Ammonium perchlorate

About: Ammonium perchlorate is a research topic. Over the lifetime, 2359 publications have been published within this topic receiving 33412 citations. The topic is also known as: AP.

Effect of Catalyst Mixing Procedure on Subatmospheric Combustion Characteristics of Composite Propellants

Abstract: Subatmospheric combustion characteristics of ammonium perchlorate (AP)/hydroxyl-terminatedpolybutadiene (HTPB) propellants prepared using two different catalyst mixing procedures were studied. In the e rst one, identie ed as the wet-mixing process, copper chromite catalyst (CC) was mixed with the binder (HTPB 1 di-2-ethylhexyl adipate ); and to this CC ‐ binder mix, AP and the curing agent [toluene di-isocyanate (TDI)] were then added. In the second, identie ed as the dry-mixing process, CC was e rst mixed with AP, and to this dry-mixture, the binder and toluene di-isocyanate were then added. For such propellants of different mixing procedures, with various AP particle sizes, the measurements of burning rates up to 1 bar, low-pressure dee agration limit (LPDL), and the scanning electron microscope (SEM) study of extinguished samples at LPDL were carried out. Results of the study show a higher burning rate for dry-mix propellants, and this higher burning rate is AP particle-size and pressure dependent. LPDL is also AP particle-size dependent, and for catalyzed propellant it is lower than that of an uncatalyzed one. The two procedures of CC mixing do not demonstrate any signie cant difference in LPDLs. The micrographs of wet-mix and dry-mix propellants look similar; however, the strong effect of low pressure in increasing the surface and subsurface reactions is brought out by the SEM study.

Performance of Ammonium-Perchlorate-Based Composite Propellant Containing Nanoscale Aluminum

Abstract: Several composite propellant mixtures of hydroxyl-terminated polybutadiene, ammonium perchlorate, and aluminum were prepared with and without the addition of small percentages of nanoscale aluminum and tested in a strandburneratpressuresupto34.5MPa.Theeffectofmonomodalversusbimodalammoniumperchlorateparticle size, coarse aluminum particle size, nano aluminum particle size, and coarse-to-fine ratios on burning rate and manufacturability were explored. A significant conclusion of the present study is that the addition of nanoscale aluminum does not always ensure an increase in the propellant’s burning rate when produced using conventional methods. It was observed that over the range of mixtures and pressures explored, a bimodal oxidizer is required for the nanoscale aluminum to affect the burning rate, and that a monomodal oxidizer tended to nullify any influence of thenanoscalealuminum.Insomecases,theadditionofnanosizedaluminumdecreasedtheburningrate.Thelevelof burning-rateincreaseordecreasedependedonthebimodalormonomodalammoniumperchlorateparticlesizes,the coarse aluminum particle size, and the pressure range.

Chemical Dynamics of Aluminum Nanoparticles in Ammonium Nitrate and Ammonium Perchlorate Matrices: Enhanced Reactivity of Organically Capped Aluminum

Abstract: Aluminum nanoparticles have been a subject of active investigation in recent years because of their potential to enhance the energy content of energetic materials. The associated kinetics of the chemical reaction and energy release are, in many cases, governed by the properties of the passivation layer protecting the particle rather than those of the underlying metal core. The passivation layer of Al particles is typically an oxide shell several nanometers thick, but other possibilities are now available. We have previously developed synthesis routes to produce air-stable Al nanoparticles that are capped by oleic acid. In the present study, we examine the chemical dynamics of these materials in ammonium nitrate and ammonium perchlorate matrices. For comparison, the analogous experiments were also performed on samples using traditional oxide-protected particles. Reactions are initiated by a 20 μs IR laser pulse and then probed via time-of-flight mass spectrometry of the evolved gases and by emission spectr...