Showing papers on "Ammonium perchlorate published in 1975"

Behavior of Several Catalysts in the Combustion of Solid Propellant Sandwiches

Abstract: Theme T two-dimensional solid propellant sandwich has evolved as a convenient test vehicle for theories dealing with both physical and chemical behavior of composite solid propellant ingredients. It allows detailed observation of the binder-oxidizer interface over a range of test conditions. Sandwiches have been used by several investigators." Hightower and Price used laminated, two-dimensional sandwiches of single crystals of ammonium perchlorate and hydrocarbon binder. They considered this configuration to be "a compromise between the complexity of the three-dimensional 'combustion zone' and the naivety of a one-dimensional approximation." Jones investigated the catalytic behavior of Harshaw Catalyst, Cu 0202 and ferric oxide, Fe2O3 in solid propellant sandwiches of polycrystalline ammonium perchlorate (AP) and carboxyl terminated polybutadiene (CTPB). Hydroxyl terminated polybutadiene (HTPB) was substituted for CTPB and the behavior of the same catalysts over the pressure range 600-3200 psia was investigated. The sandwich vertical burn rate, the normal regression rate of the oxidizer and qualitative details of the deflagration process were obtained by cinephotomacrography. The current study has extended the investigation to include two additional catalysts,

Three Possible Ways to Inhibit the Ammonium Perchlorate Combustion Process

Abstract: Proceeding from the assumption that the ammonium perchlorate (AP) combustion process is controlled by dissociation into ammonia and perchloric acid, three possible ways of decelerating the deflagration are considered: a) adding the substances readily generating in decomposition of the ammonia in order to shift the equilibrium of the dissociation to the left; b) adding the substances which can bind the perchloric acid or products of its decomposition into less reactive compounds than perchloric acid itself or original AP; and c) adding the substances which can inhibit the decomposition of perchloric acid. In all cases, the burning rate must decrease in consequence of the reduction in the oxidation rate of ammonia. The readily decomposed salts of ammonia, halogenides of the metals, deoxidants, and hexachlorethane were studied as additives. Experiments were made up in a constant pressure bomb in nitrogenous atmosphere over pressure range from lower pressure limit to 1000 atm. It was shown that the addition of 1% of the salts of ammonia or the halogenides of lead or cadmium to AP, for example, reduces Rm by a factor of 3-4 at low pressures. Deoxidants and inhibitors of the HCIO4 decomposition are less effective as burning inhibitors. The synergistic effect in deflagration of AP with inhibitors of different types is also studied in the work. It was shown that intensification of the inhibiting effect of the additives takes place when the double additives of ammonium salts and halogenides of metals are added to AP. The addition of the salts of ammonia and deoxidants to AP does not entail the intensification of the inhibiting effect. An explanation of the regularity obtained and the mechanism of synergistic effect is given in the paper. I. Introduction

Solid propellants containing polyether or polyester binders

Abstract: Useful hydroxyl-terminated polyolefin prepolymers, e.g. polybutadiene prepolymers, are provided which may be cross-linked with an epoxide to yield a polyether elastomeric material or with a mixture of an anhydride and an epoxide to form a polyester material. One such prepolymer is a carboxyl-terminated polyolefin, e.g. polybutadiene prepared by reacting a hydroxy-terminated polyolefin, e.g. polybutadiene with solid or liquid anhydrides. Polyether and polyester propellants containing up to about 88% of solid ammonium perchlorate in the powder form and aluminum powder may be prepared from the above two materials (binders). The physical and mechanical properties from these propellants depend on the ratios and on the order of addition of each ingredient, the curing temperature and the presence of surface-active agents. Polyester propellants may be made either by using the hydroxy-terminated polyolefin, e.g. polybutadiene prereacted with anhydrides or by mixing simultaneously all ingredients with the solids. Polyester propellants made by the former procedure have superior properties to those made from the latter. Polyether propellants have slightly lower mechanical and physical properties than those of polyesters. These properties are strongly dependent on the catalytic activity of ammonium perchlorate.

