Studies on energetic compounds: Part 31. Thermolysis and kinetics of RDX and some of its plastic bonded explosives

Thermal analysis of RDX and its three plastic bonded explosives (PBXs) namely RXE 9505, RXE 9010 and RXV 9010 were done using various thermo analytical techniques, under different conditions. Although, the thermal analyses do not show any significant reduction in thermal stability of RDX, there are results, which suggest that the presence of binder alters the reaction pathways. Kinetic analysis of isothermal TG data was made by model fitting methods as well as a model free isoconversional method. The merits and demerits of both modes of kinetic approaches were evaluated critically. Conventional model fitting methods fail to describe the complex reactions during thermolysis of both RDX and its PBXs. Isoconversional method shows that the mechanisms of thermolysis of RDX and its PBXs are different, in the same temperature range. Role of binder was found to be in facilitating the reaction to take place in the condensed phase and reducing the role of competing reaction channels such as evaporation and gas phase thermolysis. Rapid thermolysis of the samples was studied by measuring ignition delay and evaluating its kinetic parameters.