Studies on energetic compounds Part 43: Effect of some BEMP complexes on the combustion and condensed phase thermolysis of HTPB-AP composite solid propellants

Abstract

Hydroxyl terminated polybutadiene (HTPB)-ammonium perchlorate (AP) composite solid propellants (CSPs) have been prepared by incorporating five <i style="">bis</i>(ethylenediamine)metal perchlorate (BEMP) complexes like [M(en)₂](ClO₄)₂ (where, M = Mn, Fe, Co, Ni, Cu, Zn and en = ethylenediamine) as ballistic modifiers. The steady burning rate of the propellants was increased considerably by the additives, [Fe(en)₂](ClO₄)₂ being the most efficient one. The condensed phase thermolysis of un-modified and modified propellants was studied using simultaneous thermogravimetry (TG)-differential thermal analysis (DTA) in nitrogen atmosphere. Thermolysis of propellants is affected when these energetic additives are used as burning rate modifiers in small percentage (2% by wt.). Ignition delay (<i style="">t</i>_id) measurements on propellants have been conducted to examine the effect of these additives under the condition of rapid heating. The role of these additives on thermal decomposition of oxidizer (AP) is also investigated using simultaneous TG-DTA in N₂. Also rapid thermolysis of pure AP as well as AP + additive mixtures was assessed by <i style="">t</i>_id measurement technique. The complexes of Fe and Cu show considerable effect on both slow and rapid thermolysis of propellants and AP.