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Ammonium nitrate (AN) and ammonium perchlorate (AP) are investigated as propellants for their thermal decomposition behaviors and burning characteristics. The performance effects of AP particle size, AP content in the oxidizer (ξ), and a catalytic amount of Fe2O3 on the propellants are evaluated. A dependency exists between the thermal decomposition behaviors of the propellants and both AP particle size and ξ. Addition of Fe2O3 further affected the thermal decomposition behaviors of the propellants; these behaviors are not dependent on the added amount. Furthermore, the burning characteristics are dependent on the AP size, ξ, and the amount of Fe2O3 added. The low-pressure ignitability of the propellants containing 2% Fe2O3 with ξ = 0.2 and 0.4 is inferior to the propellant with ξ = 0 (no AP) and the propellants containing 4% Fe2O3 with ξ = 0.2 and 0.4. An increase in 4% Fe2O3 caused a positive catalytic effect, causing an equal or higher burning rate of the propellants than that of 2% Fe2O3, except in the case of AN/AP propellants with coarse AP at ξ = 0.4 and 0.6 above 4 MPa. [ABSTRACT FROM AUTHOR]

The partial substitution of ammonium perchlorate (AP) for ammonium nitrate (AN) improves the burning characteristics of AN‐based propellants, because the advantages of AP propellants compensate for the drawbacks of AN propellants and vice versa. The burning characteristics of AN/AP‐based propellants supplemented with MnO2 and Fe2O3 were measured, and the effects of these catalysts on the burning characteristics of the propellants were investigated using the collected data. The ignitability and the burning rate of the AN/AP propellant was improved by the addition of MnO2. The addition of the MnO2/Fe2O3 bicatalyst improved the ignitability of the propellants compared to adding only MnO2, but the improvement was identical to that obtained using Fe2O3. The burning rate increased in the order MnO2

The thermal decomposition behaviors and burning characteristics of propellants prepared with combined ammonium perchlorate (AP)/ammonium nitrate (AN) particles greatly depended on the AN content (?) of the AP/AN sample. The thermal decomposition behaviors of the propellants prepared with the combined samples almost matched those of the propellants prepared by physically mixing AP and AN particles, while their burning characteristics differed. The use of combined AP/AN particles decreased the heterogeneity of the combustion waves of the AP/AN propellants because of the difference in the combustion wave structure. In contrast, the addition of Fe2O3 caused unsteady combustion of the propellants prepared using samples with ? values lower than 8.1%. [ABSTRACT FROM AUTHOR]

Polytetrahydrofuran (PTHF) is an effective binder ingredient for improving propellant performance, although it is not an energetic material. PTHF becomes sufficiently rubbery for use as a binder when a triol is added as a crosslinking modifier. In this study, glycerol propoxylate (GPO), with a molecular weight of 1500, was used as a crosslinking modifier, and the curing behavior, tensile properties, and thermal decomposition behaviors of the PTHF binder with GPO were investigated. A PTHF ( Mn=650)/GPO blend with a PTHF/GPO mole ratio ( ξ) less than or equal to 4 and a PTHF ( Mn=1400)/GPO blend with ξ≤1 were used as propellant binders. The curing behaviors and mechanical properties of the PTHF/GPO blends were influenced by the molecular weight of PTHF and ξ, while the thermal decomposition behaviors were not affected. It was found that the PTHF/GPO blends had higher initial viscosity, longer pot life, and unique mechanical properties compared to those of the PTHF blends supplemented with GPO ( Mn=260). [ABSTRACT FROM AUTHOR]

Ammonium perchlorate (AP) and ammonium nitrate (AN) are used as propellant oxidizers. In this study, the preparation of combined AP/AN particles by a freeze-drying technique was attempted to improve the burning characteristics and determine the combustion wave mechanism of composite propellants. AN adhered to AP particles during the drying process to form combined AP/AN particles. Some freeze-dried sample adhered to the inside surface of the vessel. The nonadhered sample precipitated at the bottom of the vessel. It was found that the AN content of the combined AP/AN samples dominated particle properties, including shape, hygroscopicity, thermal decomposition behavior, and ignition sensitivity. [ABSTRACT FROM AUTHOR]

Although a polytetrahydrofuran (PTHF) blend with added glycerin as a crosslinking modifier is an effective binder for improving the performance of a propellant, a burning catalyst is required for the combustion of the ammonium nitrate (AN)/PTHF/glycerin propellant. MnO2 and Fe2O3 are useful burning catalysts for AN-based propellants. The thermal decomposition behaviors of the AN/PTHF/glycerin propellant supplemented with MnO2 and Fe2O3 catalysts, and the catalytic effect of these catalysts on the burning characteristics was investigated in this study. The thermal decomposition behaviors of these propellants depended on the kind of catalyst used. The propellants containing MnO2 burned above 4 MPa, while those containing Fe2O3 burned above 0.5 MPa. The burning rate increased in the order, (AN/PTHF/Fe2O3)<(AN/PTHF/MnO2)<(AN/PTHF/MnO2/Fe2O3). The improvement in the ignitability and burning rate was dependent on the kind of catalyst used. The burning characteristics of the AN/PTHF/glycerin propellants were improved by the combined effect of multiple catalysts with differing catalytic mechanisms, as compared to the propellant supplemented with any single catalyst. [ABSTRACT FROM AUTHOR]