Less Sensitive Smoke Reduced Rocket Propellants based on FOX 7

摘要

FOX 7 formulations have been prepared and investigated with 68% to 70% solid loadings, including increasing amounts from 0% to 42% AP together with energetic binder polymers like GAP or inert PU binders together with energetic plasticizers like TMETN/BTTN or BDNPF/A. Without further optimization, the calculated specific impulses amount to 220 s ≤ Isp ≤ 245 s for an expansion ratio 70:1 depending on the amount of AP and internal energy of the binder. The burning behaviour looks very promising with burn rates up to 20 mm/s at 7 MPa and low pressure exponents, similar to a plateau like burning behaviour. Processing and mechanical properties proved to give practical values, as well as chemical stability and data of impact and friction sensitivity. According to ARC measurements the FOX 7 formulations exhibit quite low thermal sensitivity with high temperatures of deflagration even above 210 °C, whe n BDNPF/A has been used as a piasticizer. Even propellants with high specific impulse based on GAP and nitrate ester plasticizers exhibit a smooth and less dangerous thermal decomposition if any kind of venting of the combustion chamber is applied. Propellants with GAP binder and nitrate ester piasticizer react in the 21 mm Gap test, but exhibit a high threshold value, which might easily correspond to a hazard classification 1.3.