DETERMINATION OF STABILIZER CONTENT AND PREDICTION OF THE SERVICE LIFE OF A SINGLE-BASE PROPELLANT USING ACCELERATED AGEING

Abstract

The chemical stability of a single base propellant was assessed through quantifying its stabilizer content and predicting its safe service life through the accelerated ageing method. The main goal was to evaluate the rate of stabilizer depletion at elevated temperatures and, based on these results, to predict the chemical stability of the propellant under standard storage conditions. According to NATO and other national military standards, storage temperatures are typically assumed to be around 20°C. Propellant samples with an initial diphenylamine stabilizer concentration of approximately 2 wt.% underwent a treatment of thermal ageing at 100°C and 110°C for varying beforehand set intervals. Following each ageing interval, the residual stabilizer and its reaction derivatives were analyzed using high performance liquid chromatography. The experimental data were used to determine the degradation of the amount of the stabilizer and to estimate the service life of the propellant. The results captured a gradual decrease in stabilizer content with increasing ageing time, and temperature was shown to significantly affect the degradation rate. Explosive materials are incorporated in different types of ammunition and explosive devices, which requires a safe life service of 20 30 years counting from the day of its development. Based on the results, the propellant is expected to maintain chemical stability for approximately 44 years under normal, expected storage conditions. High performance liquid chromatography was validated as a reliable and accurate analytical technique for assessing stabilizer depletion and evaluating the chemical stability of single base propellants. These results may support enhanced quality control procedures, improved storage safety, and more knowledgeable decisions concerning the continued use or timely withdrawal of ammunition from service. The chromatographic analyses enabled quantitative determination of the stabilizer diphenylamine together with its major degradation products, including N
nitrosodiphenylamine and nitrated derivatives, providing evaluation of the total stabilizer descending throughout the ageing process. The accelerated ageing approach combined with the Arrhenius relationship proved suitable for predicting the long term behavior of the investigated propellant under standard storage conditions. The captured results lead us to conclusion that the critical stabilizer level established to 50% of the initial concentration can be referred to as a practical criterion for estimating the remaining safe service life. The predicted service life should be taken in consideration as an approximation because practical storage conditions, packaging characteristics, propellant mass, and environmental factors may influence the actual ageing rate. Nevertheless, the presented methodology provides a rapid and reliable approach for routine surveillance of ammunition stocks and evaluation of propellant chemical stability. The proposed analytical procedure can therefore assist military and industrial laboratories in planning periodic inspections and identifying propellants approaching the end of their safe storage period. The findings of this study contribute to improving ammunition safety, optimizing storage management, and supporting evidence based decisions regarding maintenance or disposal of ageing energetic materials. The developed approach may also serve as a useful basis for future investigations involving other types of propellants and stabilizer systems under accelerated ageing conditions.