Stability of the extruded double base (NC/DEGDN) modified with graphene oxide (GO)

Abstract. Double-base propellants (DBPs) have historically benefitted from including lead-based ballistic modifiers to enhance their combustion behavior. However, impending European legislation mandates the phasing out of lead in propellant formulations, necessitating the exploration of suitable alternatives. Graphene oxide (GO) has been introduced as a promising candidate, showing potential to improve the combustion performance of nitrocellulose microfilms. Before considering GO as a ballistic modifier for DBPs, it is crucial to examine the stability of such formulations thoroughly. This Work aims to elucidate the impact of GO on the fundamental characteristics and overall stability of DBPs. GO-based propellants were prepared, utilizing varying levels of oxidation (15% and 25-30% of O2). Artificial aging of the propellant at 80°C was conducted to provide valuable insights into their storage shelf life. Small-scale thermal stability analyses, including measurements of stabilizer content, activation energy for nitrate ester decomposition, and heat flow, were performed to assess the propellant's stability. Our findings indicate that adding GO to the propellant formulation does not compromise its stability. The activation energy analysis by differential scanning calorimetry revealed that the modified propellants exhibited stability similar to that of the unmodified formulation. The results from the stabilizer depletion assessment by liquid chromatography and thermal stability evaluation by heat flow calorimetry analyses confirm the propellant's ability to withstand storage for over a decade. This study contributes valuable insights to the use of GO as a valuable alternative lead-free ballistic modifier, highlighting its favorable impact on propellant stability and paving the way for future applications in the field of propulsion technology.