Nitrocellulose
Among the first true high explosive, nitrocellulose was first synthesized in 1845 by Christian F. Schoenbein.[1] It is of the family of aliphatic nitrate esters produced by replacing hydroxyl (-OH) groups in starch molecules with nitrate (-NO2) ions. Its empirical formula is C6H7OH X
(ONO2)Y
, where X+Y=2
Nitrocellulose is closely related to nitrostarch, other than nitrocellulose polymers are straight while nitrostarch is spiral, consisting of approximately 1,000 anyhdroglucose units. [2]
While guncotton is often used synonymously, guncotton is actually a specific nitrocellulose grade most widely used in firearm propellants, both for small arms and artillery. It is the first ingredient in single-base, double-base and single-base propellants; it is plasticized with other ingredients in the multiple bases. Propellant applications are the most common today, although it is also used in some commercial blasting explosives.
As a plastic, nitrocellulose was the first flexible base for motion pictures. Over time, it decomposes, becoming increasingly flammable and explosive. Various restoration projects attempt to copy early films before they are lost forever. There have been catastrophic fires in storage areas for motion pictures on nitrocellulose.
Five grades are in use for various applications, not all explosive.
Name | Percent nitrogen | Use |
---|---|---|
Pyroxylin or collodion | 8 to 12.3 | Blasting explosives; also in adhesives and early plastics |
Pyrocellulose | 12.60±0.10 | Propellants |
Guncotton | 13.35 to 13.45 | Propellants, explosives |
High nitrate nitrocellulose | 13.75 to 14.14 | Has been used in propellants |
Blended nitrocellulose | 60 to 65 percent guncotton and 35 to 40 percent pyrocellulose | Propellants |
References
- ↑ Military Explosives, U.S. Department of the Army, September 1984, TM 9-1300-214, p. 2-5
- ↑ Military Explosives, p. 8-2 to 8-9