Comparison between Abel test stability and thermal decomposition behavior of nitrocellulose

Nitrocellulose (NC) is prone to spontaneous decomposition with exothermic heat release and thus is generally evaluated for stability during the storage process using standardized test methods such as the Abel test that measures the amount of nitrogen oxides (NOx) released from NC. In the present study, we evaluated the relative stability of various NC and NC-based propellants by monitoring the heat release behavior in an oxygen atmosphere via isothermal calorimetry. The results were compared with ones of the Abel test to evaluate the validity of the conventional stability test. The comparison revealed that there was no correlation between the stabilities predicted by the isothermal calorimetry and the results of the Abel test; some of the samples were evaluated as stable in the Abel test even if they released the decomposition heat easily, which means that the Abel test can occasionally overestimate the NC stability. In addition, the time change in the NOx release behavior based on the chemiluminescence method suggested that the Abel test mainly determined the desorption amount of NOx physically adsorbed on the surface of the samples, not that derived directly from the decomposition of NC. This possibly resulted in the incongruity with the results of the isothermal calorimetry, which instantly measures the heat released during decomposition.