Prediction of In-Service Time Period of Three Differently Stabilized Single Base Propellants

Three nitrocellulose-based propellants for use in micro gas generators equipped with different stabilizing systems have been investigated to assess the stabilization capability with regard to inset-vice time. whereby strong time-temperature profiles have been applied. The three stabilizing systems have been (i) 0.74 ;mass-% diphenylamine (DPA) and 0.48 mass-% Akardite II (Ak II): (ii) 1.25 mass-% Ak II; (iii) 2.04 mass-%,, Ak II. Several profiles were considered. Two simulate the heating at sun exposure in hot areas, others consider environmental temperatures in hot-humid and hot-dry areas. They were evaluated according to the load and finally one was chosen for the assessment. The contents of stabilizers were determined by high performance liquid chromatography after Soxhlet type extraction. To describe stabilizer consumption, the most suitable kinetic model was taken. Therewith a prediction was made using the chosen time-temperature profile named 'Phoenix', designed for temperatures at the steering wheel. The objective was to reach with this profile 15 years until the consumption of primary stabilizer content. This is conservative. because with the stabilizing action of the consecutive products of the stabilizers longer times are possible.