Polymer-bound explosives
A polymer-bound explosive or plastic-bound explosive , also PBX ( English polymer-bonded explosive ), is an explosive in which an explosive powder is bound in a matrix using small amounts of polymer ( plastic ). It should be noted that, despite the term plastic ("plastic"), PBX is not a plastic explosive that can still be shaped by hand after it has hardened. PBX is typically used for explosives that cannot be easily poured into a mold or are otherwise difficult to shape.
It was developed in 1952 by Los Alamos National Laboratory and, like hexogen, is embedded in polystyrene with dioctyl phthalate as a plasticizer . Octogen compositions with a Teflon- based binder were developed in the 1960s and 1970s for grenade and seismic experiments, although the latter experiments were typically performed with hexanitrostilbene (HNS).
advantages
- If the polymer matrix is an elastomer (rubber-like material), it tends to absorb shocks. This makes a PBX very insensitive to accidental detonation and therefore ideal for insensitive ammunition .
- Hard polymers can form a PBX that is very rigid and maintains its exact shape even under heavy loads.
- PBX powders can be pressed into a desired shape at room temperature, which avoids high critical temperatures such as those that can occur when casting other explosives. Compression molding enables the density of the material to be close to the maximum theoretical density of the explosive.
- Many PBXs can even be machined. So it can be machined by turning and milling; explosive lenses for nuclear weapons are also manufactured in this way.
binder
Fluoropolymers
Fluoropolymers offer advantages as binders due to their high density (which results in a high detonation speed ) and their inert chemical behavior (which is conducive to long storage stability and low aging ). However, the PBX generated in this way are difficult to process. The unpleasant property that their glass transition temperature is only at room temperature or a little higher makes them somewhat brittle. This restricts their use to the area of robust explosives (for example TATB ), where the brittleness does not have a detrimental effect on safety.
Elastomers
Elastomers are used for mechanically sensitive explosives ( e.g. Octogen ). The elasticity of the matrix reduces the sensitivity to shock and friction. The glass transition temperature is below the lower limit of the temperature working range (typically below -55 ° C). However, crosslinked rubber is sensitive to aging, particularly through the action of free radicals and hydrolysis of the compounds through traces of water vapor. Rubbers such as thermoplastic elastomers or hydroxyl-terminated polybutadiene are often used for these applications. Silicone rubber is also in use.
Fluororubbers such as Viton combine the advantages of the other two binders.
Energetic Polymers
Energetic polymers (e.g. nitro derivatives of polymers) can be used as binders to increase the explosive power compared to an inert binder. Energetic plasticizers can also be used, thereby reducing the sensitivity of the explosive and improving processability.
Examples of PBX
| Surname | Explosive | binder | use |
|---|---|---|---|
| EDC-29 | β- HMX 95% | HTPB 5% | UK composition |
| EDC-37 | HMX / cellulose nitrate 91% | Polyurethane 9% | |
| LX-04-1 | HMX 85% | Viton-A 15% | High speed explosives; Nuclear weapons (W62, W70) |
| LX-07-2 | HMX 90% | Viton-A 10% | High speed explosives; Nuclear weapons (W71) |
| LX-09-0 | HMX 93% | BDNPA 4.6%; FEFO 2.4% | High speed explosives; Nuclear weapons (W68). Prone to degradation and separation of plasticizer and binder. Causes serious security problems |
| LX-09-1 | HMX 93.3% | BDNPA 4.4%; FEFO 2.3% | |
| LX-10-0 | HMX 95% | Viton-A 5% | High speed explosives; Nuclear weapons (W70, W79, W82; replaces the LX-09) |
| LX-10-1 | HMX 94.5% | Viton-A 5.5% | |
| LX-11-0 | HMX 80% | Viton-A 20% | High speed explosives; Nuclear weapons (W71) |
| LX-14-0 | HMX 95.5% | Estane & 5702-Fl 4.5% | |
| LX-15 | HNS 95% | Kel-F 800 5% | |
| LX-16 | PETN 96% | FPC461 4% | FPC461 is a vinyl chloride |
| LX-17-0 | TATB 92.5% | Kel-F 800 7.5% | High-speed explosives, insensitive; Nuclear weapons (B83, W84, W87, W89) |
| PBX 9007 | RDX 90% | Polystyrene 9.1%; DOP 0.5%; Rozin 0.4% | |
| PBX 9010 | RDX 90% | Kel-F 3700 10% | High speed explosives; Nuclear weapons (W50, B43) |
| PBX 9011 | HMX 90% | Estane and 5703-Fl 10% | High speed explosives; Nuclear weapons (B57) |
| PBX 9205 | RDX 92% | Polystyrene 6%; DOP 2% | Developed in Los Alamos in 1947, later referred to as PBX 9205 |
| PBX 9404 | HMX 94% | Cellulose nitrate 3%; CEF 3% | High speed explosives; Nuclear weapons (B43, W48, W50, W55, W56, B57, B61, W69). Prone to degradation and separation of plasticizer and binder. Causes serious security problems |
| PBX 9407 | RDX 94% | FPC461 6% | |
| PBX 9501 | HMX 95% | Estane 2.5%; BDNPA-F 2.5% | High speed explosives; Nuclear weapons (W76, W78, W88). One of the best researched explosives |
| PBS 9501 | - | Estane 2.5%; BDNPA-F 2.5%; white powdered sugar 95% | Inert simulation explosive with the mechanical properties of the PBX 9501 |
| PBX 9502 | TATB 95% | Kel-F 800 5% | High-speed explosives, insensitive; Use in newer US nuclear weapons (B61, W80, W85, B90, W91), also retrofitting of older nuclear weapons with safe explosives |
| PBX 9503 | TATB 80%; HMX 15% | Kel-F 800 5% | |
| PBX 9604 | RDX 96% | Kel-F 800 4% | |
| PBXN-106 | RDX | Polyurethane | Ship grenades |
| PBXN-3 | RDX 85% | nylon | AIM-9X Sidewinder |
| PBXN-5 | HMX 95% | Fluoroelastomer 5% | Ship grenades |
| PBXN-9 | HMX 92% | HYTEMP 4454 2%, DOA 6% | Use in different systems |
| X-0242 | HMX 92% | Polymer 8% | |
| XTX 8003 | PETN 80% | Sylgard 182 20% | High speed explosives, extrudable, nuclear weapons (W68, W76) |
literature
- Cooper, Paul W. Explosives Engineering . New York: Wiley-VCH, 1996. ISBN 0-471-18636-8 .
- Norris, Robert S., Hans M. Kristensen , and Joshua Handler. "The B61 family of bombs" , http://thebulletin.org , The Bulletin of the Atomic Scientists , Jan / Feb 2003.
Individual evidence
- ^ A b Jacqueline Akhavan: The Chemistry of Explosives. January 1, 2004, accessed November 9, 2015 .
- ↑ ALSEP (ALSEP) report. NASA Information Office, April 1979, accessed November 9, 2015 .
- ^ A b c Carey Sublette: 4. Engineering and Design of Nuclear Weapons: 4.1 Elements of Fission Weapon Design. nuclearweaponarchive.org, February 20, 1999, accessed November 9, 2015 .
- ↑ a b c d e Blaine Asay: Non-Shock Initiation of Explosives. Springer Berlin Heidelberg, accessed on November 9, 2015 .