Determination of Diphenyl Amine (DPA) Stabilizer in Propellants – A Minireview

Abstract There is concern about the aged propellants as the proportion of stabilizer, diphenyl amine (DPA), keeps on reducing while maintaining the propellant formulation safe. This is a very important issue as it keeps the propellant as well as the surrounding safe from any possible mishap. Therefore, the determination of residual DPA/DPA derivatives in the propellant is of utmost importance. Various attempts have been made to determine residual DPA/derivatives content in the propellant. In this review the detection methods have been compiled and analysed for their implications, detection limit and standard deviation. The methods attempted for detection comprise volumetric, chromatographic, electroanalytical, spectroscopic and thermoanalytical techniques. The volumetric method was tried in the initial attempts by adopting chemical reactions. Chromatographic methods were reported by adopting different procedures and variations. These have been discussed in details. Electroanalytical methods have become one of the important techniques to determine the residual DPA that has been discussed in detail with incorporation of various modifications. Spectroscopic methods were also deployed to determine the DPA content in the propellant. The methods, being very straight forward and clean, have been considered effective in determination. Differential scanning calorimetry has also been tried for finding the DPA content in the propellant sample by adopting different combinations, which is also incorporated for discussion in this paper.