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The stability of Nitrocellulose (NC) and Nitroglycerine is inherently poor and therefore the stability of NC-based propellants is correspondingly poor.
The degradation of NC proceeds by two chemical reactions:
- In the first degradation reaction, NC loses Nitrogen Oxides. This reaction is an intrinsic tendency of the NC molecule.
- In the second degradation reaction, which occurs initially as a result of the first, the newly-formed nitrogen oxides 'attack' and degrade the nitrocellulose molecule.
Nothing can be done to stop the first degradation reaction, but the second degradation reaction can be controlled by introducing a chemical stabilizer in the propellant composition. As the stabilizer has a greater affinity for the Nitrogen Oxides than for NC, it absorbs the Nitrogen Oxides before they can degrade the NC molecule.
See also: Nitrocellulose-based propellants by raw material and type (diagram)
Propellant Stabilizers offered by IPI:
Diphenylamine (DPA)
Used in single-base propellants. Since it is incompatible with Nitroglycerin, it cannot be used in double-base and triple-base propellant compositions. IPI offers the material in accordance with MIL-D-98A specification.
2,4-Dintrotoluene (DNT)
Used as a stabilizer in single-base propellants. Also used as a ballistic modifier (homogenizer) for single-base propellants. IPI offers DNT in accordance with MIL-D-204A specification.
Ethyl Centralite
Also called Centralite I or Symmetrical Diethyl Diphenylurea. It is used as a stabilizer, gelatinizer, and waterproofing agent. Ethyl Centralite can be used in relatively large proportions (up to 8%) of the propellant composition.
IPI offers Ethyl Centralite in accordance with MIL-E-255A.
Methyl Centralite
Also called Centralite II or Symmetrical Dimethyl Diphenylurea. It is used as a stabilizer in double-base and triple-base propellants. IPI offers material in accordance with MIL-M-19719A.
Akardite II
Also called Methyl Diphenylurea. Used as a stabilizer for multi-base propellants and as a burning rate modifier. IPI offers the material in accordance with DOD-M-64040A specification.
N-Methyl-P-Nitroaniline (MNA)
Used as a stabilizer in the manufacture of solid fuel propellants. IPI offers the material in accordance with MIS-35107.
2-Nitrodiphenylamine (2NDPA, 2-NDPA)
Used for double-base and triple-base propellants which use Nitroglycerin as the gelatinizing agent for the Nitrocellulose. IPI offers the material in accordance with MIL-N-3399B specification.
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