Thiokol propellants

Some of these propellants are apparently very popular. They are probably the cheapest composite propellants now in use. 

The uncured binder material should be a liquid which cures with minimum heat release and shrinkage and without evolution of gases. 

The binder should not be a solvent of the oxidant and should be chemically stable for long periods in close contact with the oxidant. 

A more detailed discussion of the visco-elastic properties of rubber-like elastomers for composite propellants was recently given in a paper by Landel and T. L. Smith [8]. 

Among the composite propellants containing elastomers, those containing polyethylene sulphide rubber , so called Thiokol, are widely used. Since 1950 they have been developed by the Thiokol Chemical Corporation in the U.S.A. under the general name of Thiokol Propellants . 

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Fig. 111. A double-motion paddle mixer for premixing Thiokol propellant (Thiokol Chemical Corporation, Redstone Arsenal, according to Warren [5J).

A premix is prepared by mixing the fuel binder (i.e. a polysulphide rubber in the case of the Thiokol propellant) with the necessary curing agents, inert additives, and ballistic modifiers in a double-acting paddle mixer. This mixer is equipped... 

The final mixing takes place in a large Werner-Pfleiderer (or Baker-Perkins) type sealed mixer of the type extensively used in smokeless powder manufacture (Fig. 206). A capacity up to 2000 lb is used in the case of thiokol propellants. After the premix has been added to the mixer, the finally ground oxidant is added. This material is conveyed to the mixer in a closed container and is added so that the... 

Fig. 116. Cross-section of a Thiokol propellant for 14 ft dia. rocket 63 ft in length [14].

PBAA polybutadiene acrylic acid (used in some Thiokol propellants) ROD Rochester Ordnance Distric now absorbed into NYOD... 

R. A. McKay,M Study of Selected Parameters in S olid Propellant Processing,]et Propulsion Lab, Pasadena, Calif., Aug. 1986 J. L. Brown and co-workers. Manufacturing Technologyfor SolidPropellantIngredients/Preparation Reclamation, Morton Thiokol, Inc., Brigham City, Utah, Apt. 1985 W. P. Sampson, Eow Cost Continuous Processing of Solid Rocket Propellant, Al-TR-90-008, Astronautics Laboiatoiy/TSTR, Edwards AEB, Oct. 1990. 

Thompson E.E. Day, Development of HTPB Propellant for Ballistic Missiles . Rept No AFRPLTR-74-68, Contract F04611-72-C-0048, Thiokol Corp, Brigham City (1974) 16) F.R. 

Thiokol (structure 4.70), which was the first synthetic elastomer, was synthesized by Patrick in the 1920s, by the condensation of alkylene dichlorides and sodium polysulfides. These solvent-resistant elastomers have limited uses because of their foul odor. They can be reduced to liquid polymers that can be reoxidized to solid elastomers, which is used in caulking material and some rocket propellant formulations ... 

Chemistry of Polysulfide Polymers. Propellant chemistry based on chemically crosslinked binders had its beginning at the Jet Propulsion Laboratory in the winter of 1946 when potassium and/or ammonium perchlorate were mixed into Thiokol LP-3 polysulfide liquid polymer, to which had been added an oxidative curative, p-quinone dioxime. This polysulfide polymer, as described by Jorczak and Fettes (13), is prepared... 

The flexibility inherent in the polymer manufacturing procedure allowed for the synthesis of many variations of polymer. The examination of these materials in propellant formulations by scientists at the Jet Propulsion Laboratories, Thiokol Chemical Corp., and later other propellant companies not only resulted in many useful solid propellant formulations but laid a significant portion of the foundation on which the propellant chemists of today continue to build. 

The major ingredients of composite propellants are ammonium perchlorate (AP-68%), metal powder (-16%) and polymeric binders like CTPB, HTPB and Thiokol. As total solids loading in composite propellants is -85-88%, polyesters which are commonly used for inhibition of DB propellants, have a relatively weak bond with composite propellants. This problem is further aggravated because of higher shrinkage in the case of polyesters. 

