Double Base Propellant Nitrocellulose Decomposition

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Double Base Propellant Decomposition
Robert Weinheimer William B. Sanborn
rweinheimer@psemc.com bsanborn@psemc.com
Pacific Scientific Energetic Materials Company
7073 West Willis Road
Chandler, AZ 85226
TEL: 520-796-1100
29 th INTERNATIONAL PYROTECHNICS29 th INTERNATIONAL PYROTECHNICS
SEMINARSEMINAR
JULY 14 - 19, 2002JULY 14 - 19, 2002

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ROBERT WEINHEIMERROBERT WEINHEIMER

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Pacific Scientific EnergeticPacific Scientific Energetic
Materials Co.Materials Co.
 PS/EMC is a division of the Danaher Corporation
 PS/EMC Headquarters is located in Chandler, AZ on a 42-acre site
 SDI Aerospace acquisition 2001
 103377-XXX family
 Over 400 different Initiators
 MIL-I-23659C & MIL-STD-1512
 64,000 sq ft
 Environmental Test Lab
 Complete Machine Shop
 Powder Processing
 Pyrotechnic Blending
 Propellant Casting & Extrusion
 PS/EMC West LLC, 24908 Avenue Kearny, Valencia, CA 91355 TEL: 661-600-1100
 Safe & Arm Devices and SEA (Smart Electronic Architecture) Devices (SDI acquisition)
 Pac Sci Quantic LLC, 2751 San Juan Rd, Hollister, CA 95023 TEL: 831-637-5851
 Quantic Industries Acquisition in 2001
 Electronic S&A, Laser Initiated Ordnance

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PS/EMC Business BasePS/EMC Business Base
Major Customers
Alliant Techsystems
Textron
Lockheed Martin
ARC
Boeing
Royal Ordnance
Pratt Whitney (UTC/CSD)
Orbital Sciences
Oil Industry
Raytheon
Thiokol
U.S. Navy/Air Force
Northrop-Grumman
United Space Alliance
DOE/Sandia Labs
Various
Aerojet
Major Programs
AMRAAM, Sea Sparrow, SFW, MK50, Brimstone
SFW, WAM
Patriot, F-22, Atlas II/III/V, WCMD, Longbow
PAC-3, Tomahawk, Javelin
Tomahawk, Harpoon, SLAM, Delta II/III/IV
ASRAAM
Tomahawk, Titan IV, NMD
Pegasus, Taurus, SSST
Time Delays, Hi-Temp./Pressure Detonators
Tomahawk, Standard Missile, Patriot
Hellfire, RAM, Maverick, HARM
Initiators, Mini AFD, Rocket Motors, Gas Generators
TASSM, BAT
Space Shuttle
Classified
Fire Extinguisher Cartridges
Atlas V, Hawk, NetFires

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ABSTRACT
The US Army impulse cartridge M-796 and US Air Force
BBU-35B are used to eject countermeasure stores (flares
and chaff) from aircraft dispensers (XM-130, ALE-40,
ALE-45, ALE-47) of military aircraft (F-16, F-15, A-10, C-
130, AH-64, MH53E, and CH-47). Both the M-796 and
BBU-35B impulse cartridge are of the same configuration
with different part numbers for the Army and Air Force.
Impulse cartridges are exposed to temperature-altitude
conditions (-62°C/-80°F to 95°C/203°F) and aircraft flight,
ground, and maintenance environments.

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ABSTRACT CONTINUED
The M-796 and BBU-35B impulse cartridge use a double
base propellant for producing gas pressure against the
countermeasure piston for ejection (and to ignite a Mg-
Teflon flare) from the aircraft dispenser. In 1978 the double
base propellant (Bullseye), US Army drawing 9326769
(USAF drawing 7829435), Nitrocellulose/Nitroglycerine
(59%NC/39.5%NG/1.25%Centralite/bal graphite) was used
in the impulse cartridges M-796, USA 9311660 and BBU-
35B, USAF 7729436-10.

