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 (T_g) of both compounds 1 and 2 is −69°C and −68 °C and after addition with binder shows reduction in T_g of polymer-plasticizer blends as compared to T_g 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