Storage stability and safe storage life assessments of gradiently denitrated spherical gun propellants

As a new type of gun propellant, Gradiently denitrated spherical gun propellants (GDSP) demonstrate excellent progressive combustion performance and clean combustion performance. However, its unknown storage performance hinders its application, necessitating thorough research. In this study, three types of GDSP samples with different degrees of denitration were prepared using the denitration reaction principle and aging experiments were conducted at different temperatures. SEM and FT-IR characterization revealed changes in the surface microstructure of aged GDSP, while the shape and surface chemical functional groups remained largely unchanged. Oxygen bomb calorimetric method and DSC tests indicated that aging led to a slight decrease in the energy and apparent activation energy of GDSP, as well as a reduction in thermal decomposition stability. Closed vessel tests demonstrated that the maximum dynamic vivacity initially increased and then decreased with prolonged aging, but progressive combustion performance was maintained. Additionally, changes in stabilizer content during aging were assessed using HPLC, determining the safe storage life of GDSP with different degrees of denitration at 30 °C to be 41.9, 62.0 and 81.3 years, respectively. It was concluded that a higher degree of denitration correlates with a longer safe storage life of GDSP. The thermally accelerated aging mechanism of GDSP and the life extension mechanism of denitration treatment are also discussed detailly. These results demonstrate that GDSP possesses excellent storage stability and a long safe storage life, laying the foundation for its application.