Combustion Properties of Composite Propellants Based on Two Kinds of Polyether Binders and Different Oxidizers

Two kinds of solid propellants based on propargyl-terminated ethylene oxide-tetrahydrofuran copolyether (PTPET) and ethylene oxide-tetrahydrofuran copolyether (PET) were prepared with 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), ammonium perchlorate (AP) and aluminum (Al), respectively. The order of burning rates for PET+RDX, PTPET+RDX and PET+RDX+Cu−B propellants: PTPET+RDX > PET+RDX > PET+RDX+Cu−B. Their pressure exponents are also similar when the pressure is higher than 7 MPa. The combustion residue of PET+RDX and PET+RDX+Cu−B propellants show a loose structure and there are many bright particles distributed in its flame zone. The combustion residue of PTPET+RDX propellant shows a dense structure and its flame is uniform. The burning rates of PET+AP+Cu−B propellant is between the burning rates of PET+AP and PTPET+AP propellants at the same pressure. Their flame shape is similar. The burning rates of PET+AP+Al+Cu−B propellant is also between the burning rates of PET+AP+Al and PTPET+AP+Al propellants at the same pressure. The combustion flame of PET+AP+Al propellant differs greatly in direction and shape at different time. The combustion flame of PTPET+AP+Al and PET+AP+Al+Cu−B become almost identical in shape and direction at different time. These results show that the curing catalyst Cu−B of PTPET propellant plays a catalytic role in combustion.