History of Explosives

8/10/2019 History of Explosives

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History, Nature andClassification of High

Explosives


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6. Acetylides -C C

7. Halides of Nitrogen NX 3 (e.g. NI 3)

8. Organometalics R Mg X

Most of the military explosives belongs to nitro class ofcompounds.

Classification of Explosives based on

Chemical Groups (Contd.)


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Nature of High ExplosivesPrimary (InitiatoryExplosives)

- Very sensitive (less stability)

- Undergo very rapid transitionfrom burning to detonation

- Ability to transmit detonation toless sensitive explosives

- Detonate with heat or shock.

- Ex. Mercury fulminate, Leadazide, Silver azide, etc.

Secondary (Military orCivil Explosives)

- Less sensitive (high stability)

- Very powerful than primaryexplosives

- Can be only detonated with heator shock from primary explosives

- Ex. Picric acid, TNT, RDX, HMX,TATB, etc.


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Primary Explosives


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Lead Azide (PbN 6) Composition

Salient FeaturesIt has a good shelf life in dry conditions, but is unstable in the presence of

moisture and oxidising agents.

It is less sensitive to impact than mercury fulminate.

It has high capacity for initiating other secondary explosives to detonation.

PbN

N N

N N

NLead acetate + Sodium azide

(Curtius, 1891)

A major initiating explosive used in all blasting caps and other hot-wiredetonators due to excellent storage characteristics.


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Silver Azide (AgN 3) Composition

Salient FeaturesIt is slightly hygroscopic and is very vigorous initiator. It decomposes under the

influence of ultra-violet irradiation.

If the intensity of radiation is sufficiently high the crystals may explode by

photochemical decomposition.

Silver nitrate + Sodium azide AgN N N


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Tetrazene (C2H

8 N

10O)

Composition

Salient FeaturesIt is slightly hygroscopic and stable at ambient temperatures. It hydrolyses in

boiling water evolving nitrogen gas.

The detonation properties of tetrazene depend on the density of the material.

On compaction it will not detonate. So it is unsuitable for filling detonators.

NN

N

NH

C N N NNH 2

CNH

NH 2Sodium nitrite + Aminoguanidine

Tetrazolyl guanyltetrazene hydrate

. H 2O

(Hoffmann & Roth, 1910)


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Nitroglycerine Composition

CharacteristicsNitroglycerine has advantage over blackpowder as it contains both fuel and oxidizer

elements in the same molecule which gives intimate contact for both components.

Used for difficult mining & tunnelling operations.

Glycerol Nitroglycerine

(Ascanio Sobrero, 1846 &Immanuel Nobel, 1863)

C

C

CH

H

H

H O

O

O

H

NO 2NO 2NO 2

C

C

CH

H

H

H OH

OH

OH

H

Nitration


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Ammonium Nitrate Composition

CharacteristicsThe most common inorganic explosive which is extremely difficult to initiate.

When mixed with other explosives or with fuels in the form of powder, slurry, or

gel mixtures, it becomes an effective an inexpensive commercial explosive for use

in blasting.

NH 3 + HNO 3 (NH 4NO 3)

Ammonia Nitric acid

(Glauber, 1654)


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Picric acid (2,4,6-trinitrophenol) Composition

Characteristics

OH

NO 2

NO 2O 2NOH

Nitration

Phenol

Initially it was used as a dye for silk and wool.

It attacks common metals (Zn, Cu, Fe) and produces very explosive salts.

Its explosive power is superior than TNT.

Picric acid was used in grenade and mine fillings.

(Glauber, 1742 &Turpin, 1885)


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Tetryl

(2,4,6-trinitrophenylmethylnitramine) Composition

Characteristics

NCH 3H3C N

NO 2

NO 2O 2N

H3C NO 2

Nitration

Dimethylaniline (Mertens, 1877)

It is pale, yellow, crystalline solid with melting temp. 129 OC

It is moderately sensitive to initiation by friction.

It was extensively used during World War II.

Tetryl is quite toxic to handle and is therefore replaced by RDX.


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TNT (2,4,6-trinitrotoluene) Composition

Characteristics

CH 3

NO 2

NO 2O 2NCH 3

Nitration

3 step processToluene (Wilbrand, 1863)

It is pale, yellow, crystalline solid with melting temp. 80.8 OC.

It has good chemical and thermal stability and has good compatibility withother explosives.

It has low manufacturing cost and is safe in handling with low sensitivity to

impact and friction.


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Nitroguanidine (Picrite) Composition

Characteristics

HN CNH2

NH

NO 2HN C

NH 2

NH 2

Nitration

Guanidine (Jousselin, 1877)

It is stable below its melting point (232 OC) but decomposes very fast on

melting to form ammonia, water vapor and solid products.

It is also used as propellants as it possesses a low heat and temperature of

explosion.


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PETN (Pentaerythritol tetranitrate) Composition

Characteristics

C

H2C

H2C

H2C

CH2

O

O

O

O

NO 2

NO2

O 2N

O2N

C

H2C

H2C

H2C

CH2

OH

OH

HO

HO

Nitration

Pentaerythritol

It is most stable and least reactive nitric ester explosive.

A powerful secondary explosive and has a great shattering effect therefore,

used in commercial blasting caps, detonation cords and boosters.

It is sensitive to friction and impact and hence mixed with polymer bondedexplosives (PBX).


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RDX(Hexogen/Cyclonite/Cyclotrimethylenetrinitramine)

Composition

Characteristics

CH 2N

CH2

NCH 2

NNO 2

NO 2O 2NN N

N

Nitration

NHexamethylenetetramine

RDX is white crystalline solid with melting temp. 204 OC.

It is chemically and thermally more stable than PETN.

Insensitive explosive compositions containing RDX can be achieved byembedding the RDX crystals in a polymeric matrix as PBX.

(Henning, 1899 &Herz, 1920)


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TATB (triaminotrinitrobenzene) Composition

Characteristics

NH2

NO 2

NO 2O 2N

NH2H2N

Cl

NO 2

NO 2O 2N

ClCl

Cl

ClCl

Nitration Amination

(Jackson and Wing, 1888)

It is a yellow-brown coloured.

It is known as heat-resistant explosive as it has very high melting and

decomposition temp. (350 OC).


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HNS (Hexanitrostilbene) Composition

Characteristics

C CH

H

NO 2 O 2N

NO 2O2N

NO 2 O 2N

CH 3NO 2

NO 2

O 2NNaOCl

Oxidation

It is insensitive to electric spark.

It is resistant to heat as well as radiation. Therefore used in heat-resistant

booster explosives.


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NTO (5-nitro-1,2,4-triazole-3-one) Composition

Characteristics

CHN

HN

C NO 2N

OC

O

HNH2N

NH2

HCl

Semicarbazidehydrochloride

C

HN

HN

CH

N

O NitrationHCOOH

TO NTO

It is a new energetic material having stability greater than RDX. It is

also less sensitive.

NTO is a substitute for ammonium perchlorate or ammonium nitrate in

solid rocket propellants (since it does not liberate undesirable products

such as HCl).


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TNAZ (1,3,3-trinitroazetidine) Composition

Characteristics

O Cl

(Epichlorohydrin)

Multi-stepSynthesis

Fluorochem Process

N

H2C CH 2C

O 2N NO 2

NO 2

It is a white crystalline solid having melting temp. 101 OC.

It has relatively high vapor pressure compared to other explosives.

It forms eutectic mixtures with TNT, Tetryl and HMX.


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History of Explosives

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