Shock tube propellant reactions: Ignition of M-9 and catalysis of RDX

The preliminary results of shock tube experiments to study RDX catalysis are presented. It is shown that using N2 as the test gas (P approximately equal to 90 KPa, T bar approximately equal to 650K), the replacement of RDX powder with NaBH4 (20% by weight) leads to a large increase in the amount of RDX reacting and a small decrease in ignition delays T sub i. It is further shown that higher temperatures due to exothermic pyrolysis reactions of NaBH4 are not responsible for these effects. Replacement of N2 by NO2 (10% by volume) in the environment of RDX powders (T bar approximately equal to 650K, P = 90-400 KPa) leads to an increase in T sub i and T sub i is directly proportional to NO2 pressure. Inhibition appears to be initiated by reactions between NO2 and either RDX or the RDX decomposition products.