Comparing the impact safety between two HMX-based PBX with different binders

Binders play an important role in the safety of plastic bonded explosives (PBX). For the performance improvement of HMX-based explosive, the impact safety for the explosive using thermoplastic polyurethane (Estane5703) as binder, was investigated by comparing with that using fluorine rubber (F2604). By experiments performed with a self-designed impact test device to measure critical ignition velocity, it was found that the critical ignition velocity (277.36 m/s) of Estane5703-containing explosive was 9.3% higher than that of F2604-containing explosive. By analyzing the particle size distribution and morphological characteristics of the impacted powder, it could also be inferred that Estane5703 binder had better bond behavior than F2604. Beside, combustion characteristics of impacted powder were compared in a closed combustion vessel. The results indicated that the maximum combustion pressure (Pmax) of the Estane5703-containing impacted explosive powder was 56.5% lower than that of F2604-containing impacted explosive powder. The combustion duration of the Estane5703-containing impacted powder was 24.1% longer than that of F2604-containing powder, suggesting that the combustion of the former was milder. Therefore, it can be concluded that the Estane5703-containing explosive has better impact safety than the F2604-containing explosive due to the higher bond strength of Estane5703.