Biodegradeable, Direct Replacement Hydraulic Fluids for MIL-H-5606 and MIL-H-83282

The hydraulic fluids that are currently used by the Air Force are not biodegradable and represent a potential environmental hazard if they leak or are accidentally spilled while work is performed on the hydraulic system of an aircraft. Upon entering the soil, the hydraulic fluid becomes a contaminant which can, ultimately, enter the water table creating possible health problems with are drinking water. Because of these potential environmental problems with the current hydraulic fluids (Mil-H-5606 and Mil-H-83282) it is desirable to develop and qualify a biodegradable/bio-friendly hydraulic fluid that would act as a direct replacement fluid to these two current military specification hydraulic fluids. These new fluids must meet the rigid performance specifications of the current hydraulic fluids in order to qualify to replace the current hydraulic fluids (e.g. must be able to operate over the temperature range of -40 to 135 C). There are several approaches that can be used to develop a biodegradable hydraulic fluid including substitution with stabilized vegetable oils. synthetic esters, synthetic polyalphaolefins, multipli-alkylated cyclopentanes (MACs), and synthetic polyol-polyesters.