Exploring highly energetic aliphatic azido nitramines for plasticizers

Abstract

A set of energetic aliphatic azido nitramines was designed and studied with the B3LYP/6-31G* method of density functional theory to find new promising azido nitramines applicable to propellants as plasticizers and to investigate the effect of the methylene nitramino group (–CH₂NNO₂–) on performance. The reliability of the theoretical method was tested by comparing the theoretical densities with the experimental data. The thermodynamic properties (heat capacity, enthalpy, entropy, and heat of formation), density (ρ), detonation pressure (P), detonation velocity (D), specific impulse (I_s) and stability were predicted. With the increase in the number of –CH₂NNO₂– groups (n), the thermodynamic properties, ρ, P, and D increase, while the stability decreases slightly. There are linear relationships between thermodynamic properties and n. A –CH₂NNO₂– group improves the heat of formation by 67.59 kJ mol⁻¹ on average. I_s reaches the maximum when n = 4 and changes little when n ≥ 5. It is worth noting that I_ss of all title compounds are higher than that of HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, a famous explosive).