Grading Effect of Ammonium Perchlorate on Mechanical Properties of Propellant Based on Glycidyl Azide Polymer

Composite solid propellant containing aluminum (Al), ammonium perchlorate (AP) particles and glycidyl azide polymer (GAP) are used in various missiles and rockets as high energy propellants. Selections of particles size and grading type in the propellant formulations, with a change in the viscosity and rheological properties of the propeller slurry, have a great effect on the mechanical and ballistic properties of the final product. In this paper in addition to introducing various classes of propellants with different grading, several samples of Al-AP/GAP propellants were prepared and along with their properties comparing, the propellant with the optimum class was presented. The results showed that the best mechanical properties belonged to a propellant containing three different grading of AP (20, 100 and 250 microns). Mechanical properties of this sample under optimal conditions was obtained of yang modulus 4.16 megapascal (MPa), yield stress 0.49 MPa, yield strain 12 %, stress at failure 0.2 MPa, strain at failure 20 %, toughness 28.8 kJ/m3 and hardness 64 Shore A.