Investigating the Catalytic Effect of a Zeolitic Imidazolate Framework, ZIF-8, on the Phase Transition and Thermal Decomposition of Ammonium Nitrate

Ammonium nitrate (AN) is a well-known energetic material that is used as a chlorine-free oxidizer for substituting the ammonium perchlorate in composite and gas generators propellants. In this work we have utilized ZIF-8 as a well-known Zinc-based zeolitic imidazolate framework, to study the thermal behavior of ammonium nitrate (AN). Different percentages of AN/ZIF-8, i.e., 0.95 : 0.05, 0.9 : 0.1, and 0.85 : 0.15, were prepared by the solvent and mechanical methods, and their phase transition and thermal decomposition have been studied by TG-DSC. To investigate the interactions between AN and ZIF-8, the UV–Vis-DRS, XRD, and FT-IR techniques were used. Our results indicate that ZIF-8, despite its low weight percentage (at least 5 wt %), stabilized the AN up to 125°C and improved its thermal decomposition behavior. In addition, the catalytic combustion of AN/ZIF-8 species showed exothermic peaks. Moreover, the results showed that ZIF-8, due to its Lewis acid-base sites as well as the porous structure, could be stated as an excellent catalyst that improves the thermal decomposition of AN and removes its inappropriate phase transitions.