Green Propellants

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Doctoral Thesis. E-Print. Stockholm: KTH Chemical Scienceand Engineering, Royal Institute of Technology, SE-100 44, Sweden, 2010. - 77 p. ISBN 978-91-7415-758-1 ISSN 1654-1081Abstract To enable future environmentally friendly access to space by means of solid rocket propulsion a viable replacement to the hazardous ammonium perchlorate oxidizer is needed. Ammonium dinitramide (ADN) is one of few such compounds currently known. Unfortunately compatibility issues with many polymer binder systems and unexplained solid-state behavior have thus far hampered the development of ADN-based propellants. Chapters one, two and three offer a general introduction to the thesis, and into relevant aspects of quantum chemistry and polymer chemistry. Chapter four of this thesis presents extensive quantum chemical and spectroscopic studies that explain much of ADN’s anomalous reactivity, solid-state behavior and thermal stability. Polarization of surface dinitramide anions has been identified as the main reason for the decreased stability of solid ADN, and theoretical models have been developed to explain and predict the solid-state stability of general dinitramide salts. Experimental decomposition characteristics for ADN, such as activation energy and decomposition products, have been explained for different physical conditions. The reactivity of ADN towards many chemical groups is explained by ammonium-mediated conjugate addition reactions.It is predicted that ADN can be stabilized bychanging the surface chemistry with additives, for example by using hydrogen bond donors, andby trapping radical intermediates using suitable amine-functionalities. Chapter five presents several conceptual green energetic materials (GEMs), including different pentazolate derivatives, which have been subjected to thorough theoretical studies. One of these, trinitramide (TNA), has been synthesized and characterized by vibrational and nuclear magnetic resonance spectroscopy. Finally, chapter six covers the synthesis of several polymeric materials based on polyoxetanes, which have been tested for compatibility with ADN. Successful formation of polymer matrices based on the ADN-compatible polyglycidyl azide polymer (GAP) has been demonstrated using a novel type of macromolecular curing agent. In light of these results further work towards ADN-propellants isstrongly encouraged. Keywords: Quantum chemistry, reaction kinetics, ammonium dinitramide,high energy density materials, rocket propellants, chemical spectroscopy, polymer synthesis.Dinitraminic acid (HDN) Isomerization and Self-Decomposition Revisited Novel 1,3-Dipolar Cycloadditions of Dinitraminic Acid: Implications for the Chemical Stability of Ammonium Dinitramide The Anomalous Solid State Decomposition of Ammonium Dinitramide: A Matter of Surface Polarization On the Anomalous Decomposition and Reactivity of Ammonium and Potassium Dinitramide The Molecular Surface Structure of Ammonium and Potassium Dinitramide: A Vibrational Sum Frequency Spectroscopy and Quantum Kinetic Stability and Propellant Performance of Green Energetic Materials Envisioning New High Energy Density Materials: Stability, Detection and Performance Experimental Detection of Trinitramide Tri-Block Copolymers of Polyethylene Glycol and Hyperbranched Poly-3-ethyl-(hydroxymethyl)oxetane Through Cationic Ring Opening Polymerization Design of an Ammonium Dinitramide Compatible Polymer Matrix

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