Combustion of ammonium dinitramide based solid propellant with PBT as energetic binders

Focusing on a new kind of solid propellants, which takes the ammonium dinitramide (ADN) as the high-energetic oxidant, and 3,3-bis(azidomethyl)oxetane and tetrahydrofuran copolymers (PBT) as the high-energetic fuel binder, the burning rates and the theoretical performance of the propellant were measured under different ADN contents, ADN sizes and pressures. The burning rates increased from 7.9 mm/s to 117.4 mm/s and 49.1 mm/s to 74.2 mm/s when the pressure increased from 0.1 MPa to 10 MPa and from 12 MPa to 20 MPa separately, with a singularity in the pressure dependence of the burning rate at around 10 MPa. In terms of the effect of the ADN content, under the experiment pressures from 0.5 MPa to 5.0 MPa, the burning rates of the propellant were promoted by the increase of the oxidizer loading in a range of 50 wt% to 75 wt%, with a transition from a kinetically-controlled reaction to a diffusion-controlled one. Within the condition scope of this study, no obvious effect of the ADN sizes on the propellant combustion properties was observed. This could be attributed to the solid-liquid mixed multiphase layer and the binder which served as a heat sink for the smaller ADN particles.