RDX propellant

Since the physical structure of nitramine composite propellants is heterogeneous, the combustion wave structure is considered to be also heterogeneous, as in the case of AP composite propellants. However, the difference between AP propellant and RDX propellant is evident in Figs. 7-17 (a) and (b). The luminous flame produced above the burning surface is almost attached the burning surface of the AP propellant (a). On the other... 

Both RDX and HMX are substantially desensitized by mixing with TNT to form cyclotols (RDX) and octols (HMX) or by coating with waxes, synthetic polymers, and elastomeric biaders. Most of the RDX made ia the United States is converted to Composition B (60% RDX, 40% TNT, 1 part wax added). Composition A5 (RDX 98.5/stearic acid 1.5) and composition C4 (RDX91/nonexplosive plasticizer) account for the next largest uses. HMX is used as a propellant and ia maximum-performance plastic bonded explosives such as PBX 9401 and PBX N5 and the octols (147—150). 

Military. The single-component explosives most commonly used for military compositions are TNT, RDX or HMX, nitrocellulose, and nitroglycerin. The last two are used almost exclusively to make propellants. The production volume of TNT far exceeds that of any other explosive. It is used as manufactured, as a base of biaary slurries with other high melting explosives, or ia ternary systems generally containing a biaary mix and aluminum. 

Polymer-based rocket propellants are generally referred to as composite propellants, and often identified by the elastomer used, eg, urethane propellants or carboxy- (CTPB) or hydroxy- (HTPB) terrninated polybutadiene propellants. The cross-linked polymers act as a viscoelastic matrix to provide mechanical strength, and as a fuel to react with the oxidizers present. Ammonium perchlorate and ammonium nitrate are the most common oxidizers used nitramines such as HMX or RDX may be added to react with the fuels and increase the impulse produced. Many other substances may be added including metallic fuels, plasticizers, stabilizers, catalysts, ballistic modifiers, and bonding agents. Typical components are Hsted in Table 1. 

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. 

Gun Propellents. Low sensitivity gun propeUants, often referred to as LOVA (low vulnerabUity ammunition), use RDX or HMX as the principal energy components, and desensitizing binders such as ceUulose acetate butyrate or thermoplastic elastomers (TPE) including poly acetal—polyurethane block copolymers, polystyrene—polyacrjiate copolymers, and glycidyl azide polymers (GAP) to provide the required mechanical... 

Uses. NMe has been used as a solv, a chem intermediate, a propellant, and an expl. For a review see Ref 10. It is used as a solv for the detn of the HMX content of RDX by differential refracto-metry (Ref 27). It is used as a solv in the prepn of fine particle size NC (plastisol NC) (Ref 53). 

The polymer has an impact sensy of 40cm at the 50% point using a BM machine with a 2kg wt (RDX, 28cm), a thermal stability of 13 mins using a 1.3g sample with Kl-Starch indicator paper (Ref NC, 10 mins, no color), also, a rel vise of 1.50 centipoises at 25° using a 1% acet soln Ref PJ. Blatz et al, Research In Nitropoly-mers And Their Application To Solid Smokeless Propellants , Report No 907, Aerojet-General Corp, Azusa, Calif ONR Contract N7 onr-462, Task Order I and Contract NO as 54-399-C (15 Dec 1954), 16 17... 

Tetranitrohexahydropyrimidine (DNNC) (94) has been synthesized from the nitrolysis of the A(iV -di-fert-butylpyrimidine (93). Levins and co-workers reported the synthesis of DNNC (94) from the nitrolysis of the analogous A. V -di-wo-propylpyrimidine (92). DNNC is a high performance explosive with a detonation velocity of 8730 m/s, impact sensitivity lower than RDX and a very favourable oxygen balance. DNNC has been suggested " for use as an oxidizer in propellant compositions. This is also considered as an excellent oxidant for pyrotechnic compositions. ... 

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