Design, synthesis and characterization of new energetic phthalate plasticizers based on imidazolium ionic liquids

In this study, a new class of energetic phthalate plasticizers based on imidazolium ionic liquids (ILs) were synthesized. The structure of the synthesized compounds was confirmed by 1HNMR, 13CNMR, and FT-IR. The thermal stability of nitrocellulose (NC)/plasticizer blends was also evaluated by thermogravimetric analysis (TGA). The compatibility of the NC with three synthesized energetic plasticizers was studied by differential scanning calorimetry (DSC), scanning electron microscope (SEM), and density functional theory (DFT) methods. The glass transition temperatures of the NC/synthesized plasticizer blends were determined by DSC and showed desirable lowering of glass transition temperature with a single peak and low temperature, which indicates the compatibility of NC with the synthesized IL plasticizers. The SEM images of plasticized films show smooth surfaces which are resulted from the good compatibility of the plasticizers with NC. The predicted relative trend of interaction energies between NC and plasticizers is well correlated with the corresponding trend of Tg of NC/plasticizer blend. In addition, molecular electrostatic potential (MEP) calculations were performed for all plasticizers/NC. Total electron density for the DEP/NC, 3a/NC, 3b/NC and 3c/NC samples are respectively 0.0388, 0.0942, 0.0944 and 0.0823. There is a very good regression (R2 = 0.9126) between these values and the calculated values of the interactions energy. In this study, a new class of energetic phthalate plasticizers based on imidazolium ionic liquids were synthesized. The compatibility of NC with these energetic plasticizers was studied by differential scanning calorimetry (DSC) and density functional theory (DFT) methods.