Synergistic Effects of Catalyst on Phase Stabilization and Combustion Promotion of Ammonium Nitrate in Hydroxyl‐terminated Polybutadiene‐based Composite Solid Propellant

ABSTRACT Conventional solid propellants have used ammonium perchlorate (AP) as the efficient oxidizer; however, it emits toxic HCl gas during combustion. Therefore, employing green oxidizers such as ammonium nitrate (AN) is one approach to reduce exhaust emissions. However, AN suffers from the drawback of phase transitions at room temperatures. The present study tries to stabilize phases of AN and increase the performance of AN/AP‐based composite solid propellants (CSPs) by adding ferrocene and vanadium pentoxide (V 2 O 5 ). AP has been partially replaced by AN because utilization of pure AN‐based propellant has been challenging in hydroxyl‐terminated polybutadiene‐based CSPs. The theoretical studies are carried out to understand the effects of AN/AP on specific impulse (I sp ), characteristic velocity (C*), I vac , etc. on the propellant. Burning rate studies have been carried out at different pressures and flame characterization studies have been conducted at ambient pressure conditions. From the above studies, it was observed that in the presence of AP and catalysts such as ferrocene and V 2 O 5 , the burning rate, and flame temperature of the propellant sample have increased significantly. Thermal decomposition studies have been performed for AN/AP‐based propellant samples. Initially, it was observed that there are three phase transition peaks of AN in the AN/AP‐based propellant sample but with the addition of both ferrocene and V 2 O 5 the numbers of endothermic peaks are found to decrease. Ferrocene and V 2 O 5 help to stabilize the endothermic phases of AN and also act as burning rate additives by participating in the combustion process of the propellant samples.