RESUMEN
New energetic polymers were synthesized from monomers containing a trans-2-tetrazene unit. In contrast to traditional binders, such as inert hydroxytelechelic polybutadiene or glycidyl azide polymers-in which the energetic features are on the side chains-the energetic groups in the polytetrazenes are incorporated directly in the polymer backbone. Thermal analyses demonstrated that decomposition occurs at approximately 130 °C, regardless of the polymer structure. Glass-transition temperatures ranged from -34.2 to 0.2 °C and could be lowered further (to -61 °C) with the help of a new diazidotetrazene energetic plasticizer. Interestingly, hexafluoroisopropanol (HFIP) enabled complete, room-temperature depolymerization within 1â week. This depolymerization should enable the recycling of unused pyrotechnic compositions based on these new binders.
RESUMEN
Functionalized hydrazines and bishydrazines are interesting straightforward precursors for accessing higher nitrogenated compounds. They offer structural diversity and promising energetic properties as well, namely for propulsion applications. A novel and scalable synthesis has been developed for a new family of bishydrazines, starting from monomethylhydrazine (MMH). This solvent-free route represents a suitable alternative to the one described in the literature. It was extended to design a new family of unsymmetrical hydrazines bearing various functional groups. A selected series of promising compounds, densified with nitrogenated groups (amino, hydrazino or azido functions), was identified as a class of plausible candidates for liquid propulsion. Indeed, the energetic interest of such hydrazines was demonstrated by computing their heats of formation and specific impulse values in bipropellant systems. This led to theoretical energetic performances comparable to that of the MMH/N2 O4 system already in use today.