Stability of Non-isothermally Treated Double-Base Propellants Containing Different Stabilizers in Comparison with Molecular Orbital Calculations

In this research work some malonanilide derivatives (M1-M5) have been prepared and used as stabilizers for double-base propellants (DBPs). Their stabilization effect has been compared with the effect of N,N-diethyldiphenylurea (C1) as a classical stabilizer. Thermal analysis (TA) study under non-isothermal conditions was carried out on propellant samples containing stabilizers. This study gave information about the thermal stability effect of different stabilizers on DBPs, thermal decomposition and some thermodynamic parameters. The non-isothermal (TGA and DSC) results show that the o-dinitromalonanilide (M3) has the highest thermal stability effect on the propellant samples. The molecular orbital calculations such as energy gap (Delta E), net charge, E-LUMO, E-HOMO, IP, and E-a were done and compared with TA experimental data. It was finally concluded that there is no single factor controlling the stabilizing effect of different stabilizers on thermal stability of DBPs. There is a group of factors that play important role in detecting the stabilizing effect of stabilizers on DBPs such as energy gap, charge density on the o-position of the benzene ring and the net charge on the benzene ring itself.