Synthesis and performance of a series of polyisobutylene substituted succinic acid ester dispersants for reducing thermal oxidation deposition of jet fuel

The thermal oxidation deposition of jet fuel is of great concern for the advanced fuel-cooled thermal management technologies of advanced aircraft and could be solved by many methods in which pre-adding dispersants is the most economical and efficient way. In this paper, a series of new ester-type dispersants were synthesized from polyisobutylene-substituted succinic acid (PIBSA) and polyglycerol. The polyisobutylene-substituted succinic acid ester (PIBSAE) dispersants were characterized by Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC), and their anti-deposition performances in Chinese jet fuel (RP-3) were determined by an electrically heated tube test and Jet Fuel Thermal Oxidation Stability test (JFTOT). The structure and performance of the dispersant were greatly influenced by the molar ratio of PIBSA to polyglycerol and the degree of polymerization of polyglycerol in the reactant. The dispersant synthesized from PIBSA with triglycerol at a 1:1 molar ratio, which not only has a moderate total hydroxyl value but also contains sufficient poly-PIBSAE molecules with moderate molecular weight, showed the best performance in the electrically heated tube test by reducing 84.6% of the thermal oxidation deposit of a commercial RP-3. Furthermore, JFTOT at 355 degrees C also showed that this dispersant can greatly reduce the deposit of low-quality jet fuel by decreasing the deposit rating from >4 to 1 and the maximum differential pressure from 2.10 to 0.20 kPa.