Formulation and characterisation of a low-sensitive PBX based on FOX-7

A lot of research is devoted to find low-vulnerability replacements for Composition B explosives. 1,1-diamino-2,2-dinitroeten (FOX-7) is a good candidate since it has been shown that it is very insensitive. Thermochemical calculations have also shown that it is possible to obtain a higher performance than Comp. B if energetic binders are used together with FOX-7. The aim of this work was to find a composition based on FOX-7 and an energetic binder. We have chosen a binder based on polyGlyN (a prepolymer), butyl-NENA (a plasticiser) and Desmodur-W (a diisocyanate, curing agent). A formulation based on 70 wt% of FOX-7 has been prepared and its low-temperature properties, its sensitivity and detonations characteristics have been investigated. The thermal stability at 65°C was excellent. The composition has a glass transition temperature of -35°C, which provide for a good elasticity at relatively low temperatures. Small-scale- safety tests (BAM drop test and BAM friction test) showed the composition is relatively insensitive. A detonation test has been performed and the composition did not detonate at a diameter of 25 mm.