Forty
nitramines by incorporating −CO,
−NH2, −N3, −NF2, −NHNO2, −NHNH2, −NO2, −ONO2, −C(NO2)3, and −CH(NO2)2 groups based on a 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane
(HMX) framework were designed. Their electronic structures, heats
of formation (HOFs), detonation properties, thermal stabilities, electrostatic
potential, and thermodynamic properties were systematically investigated
by density functional theory. The comprehensive relationships between
the structures and performance of different substituents were studied.
Results indicate that −C(NO2)3 has the
greatest effect on improvement of HOFs among the whole substituted
groups. Thermodynamic parameters, such as standard molar heat capacity (C
p,m
θ), standard
molar entropy (S
m
θ), and standard molar enthalpy (H
m
θ), of all designed compounds increase with the increasing number
of energetic groups, and the volumes of energetic groups have a great
influence on standard molar enthalpy. Except for −NH2(R1), −NHNH2(R5), and B3, all of the designed compounds have higher detonation velocities
and pressures than HMX. Among them, E7 exhibits an extraordinarily
high detonation performance (D = 10.89 km s–1, P = 57.3 GPa), E1 exhibits a relatively
poor detonation performance (D = 8.93 km s–1, P = 35.5 GPa), and −NF2 and
−C(NO2)3 are the best ones in increasing
the density by more or less 12%.