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ABSTRACT CONTINUED
During qualification testing, the M-796 impulse cartridge
had experienced inconsistent function time failure mode.
The failure occurred after exposure to Temperature –
Altitude test per the customer’s procurement specification
tailored from MIL-STD-810C, Method 504.1.
Failure investigation identified decomposition of the
Nitrocellulose/Nitroglycerine (NC/NG) double base
propellant which most likely occurred during temperature
cycling where the temperature was held at +95°C (+203°F)
for 16 hours.
This paper describes the failure investigation, test results
and corrective action.

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IMPULSE CARTRIDGE, INFRARED FLARE &IMPULSE CARTRIDGE, INFRARED FLARE &
CHAFF ASSEMBLY, DISPENSERCHAFF ASSEMBLY, DISPENSER
M-796
IMPULSE
CARTRIDGE

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MH53E SEA DRAGON HELICOPTER INFRARED FLARE DEPLOYMENTMH53E SEA DRAGON HELICOPTER INFRARED FLARE DEPLOYMENT

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C-130 FLARE DEPLOYMENTC-130 FLARE DEPLOYMENT
(THE MOVIE)(THE MOVIE)

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M-796 IMPULSE CARTRIDGE
TEMPERATURE-ALTITUDE
QUALIFICATION TESTING
 Cartridge testing based on MIL-STD-810C,
Method 504.1
 14 step test, involves frost and temperature cycling
 temperatures from -62 ⇒ 95 °C
 pressures from ambient to altitude eqv. of 60,000 ft.
 one step is 95 °C, 16 hour soak
 After 95 °C soak, discs bulged
 After full temperature/altitude testing, unit
function was erratic

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BULLSEYEBULLSEYE ®®
DOUBLE BASEDOUBLE BASE
PROPELLANTPROPELLANT
• Constituents per dwg 7829435:
• ~58% Nitrocellulose (13.2% N) - NC
• ~40% Nitroglycerin - NG
• ~0.8% Ethyl Centralite (stabilizer) - Centralite I
• ~0.4% Graphite
• ~1.2% Potassium Sulfate

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BULLSEYE INVESTIGATION AT +85°C (+185°F)BULLSEYE INVESTIGATION AT +85°C (+185°F)
GROUP I
LOT#B-E-259
LOT#B-E-259
COMMENT
GROUP II
LOT#B-E-269
LOT#B-E-269
COMMENT
2 hr No Change 2 hr Slight Condensation
15 hr Yellow Condensation 9 hr Clear Condensation
22 hr Increased Yel Condensation 24 hr Clear Droplets Appear
37 hr Yellow Droplets Appear 32 hr Increased Droplets
Condensation determined not to be water

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CARTRIDGE INVESTIGATIONCARTRIDGE INVESTIGATION
BULLSEYEBULLSEYE®®
LOT# B-E-259LOT# B-E-259
+85 °C (+185 °F) FOR 16 HOURS+85 °C (+185 °F) FOR 16 HOURS
Lot#B-E-259 CLOSURE UP CLOSURE DOWN CONTROL GROUP
GROUP # GROUP 4 GROUP 5 GROUP 6 (AMB)
FUNCTION X bar, ms Std Dev, ms X bar, ms Std Dev, ms X bar, ms Std Dev, ms
BWBO 6.0 0.00 5.8 .45 5.8 .45
1ST
Ind Press 20.2 2.17 20.6 1.82 20.2 1.79
Time to 100 psi 32.6 2.51 32.2 2.17 26.4 1.67
Critical Slope Psi/ms 62.0 5.6 60.4 7.72 73.3 5.27
Time to Peak Press 43.6 2.97 43.0 2.65 35.6 1.52
Peak Press 590 psi 23.5 psi 584 psi 21.9psi 624 psi 8.94 psi

