Rocket propellant grains

Solventless Extrusion Process. The solvendess process for making double-base propellants has been used ia the United States primarily for the manufacture of rocket propellant grains having web thickness from ca 1.35 to 15 cm and for thin-sheet mortar (M8) propellant. The process offers such advantages as minimal dimensional changes after extmsion, the elimination of the drying process, and better long-term baUistic uniformity because there is no loss of volatile solvent. The composition and properties of typical double-base solvent extmded rocket and mortar propellant are Hsted ia Table... 

Sieg et al, Bonding a Rocket Motor Liner to a Solid Rocket Propellant Grain , USP 3904715 (1975). CA 84, 7210 (1976)... 

Rugg, Feasibility Studies Relative to using New Polymers and Plastics as Inhibitors to Replace Composition Presently Being Used With Rocket Propellant Grains of 155mm HE RAP (Rocket Assisted Projectile) , Final Rept — May-Dec 75, Contract DAAA21-75-C-0267, NY Univ, NY (1975) 11) T. Takayama, JapP 7518052... 

Double-base propellants containing azide polymers are termed nitro-azide polymer propellants. DEP used as a plasticizer of double-base propellants is replaced with azide polymers in order to increase energy density. The compatibility of GAP prepolymer with NG serves to suitably desensitize the mechanical sensitivity of NG and gives superior mechanical properties in the formulation of rocket propellant grains. 

Similar to nitramine composite propellants and TAGN composite propellants, AN composite propellants produce halogen-free combustion products and thus represent smokeless propellants. However, their ballistic properties are inferior to those of other composite propellants the burning rate is too low and the pressure exponent is too high to permit fabrication of rocket propellant grains. In addition, the mechanical properties of AN composite propellants vary with temperature due to the phase transitions of AN particles. 

Accdg to the paper of 1962 by Macek (Ref 14) "The shift of attention to the problem of transition to detonation in solid explosives, about a decade ago, was occasioned by the awareness that the problem may be pertinent to the proper functioning of large rocket propellant grains, and was given additional impetus by the scientific approach to shock initiation. From initial qualitative suggestions of Kistiakowsky (Refs 4 6) and Ubbelohde (Ref 5) there developed the hypothesis of precursor shock, which postulates a sequence of events rather analo-... 

---