Polymer-bonded explosive
Polymer-bonded explosives, also called PBX or plastic-bonded explosives, are explosive materials in which explosive powder is bound together in a matrix using small quantities (typically 5–10% by weight) of a synthetic polymer. PBXs are normally used for explosive materials that are not easily melted into a casting, or are otherwise difficult to form.
PBX was first developed in 1952 at
Potential advantages
Polymer-bonded explosives have several potential advantages:
- If the polymer matrix is an insensitive munitions.
- Hard polymers can produce PBX that is very rigid and maintains a precise engineering shape even under severe stress.
- PBX powders can be pressed into a desired shape at room temperature; casting normally requires hazardous melting of the explosive. High pressure pressing can achieve density for the material very close to the theoretical crystal density of the base explosive material.
- Many PBXes are safe to machine; turning solid blocks into complex three-dimensional shapes. For example, a CNC machine. This technique is used to machine explosive lenses necessary for modern nuclear weapons.[3]
Binders
Fluoropolymers
Fluoropolymers are advantageous as binders due to their high
Elastomers
Elastomers have to be used with more mechanically sensitive explosives like
Energetic polymers
Energetic polymers (e.g. nitro or azido derivates of polymers) can be used as a binder to increase the explosive power in comparison with inert binders. Energetic plasticizers can be also used. The addition of a plasticizer lowers the sensitivity of the explosive and improves its processibility.[1]
Insults (potential explosive inhibitors)
Explosive yields can be affected by the introduction of mechanical loads or the application of temperature; such damages are called insults. The mechanism of a thermal insult at low temperatures on an explosive is primarily thermomechanical, at higher temperatures it is primarily thermochemical.
Thermomechanical
Thermomechanical mechanisms involve stresses by thermal expansion (namely differential thermal expansions, as thermal gradients tend to be involved), melting/freezing or sublimation/condensation of components, and phase transitions of crystals (e.g. transition of HMX from beta phase to delta phase at 175 °C involves a large change in volume and causes extensive cracking of its crystals).
Thermochemical
Thermochemical changes involve decomposition of the explosives and binders, loss of strength of binder as it softens or melts, or stiffening of the binder if the increased temperature causes crosslinking of the polymer chains. The changes can also significantly alter the porosity of the material, whether by increasing it (fracturing of crystals, vaporization of components) or decreasing it (melting of components). The size distribution of the crystals can be also altered, e.g. by Ostwald ripening. Thermochemical decomposition starts to occur at the crystal nonhomogeneities, e.g. intragranular interfaces between crystal growth zones, on damaged parts of the crystals, or on interfaces of different materials (e.g. crystal/binder). Presence of defects in crystals (cracks, voids, solvent inclusions...) may increase the explosive's sensitivity to mechanical shocks.[4]
Some example PBXs
| Name | Explosive ingredients | Inert ingredients | Usage | |
|---|---|---|---|---|
| AFX-757 | RDX 25%, ammonium perchlorate 30%, aluminium 33% | HTPB 4.44%, dioctyl adipate 6.56% | Used in warheads for JASSM, GBU-39 Small Diameter Bomb and similar weapons.[5] Has high air blast equivalent, 1.39 times more than Composition B, but low brisance due to low high explosive content.[6] |
[7] |
| EDC-8 | PETN 76% | RTV silicone 24% | [8] | |
| EDC-28 | RDX 94% | FPC 461 6% | [9] | |
| EDC-29 | β-HMX 95% | HTPB 5% | UK composition[4] | |
| EDC-32 | HMX 85% | 15% Viton A 15% | [9] | |
| EDC-37 | HMX 91%, NC 1% | K-10 liquid 8% | [9] | |
| LX-04 | HMX 85% | Viton -A 15% |
High-velocity; | |
| LX-07 | HMX 90% | Viton -A 10% |
High-velocity; | |
| LX-08 | PETN 63.7% |
Sylgard 182 (silicone rubber) 34.3%, 2% Cab-O-Sil | [10] | |
| LX-09-0 | HMX 93% | 2,2-dinitropropyl acrylate (pDNPA) 4.6%; FEFO 2.4% | High-velocity; nuclear weapons (W68). Prone to deterioration and separation of the plasticizer and binder. Caused serious safety problems. FEFO is 1,1-[methylenebis(oxy)]-bis-[2-fluoro-2,2-dinitroethane], liquid explosive.[3]
| |
| LX-09-1 | HMX 93.3% | pDNPA 4.4%; FEFO 2.3% | ||
| LX-10-0 | HMX 95% | Viton -A 5% |
High-velocity; | |
| LX-10-1 | HMX 94.5% | Viton -A 5.5% |
||
| LX-11-0 | HMX 80% | Viton -A 20% |
High-velocity; nuclear weapons (W71 )
