Thermal decomposition of energetic materials 52. On the foam zone and surface chemistry of rapidly decomposing HMX

Abstract

Studies designed to perturb selected surface and foam zone reactions characteristic of burning HMX are described. This was done by determining the gas product ratios from carefully controlled fast thermal decomposition (> 100 K/s) of a thin film of HMX in atmospheres of Ar, H 2, O 2, CO, NO, NO 2, and NH 3. The results are correlated with experimental combustion data and thermochemical modeling studies of nitramines. A consistent picture about some of the probable reactions in the heterogeneous foam and fizz zones emerges. H 2, CO, O 2, and NO affect the secondary thermolysis reactions in these zones. NH 3 appears to affect both the primary and secondary reactions, while NO 2 is directly involved in primary decomposition reactions. HNCO and CH 2O appear to be products from secondary condensed phase reactions. The results suggest that NH x sites and NO 2 are catalyzable species for burn-rate modification of nitramine propellants.