Effect of propellant components on degradation of polyether-urethane binder. (II) Effects of energetic fillers and additives

The effect of some commonly used propellant ingredients on the thermooxidative degradation of polyurethane binder was studied by using FT-IR and NMR to detect the structural changes of the binder during the degradation process which was carried out at 90 °C in air. Energetic fillers and additives, including ammonium perchlorate (AP), HMX, aluminum power, black carbon, nitrocellulose and a coupling agent, can't modify the degradation mechanism of the polyurethane binder but show some different stabilizing effect. The sample containing AP kept its solid state in the whole procedure while other samples were all gradually changed into liquid. The thermooxidative degradation of NEPE propellant started with the evaporation and decomposition of nitrate esters and centralite, followed by the degradation of polyurethane binder, resulting in the loss of mechanical properties of the propellant.