Chapter 13 Chemistry and applications of dinitramides

Abstract

This chapter begins with the history of ammonium dinitramide (ADN), NH 4 N(NO 2 ) 2 . The potential importance of ADN is because it is a stronger oxidant than ammonium perchlorate (AP) and does not contain chlorine. There is description of the synthetic methods of production and details of its chemistry and properties. The chapter describes its reactivity, physical properties, chemical stability and compatibility, and sensitivity. There is also description of the various applications of the compound, the first being propulsion. ADN and compositions of ADN have been shown to be able to undergo self-sustained combustion with higher burn rates than the commonly used oxidizer AP. ADN has a surplus of oxygen, so its burn rate increases if a carbon source is added. The low-pressure burning is dominated by the decomposition of ADN to AN and N 2 O. The replacement of AP by ADN in metal fuels gives an energy increase of 10–20% based on theoretical studies. In addition to its performance, the fact that ADN does not contain any halogens makes it important for tactical and environmental reasons. The other applications are in explosive compositions—phase-stabilizer in ammonium nitrate, liquid monopropellant and in automotive safety. Guanylurea dinitramide (GUDN) mixed with oxidizers burns at a high rate with a low pressure coefficient, down to 0.2, and nearly without any temperature dependence in the range of −40° to +70°C. This has made it interesting as a substance for gas-generating compositions in automotive safety devices. There are suggestions on improvement of ADN—stabilization and handling properties. The ill-shaped crystals limit the amount of ADN in cast-cured compositions because of high viscosity. The only solution to this problem is to reshape the ADN crystals to be more regular.