Nitrocellulose-Based Propellant Chemicals
Nitrocellulose-Based Propellants
Propellant chemicals consist of a main fuel and oxidizer component, plus additives including plasticizers, stabilizers, burn-rate modifiers and binders. They are used in ammunition, rocketry and civil propellants as propellant stabilizers, ballistic modifiers and plasticizers; and as explosive components, typically binders and plasticizers.
Typical uses:
- Gunpowder for Small-Caliber Ammunition
- Single, Double and Triple-Based Ammunition Propellants
- Double-Based Rocket Propellants
Nitrocellulose is the commercial term for cellulose nitrate, the nitric ester of cellulose. It is obtained by esterification of cellulose and nitric acid.
The degree of esterification—the number of nitrate groups per glucose unit—is characterized by the nitrogen content, and can be influenced by the composition or the concentration of the nitrating acid. NC with a nitrogen content of 10.7–12.2% is typically used in the production of inks and lacquers; NC with 12.6–13.4% nitrogen content is used in energetic formulations such as propellants and dynamite.
IPI provides nitrocellulose for use in propellants and dynamite.
- Wetted with 27–30% water
- Nitrogen content: 13.6% max
- CAS No. 9004-70-0
- UN No. 2555
- MIL-DTL-244B
Molecular structure of nitrocellulose
As Nitrocellulose (NC) based propellants are inherently unstable, they degrade in time. This occurs when the NC loses nitrogen oxides, which attack the NC molecule.
To solve the problem, stabilizers, which have a greater affinity toward the nitrogen oxides than NC, absorb the nitrogen oxide before they can attack the NC molecule.
| Stabilizer (click for spec sheet) | Type | Specifiation |
|---|---|---|
| 2,4-Dinitrotoluene (DNT) | Single-Base | MIL-D-204 |
| 2-Nitrodiphenylamine (2-NDPA) | Double-Base | MIL-N-3399 |
| Akardite II | Multi-Base | DOD-M-64040 |
| Diphenylamine (DPA) | Single-Base | MIL-D-98 |
| Ethyl Centralite | Multi-Base | MIL-E-255 |
| Methyl Centralite | Multi-Base | MIL-M-19719 |
| N-Methyl-p-Nitroaniline (MNA) | Solid Fuel | MIS-35107 |
2,4 Dinitrotoluene (DNT) is a single-base propellant stabilizer for NC-based propellants.
| Additive (click for spec sheet) | Function | Specification |
|---|---|---|
| Carbon Black | Opacifier | |
| Di-Normal Propyl Adipate (DNPA) | Plasticizer | MIL-D-22346 |
| Diethyl Phthalate | Plasticizer | JAN-D-242 |
| Graphite | Opacifier/Lubricant | MIL-G-155 |
| Oxamide | Coolant | MIL-O-60863 |
| Potassium Nitrate (KNO3) | Flame Suppressant | MIL-E-255 |
| Potassium Sulfate (K2SO4) | Flame Suppressant | MIL-P-193 |
| Triacetin (Glyceryl Triacetate) | Plasticizer | MIL-T-301 |
| Zirconium Carbide (ZrC) | Combustion Instability Suppressant | MIL-Z-85500 |
Adding small quantities of lead compounds to double-base rocket propellants results in increased burning rate at low pressure.
Lead salts render the burning rate independent of pressure and ignition temperature. A high burning rate/pressure relationship is desirable because it facilitates the production of lighter rocket motors due to lower safety requirements.
| Chemical (click for spec sheet) | Specification |
|---|---|
| Copper Beta Resorcylate, Monobasic | |
| Copper Monobasic Salicylate | AS-3236 |
| LC-12-0 to LC-12-20 | |
| Lead 2-Ethyl Hexoate (Lead Octoate) | MIL-L-17699 |
| Lead Beta Resorcylate | AS-2853 |
| LC-12-15 Ballistic Modifier | MIL-B-85735 |
| Lead Salicylate | MIL-L-13788, MIL-L-17700 |
| Lead Stearate | MIL-L-758A |
LC-12-15 Ballistic Modifier