Impact of Synthetic Hydrocarbon in Biofuels on Two Polysulfide Aircraft Fuel-Tank Sealants

Abstract The impacts of synthetic hydrocarbon in biofuels on two fuel-tank polysulfide sealants were systematically studied in this research. Synthetic hydrocarbon was derived from waste oils and fats and produced by hydroprocessed esters and fatty acids process (HEFA). The experimental results revealed that the volume of two polysulfide sealants shrunk after being immersed in the pure biofuels for 28 days at 93°C. Furthermore, mechanical properties, such as elongation rate and hardness, failed to satisfy the requirement of the specification. The experimental results also showed that the volume swell of two polysulfide sealants varied from jet reference fuel (JRF) more than 5 % after being immersed in the blended fuels when neat biofuel component was mixed with No. 3 jet fuel in a volume ratio of 50/50. The mechanical properties of elongation and hardness still cannot meet the requirements of the specification. The results demonstrated that synthetic hydrocarbons in biofuels would have a significant impact on the polysulfide sealants of the aircraft fuel tank.