Binder components, propellant

Abbreviation for methylaziridine phosphine oxide, a binder component in -> Composite Propellants. 

Poly-AMMO is synthesized via cationic polymerisation from the monomer 3-azidomethyl-methyl-oxetane (AMMO). The polymerisation reaction is quenched with water to get polymer chains with hydroxyl endgroups which enable to react these pre-polymers later with isocyanate for curing reaction. Poly-AMMO is suggested as - energetic binder component in -< composite propellants and is in the scope of actual research. 

Thermal degradation of UPRs used as a component of a binder in propellants was investigated [125]. 

Gun Propellents. Low sensitivity gun propeUants, often referred to as LOVA (low vulnerabUity ammunition), use RDX or HMX as the principal energy components, and desensitizing binders such as ceUulose acetate butyrate or thermoplastic elastomers (TPE) including poly acetal—polyurethane block copolymers, polystyrene—polyacrjiate copolymers, and glycidyl azide polymers (GAP) to provide the required mechanical... 

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

The burning rates of AP composite propellants are not only dependent on the AP particles, but also on the binder used as a fuel component. There are many types of binders, with varying physicochemical properties, as described in Section 4.2. The... 

The burning rate of propellants is one of the important parameters for rocket mo-tordesign. As described in Section 7.1.2, the burning rate of AP composite propellants is altered by changing the particle size of the AP used. The diffusional mixing process between the gaseous decomposition products of the AP particles and of the polymeric binder used as a fuel component determines the heat flux feedback from the gas phase to the condensed phase at the burning surface. - This process is a... 

Since rocket propellants are composed of oxidizers and fuels, the specific impulseis essenhally determined by the stoichiometry of these chemical ingredients. Ni-tramines such as RDX and HMX are high-energy materials and no oxidizers or fuels are required to gain further increased specific impulse. AP composite propellants composed of AP particles and a polymeric binder are formulated so as to make the mixture ratio as close as possible to their stoichiometric ratio. As shown in Fig. 4.14, the maximum is obtained at about p(0.89), with the remaining fraction being HTPB used as a fuel component. 

Hydrocarbon polymers (HCP) are used not only as fuel components but also as binders of crystalline oxidizers and metal powders in the formulation of pyrolants, similar to composite propellants and plastic-bonded explosives. There are many types of HCP, the physicochemical properties of which are dependent on their molecular structures. The viscosity, molecular mass, and functionality of the poly-... 

When black powder is used to propel rockets it is classed as a composite propellant (where the fuel and oxidiser are intimately mixed) and forms part of a rocket motor in which the powder is compressed to form a monolithic single grain inside a combustion chamber as shown in Figure 3.1. As well as gunpowder, the composite propellant mix will contain a binder which is used to improve the cohesion of the ingredients. Binders form a distinct phase and tend to reduce the sensitiveness of the propellant to shock and impact. When based on organic materials, as is normally the case, they will serve as part of the fuel component also. 

In the simple two-component system of PVC binder and oxidizer, the important propellant properties of specific impulse, density, adiabatic flame temperature, and burning rate increase with an increase in solids loading. This is shown in Figure 8, where theoretical calculated values of specific impulse, adiabatic flame temperature, and density are given for a range of oxidizer content for PVC plastisol propellants comprised of only binder and oxidizer. [Calculated values of specific impulse reported throughout this paper are for adiabatic combustion at a rocket chamber pressure of 1000 p.s.i.a. followed by isentropic expansion to 1 atm. pressure with the assumptions that during the expansion process chemical compo-... 

This structure has superior water-resistant properties in comparison to conventional polyols used for PU synthesis. Room temperature cures are easily obtained with typical urethane catalysts. Short chain diols, fillers and plasticizers may also be used in their formulations in order to vary physical properties. Formulations usually with NCO/OH ratio of 1.05 are used for this purpose. Such urethanes are reported to be flexible down to about -70 °C. HTPB is regarded as a work horse binder for composite propellants and PBXs. HTPB also successfully competes with widely used room temperature vulcanizing (RTV) silicones and special epoxy resins for the encapsulation of electronic components. HTPB-based PUs are superior in this respect as epoxy resins change their mechanical properties widely with temperature. 

Solid composite propellants are usually rich in combustible ingredients and the amount of oxidant is usually limited by the mechanical properties of the mixtures. Careful c hoice of components is needed to obtain high loadings without jeopardizing fluidity in mixing and creating discontinuities in the binder. A common procedure consists of using oxidants in two or more sizes. 

TDI has a flash pt of 132° (open cup) and flammable vapor level limits of 05 to 9.5% 2,4-Tolylene diisocyanate is used as a constituent (cross-linking agent) of polyurethane expls, proplnt binders, and as a component of a ballistic modifier (Refs 2a, 8 9). Se in Vol 8, P6 8-Table 3 under PBX Type Explosives-Composition (listed as Polyurethane in the Binder, % column), and P409-R to P415-Table 17 under B. Composite Propellants ... 

A typical product has the following characteristics number average molecular weight, — 1800 carboxyl assay, — 1.1 meq./gram color, amber bulk viscosity (Brookfield synchrolectric viscometer) 70°F., 8000 poises, 100°F., 2000 poises, 150°F., 250 poises, and 250°F., 15 poises. The product can be cured with polyfunctional epoxides, aziridines, and isocyanates for applications such as thermoset and pressure sensitive adhesives, electronic component encapsulation, rocket propellant binders, epoxy flexibilizers, etc. Detailed vulcanization data can be obtained for the 1800 molecular weight material, EMD-590, from the Enjay Chemical Co., Cranford, N. J. 

In recent years, the great majority of solid rockets have utilized composite propellants. Most composite propellants are based on a solid oxidizer and a curable liquid polymeric binder. The binder also serves as fuel. Optionally, metallic fuels such as aluminum or boron may also be used.45 The propellant components are mixed together, and then the binder is cured to give the tough, flexible, elastomeric (rubbery thermoset) solid propellant required for modem missile use. An excellent source of information on the formulation of solid propellants is a report by Oberth.46... 

Glycidyl azide polymer was originally developed in the USA as an -> Active Binder tor - Composite Propellants. Because this gas-producing component has been shown to have a low explosion temperature, it has been used in recent years as an active binder compound in -> LOVA gun propellant. 

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