Reaction Model for the Aging and Shelf-Life Prediction of Double-Base Propellant SF-3

The prediction and determination of shelf-life is an important step in the storage and use of ammunition. In this study, the aging reaction model and shelf-life prediction model of SF-3 double-base propellant were studied. First, a theoretical aging reaction model of SF-3 was developed based on scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis and the aging reaction process. The aging reaction model was also experimentally validated. Then, based on the theoretical aging reaction model and the Arrhenius equation, the stabilizer depletion and mass loss kinetics models were developed. The aging reaction model showed a linear relationship between the stabilizer depletion rate x_n and the aging time t, which indicated that the aging reaction is a zero-order reaction. The rate-limiting step of the SF-3 aging reaction was the decomposition rate of nitrate ester compounds. The reaction kinetics model showed that the equation to predict the shelf-life of SF-3 was t[d]=1.44×10⁻¹³exp(11428.38/T[K]). Additionally, the relationship between the mass loss rate x_w and storage temperature T was x_w[%]=53.93exp(−446.97/T[K]) at the end of the shelf-life of SF-3. The results of this study provide a reference for predicting the aging process of other propellants that use nitrate ester compounds as the main energetic components. It also provides theoretical support for using the mass loss rate to predict the shelf-life of SF-3.