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CARTRIDGE INVESTIGATIONCARTRIDGE INVESTIGATION
BULLSEYEBULLSEYE®®
LOT# B-E-269LOT# B-E-269
+85 °C (+185 °F) FOR 16 HOURS+85 °C (+185 °F) FOR 16 HOURS
Lot#B-E-269 CLOSURE UP CLOSURE DOWN CONTROL GROUP
GROUP # GROUP 1 GROUP 2 GROUP 3 (AMB)
FUNCTION X bar, ms Std Dev, ms X bar, ms Std Dev, ms X bar, ms Std Dev, ms
BWBO 6.6 .45 6.0 0.0 4.6 .89
1ST
Ind Press 21.5 3.5 22.0 2.74 18.6 2.4
Time to 100 psi 31.5 5.3 40.4 3.96 23.8 2.75
Critical Slope Psi/ms 76.6 10.5 45.9 22.2 75.0 4.69
Time to Peak Press 41.6 6.39 51.8 3.03 34.8 3.42
Peak Press 620 psi 21.2 psi 488 psi 111.7 psi 630 psi 12.2 psi

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DOUBLE BASE AREAS OF CONCERNSDOUBLE BASE AREAS OF CONCERNS
• Exudate
• NG becomes mobile at higher temperatures
• NG has vapor pressure
• NG, NC are nitrate esters
• R-O-NO2
• Two steps to thermal decomposition
• step 1 - Loss of NOx - step controlled by chemistry and
thermal environment (kinetic process)
• step 2 - NOx reacts with water to form acids, which attacks
base molecule (autocatalysis phase)

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NITRATE ESTERS - cont.NITRATE ESTERS - cont.
• NOx loss- kinetic process -
• chemistry defines rate of NOx loss
• temperature changes rate (R.O.T.: rate at least
doubles for 10 °C change - Berthelot’s law)
• Autocatalysis
• stabilizer controls this process
• negligible until approximately 70% stabilizer
depletion
• “runaway” at near 100% stabilizer depletion

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BULLSEYE®
DOUBLE BASE PROPELLANT
• Constituents per dwg 7829435:
• ~0.4% Graphite
• ~1.2% Potassium Sulfate
M9 DOUBLE BASE PROPELLANT
• Constituents (N. S. Garmen):
• ~0.15% Graphite
• ~2.0% Potassium Nitrate

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STABILIZER DEPLETION IN M9 (BULLSEYESTABILIZER DEPLETION IN M9 (BULLSEYE®®
EQV.)EQV.)
N. S. Garman, et al., Technical Report 4505 “Prediction of Safe Life of Propellants,” Picatinny Arsenal, May 1973.

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PREDICTION OF STABILIZER DEPLETIONPREDICTION OF STABILIZER DEPLETION
IN M9 (BULLSEYEIN M9 (BULLSEYE®®
EQV.)EQV.)
N. S. Garman, et al., Technical Report 4505 “Prediction of Safe Life of Propellants,” Picatinny Arsenal, May 1973.

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LESSONS LEARNED (DIRECT)LESSONS LEARNED (DIRECT)
• Bullseye®
double base propellant outgasses and exudes
NG high temperatures
• Manufacturer did not recommend extended use above
+75 °C (+167°F)
• Exudate can affect ignition properties of BW charge and
is affected by testing orientation
• Bullseye®
lots vary in properties, physical and
performance

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LESSONS LEARNED (DIRECT) - cont.LESSONS LEARNED (DIRECT) - cont.
• Bullseye®
chemically degrades faster at
temperature
• On plus side - all units functioned after
thermal exposure
• Bullseye®
replaced with HPC-1, another
double base with different composition and
grain geometry
Know the limitations of your energetic
materials!

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ROUGH DESIGN GUIDELINES FOR PROPELLANTSROUGH DESIGN GUIDELINES FOR PROPELLANTS
• Estimated propellant temperature limit:
• Double-base 75 °C (167 °F)
• Single-, triple-base 90 °C (195 °F)
• LOVA (Low Vulnerability Ammo) 120 °C (250 °F)
• Composites (e.g. HTPB/AP) 150 °C (300 °F)
• Specialty (e.g. TMAP/KP) 230 °C (450 °F)

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GLOBAL IMPLICATIONSGLOBAL IMPLICATIONS
• Data is from 1978
• WHY NOW? Why are 25 year old
qualification problems significant?
• Same mistakes being made
⇒Know the limitations of energetic materials!
• As we try to increase life times on ordnance,
• accept limitations of energetics
• design around them
• use alternate materials
• develop new materials

Double Base Propellant Nitrocellulose Decomposition

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Double Base Propellant Nitrocellulose Decomposition