FTIR Characterization and Thermal Decomposition Kinetics of AN/AP-Based Composite Solid Propellants

ABSTRACT

Solid Rockets are one of the most efficient and reliable rockets, but production of chlorine gases in the exhausts of these rockets is a major drawback. The toxic exhaust is due to the presence of ammonium perchlorate (AP) as the oxidizer. Thus, the solution to decrease this exhaust is the use of green oxidizers such as ammonium nitrate (AN), but it suffers from the drawback of low energetics and hygroscopicity, phase transitions at room temperatures, and incomplete combustion in pure form. The present work emphasizes the phase stabilization of AN in the presence of AP and cobalt nitrate hexahydrate (CNH) catalyst. FTIR study helps to identify present functional groups in the propellant samples. The thermal decomposition of AN/AP-based propellant samples was investigated with an STA Instrument under a nitrogen atmosphere with different heating rates. The kinetic studies reveal the steps of reactions and activation energy of propellant samples which were observed to change with the addition of AN and CNH. The overall studies confirm that AP and catalyst CNH help in the phase stabilization of AN in propellant samples and enhance the combustion reactions at lower temperatures. The burn rate and flame temperature of the AN-AP propellant sample are found to increase with the addition of a catalyst. The catalyst positively effects the energy barrier or activation energy, burn rate, and flame temperature of AN-AP propellant, thus confirming that the catalyst helps in the combustion process.

KEYWORDS:

• Ammonium nitrate
• ammonium perchlorate
• thermal decomposition
• kinetic studies
• catalyst

Acknowledgements

The authors would like to thank the Central Instrumentation Facility (CIF), BIT Mesra, for carrying out the FTIR studies.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.