Composite proplnts

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... 

Without the influence of burning rate catalysts most of these hydrocarbon prop bits have similar burning rates and ballistic behavior. They may differ significantly in mechanical properties, particularly as a function of temp. Most hydrocarbon-based composites are used in larger rockets because of their ease of fabrication and high specific impulse. Polaris first and second stages, the Titan 3C booster rocket and Mlnuteman are all powered with composite proplnts... 

To achieve higher energy in solid proplnts the most notable advances were achieved with the addition of aluminum and beryllium to both double-base and composite proplnts. Energy in this case is commonly equated to high specific impulse. Later developments added aluminum hydride and beryllium hydride to this list. In Table 16, the specific impulse performance of proplnts using AP with various metals and hydrides is compared to those systems without these additives (Ref 43)... 

Since these double-base proplnts consist essentially of a single phase which bears the total load in any application of force, their mechanical property behavior is significantly different from composite proplnts. In the latter formulations, the hydrocarbon binder comprises only about 14% of the composite structure, the remainder being solid particles. Under stress, the binder of these proplnts bears a proportionately higher load than that in the single phase double-base proplnts. At small strain levels, these proplnts behave in a linear viscoelastic manner where the solids reinforce the binder. As strain increases, the bond between the oxidizer and binder breaks down... 

The burning rates of standard aluminized hydrocarbon binder composite proplnts may be increased significantly not only with ferrocene derivatives but also with compatible carborane-type burning rate additives. However, most ferrocene derivatives are volatile solids or liquids which have a tendency to evaporate from the proplnt during storage, thereby degrading ballistic performance. Rudy (Ref 71) minimized this problem by the use of polynuclear ferrocene... 

An unusual "critical density phenomenon is encountered with AN/fuel expls. This has been attributed by Gordon to diffusion-limited reaction. This case is reviewed, and the implications concerning the question of detonability in solid composite proplnts are examined... 

E-7. A solvent-extruded composite proplnt developed in USA during WWIL It was described as Unit No 593 in conf Propellant Manual SPIA/M2 1962)... 

It does not actually belong to the group of EJ proplnts developed during WWII, because they are solvent-extruded composite proplnts, while EJC is castable... 

Utilization of waxes as fuels in composite proplnts is not widespread. Waxes do not lend themselves to producing good mechanical proper-... 

PATR 2488(1958)(New formulas for rapid calcn of linear burning rates of solid proplnts) 32)J. Delacarte et al, MP 41, 223 65(1959)(Contribution to study of rates of burning and other props of composite proplnts) 33)J Taylor, "Solid Propellant and Exothermic Compositions , Interscience, NY(1959), 55-6 34)C.Napoly, MP 42, 229-46(1960)(4 refs)(Relations between linear rate of burning, apparent potential and pressures for proplnts consisting of only NC, NG and Centralite) 35)Anon, "Ordnance Proof Manual , Aberdeen Proving Ground, Md,7-24 36)L.Shulman et al, PATR FRL-TR 41(1961)... 

Two kinds of proplnts are used in rockets solid and liquid. Solid rocket proplnts can be either colloidal double-base or composite proplnts, while liquid proplnts can be either mono-or bipropellants... 

Accdg to compositions, cannon smokeless proplnts may be subdivided into single-base-, double-base- and triple-base-proplnts. The last two proplnts are sometimes called "compound proplnts. The so-called "composite proplnts, used in JATOS and rockets, are described under Composite Propellants... 

Casting of proplnts techniques may be subdivided into A)Manuf of cast homogeneous proplnts B)Manuf of proplnts by slurry casting and C)Manuf of cast composite proplnts A)tAanuf of Cast Homogeneous Propellants. This includes, solvent, solventless- or ball-proplnrs as srarting materials. The method consists of the following operations ... 

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