Description of consumption of stabilizers in gun propellants showing pseudo-sigmoid decrease

摘要

There could be the rare case that typical stabilizers as DPA, acardite II, 2-Nitro-DPA, used to stabilize NC-based gun and rocket propellants, show a shape in the decrease of their concentration, which is unusual. The normal stabilizer decrease shows not a horizontal tangent at the data at time equal zero, but it starts immediately with a monotonic decrease. The unusual shape can have similarities with a sigmoid curve. Such shapes could be described with kinetic autocatalytic models or with Avrami-Erofeev description of crystallization. But decrease of stabilizer is by no means autocatalytical nor is it a crystallisation. To apply such descriptions is therefore wrong from the conceptual view and they should not be used, even when the data can be described formally in a good manner. To have the right way of description, concepts of modelling have been developed, which can describe the normal stabilizer decrease and the pseudo-sigmoid one. They will be explained and demonstrated. Further on, it will be argued in detail that an autocatalytic stabilizer decrease is a contradiction in itself.