| |
| LX-14-0 | HMX 95.5% | Estane & 5702-Fl 4.5% | [9] | |
| LX-15 | HNS 95% | Kel-F 800 5% | ||
| LX-16 | PETN 96% |
FPC461 4% | FPC461 is a vinyl chloride:chlorotrifluoroethylene copolymer and its response to gamma rays has been studied.[11] | |
| LX-17-0 | TATB 92.5% | Kel-F 800 7.5% | High-velocity, ) | |
| PBX 9007 | RDX 90% | DOP 0.5%; rosin 0.4% |
[9] | |
| PBX 9010 | RDX 90% | Kel-F 3700 10% | High-velocity; | |
| PBX 9011 | HMX 90% | Estane and 5703-Fl 10% |
High-velocity; | |
| PBX 9205 | RDX 92% | DOP 2% |
Created in 1947 at Los Alamos, later given the PBX 9205 designation.[12] | |
| PBX 9404 | HMX 94%, NC 3% | Tris(b-chloroethyl)phosphate (CEF) 3% | High-velocity; | |
| PBX 9407 | RDX 94% | FPC461 6% | [9] | |
| PBX 9501 | HMX 95%, BDNPA-F 2.5% | Estane 2.5% | High-velocity; | |
| PBS 9501 | - | Estane 2.5%; BDNPA-F 2.5%; sieved white sugar 95% | Inert simulant of mechanical properties of PBX 9501[4] | |
| PBX 9502 | TATB 95% | Kel-F 800 5% | High-velocity, | |
| PBX 9503 | TATB 80%; HMX 15% | Kel-F 800 5% | Also known as X-0351.[9] | |
| PBX 9604 | RDX 96% | Kel-F 800 4% | ||
| PBXN-101 | HMX 82% | |||
| PBXN-102 | HMX 59%, Aluminum 23% | |||
| PBXN-103 | TMETN 23% |
TEGDN 2.5% |
Mk 48 torpedoes
| |
| PBXN-104 | HMX 70% | |||
| PBXN-105 | RDX 7%, AP 49.8%, Aluminum 25.8% | |||
| PBXN-106 | RDX 75% | polyethylene glycol/BDNPA-F binder | Naval shells | |
| PBXN-107 | RDX 86% | polyacrylate binder |
BGM-109 Tomahawk missiles
| |
| PBXN-109 | RDX 64%, Aluminum 20% | HTPB, DOA (dioctyladipate), and IPDI (isophorone diisocyanate) | Used in some versions of the Mark 82, Mark 83 and Mark 84 general-purpose bombs.[14] | |
| PBXN-110 | HMX 88% | 5.4% Polybutadiene, 5% Isodecylpelargonate | [15] | |
| PBXN-111 | RDX 20%, AP 43%, Aluminum 25% | |||
| PBXW-114 | HMX 78%, Aluminum 10% | |||
| PBXW-115 | RDX 20%, AP 43%, Aluminum 25% | |||
| PBXN-1 | RDX 68%, Aluminum 20% | |||
| PBXN-3 | RDX 85% | Nylon | AIM-9X Sidewinder Missile | |
| PBXN-4 | Diaminotrinitrobenzene (DATB) 94% | |||
| PBXN-5 | HMX 95% | fluoroelastomer 5% | Naval shells | |
| PBXN-6 | RDX 95% | |||
| PBXN-7 | RDX 35%, TATB 60% | |||
| PBXN-9 | HMX 92% | HYTEMP 4454 2%, Diisooctyl adipate (DOA) 6% | ||
| XTX 8003 | PETN 80% |
Sylgard 182 (silicone rubber) 20% | High-velocity, extrudable; ) | [15] |
| XTX 8004 | RDX 80% | Sylgard 182 (silicone rubber) 20% | [15] |
References
- ^ ISBN 978-0-85404-640-9. Archivedfrom the original on 2023-02-15. Retrieved 2021-12-13.
- ^ James R.Bates; W.W.Lauderdale; Harold Kernaghan (April 1979). "ALSEP (Apollo Lunar Surface Experiments Package) Termination Report" (pdf-8.81 mb). NASA-Scientific and Technical Information Office. Archived (PDF) from the original on 2010-01-13. Retrieved 2014-06-29.
- ^ a b c Carey Sublette (1999-02-20). "4.1.6.2.2.5 Explosives". 4. Engineering and Design of Nuclear Weapons: 4.1 Elements of Fission Weapon Design. Retrieved 2010-02-08.
- ^ ISBN 978-3-540-88089-9.
- S2CID 115831591.)
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help - S2CID 244902961.
- ^ US patent 6523477B1, George W. Brooks & Eric E. Roach, "Enhanced Performance Insensitive Penetrator Warhead", issued 2003-02-25, assigned to Lockheed Martin Corporation
- ^ Technical Area 36 Open Detonation Unit — SUPPLEMENT 2-1 Waste Explosives Detonated at Technical Area 36 (PDF) (Report). September 1999. p. 2. Archived (PDF) from the original on 2022-10-01.
- ^ a b c d e f g h i j k l m Technical Area 36 Open Detonation Unit — SUPPLEMENT 2-1 Waste Explosives Detonated at Technical Area 36, p. 2.
- ^ H K Otsuki; E Eagan-McNeill (May 1997). A Blue Print for Building a Risk Assessment (Report). Lawrence Livermore National Laboratory. p. 6. UCRL-JC-127467. Archived from the original on 2022-09-29.
- from the original on 2022-04-17. Retrieved 2019-09-09.
- ^ Anders W. Lundberg. "High Explosives in Stockpile Surveillance Indicate Constancy" (PDF). Lawrence Livermore National Laboratory (LLNL). Archived (PDF) from the original on 2012-10-10. Retrieved 2014-03-02.
- ^ Kinetics of PBX 9404 Aging Archived 2017-02-11 at the Wayback Machine Alan K. Burnhamn; Laurence E. Fried. LLNL, Unclassified, 2007-04-24 (pdf)
- ^ Janes (26 July 2022), "Mk 80 general‐purpose bombs (BLU‐110/111/117/126/129)", Janes Weapons: Air Launched, Coulsdon, Surrey: Jane's Group UK Limited., retrieved 29 May 2023
- ^ a b c Technical Area 36 Open Detonation Unit — SUPPLEMENT 2-1 Waste Explosives Detonated at Technical Area 36, p. 3.
- 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"[permanent dead link], http://thebulletin.org, The Bulletin of the Atomic Scientists, Jan/Feb 2003.