Solid Amine–Boranes as High-Performance and Hypergolic Hybrid Rocket Fuels

Metal–organic frameworks as hypergolic additives for hybrid rockets

“…52 The values obtained were then compared to those for paraffin fuels containing AB and aluminum for reference. AB in a paraffin matrix can yield hypergolic ignition, 14,19,34 just as our proposed use of HMOFs. Although aluminum particles as fuel additives do not yield hypergolicity, they were considered here for comparison as energetic rocket fuel additives.…”

Characterization of the Hypergolic Ignition Delay of Ammonia Borane

“…To reduce the effects of varying particle size on ignition delay, the AB used for these initial tests was sieved into two particle size ranges: 45 < D < 150 μm, and D > 150 μm. These particle size ranges were selected to provide a comparison with previously published work by Pfeil et al [3]. To provide the most accurate comparison between the different synthesis methods, the primary focus of these initial tests was comparing the ammonia borane in the 45-150 μm particle size range.…”

“…For ammonia borane to be used in a conventional hybrid propellant system, it must first be mixed with a fuel binder to create a fuel grain with adequate mechanical properties. One of the major issues that has prevented further study of ammonia borane in solid and hybrid propellant formulations is that ammonia borane is incompatible with many of the fuel binders commonly used in propellant formulations [3]. Lee et al investigated using ammonia borane in a typical HTPB-AP composite propellant and found that adding ammonia borane to the propellant formulation resulted in the propellants failing to cure [13].…”

“…The assumed properties of Sylgard-184 and ammonia borane for these theoretical performance calculations can be found in Table 6. The properties for Sylgard-184 were taken directly from the Cheetah 7.0 library, whereas the properties for AB were previously reported by Pfeil et al [3].…”

“…One fuel of interest as a hypergolic solid fuel is ammonia borane (NH 3 BH 3 ) [1][2][3]. Under typical atmospheric conditions, ammonia borane is a stable solid material with 19.6% hydrogen by mass.…”