IV.

High Explosives

A great number of explosives undergo detonation. Some of these, such as TNT, trinitrotoluene, have a high resistance to shock or friction and can be handled, stored, and used with comparative safety. Others, such as nitroglycerin, are so sensitive that they are almost invariably mixed with an inert desensitizer for practical use. To obtain desirable characteristics, explosives of different characteristics are often mixed.

During World War I, TNT was the high explosive most generally employed, but before and during World War II a number of extremely efficient new high explosives were developed. Among the most important are cyclonite and pentaerythritol tetranitrate.

Cyclonite, also called RDX, is used in detonators. A mixture with TNT and wax is called Composition B and is used in bombs. A similar mixture, containing aluminum and called torpex, has an underwater effect about 50 percent greater than that of TNT. A plastic composition containing cyclonite and an explosive plasticizer is used for demolition charges.

Pentaerythritol tetranitrate, also called PETN, has characteristics similar to those of cyclonite and is mixed with TNT to form the explosive pentolite. It also forms the core of the explosive primacord fuses used for detonating demolition charges and the booster charges used in blasting.

Two types of high explosives introduced since 1955 have largely replaced dynamite. A mixture of ammonium nitrate and fuel oil has explosive strength 25 percent greater than that of TNT. The so-called slurry explosives, which are also used for blasting, are mixtures containing sufficient water to form flowable material.