Glycidyl azide polymer (GAP), due to its energy, has found widespread applications in propellants. However, one of the most critical challenges in the propellants is preventing the migration of the plasticizer material from the polymeric matrix. To counter this, a covalent bond was established between GAP and propargyl imidazolium as the reactive plasticizer via click chemistry reaction. Fourier-transform infrared spectroscopy (FTIR) and 1 H NMR analyses were implemented to confirm that the connection has been made properly to minimize the plasticizer migration. Optimization of the amount of the reactive ionic liquid plasticizer in GAP was another issue investigated in this study. Examinations by Differential scanning calorimetry (DSC) analyses, viscometer, and heat of combustion showed that increasing the reactive plasticizer content leads to the lower glass transition temperature, the higher viscosity, and the lower GAP energy. In order to compensate for the lost energy, due to the formation of the covalent bond, a dicyanamide based ionic liquid plasticizer was synthesized as a replacement for the bromide one. It was found that in addition to the reduction of the glass transition temperature (from À50 8C to À59 8C), it was possible to achieve lower viscosity (from 7 Pa.s to 2 Pa.s) and greater propulsion energy (from 19.24 kJ/g to 21.31 kJ/g).

Reactive plasticizers (RPs) used in glycidyl azide polymer (GAP) were studied. These compounds consisted of an activated terminal alkyne group expected to give rise to Huisgen azide‐alkyne 1,3‐dipolar cycloaddition, which couldprevent the migration of plasticizers. FTIR, 13C and 1H NMR analyses were implemented to confirm that the connection was made properly. The properties GAP/RPs were investigated by DSC analyses, a viscometer, and heat of combustion. The RPs could effectively reduce the viscosity of the GAP from 5.5 Pa.s to 2.5 and 3.8 Pa.s when 40 % (w/w) of the reactive plasticizers are respectively added. Also, the glass transition temperature of GAP reduced from (−38) °C to −41 and −47.7 °C. The heats of combustion were measured by a calorimetric method. A significant difference in the heats of combustion was observed between the reactive plasticizers and reactive energetic plasticizers (from 17.31 kJ/g to 21.42 kJ/g).

Molecular dynamics (MD) simulations and experiments were carried out to study the glass transition temperature of glycidyl azide polymer (GAP) which is widely used in propellants as an energetic binder. A modification method was applied to improve the mechanical properties of GAP at low temperatures, through the addition of energetic ionic liquid plasticizers to the polymer matrix. The design and simulate under the COMPASS force field, with the ensembles of constant particle number, pressure, temperature (NPT) done. The variation of density and free volume of polymers was observed with decreasing the temperature, and the glass transition temperatures (Tg) were estimated based on the variation of density and free volume vs. temperature. Simulation and experimental results revealed that the addition of energetic ionic liquid plasticizer to the polymer matrix reduced Tg. Also, by changing the anion of ionic liquid, the size of the molecule and the number of atoms, the value of Tg was changed. The variations were 235 K (GAP), 233 K (GAP/IL‐N3), 230 K (GAP/IL‐NO3) and 214 K (GAP/IL–DCA).