Combustion of Composite Propargyl-Terminated Copolyether Propellant Containing Ammonium Dinitramide

A kind of composite propellant based on a click-chemistry binder, the propargyl-terminated ethylene oxide-tetrahydrofuran copolyether (PTPET), and ammonium perchlorate (AP), aluminum (Al) were studied with ammonium dinitramide (ADN), hexahydro-1,3,5-trinitro-s-triazine (RDX) and hexanitroisowurtzitane (CL20), respectively. Thermogravimetric analysis (TG) and energy calculation of the composite propellants containing ADN and CL20 were carried out. The burning rates of the composite propellants were measured in the pressure range of 3-17 MPa with measurement system of Charge Coupled Device (CCD) line scan camera and high-pressure chamber. Scanning electron microscopy was used to characterize the quenched surfaces of the burning propellants. Microscopic high-speed photography was used to record the flame structure and dynamic burning surface of the propellants in the argon atmosphere. The replacement of RDX with CL20 had less effect on the thermal decomposition of the components in the propellant, but increased the burning rates of the propellant. The replacement of AP with ADN could significantly accelerate the thermal decomposition of the plasticizer A3, AP and PTPET binder, so that the burning rates under high pressure was raised obviously. For the propellants containing ADN and CL20, there were dense and thick molten layer of ADN on the burning surface. The propellants containing ADN and CL20 exhibited characteristic flame different from the propellant containing only AP and RDX. These results were considered to correlate with the early thermal decomposition of ADN and higher burning rate of the propellants.