The correlations among detonation velocity, heat of combustion, thermal stability and decomposition kinetics of nitric esters

In this paper, the thermal stability and decomposition kinetics of 10 nitric esters including nitroglycerine (NG), pentaerythritol tetranitrate (PETN), trimethylolethane trinitrate (TMETN), dipentaerythritol hexanitrate (DiPEHN), trimethylolpropane trinitrate (TMPTN), xylitol pentanitrate (XPN), sorbitol hexanitrate (SHN), erythritol tetranitrate (ENT), mannitol hexanitrate (MHN) and nitroisobutylglycerol trinitrate (NiBGT) are investigated by non-isothermal TG and DSC. It has been shown that the mass loss processes of NG, TMETN and TMPTN are more dependent on the heating rate, and the simultaneous evaporation makes the initial temperatures for their mass loss lower than those of the other nitric esters. Based on the correlations among their thermal stability, activation energy, detonation velocity and heat of combustion, one could conclude that the oxygen coefficient (α) plays a positive role on the decomposition heat release efficiency (η_d) when it is less than one, whereas when the α is greater than or equals to one, the fuel elements such as C and H contents would play a decisive role on η_d. It has been further proved that the order of contribution rate of function groups on the tertiary carbon to the detonation velocity could be –CH₃ < –NO₂ < –C₂H₅ < –ONO₂. In addition, the introduction of function groups to the tertiary carbon is in favor of increasing the thermal stability of nitric esters due to increase in symmetry and rigidity of their molecules. The proportion numbers (C_s) of methylene group (–CH₂–) to tertiary carbon or quaternary carbon will, to some extent, determine the thermal stability of the nitric esters.