Kinetic studies of the thermal decomposition of KDNBF, a primer for explosives

KDNBF (potassium 4,6-dinitrobenzofuroxan) has been used as a primer explosi ve in igniters and detonators for many years. Considerable information abou t the sensitivity of KDNBF to various stimuli, such as impact, friction, sh ock and electrostatic charge, is known. However, the thermal sensitivity of KDNBF has been relatively unexplored. Hence, there is very little informat ion available concerning the fundamental thermal properties of KDNBF. There fore, as part of an extensive thermal hazard assessment, DSC, TG, accelerat ing rate calorimetry (ARC) and heat flux calorimetry (HFC) measurements hav e been undertaken on KDNBF. The results demonstrate that KDNBF decomposes v ia a multi-step exothermic process directly from the solid state. The decom position process does not appear to depend on the nature of the atmosphere, except in the final stage of the TG decomposition in air, where remaining carbonaceous material is converted to CO2. The first stage of the decomposi tion is sufficiently rapid that ignition occurs if too large a sample is us ed. Dynamic and isothermal methods were used to obtain the kinetic paramete rs and a range of activation energies were obtained, depending on the exper imental conditions. The kinetic results have been analyzed in terms of vari ous solid state decomposition models.