Kay and Fust postulated the use of epoxy resin for inhibition of composite propellants [335] and as a consequence, epoxy resins were tried for the first time for the inhibition of HTPB-based composite propellants at Thiokol Corporation, USA. Subsequently, use of the amido-amine hardened modified bisphenol-A-based epoxy resin was reported as inhibitor for fluorocarbon-based composite propellants [336]. Epoxy resins are the most versatile resins for bonding applications for a variety of substrates. This is because of the following characteristics. 

THE TECHNOLOGY OF THE MANUFACTURE OF ROCKET CHARGES CONTA NIG COMPOSITE PROPELLANTS WITH THIOKOL... 

It is characteristic of the technology of the manufacture of rocket charges containing composite propellants with thiokol that the semi-liquid mixture is poured directly into the rocket chamber lined from within with an insulating layer to which the charge adheres tightly ( case-bonded charge). This is a very cheap and rapid method of manufacture. 

Composite propellants with elastomers (thiokol, polyurethane) do not detonate readily and this is due to their non-porous texture [29]. 

In the US the, Thiokol Chemical Corp, Trenton, NJ proposed it as a curing accelerator in some of their Polysulfide Composite Propellants . The composition and properties of these propints are given in conf Propint Manual SPIA/M2 (1962) (Unit Nos 618, 619,... 

O) R.C, Kopituk, A New Impact Detonability Tester for Evaluating Materials with Highly Reactive Oxidizers , Reaction Motor Div, Thiokol Chem Corp, Denville, NJ. Paper 1707-61 presented at the American Rocket Society Conference on Propellants, Combustion and Liquid Rockets, Palm Beach, Fla (26-28 April 196l)... 

BA-107. Polybutadiene-Acrylic Acid Composite Propellant tot Rocket Motors developed by Thiokol Chemical Corp. Its compn and props are given in conf Propellant Manual ,SPIA/m2 (1959), Unit No 572 B(AM) or BAm(poudre). 

BF.122 BF.I51 are composite polysulfide pro-pints for rocket motors developed by the Thiokol Chem Corp. Their compn props are given in conf Propellant Manual,SPIA/M2( 1959),Unit Nos 570 571... 

Naval Powder Factory (now Naval Propellant Plant), Indian Head, Md Olin-Mathieson Chemical Corp, East Alton, 111 Picatinny Arsenal, Dover, N J Redstone Arsenal, Huntsville, Ala Rockedyne Solid Propulsion Operations (North American Aviation Co), El Segundo, Calif Rohm and Haas, Philadelphia 5, Penna Thiokol Chemical Corp, Trenton,... 

Polysulfide Solid Composite Propellants , Kept E58-58, Contract AF 33 (606)-3971, Thiokol Chemical Co, Elkton (1958) (AD-301364)... 

Physical and Ballistic Properties of Minuteman Solid Propellant , Rept AS60-Y002-02622, Thiokol Chem Corp, Elkton (1960) also in Trans of 5th Syuip on Ballistic Missile Space Technol, Vol II (1960) (AD-323311) 87) G.S. 

F.H. Bell, Wafer Gun Propellant , USNatnl-Techlnform Rept, Thiokol Chem Corp, Brigham City (1973) (AD 771651/76GA) USGovtRep-Announce 74 (5), 159 (1974) CA 81, 5170 (1974) [The author reports on a plastic composite solid proplnt contg HMX. The proplnt is... 

Early in the development of solid propellant, the asphalt composites were found to have poor physical properties, such as cracking under normal temperature cycling, poor tensile characteristics, etc. They were replaced with the elastomeric polymers which have become the present-day binders. The first of these was Thiokol rubber, a polysulfide rubber, whichgives the propellant with good physical properties. The presence of the sulfur atom in the Thiokol rubber decreases the performance compared to a CHO polymer thus the most frequently used binders are polyurethane, polybutadiene acrylic acid (PBAA), epoxy resin, etc. The choice of the latter binders is made with regard to physical properties rather than performance. 

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