United Kingdom/Sweden collaboration on ADN and PolyNIMMO/PolyGLYN formulation assessment

This report gives details of a collaborative programme between Sweden and the United Kingdom in conducting characterisation and basic assessment of Ammonium Dinitramide (ADN). ADN is a new energetic oxidiser which has potential for use in improved propellant and high explosive formulations. Theoretical calculations have shown that high performance can be expected of formulations using the ingredient. Rocket propellants are also predicted to be minimum smoke, and ADN therefore has a number of advantages compared with the currently used oxidiser, ammonium perchlorate. The areas addressed in the collaboration were sensitiveness, chemical compatibility, chemical stability, assessment of plasticisers, optimisation of crystal form, cure characteristics and basic burn rate assessment. A number of difficulties were identified with the use of ADN, particularly in terms of compatibility and stability. The crystal form currently commercially available is not ideal for production of formulations, but viable methods of producing the material in a suitable form were demonstrated. The work identified that burn rates are comparable with those for HTPB/ammonium perchlorate formulations but the pressure exponent is currently higher than is desirable. Overall, the programme has identified and provided an understanding of the critical properties of ADN, and has indicated the way forward for further development. A number of areas suitable for further collaboration were also identified.