Burning rate enhancement of AN-propellants by TAGN and GZT

To overcome the disillusioning combustion behavior of AN propellants, burn rate augmentations by TAGN and GZT have been investigated on a propellant system based on ammonium nitrate, GAP/PolyGLYN and nitrate ester plasticizers . Additional ingredients are HMX, CL20 and Al. When TAGN is incorporated up to 30% the specific impulse of AN/GAP/NE propellants drops only a little. With 10 and 20% Al the Isp of TAGN containing formulations is even higher than for a traditional composite based on AP/Al/HTPB with 88% solid loading. Only the volumetric specific impulse drops a little with 20 - 30% TAGN. With more than 10% GZT there is however a dramatic drop in Isp due to its more negative oxygen balance. Burn rate enhancement caused by GZT is of similar magnitude than it is caused by TAGN. The latter produces however a beneficial reduction of pressure exponents which is not seen with GZT. Additional enhancement of burn rates can be achieved by nitramines, with CL20 much more and with additional reduction of pressure exponents than by HMX and with aluminum. Although TAGN is very favorable for thermodynamic performance and combustion, problems still exist with chemical stability in connection to nitrate esters. Lead citrate proves to be beneficial in that case and serves together with 20 to 30% TAGN not only for a good burning behaviour but for acceptable values of chemical stability in short term tests. GZT proves to be less problematic, but is not able to reduce the pressure exponents sufficiently. If these problems can be overcome, AN/TAGN propellants may play an important role in the field of rocket propellants, AN/GZT formulations for gasgenerating propellants