Experimental Study on the Effect of Storage Conditions on Thermal Stability of Nitrocellulose

Nitrocellulose (NC) is an energetic material that is widely used in the industrial and military fields. However, as a kind of hazardous chemical, it has potential thermal hazards during actual storage, especially when stored improperly. In order to study the effect of storage conditions on the thermal stability of NC, experimental analysis was carried out using the CALVET heat flux calorimeter and three representative conditions were considered in the experiments: (1) drying time, (2) moisture content, (3) cycles. The results show that with the increase of drying time, the onset temperature of NC samples changes little, while the peak heat flow increases obviously. Increased moisture content leads to an obvious increase both in the reaction onset temperature and in the maximum heat flow, which reveals a double action of evaporation cooling and hydrolysis. Compared with the original NC sample, the cycles can not only reduce the onset temperature of the reaction, but also change the peak shape obviously. A small "peak envelope" is formed before the main peak. Besides, relevant kinetic parameters such as heat of reaction, activation energy, and the self-accelerating decomposition temperature (SADT) under different conditions were obtained. Comprehensive analysis reveals that dry environment and multiple water addition cycles under damaged packing conditions are not conducive to safe storage, while the increase of moisture content lowers the thermal hazard of NC. The results have practical significance for revealing the effect of actual storage conditions on thermal stability of NC.