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Accelerated Aging of Lead-Free PropellantFollowing higher than expected 2-NDPA depletion rates in a lead-free doublebase formulation (RPD-422), an accelerated aging study was conducted to verify the depletion rates. A test plan was prepared to compare the aging characteristics of lead-free propellant and NOSIH-AA2. The study was also designed to determine which lead-free ballistic modifiers accelerated 2-NDPA depletion. The increased depletion rate occurred in propellants containing monobasic copper salicylate. Four lead-free propellants were then formulated to improved aging characteristics over previous lead-free propellant formulations. The new formulations reduced or replaced the monobasic copper salicylate. The new formulations had improved aging characteristics. Their burn rates, however, were unacceptable for use in a 2.75 inch rocket. To compare aging characteristics, stabilizer depletion rates of RPD-422, AA2, M28, and RLC 470/6A were measured or taken from the literature. The data were fit to a kinetic model. The model contained first and zero order terms which allowed the stabilizer concentration to go to zero. In the model, only the concentration of the primary stabilizer was considered. Derivatives beyond the first nitrated or nitroso derivative of 2-NPDA were not considered. The rate constants were fit to the Arrhenius equation and extrapolated to lower temperatures. The time to complete stabilizer depletion was estimated using the kinetic model. The four propellants were compared and the RPD-422 depleted faster at 45 C than both A22 and M28. These types of predictions depend on the validity of the model and on confidence in the Arrhenius relationship holding at lower temperatures. At 45 C, the zero order portion of the model dominates the depletion rate.
Document ID
20000116528
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Furrow, Keith W.
(Alliant Techsystems, Inc. Radford, VA United States)
Jervey, David D.
(Alliant Techsystems, Inc. Radford, VA United States)
Date Acquired
August 19, 2013
Publication Date
May 1, 2000
Publication Information
Publication: JANNAF 29th Propellant Development and Characterization Subcommittee Meeting
Subject Category
Propellants And Fuels
Meeting Information
Meeting: Propellant Development and Characterization
Location: Cocoa Beach, FL
Country: United States
Start Date: May 8, 2000
End Date: May 12, 2000
Sponsors: NASA Headquarters, Department of the Army, Department of the Air Force, Department of the Navy
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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