Synthesis, characterization, thermal and computational studies of novel tetra-azido esters as energetic plasticizers

This paper describes the synthesis and characterization of two novel tetra-azido energetic plasticizers from readily available commercial sources possessing good thermal stability. Two new energetic azido esters named bis(1,3-diazido prop-2-yl)malonate (1) and bis(1,3-diazido prop-2-yl)glutarate (2) have been synthesized and characterized by IR, 1H NMR, 13C NMR, HRMS, thermal analysis, and compatibility tests. Both azido esters (1 and 2) show good thermal stability with decomposition temperatures of 233.5 °C and 232.6 °C. Their densities are measured to be 1.25 g/cm3 and 1.27 g/cm3, respectively. Glass transition temperature (Tg) of both compounds 1 and 2 is −69 °C and −68 °C and after addition with binder shows reduction in Tg of polymer-plasticizer blends as compared to Tg of polymer only with single decomposition temperature values which indicate the presence of single phase homogeneous system. Thermal decomposition kinetics of both compounds was determined by DSC, using non-isothermal Kissinger and Friedman differential isoconversional method. Density functional theory calculations on compounds 1 and 2 predict positive heats of formations.