Casting of propellants

The compound acts as a hydroxy curing agent in the formation of polyurethane binders of -> Composite Propellants-, - also Casting of Propellants. 

Table 11. Composition and Properties of Polymer-Based Cast Composite Propellants...

Figure 10. Effect of casting powder SLD on tensile strength of propellant...

Curing. The curing process of a double-base propellant converts a bed of casting powder granules whose interstices are filled with casting solvent to a macroscopically homogeneous mass of propellant. It is convenient to discuss the theory of curing on a microscale and on a macroscale separately. 

Material Properties. The elementary form of the analysis used requires the following properties of propellant during cure tensile modulus, effective bulk modulus, and propellant volume change. Each of these properties changes with temperature and time elapsed since casting. Because of the unusual nature of the material (sticky, wet, explosive, gravel ), special tests, equipment, and techniques were developed for these measurements. 

A special split tensile specimen mold was made to measure tensile properties of propellant during cure. A miniature casting is made in a dumbbell-shaped mold. The gage section of the mold is split axially so that it can be removed to expose the partially cured propellant. The mold is placed in a tensile tester, and the specimen is pulled with the end parts in place. Figure 17 shows that during the early stages of cure... 

Casting of composite propellants is usually conducted under reduced pressure to eliminate air or other gases from the liquid propellant mix. Any voids caused by expanded gases will remain fixed in the propellant grain if gelation occurs before the vacuum is released. Hence, the vacuum must be released after volatiles are removed but before gelation... 

Ultrafine carbon fibers Non-toxic burn-rate modifiers for cast DB propellants in the absence of lead salts [248]. 

The composition of various more modern cast double base propellants (according to Sutton [56] and J. Taylor [57] is shown in Table 194. Table 195 gives the physico-chemical properties of propellant I. 

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 ... 

Refs l)R.A.Connor, Edit, "Summary Technical Report of Division 8, NDRC, Vol 1, Washington, DC(1946), 89(Casting techniques) 101-2(Cast perchlorate proplnts) 102-4(Cast double-base proplnts) 2)F. A. Warren, r<Rocket Propellants", Renhold, NY(1958), 58-68 3)R.Steinberger, pp 249 51 in "The Chemistry of Propellants", A Meeting Organized by the AGARD Combustion and Propulsion Panel, Paris, France in June 1959, Pergamon Press, NY(1960), 249-51 4)B.Kit D.S.Evered, "Rocket Propellants Handbook, Macmillan, NY(1960), 32-3... 

Composite proplnts may be divided into three classes, according to their methods of manuf. These include cast composite propellants, molded composite propellants and solvent-extruded composite propellants (Ref 1, pp 95, 99 101 and Ref 16, pp 336 -37 345-52)... 

It contd 300-400 lbs of cast TNT. These charges were launched from a gin which was located at the stern of the ship. The K type of gun consisted of a smodth-bore barrel attached to an expansion chamber fitted with a breech mechanism. The gun was secured to the rail of the ship and could not be elevated or trained. Variations in the range were obtd by changing the weights of propelling charges... 

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