Rocket binders

In conclusion, it is evident from the above discussion that anionic polymerization has emerged from a laboratory curiosity to an important industrial process in a relatively short span of time. Currently, over a million tons of polymers are produced by the anionic route in about twenty manufacturing plants around the world. We at Phillips are quite proud of being one of the pioneers along with Firestone and Shell in harnessing this new technology to commercial applications. The fact that our polymers find such wide ranging applications from tire treads to injection molded blood filters and from lubricant additives to solid rocket binders bears ready testimony to this. 

Oxidizers. The characteristics of the oxidizer affect the baUistic and mechanical properties of a composite propellant as well as the processibihty. Oxidizers are selected to provide the best combination of available oxygen, high density, low heat of formation, and maximum gas volume in reaction with binders. Increases in oxidizer content increase the density, the adiabatic flame temperature, and the specific impulse of a propellant up to a maximum. The most commonly used inorganic oxidizer in both composite and nitroceUulose-based rocket propellant is ammonium perchlorate. The primary combustion products of an ammonium perchlorate propellant and a polymeric binder containing C, H, and O are CO2, H2, O2, and HCl. Ammonium nitrate has been used in slow burning propellants, and where a smokeless exhaust is requited. Nitramines such as RDX and HMX have also been used where maximum energy is essential. 

Propellants cast into rockets are commonly case-bonded to the motors to achieve maximum volumetric loading density. The interior of the motor is thoroughly cleaned, coated using an insulating material, and then lined with a composition to which the propellant binder adheres under the environmental stresses of the system. The insulation material is generally a mbber-type composition, filled with siUca, titanium dioxide, or potassium titanate. SiUca-filled nitrate mbber and vulcanizable ethylene—propylene mbber have been used. The liner generally consists of the same base polymer as is used in the propellant. It is usually appHed in a thin layer, and may be partially or fully cured before the propellant is poured into the rocket. 

A mixture of PhenoHc MicrobaUoons and resin binder has a putty-like consistency. It can be molded to shape, troweUed onto surfaces, or pressed into a core. Curing gives a high strength, low density (0.144 g/cm ) foam free of voids and dense areas, and without a brittle skin. Syntactic foams are used in widely diverse appHcations, including boat flotation aids stmctural parts in aircraft, submarines, and missiles stmctural cores for waU panels and ablative heat shields for reentry vehicles and rocket test engines. 

Phenolic resins are adaptable to many applieations. The list is very long, however, the major uses are wood binders, glass insulation binders, molding compounds, laminates, foundry binders, coatings, friction linings, abrasives, and oil well propants [59-66]. They have found their way into a number of new, high technology uses such as rocket motor wear parts, military armor, sports equipment. 

Dynamic differential thermal analysis is used to measure the phase transitions of the polymer. IR is used to determine the degree of unsaturation in the polymer. Monitoring of the purity and raw is done commercially using gas phase chromatography for fractionization and R1 with UV absorption at 260 nanometers for polystyrene identification and measurement Polystyrene is one of the most widely used plastics because of fabrication ease and the wide spectrum of properties possible. Industries using styrene-based plastics are packaging, appliance, construction, automotive, radio and television, furniture, toy, houseware and baggage. Styrene is also used by the military as a binder in expls and rocket propints... 

HMX, binders, etc b) combination of ingredients into blends, grains or formulations, such as cannon powder, Comp B, extruded doublebase proplnt grains, etc c) loading of warheads, bombs, rocket motors, etc, with the blends or formulations and d) final assembly and pack-out of complete munitions, including metal parts... 

A Small but important daSS of fOi mUlatiOnS comprises the Composite Solid Rocket Propellants. Composites typically contain a major amount of an oxidizer such as AP or HMX, a metal powder such as Al, a binder which is one or another type of rubber (or double-base), and up to a dozen trace ingredients such as catalysts, stabilizers, etc. There are literally hundreds of formulations, all to a degree similar and the choice comes down to specific missions, economics, and special requirements Loading of End Items. The blends and formulations described above may be loaded into their hardware in the plant where they are made, or they may be shipped to another plant for Load/... 

J.D. Martin, Rocket Propellant with Acrylate Binder and Difluoroamino Plasticizer , USP 3933542 (1976) CA 84, 138050 (1976) (unlimited)... 

Some ordn uses have been found for carboxyl terminated polybutadiene viz, as rocket motor liners for proplnt mixts contg HTPB (Ref 17) and as part of a terpolymer binder for propints (Ref 16)... 

The ordn uses of polyesters are varied. They range from adhesives (Ref 4), ammo boxes (Ref 5), grenade deactivator (ftef 7), component sealers (Refs 4 8), rocket launchers (Ref la), minesweeper hulls (Ref 14), to binders in expls (Refs 3,6, 19,21,32,33,34,35,37 40),... 

Polystyrene. A thermoplastic used as a binder and fuel in expls and rocket propints. See Plastic fuels (Vol 3, C465-L) under Composite Propellants also Dinitropolystyrene in this Vol, N143-L to N144-R under Nitro Polymers and Propellants, Solid , also in this Vol... 

PVA is also used as a polar polymer binder for rocket propliits (Ref 4)... 

Composite proplnts, which are used almost entirely in rocket propulsion, normally contain a solid phase oxidizer combined with a polymeric fuel binder with a -CH2—CH2— structure. Practically speaking AP is the only oxidizer which has achieved high volume production, although ammonium nitrate (AN) has limited special uses such as in gas generators. Other oxidizers which have been studied more or less as curiosities include hydrazinium nitrate, nitronium perchlorate, lithium perchlorate, lithium nitrate, potassium perchlorate and others. Among binders, the most used are polyurethanes, polybutadiene/acrylonitrile/acrylic acid terpolymers and hydroxy-terminated polybutadienes... 

Klunsch (Ref 72) has incorporated hydra-zinium nitroformate and aluminum hydride in plastisol NC formulations which cure at room temp without undesirable gas formation. A number of such formulations and calculated ballistic results are given in Table 21. Although these are attractive propint s from the standpoint of potential energy, their impact sensitivity was not described. Similar plastisol binder propellants in Table 18 were sensitive enough to impact to warrant extreme caution in processing into rockets. 

The third type of propellent explosive, the composite type, is a more recent development, the purpose of which is to provide rocket propellants of increased thrust, compared with the ordinary varieties. Composite propellants are based on an oxidising solid, commonly a perchlorate, together with an organic binder which both acts as fuel and gives adequate mechanical strength to the mixture. The search for even more energetic compositions continues, but because of the military importance of the... 

The propellant mixture in each solid rocket booster of the Space Shuttle contains ammonium perchlorate ( the oxidizer, 69.6% by weight), aluminum ( the fuel, 16% by weight), an iron oxide catalyst (0.4% by weight), a polymeric binder that... 

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. 

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. 

At the same time binders were introduced which gave mechanical integrety to the grains as well as acting as fuels. The list of fuel/binders used in solid propellant rockets is extensive and has ranged from as-phalt/oil mixtures to polybutadiene rubbers. 

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