A three‐dimensional X‐ray redetermination of the crystal structure of ammonium perchlorate

Abstract: The crystal structure of ammonium perchlorate has been redetermined by X-ray three-dimensional analysis of 800 reflexions collected with Mo Kc¢ monochromatized radiation on an automatic fourcircle diffractometer. The cell parameters, redetermined with the same apparatus are: a=9.227, b= 7.454, c=5.819 A (24°C), Z=4, space group Pna21 (C9,,) from systematic absences and by successful refinement. The previous space group, Puma, used for the two-dimensional analysis, did not allow a three-dimensional refinement. The positional and anisotropic thermal parameters of the non-hydrogen atoms were refined by the least-squares method. An almost spherical distribution of the hydrogen atoms around the nitrogen atom was introduced into the calculation. Final R = 0-050. Residual electron density maxima were observed from difference Fourier syntheses around the nitrogen atom at distances of 0\"8-0.9 A. They make tetrahedral angles to nitrogen and have short H . . . O distances (2.15-2.50 .~) from eight neighbouring oxygen atoms, indicating that the ammonium ion does not have a completely free rotation.

High-Temperature Decomposition of Ammonium Perchlorate-Polystyr ene-Catalyst Mixtures

Abstract: The study was performed on the kinetics and mechanism of chemical reactions in the ammonium perchlorate (AP)-polystyrene (PS)-Fe2O3 mixtures. The experiment simulated the processes of thermal decomposition and combustion, as well as the catalysis of these processes. By means of an elaborate technique using a time-of-flight mass-spectrometer, a study was made of the influence of AP particle size (4-300//), the ratio of AP and PS, temperature (305-390°C), pressure (15 mm Hg, 1 atm.) and concentration of the catalyst Fe2O3 (2.5%-12.5%) on kinetic parameters of the decomposition of rich and stoichiometric (8 :1) AP and PS mixtures. It was concluded from analyses of the kinetic data that the thermal decomposition of these systems is a multistage process. Such stages are reactions of perchloric acid (primary product of the AP dissociation) with PS and condensed products of this interaction. The validity of this follows from direct experiments on the reaction kinetics of HC1O4-PS. It has been shown that in the decomposition of mixtures with AP (250-400/i), HC1O4 diffusion from the AP surface through a polymer film, and its simultaneous reaction with the latter are limiting stages. The developed model of the thermal decomposition of the AP-PS-catalyst system is based on the data obtained.

Condensed phase reactions in solid propellants

Abstract: The paper investigates the cause for the difference between differential scanning calorimetric results and mass spectrometric studies on polystyrene (PS) ammonium perchlorate (AP) propellants as related to the method of preparation of the propellant and the difference in experimental conditions by the use of mass spectrometry Sufficient time is given for the product sublimates to interact with each other and attain equilibrium It is shown that the propellant decomposition is a nonadditive phenomenon and that even a physical mixture of AP and PS does not yield additive decomposition products of its components Results on the identification of a yellow compound containing chlorine in the bulk of the propellant suggest a condensed phase reaction The occurrence of the reaction in the porous condensed phase of the propellant may explain the larger exothermicity of the propellant compared to the additive heats of decomposition of its components

Solid Propellant Sandwich Deflagration Analysis

Abstract: A theoretical solution has been obtained for the shape of a deflagrating ammonium perchlorate surface when it is adjacent to an inert, pyrolysing, dry binder. The eigenvalue, the regression rate, is shown to be independent of binder type and very close to the burn rate of pure AP, as has been experimentally observed. A slope discontinuity of the surface should exist at the binder-oxidizer interface and typical binders should incline very near to 90° to the nearly horizontal AP surface, at the junction of the two. The transition from AP to binder should take place on a distance scale of the order of microns and all results are quite insensitive to pressure level.

Two component field mix hydrazine base explosive

Abstract: A two component field mix explosive composition comprising a first solid component comprising ammonium nitrate or mixtures of ammonium nitrate with ammonium perchlorate, and a second liquid component comprising as a first ingredient hydrazine, a second ingredient which is water, alcohol or a mixture thereof, and as a third ingredient ammonium nitrate in an amount no greater than about one-sixth of the total weight of the second component. At the site of use the liquid component is poured into the solid component to form an explosive composition. This composition is detonable in elongate packages as small as one inch in diameter, by use of a blasting cap.

