| Abstract: | Currently formulated propellants comprise RDX and polymeric binders, such as hydroxy‐terminated polybutadiene (HTPB) and cellulose‐acetate butyrate (CAB) as well as the energetic substances glycidyl azide polymer (GAP) and nitrocellulose (NC). Propellants based on GAP are often brittle if they are formulated with a high content of cyclotrimethylene trinitramine (RDX) and due to the usually insufficient mechanical properties of GAP. On the other hand formulations based on RDX and NC may exceed the tolerable burning temperature with increasing RDX concentration. Therefore, in this study propellants with a high force and with relatively low burning temperature has been formulated by using a compound of NC and GAP as energetic binder. According to thermodynamic calculations GAP/NC composite propellants can be formulated with up to 15 percent more specific energy than seminitramines at the same burning temperature. By choosing appropriate polymerization conditions chemical stable compositions can be produced. ARC experiments give evidence that at temperatures from 120°C to 160°C the binder decomposes similar to NC. At higher temperatures the behaviour switches from NC type to GAP type decomposition. In comparison to GAP bound propellants the compressive strength of propellants bound by the GAP/NC compound can be significantly increased by up to 420 percent at room temperature. Although the examined seminitramine propellants bound with NC show a compressive strength which is about 10 percent higher at room temperature, the GAP/NC compositions are quite superior at elevated temperature. |
