Abstract
To evaluate the effect of porous magnesium oxide (MgO-P) as a stabilizer for nitrocellulose (NC), we investigated the release behavior of nitrogen oxides (NOx) and the exothermic decomposition of NC mixed with MgO-P and other reference samples. The NOx measurements under 100-135°C isothermal conditions showed that NC/MgO-P barely released NOx at the beginning of the measurement (especially at 100°C), suggesting that the MgO-P can absorb NOx derived from NC into its pores on the particle surface. The NOx-reducing effect of some of the tested MgO-P additives was stronger than the effects of NC alone, its mixture with nonporous MgO, and even its mixture with a conventional stabilizer (acardite II (AKII)). The isothermal calorimetry results obtained at 135°C in an O2 atmosphere showed that, irrespective of the difference in porous and nonporous morphology, the NC/MgO prolonged the induction time of the exothermic peak for NC decomposition to a greater extent than the NC/AKII. Among the investigated MgO samples, the one with the highest alkalinity resulted in the longest induction time of NC decomposition, indicating that MgO suppresses NC exothermic decomposition by neutralizing NC-derived acid, which can accelerate the decomposition.
