NEW SOLID PROPELLANTS DEVELOPMENTS AT SNPE MATÉRIAUX ENERGÉTIQUES

The new solid propellants studied by SNPE Matériaux Energétiques (SME) are mainly based on: fillers, such as ADN, nitramines, RDX, HMX, HNIW, etc.; cross-linked binders formulated with energetic or non-energetic polymers, such as GAP and polyether polymer; and energetic plasticizers. The effect of nano-sized aluminium on the properties of HTPB/AP/Al is also assessed. In this paper, we will only discuss the effects of nano-sized aluminium on propellant properties and GAP-based propellants. Nano-sized aluminium leads to an increase of the burning rate of composite propellants. The effect greatly depends on the quality of the powder. For some formulations, a mesa effect is observed between 7 and 15 MPa. The use of GAP-based binder and HNIW brings an increase in volumetric specific impulse around 12% compared to current XLDB propellants. The mechanical properties are good. GAP-based binder and HNIW lead to an increase in the burning rate. In its industrial plant, SME has recently set up a new mixing facility equipped with a twin-screw machine. This workshop can produce current solid composite propellants or new energetic formulations. The hazards are greatly reduced owing to the small quantity of propellant mixed at the one time. Cryogenic solid propellants are a new concept of chemical propellants that use frozen products in solid rocket motors. The objective is to combine the high performance of liquids and the simplicity of solids. SME is developing a formulation with a freezing point near 0°C to limit the storage constraints; these are called Refrigerated Solid Propellants and are named Hydroxalane™. They offer opportunities to reach mid-term high-energetic performances. The compositions are based on water, hydrogen peroxide, polymer, and aluminium. BATES grains with a 90-mm diameter have been manufactured and tested successfully. The high energy density materials carry great potential in terms of increased energetic performance and are likely to introduce a long-term breakthrough for solid propulsion. These molecules require the use of a particular process for their synthesis study. The methodology used and the advance of research will be described herein.