Anti-erosive, solid rocket propellant compositions

Abstract: A means for reducing or eliminating the erosive burning which takes place ring the burning phase of solid propelled rocket motors which have a large length-to-diameter ratio and/or slow-burning propellants is disclosed. The means comprises incorporating into the solid propellant, in limited percentages (0.1-1.0%), a silicate selected from talc, kaolinite, kaolin, muscovite mica, and feldspar. The silicate additive is effective for composite or double-base solid propellant compositions. The solid composite propellant compositions can vary widely in formulation ingredients to include numerous ballistic modifiers; however, the general formulation for a composite propellant contains in addition to the silicate, a high solids loading of an inorganic oxidizer such as ammonium perchlorate, a polybutadiene binder with curatives and crosslinking agents, and optional metal fuel, preferably aluminum. The polybutadiene can have carboxyl- or hydroxyl-terminal groups. The crosslinking agent for the carboxyl-terminated polybutadiene can be an epoxy compound. The hydroxyl-terminated polybutadiene can be crosslinked with a diisocyanate crosslinking agent. The double-base propellants include the cast double-base or the castable composite double-base compositions. The double-base propellants can also vary over a wide range in their formulations. In addition to including ballistic additives to meet the required performance criteria, these propellants contain nitrocellulose (12.6% N) or Fluid ball powder, energetic plasticizer such as triethylene glycol dinitrate (TEGDN), crosslinking and curing agents, and optional metal fuel.

Azafulvenes. 2. Formation of Iminium Salt from Pyrrole- and Indolecarbaldehyde and Its Reaction with Bases

Abstract: Pyrrole- and indolecarbaldehyde reacted with secondary ammonium perchlorate to produce the corresponding iminium perchlorate, which did not afford azafulvene, but instead its dimer, in good yield by deprotonation. These results indicate that the iminium perchlorate from pyrrole- and indolecarbaldehyde appears to be a convenient precursor of azafulvene.

Method of manufacturing a cap-sensitive and non-sensitive aqueous gel suspension explosive

Abstract: Non-cap sensitive aqueous gel explosives containing no suspended solid fuels are made by combining water, hexamethylenetetramine, ammonium nitrate, sodium nitrate, ammonium perchlorate and nitric acid, along with sufficient polysaccharide gum to thicken the mixture. These explosives are rendered cap sensitive by mixing therewith paint grade aluminum powder or other conventional sensitizing agents. According to a preferred procedure, a cap sensitive aqueous gel explosive is made by a procedure in which nitric acid and aqueous hexamethylenetetramine solution are first combined under controlled conditions of temperature and pH and ammonium nitrate, sodium nitrate, ammonium perchlorate, thickening agent and aluminum powder are added in controlled amounts in a specified order. The products possess cap sensitivity, even at temperatures as low as minus 23°C.

Combustion problems of nitramine propellants

Abstract: This report summarizes a theoretical investigation of the current problems of nitramine (composite) propellant combustion. This study has, as its distinctive feature, a detailed examination of the condensed-phase processes in the combustion of nitramine propellants. As a consequence of a recently developed model for the combustion of ammonium perchlorate (AP)/ composite propellants, it is hypothesized that the condensed-phase degradation of the nitramine oxidizer particles to a vaporizable state is the overall rate-limiting step. It is also assumed that the gas-phase details are secondary in importance and need be studied only to the extent of supplying the correct boundary conditions on the condensed-phase/vapor-phase heat transfer. Because of our imprecise understanding of the gas-phase processes in the presence of combustion, several plausible models are considered for the gas phase. It is found that all of the gas -phas e models considered lead to predictions sufficiently clos e to experimental trends for us to conclude that the precise details of gas -phase processes are not of critical importance in determining propellant combustion behavior. More to the point, we are led to believe that a thorough examination of the condensed-phase details may be sufficient in itself not only to interpret most of the available data on experimental regression rate vs. pressure of nitramine propellants but also to aid in the formulation of propellants to suit our needs.

Incendiary tracer projectile

Abstract: Incendiary or flame projectile for use with conventional igniter-tracer sems and capable of being propelled over distances up to about 600 yards to ignite hard-to-ignite combustible materials such as wood or canvas, the projectile being operable and efficient at atmospheric pressures and containing a flame-producing composition similar to gas generator propellants of double-base or ammonium perchlorate formulations.

