Kinetic modelling of the chemical transformations of the stabiliser in single base gun propellants during ageing

Scientific Technical Review,Vol.LIV,No.3-4,2004A suitable kinetic model for the chemical transformations of the stabiliser (diphenylamine, DPA) in single base gun propellants during aging was investigated and successfully verified. This model assumes that chemical transformations of stabilisers in single base gun propellants occur in three concurrent ways, each of them representing a complex reaction, the kinetics of which can be described by the reactions of the shifting order. It was found that the experimental data were well evaluated by a first-order reaction at high concentrations of diphenylamine in the propellant, but by a zero-order reaction at low concentrations during the final phase of the propellant lifetimes. The mechanism of chemical transformations of diphenylamine was discussed in relation to the model and the ageing behaviour of these propellants.