A Brief History of Chemical Explosives

Materials That Result in an Instantaneous Release of Gas or Heat

An explosion can be defined as the rapid expansion of a material or device that exerts a sudden pressure on its surroundings. It can be caused by one of three things: a chemical reaction that occurs during conversion of elemental compounds, a mechanical or physical impact, or a nuclear reaction on the atomic/subatomic level. 

Gasoline exploding when ignited is a chemical explosion brought about by the sudden conversion of a hydrocarbon to carbon dioxide and water.

The explosion that occurs when meteor strikes the earth is a mechanical explosion. And a nuclear warhead explosion is the result of the nucleus of a radioactive substance, like plutonium, suddenly splitting apart in an uncontrolled fashion. 

But it is chemical explosives that are the most common form of explosives in human history, used both for creative/commercial and destructive effect. The strength of a given explosive is measured that the rate of expansion it exhibits during detonation. 

Let's look briefly at some common chemical explosives. 

Black Powder

It is unknown who invented the first explosive black powder. Black powder, also known as gunpowder, is a mixture of saltpeter (potassium nitrate), sulfur, and charcoal (carbon). It originated in China around in the ninth century and was in wide use throughout Asia and Europe by the end of the 13th century. It was commonly used in fireworks and signals, as well as in mining and building operations.

Black powder is the oldest form of ballistic propellant and it was used with early muzzle-type firearms and other artillery uses. In 1831, William Bickford an English leather merchant invented the first safety fuse. Using a safety fuse made black powder explosives more practical and safer.

But because black powder is messy explosive, by the end of the 18th century it was replaced by high explosives and by cleaner smokeless powder explosives, such as what is currently used in firearm ammunition.

Black powder is categorized as a low explosive because it expands and subsonic speeds when it detonates. High explosives, by contract, expand as supersonic speeds, thereby creating much more force. 

Nitroglycerin

Nitroglycerin is a chemical explosive that was discovered by Italian chemist Ascanio Sobrero in 1846. It was the first explosive developed that was more powerful than black powder, Nitroglycerin is a mix of nitric acid, sulphuric acid, and glycerol, and it is highly volatile. Its inventor, Sobrero, warned against its potential dangers, but Alfred Nobel adopted it as a commercial explosive in 1864. Several serious accidents, however, caused pure liquid nitroglycerin to be widely banned, leading to Nobel's eventual invention of dynamite. 

Nitrocellulose

In 1846, Chemist Christian Schonbein discovered nitrocellulose, also called guncotton, when he accidentally spilled a mixture of potent nitric acid on a cotton apron and the apron exploded as it dried. Experiments by Schonbein and others quickly established a means of manufacturing guncotton safely, and because it had a clean, explosive power almost six times greater than black powder, it quickly was adopted for use as means for propelling projectiles in weapons.

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TNT

In 1863, TNT or Trinitrotoluene was invented by German chemist Joseph Wilbrand. Originally formulated as a yellow dye, its explosive properties were not immediately evident. Its stablity was such that it could be safely poured into shell casings, and in the early 20th century it came into standard usage for German and British military munitions.

Considered a high explosive, TNT is still in common use by the U.S. military and by construction companies around the world. 

Blasting Cap

In 1865, Albert Nobel invented the blasting cap. The blasting cap provided a safer and dependable means of detonating nitroglycerin.

Dynamite

In 1867, Albert Nobel patented dynamite, a high explosive that consisted of a mixture of three parts nitroglycerine, one part diatomaceous earth (ground silica rock) as an absorbent, and a small amount of sodium carbonate antacid as a stabilizer.

The resultant mixture was considerably safer than pure nitroglycerine, as well as being much more powerful than black powder. 

Other materials are now used as the absorbent and stabilizing agents, but dynamite remains the premier explosive for use in commercial mining and construction demolition. 

Smokeless Powders

In 1888, Albert Nobel invented a dense smokeless powder explosive called ballistite. In 1889, Sir James Dewar and Sir Frederick Abel invented another smokeless gunpowder called cordite. Cordite was made of nitroglycerin, guncotton, and a petroleum substance gelatinized by addition of acetone. Later variations of these smokeless powders form the propellant for most modern firearms and artillery. 

Modern Explosives

Since 1955, a variety of additional high explosives has been developed. Created mostly for military use, they also have commercial applications, such as in deep drilling operations.  Explosives such as nitrate-fuel oil mixtures or ANFO and ammonium nitrate-base water gels now account for seventy percent of the explosives market. These explosives come in various types including: 

  • HMX
  • RDX
  • HNIW
  • ONC