A more powerful but less sensitive explosive

Pharmaceutical companies exploit a process called co-crystallisation to optimise the physical properties of drugs. Now scientists developing new explosives have done the same. As I report in The Economist, researchers from the University of Michigan have developed a method to lower the sensitivity of an explosive without losing its explosive power. 

Explosive power depends on two factors: detonation velocity (the speed at which the shock wave travels on explosion) and oxygen value (number of oxygen atoms per carbon atom). The higher the detonation velocity the more destruction it will cause. Oxygen value matters because when the explosion occurs carbon atoms within the explosive would like to react with oxygen atoms to form carbon dioxide. But because there is little time for carbon atoms to find oxygen from the air. Instead it has to rely on oxygen atoms within the explosive. Thus the closer the number of oxygen atoms per carbon atom is to two, the better the explosive.

One such explosive that has a higher detonation velocity and a better oxygen value than any of the commonly used explosives is CL-20. But it suffers from low sensitivity, which means that it will explode very easily if dropped or rubbed. This has meant that despite its early development it has mainly remained on the army barracks shelves.

Not anymore. Adam Matzger and colleagues have now made a hybrid explosive that has the same explosive power of CL-20 with reduced sensitivity. Find out how they made it here.

List of main references:

1. Matzger et al, Crystal Growth & Design, 2012
2. Matzger et al, Angew Chem Int Ed, 2009

Free image from here.