THE EFFECT OF AROMATIC TYPE ON THE VOLUME SWELL OF NITRILE RUBBER IN SELECTED SYNTHETIC PARAFFINIC KEROSENES

摘要

A barrier impeding the full adoption of synthetic paraffinic kerosenes (SPKs) as alternative fuels is concerns with their material compatibility. As-produced SPKs are composed of normal, branched, and cyclic paraffins resulting in fuels that are very inert with respect to their interactions with polymers. This contrasts with conventional fuels which can show significant solvent character in the form of swelling and softening polymeric fuel system materials. There is concern that exposing materials that have been in service with conventional fuel to an alternative . fuel may cause them to shrink, harden and fail. The most acute concern is for O-rings which rely on their size and resiliency to perform their function. The near-term solution is to blend aromatics with the SPKs to increase their solvent character. It is desirable to identify the most effective aromatics that could be used for this purpose. In this study the volume swell of nitrile rubber was measured using 6 reference JP-8s, 4 SPKs and 11 aromatics. The aromatics were selected to examine the influence of molar volume, polarity, and hydrogen bonding on their performance as swelling promoters. It was found that hydrogen bonding had the largest effect followed by polarity and molar volume. Furthermore, it was found that the same rules apply to the SPK itself with lighter fuels providing a higher baseline volume and this characteristic had a significant effect on the minimum treatment level. Overall, it was found that within the boiling range of jet fuel the individual effects of molar volume and polarity are relatively subtle and the ability to introduce hydrogen bonding is limited. The most effective fuels combine these factors by minimizing molar volume and maximizing polarity and hydrogen bonding.