| The early, highly exothermic reactions which take place at the surface of a burning propellant play an important role in the burn-rate, flame stability, and ignition sensitivity of energetic materials. However, direct study of this region is prohibited by the complexity of the chemical and physical details of a burning propellant. A novel experimental technique, Temperature Jump/Fourier Transform Infrared (T-Jump/FT-IR) spectroscopy, is described which approximates the conditions of the surface reaction zone of a burning propellant while spectroscopically probing its chemistry.;T-Jump/FT-IR spectroscopy uses a rapidly heated thin film of material as an instantaneous simulation of the surface reaction zone. The thin film of material is placed on a Pt ribbon filament and is housed inside a gas-tight IR cell. The filament is then heated by the pyrolysis control unit at 2000;The application of T-Jump/FT-IR spectroscopy is illustrated with rapid, isothermal thermolysis data from several classes of energetic materials. The materials studied are: the organoazide polymers azidomethylmethyloxetane (AMMO), bis(azidomethyl)oxetane (BAMO), and glycidylazide (GAP); the cyclic nitramines octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazacine (HMX) and hexahydro-1,3,5-trinitro-s-triazine (RDX); and the salts ammonium nitrate (AN) and ammonium perchlorate (AP). The dominant, initial, heat producing decomposition reactions of the aforementioned materials are discussed in the context of the burning surface. |
