Editing C-4 (explosive) (section)

=== Composition ===
The Composition C-4 used by the [[United States Armed Forces]] contains 91% [[RDX]] ("Research Department Explosive", an explosive [[nitroamine]]), bound by a mixture of 5.3% [[dioctyl sebacate]] (DOS) or [[dioctyl adipate]] (DOA) as the plasticizer (to increase the [[plasticity (physics)|plasticity]] of the explosive), thickened with 2.1% [[Polyisobutene|polyisobutylene]] (PIB, a [[synthetic rubber]]) as the [[binder (material)|binder]], and 1.6% of a [[mineral oil]] often called "process oil". Instead of "process oil", low-viscosity [[motor oil]] is used in the manufacture of C-4 for civilian use.<ref name="atf">{{cite journal|last1=Reardon|first1=Michelle R.|last2=Bender|first2=Edward C.|year=2005|title=Differentiation of Composition C4 Based on the Analysis of the Process Oil|journal=Journal of Forensic Sciences|volume=50|issue=3|pages=1–7|doi=10.1520/JFS2004307|url=http://www.astm.org/DIGITAL_LIBRARY/JOURNALS/FORENSIC/PAGES/JFS2004307.htm|publisher=Bureau of Alcohol, Tobacco, Firearms, and Explosives, Forensic Science Laboratory|location=Ammendale, MD|issn=0022-1198}}</ref>

The British PE4 consists of 88.0% RDX, 1.0% pentaerythrite dioleate and 11.0% DG-29 [[Lithium soap|lithium grease]] (corresp. to 2.2% [[lithium stearate]] and 8.8% mineral oil [[British Pharmacopoeia|BP]]) as the binder; a taggant (2,3-dimethyl-2,3-dinitrobutane, [[DMDNB]]) is added at a minimum of 0.10% weight of the plastic explosive, typically at 1.0% mass.  The newer PE7 consists of 88.0% RDX, 1.0% DMDNB taggant and 11.0% of a binder composed of low molecular mass [[hydroxyl-terminated polybutadiene]], along with an [[antioxidant]] and an agent preventing hardening of the binder upon prolonged storage. The PE8 consists of 86.5% RDX, 1.0% DMDNB taggant and 12.5% of a binder composed of di(2-ethylhexyl) sebacate thickened with high molecular mass polyisobutylene.

Technical data according to the [[United States Department of the Army|Department of the Army]] for the Composition C-4 follows.<ref name ="armymanual 8-111" />
{| class="wikitable"
 |-
 | Theoretical '''maximum density''' of the mixture, grams per cubic centimeter
 | style="text-align:right;" | 1.75
 |-
 | '''Nominal density''', grams per cubic centimeter
 | style="text-align:right;" | 1.72658
 |-
 | '''Heat of formation''', calories per gram
 | style="text-align:right;" | −32.9 to −33.33
 |-
 | Max heat of detonation with liquid water, kilocalories per gram
 | style="text-align:right;" | 1.59 (6.7 MJ/kg)
 |-
 | Max heat of detonation with gaseous water, kilocalories per gram
 | style="text-align:right;" | 1.40 (5.9 MJ/kg)
 |-
 | Remains plastic with no exudation, Celsius
 | style="text-align:right;" | −57 to +77
 |-
 | '''Detonation pressure''' with density of 1.58 grams per cubic centimeter, kilobars
 | style="text-align:right;" | 257
 |}

==== Manufacture ====
C-4 is manufactured by combining the above ingredients with binders dissolved in a [[solvent]]. Once the ingredients have been mixed, the solvent is extracted through drying and filtering. The final material is a solid with a dirty white to light brown color, a putty-like texture similar to modeling clay, and a distinct smell of motor oil.<ref name ="armymanual 8-111" /><ref name="fuelsource" /><ref name="homelandpresentation">{{cite web | url=https://info.publicintelligence.net/DHS-Explosives.pdf | title=Introduction to Explosives | publisher=U.S. Department of Homeland Security | work=C4: Characteristics, Properties, and Overview | access-date=18 July 2014 | pages=4–5}}</ref> Depending on its intended usage and on the manufacturer, there are differences in the composition of C-4.  For example, a 1990 U.S. Army technical manual stipulated that Class IV composition C-4 consists of 89.9±1% RDX, 10±1% polyisobutylene, and 0.2±0.02% dye that is itself made up of 90% [[Lead(II) chromate|lead chromate]] and 10% [[Carbon black|lamp black]].<ref name="armymanual 8-111">{{citation | url=http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf | title=Department of the Army Technical Manual – Military Explosives| author=Headquarters, U.S. Department of the Army | date=25 Sep 1990 |postscript=.}}</ref> RDX classes A, B, E, and H are all suitable for use in C-4. Classes are measured by granulation.<ref>{{citation | url=http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf | title=Department of the Army Technical Manual – Military Explosives| author=Headquarters, U.S. Department of the Army | date=25 Sep 1990 | pages=8–37–38 (124–125)|postscript=.}}</ref>

The manufacturing process for Composition C-4 specifies that wet RDX and plastic binder are added in a stainless steel mixing kettle. This is called the aqueous slurry-coating process.<ref name="bae">{{cite web |title=Recent Developments in Composition C-4: Towards an Alternate Binder and Reduced Sensitivity|last1=Owens|first1=Jim |last2=Vinh |first2=Paul |url=http://www.dtic.mil/ndia/2009insensitive/10Aowens.pdf|archive-url=https://web.archive.org/web/20130719235154/http://www.dtic.mil/ndia/2009insensitive/10Aowens.pdf|url-status=dead|archive-date=July 19, 2013|publisher=[[BAE Systems]] OSI|location=Holston Army Ammunition Plant}}</ref> The kettle is tumbled to obtain a homogeneous mixture. This mixture is wet and must be dried after transfer to drying trays. Drying with forced air for 16 hours at 50&nbsp;°C to 60&nbsp;°C is recommended to eliminate excess moisture.<ref name="armymanual 8-111" />{{rp|198}}

C-4 produced for use by the U.S. military, commercial C-4 (also produced in the United States), and PE-4 from the United Kingdom each have their own unique properties and are not identical. The analytical techniques of time-of-flight [[secondary ion mass spectrometry]] and [[X-ray photoelectron spectroscopy]] have been demonstrated to discriminate finite differences in different C-4 sources. Chemical, morphological structural differences, and variation in atomic concentrations are detectable and definable.<ref>{{cite journal|last1=Mahoney|first1=Christine M.|last2=Fahey|first2=Albert J.|last3=Steffens|first3=Kristen L.|last4=Benner|first4=Bruce A.|last5=Lareau|first5=Richard T.|year=2010|title=Characterization of Composition C4 Explosives using Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy|journal=[[Analytical Chemistry (journal)|Analytical Chemistry]] |volume=82|issue=17|pages=7237–7248|doi=10.1021/ac101116r|pmid=20698494}}</ref>