Effect of Nitrocellulose Gasifying Binder on Thrust Performance and High‐g Launch Tolerance of Miniaturized Nanothermite Thrusters

Abstract

Nanothermites are promising propellants for miniaturized thruster applications, but in their pure state can be very sensitive to ignition stimuli and prone to phase separation. Consequentially, a need exists for desensitizing binders that do not inhibit nanothermite thrust performance. We investigate the effects of incorporating small weight concentrations of nitrocellulose as a gasifying binder in bismuth trioxide‐aluminum nanothermites. Thrust measurements revealed improvements in specific impulse up to 63.2 s using nitrocellulose. The launch tolerance of the nanothermites in response to high‐g acceleration was also explored and substantial improvements were realized for nanothermites prepared with nitrocellulose. As small as 5 % nitrocellulose content suppressed the sensitivity of the nanothermites to less than 1 % ignition probability after exposure to 30 kg acceleration events. Some nanothermite charges experimentally survived up to 90 kg loads. Most importantly, nitrocellulose predictably modulated the thrust performance and ignition sensitivity of the nanothermites as a function of weight content. Employing nitrocellulose as a binder, high performance nanothermite propellants can be synthesized for miniaturized thruster applications with tailored impulse generation and ignition sensitivity.

Progress in Additive Manufacturing of Energetic Materials: Creating the Reactive Microstructures with High Potential of Applications

“…For other systems, gunpowder propellants [225], nonmetalized [226] and metalized [223] composite propellants, metalized pyrolants (Zr/ KClO 4 [223], boron/KNO 3 [227]), and novel high-nitrogen materials [228] have been suggested. Several nanothermites, including Al/CuO and Al/Bi 2 O 3 , have been recently considered and show promising results for microthruster applications [148,229,230]. Apperson et al revealed that the density of nanothermites is an effective parameter for thruster operation, changing the combustion regime and defining the duration [230].…”

Influence of Stoichiometry on the Thrust and Heat Deposition of On‐Chip Nanothermites

“…With advancements in lithography, the possibility of integrating energetic materials in microelectromechanical systems and electronic devices has increased, resulting in the emergence of the onchip microenergetics field [4]. Nanoenergetic composite materials have been widely investigated for a variety of applications including safe-and-arm devices [5], actuation [6,7], micro-propulsion [8][9][10][11][12] and power generation [13]. These materials can contain even greater energy densities than traditional monomolecular explosives.…”

“…Both the nAl-CuO and nAl-Bi 2 O 3 reactive systems have also been investigated for potential uses in micro-thruster devices, and the implementation of nanothermites into such devices has made use of pressed pellets processed with materials being mixed ultrasonically [8][9][10]. Prior work has shown that nanothermites prepared at near-stoichiometric conditions are useful for applications requiring high amounts of thrust over short durations, but the authors tested larger amounts of materials to measure thrust in comparison to what is presented in this paper [8][9][10]. Other experiments integrate smaller quantities of nanothermites into micromachined silicon substrates; however, there is no investigation of thrust behavior over a wide range of stoichiometries [11,12].…”

Enhanced Combustion Characteristics of Bismuth Trioxide‐Aluminum Nanocomposites Prepared through Graphene Oxide Directed Self‐Assembly

“…Enhanced energy contentw as due to improvedf uel and oxidizer intermixing from self-assembly as well as the participation of GO as ar eactant duringc ombustion.The motivation of this work was to evaluate the role of GO directed self-assembly in modifying the combustion behaviors and ignition sensitivities of Al/Bi 2 O 3 nanocomposites. Al/Bi 2 O 3 was the material systemo fi nterest here due to its highd ensity,e nergy content, and gas production by weight, whichh ave encouraged many otherr ecent studies [9,[12][13][14][15][16].T he pressure generating capability,l inear combustion rate, thrust behavior,a nd electrostatic discharge (ESD) sensitivity of GO self-assembled Al/Bi 2 O 3 were measured in direct comparison to randomly mixed Al/Bi 2 O 3 nanopowders. Combustion behaviors were measured across ar ange of %Theoretical Maximum Densities (TMD) to evaluate the effect of GO self-assembly in various combustion regimes [15][16][17].W epostulate that the enhanced energy content realized through GO directed self-assembly extends towards predictably improvingt he combustion performance of Al/Bi 2 O 3 nanocomposites.…”

“…Al/Bi 2 O 3 was the material systemo fi nterest here due to its highd ensity,e nergy content, and gas production by weight, whichh ave encouraged many otherr ecent studies [9,[12][13][14][15][16].T he pressure generating capability,l inear combustion rate, thrust behavior,a nd electrostatic discharge (ESD) sensitivity of GO self-assembled Al/Bi 2 O 3 were measured in direct comparison to randomly mixed Al/Bi 2 O 3 nanopowders. Combustion behaviors were measured across ar ange of %Theoretical Maximum Densities (TMD) to evaluate the effect of GO self-assembly in various combustion regimes [15][16][17].W epostulate that the enhanced energy content realized through GO directed self-assembly extends towards predictably improvingt he combustion performance of Al/Bi 2 O 3 nanocomposites. The formation of macroparticulates from the self-assembly processa nd introductiono fc arbon also augers well for reducing the ignition sensitivities of the nanocomposites, which in their pure state can be extremely sensitive.T he fundamental [a] R.Abstract:W ep resent af acile, spontaneous, and surfactantfree methodt oc ontrollably self-assemble aluminum and bismuth trioxide nanoparticles through the introductiono f grapheneo xide as as elf-assembly directing agent.…”