Thermomechanical investigation on the effect of nitroguanidine on the thermal expansion coefficient and glass transition temperature of double-base gun propellant

Thermal expansion coefficient (CTE) is a critical parameter of gun propellant because of its major role in fabrication, storage and combustion performance of the propellant. Further, controlling the CTE of the propellant is an effective solution to improve its loading density. Therefore, it is important to understand the thermal expansion of the propellant. To obtain the linear CTE of insensitive gun propellant, different weight percentages of NQ are added to the B# double-base absorbent propellant, the thermal mechanical analyzer (TMA) is employed to estimate their dimensional change over the temperature range of 213–323 K. The pure NQ flaky gun propellant exhibits a negative thermal expansion with a linear CTE of −2.006 × 10−4 mm/mm K−1. The results show that the linear CTE of the B# double-base absorbent propellant is decreased by 53.74% as the concentration of NQ is increased to 30%, whereas the glass transition temperature increases with increasing the NQ content.