The effects of cure ratio, crosslinking density, ammonium perchlorate (AP) particle size, and other additives on the mechanical properties of azide polymer composite propellants were characterized. The equivalence ratio of 1.0 and IPDI/TPA = 7/3 were effective on low temperature mechanical properties. Relatively high amount of plasticizer was required in BAMO/NMMO binder and preferred the equivalence ratio of 1.0 to retain itself in the three-dimensional binder matrix. Excellent elasticity was obtained at a temperature range between -20 degrees C and 2 degrees C and normal strain rate dependency was obtained at from 54 degrees C to -20 degrees C. Glass transition occurred at -30 degrees C to -35 degrees C in Sample 17. The increase in contact area between AP particle and binder and in bonding strength played an important role on the prevention of the propagation of crack around a boundary and, therefore, is an element of(m) was increased with decrease of particle size. Almost exactly the same sigma(m), however, was observed in whole temperature range with increment of 5% to 10% in is an element of(m).