SPK) produced via HEFAs is of great interest for civil aviation industry as it exhibits an excellent thermal oxidative stability with significantly lower particulate matter emission. However, due to its aromatic free characteristics, the widespread use of SPK is limited by its compatibility with non-metal materials such as fuel tank elastomers. In this research the compatibility of SPK and its blends with widely used aircraft fuel tank elastomers were systematically studied. Experimental results demonstrated the volume swellability of all selected materials showed a linear relationship with volume percentage of No.3 jet fuel in SPK blend. The increase of volume percentage of No.3 jet fuel in the SPK blend increased volume swellability for all materials except fluorosilicone gasket. The alkyl benzenes and naphthalenes in the blend acted as the hydrogen donors, which facilitated the formation of polymer matrix and led to the increase of the distance between polymer chains. The poor volume swellability of fluorosilicone gasket was attributed to material itself highly fluorinated and relatively inert characteristics. Experimental results verified the material swelling performance was not only related to fuel properties but also influenced by material properties. Material elongation and hardness were also evaluated after aging in SPK and its blends at specified temperature for certain amount of time. Moreover, experimental results showed that the fuel properties were also impacted by the material used for fuel transportation. The synthetic rubber seal cap of storage can may cause high halogen content in the SPK and its blends.