FORMULATION AND INITIAL CHARACTERISATION OF A FOX-7/ POLYPHOSPHAZENE BASED PBX

摘要

Compatibility between FOX-7 and PolyPZ-E has been demonstrated using Differential Scanning Calorimetry and Heat Flow Calorimetry (HFC). The HFC data further suggest that PolyPZ-E, despite being a nitrate ester based polymer, is significantly more stable than nitrocellulose and may self-stabilise. A 95:5 FOX-7:PolyPZ-E formulation has been successfully prepared on a 0.5kg scale using a solvent/anti-solvent precipitation method and the resultant granules shown to press satisfactorily, although pressing density has yet to be optimised. Small-scale powder hazard tests on the FOX-7:PolyPZ-E granules suggest that whilst the binder reduces the friction sensitivity of FOX-7, it has little effect upon its impact sensitivity. Pressed pellets of FOX-7/PolyPZ-E have been examined using the NOL Large Scale Gap Test. The data from these experiments indicate that the shock sensitivity of the formulation is considerably lower than that of RDX and Composition B, but falls within a similar range to that of pressed TNT; others have observed that the shock sensitivity of pure FOX-7 falls in a similar range. These data together are consistent with previous observations that this parameter is determined more by the porosity and crystal size distribution of the FOX-7 than by the amount or type of binder present. However, it is predicted that the energetic binder is likely to be more beneficial with respect to the performance of the FOX-7:PolyPZ-E composition.