Anti-erosive, solid rocket double-base propellant compositions

Abstract: A means for reducing or eliminating the erosive burning which takes place ring the burning phase of solid propelled rocket motors which have a large length-to-diameter ratio and/or slow-burning propellants is disclosed. The means comprises incorporating into the solid propellant, in limited percentages (0.1-1.0%), a silicate selected from talc, kaolinite, kaolin, muscovite mica, and feldspar. The silicate additive is effective for composite or double-base solid propellant compositions. The solid composite propellant compositions can vary widely in formulation ingredients to include numerous ballistic modifiers; however, the general formulation for a composite propellant contains in addition to the silicate, a high solids loading of an inorganic oxidizer such as ammonium perchlorate, a polybutadiene binder with curatives and crosslinking agents, and optional metal fuel, preferably aluminum. The polybutadiene can have carboxyl- or hydroxyl-terminal groups. The crosslinking agent for the carboxyl-terminated polybutadiene can be an epoxy compound. The hydroxyl-terminated polybutadiene can be crosslinked with a diisocyanate crosslinking agent. The double-base propellants include the cast double-base or the castable composite double-base compositions. The double-base propellants can also vary over a wide range in their formulations. In addition to including ballistic additives to meet the required performance criteria, these propellants contain nitrocellulose (12.6% N) or Fluid ball powder, energetic plasticizer such as triethylene glycol dinitrate (TEGDN), crosslinking and curing agents, and optional metal fuel.

Role of Ferric Oxide Surface Area in Propellant Burn Rate Enhancement (First Step Toward Modeling)

Abstract: : Results of efforts to correlate composite propellant burn rate, ammonium perchlorate particle size distribution, and ferric oxide specific surface and level are presented. Results from laboratory-scale motor firings with HTPB- and CTPB-based propellants containing ferric oxides of 3 to 26.4 m squared/gm were used. The oxides had been prepared by precipitation and by calcination of either ferric sulfate or yellow iron oxide. Outcome of the analysis is a quantitative summarization of a mass of data showing how the several oxides perform in terms of their specific surface and level and as a function of oxidizer particle size distribution. Results indicate Fe2O3 specific surface is more significant at high fine-AP levels than at low fine-AP levels. Efforts to use the correlations in combustion modeling have barely begun. Catalysis probably takes place in the primary diffusion flame located at the AP-binder interface.

Vapor phase method of making ammonium perchlorate

Abstract: A method for making finely particulate ammonium perchlorate by vapor phase reaction between gaseous ammonia and anhydrous perchloric acid vapor. The gaseous ammonia and perchloric acid vapor are separately mixed with an inert carrier gas and the resulting mixtures reacted to form fine ammonium perchlorate particles. The ammonium perchlorate particles may be recovered by means of a dust bag filter.

The Thermal Decomposition of Ammonium Perchlorate Doped with Cu+2 and Mn+2

Abstract: The thermal decomposition of ammonium perchlorate doped with Cu+2 and Mn+2 was studied, using DTA and TGA Small concentrations (01 − 001%) of these ions inhibit the decomposition by eliminating the first exotherm At higher concentrations a catalyzed decomposition is observed Either the influence of doping ions on the mechanism of the thermal decomposition is different from that of added oxides or a modification of the electron transfer mechanism is needed

Role of Cross-Linking in the Combustion of Polyester/Ammonium Perchlorate Propellants

Abstract: In order to understand the influence of cross-linking and the nature of binder on the combustion of polymer/AP propellants, combustion studies on polyester fuel binder, cross-linked with methyl-methacrylate, have been made. Compression strength, hardness and tensile properties of polymers and propellants have been measured. Thermal degradation data on polymers in presence of oxygen and the data on propellants obey the relation. where Kt is the rate constant which depend upon the extent of cross-linking and temperature. Interface reactions between oxidizer and binder and the concentration of carbon-carbon double bonds are important factors which affect the thermal degradation as well as burning rate.

Propellant composition containing triferrocenylmethyl perchlorate as catalytic oxidizer

Abstract: Triferrocenylmethyl perchlorate as a partial or complete replacement for ammonium perchlorate and the standard burning rate catalyst in a propellant composition. Triferrocenylmethyl perchlorate functions as a combination burning rate catalyst and oxidizer.