Development of PIBSI type dispersants for carbon deposit from thermal oxidative decomposition of Jet A-1

When Jet fuels are exposed to high temperatures and pressures, carbon deposits are formed, and cause a number of performance issues in aircraft systems. One method for reducing the amount of carbon deposits is by the addition of dispersants to jet fuels. In this study, we investigated the effectiveness of polyisobutenyl succinimide (PIBSI) type dispersants in reducing the carbon deposits formed by thermal oxidative decomposition of Jet A-1. PIBSI type dispersants have amphiphilic structures consisting of a polar head and a nonpolar tail. The polar head adsorbs onto the carbon deposit precursors and the nonpolar tail prevents the aggregation of the precursors. An important factor governing the extent of adsorption is the polarity of the head, which is dependent on the polar surface area and the orbital electronegativity. Diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and pentaethylenehexamine (PEHA) were used as the head groups of alkyleneamines in this study. It was found that the dispersants that had head groups with a large polar surface area and orbital electronegativity strongly adsorbed onto the carbon deposit precursors and exhibited high efficiency with carbon deposit reduction. Based on these results, we propose dispersants containing amino ether groups in the head, as they showed improved carbon deposit reduction efficiencies compared to typical dispersants containing alkyleneamines in the head group.