Determination of Berthelot Life Time Equation of Propellants Based on Nitrocellulose via Vacuum Stability Test in Semi-Continuous Mode

One of the most widely used propellants is nitrocellulose (NC) based propellant, which is divided into three general groups including single base propellant (SBP), double base propellant (DBP), and triple base propellant (TBP). In this paper, the life time of three types of NC-based propellants has been examined by using the vacuum stability test (VST). In this method, kinetic equations have been used in a semi-continuous manner. Accordingly, the activation energy for three propellant samples has been calculated by using the model-free and model-fitting kinetic methods. The kinetic model of three propellants is related to the zero-order (F0) model. Berthelot life time equations of propellants are calculated based on the gas evolution in the thermal decomposition at different percentages of reaction progress (α) under VST conditions. Based on the Berthelot equations, under the similar α and the storage temperature, the life time of propellants is as follows: SBP>DBP>TBP. But, because of the differences between parameters in the determination of critical α for these propellants, the comparison of a lifetime by using the Berthelot equation is not the only reason for having a short or long life time.