Investigation of Energetic Imidazolium Ionic Liquid Plasticizer Effect on the Thermal Properties of Nitrocellulose

In this paper, the effect of an energetic imidazolium ionic liquid plasticizer (ILP) on the degradation kinetics of nitrocellulose, which is a important component of double based solid propellants, is investigated. For better comparison, diethyl phthalate (DEP) plasticizer, which has a structure similar to ILP, was also evaluated. Heat of combustion analysis was performed to evaluate the energetic ILP plasticizer. Enthalpy of combustion for synthesized ILP and DEP plasticizers were respectively 7269±1% and 5468±1% cal/g. Then thermal analysis was performed for NC and NC/Plasticizer blends with 20% by weight of ILP and DEP plasticizers at different heating rates. In this study, DSC analysis was used to evaluate the compatibility of plasticizers with NC. The results of DSC analysis for NC/plasticizer blends showed that NC is well compatible with DEP and ILP plasticizers. The ILP plasticizer was more compatible with NC because its glass temperature was lower. Calculated activation energy, reaction rate constant, thermodynamic parameters and other thermal parameters of NC with 12% nitrogen content and NC/plasticier blended by Kissinger, Starink and Ozawa Flynn-Wall (OFW) kinetic methods. The calculated results were in good agreement with each other in different methods. The results of the calculations showed that the ILP plasticizer did not cause much change in reducing the Critical temperature for the thermal explosion. Degradation activation energy (α = 0.5) using the Ozawa Flynn-Wall method for pure NC, NC-DEP and NC-ILP blends ILP were respectively 145.62, 139.09 and 119.36 kJ/mol