Ignition Delay Times of Composite Solid Propellants Using Novel Nano-Additive Catalysts

The ignition delay times of propellants provide insight for the fundamental understanding of the ignition process. This study demonstrated a refined method to measure the of ammonium-perchlorate-based propellants at pressures between 3.5 and 15.5 MPa. Both aluminized and nonaluminized ammonium perchlorate/hydroxyl-terminated polybutadiene composite propellants were studied with and without metal oxide nanoparticle catalysts. A laser was used to obtain quantifiable and reliable ignition times over a 30–100 W power range. The results were compared to literature values for similar power fluxes at comparable pressures and to a simple ignition model based on heat conduction. Catalytic additives were seen to modify the , depending primarily on whether they impact the lower- or higher-temperature decomposition of ammonium perchlorate. Examining the effects of in situ titania nanoparticles on the ignition delay times led to the conclusion that the nano-additives only altered the ignition behavior of the aluminized samples, but had no effect on the nonaluminized ones. Conversely, when nano-sized was used, the was halved at lower pressures. As a result, additives that assist in the low-temperature decomposition of ammonium perchlorate, such as , are believed to have the greatest impact on ammonium perchlorate/hydroxyl-terminated polybutadiene ignition delay times.