1 Distribution Statement A. Approved for public release. Distribution unlimited.

Integrity Service Excellence

Materials Susceptibility in Contaminated Alternative Fuel

22 July 2013

Wendy J. Goodson, PhD Principal Investigator/Technical Lead

Materials and Manufacturing Directorate

Wright-Patterson AFB, OH 45433

wendy.goodson@wpafb.af.mil

2 Distribution Statement A. Approved for public release. Distribution unlimited.

Biocorrosion* in the AF? *DoD definition of corrosion = deterioration of metallics and non-metallics

lavatories

cockpits

What is the frequency of biocorrosion in the AF?

Systems exposed to extended moisture,

standing water, biological fluids

Fuel systems and infrastructure

cabins, cargo areas

wing tanks storage tanks

How do rates of (aerobic) biocorrosion compare to other types of corrosion?

3 Distribution Statement A. Approved for public release. Distribution unlimited.

Factors Contributing to Biocorrosion

Biocorrosion

Materials (metals, polymers)

Microbes (high diversity; survival in

many environments)

Growth conditions (nutrients, fuel types, oxygen,

pH, temperature)

Alternative fuels

Cr+6-free

?

4 Distribution Statement D. Distribution authorized to the Department of Defense and U.S. DoD contractors only.

Biodiesel B20 Issues

as received Tank 2 Tank 3 Tank 4

Distribution Statement A. Approved for public release. Distribution unlimited.

Collaboration with Dr. Bradley Stevenson & Blake Stamps, OU • quarterly field assessments • microbiome analysis: liquid phases and biofilm • enrichments/isolations • in-tank and in-lab corrosion study • metabolite analysis for fuel degradation (Suflita lab)

5 Distribution Statement A. Approved for public release. Distribution unlimited.

Jet Fuel certification

• Certify 100% of fleet for bio-based aviation fuel by 2013

• 50% of fuel should be alterative fuel blends by 2025

• Many alternative fuels have already been certified

• includes materials compatibility testing

Current fuel certification process:

− 33 metallic, 38 non-metallic materials − 28 day exposures, elevated temperatures (250°C)

• may include testing for microbial growth (O. Ruiz, AFRL/RQ)

− co-inoculum: B. licheniformis, P. aeruginosa, C. resinae

Day 2 Day 42

Jet A/hydrorenewable jet (HRJ) blend

Jet A

6 Distribution Statement A. Approved for public release. Distribution unlimited.

MATERIALS, 2 phases: • non-metallics (2012-2013)

− coatings − bladder materials − sealants − insulating materials − hose materals − foam

• metallics (2013-2014)

Materials Susceptibility to Contaminated Alternative Fuel: APPROACH

leaking fuel bladder, Middle East

EXPOSURES • Jet A or Jet A/HRJ blend • 1:1 mix of fuel:Bushnell-Haas medium • Inoculum: enriched soil sample • 60 day exposure • Static @ 28°C, no medium exchange

ASSESSMENTS: ASTM standard methods • Tensile • Elongation • Volume swell

Collaboration with Dr. Oscar Ruiz (AFRL/RQPF), Susan Mueller, Lisa Brown and Bill Fortener (Univ. of Dayton Research Institute)

• Hardness (Shore A and Pencil) • Lap shear

7 Distribution Statement A. Approved for public release. Distribution unlimited.

Materials Exposures

Medium

Fuel

Volume swell specimens Tensile specimens

8 Distribution Statement A. Approved for public release. Distribution unlimited.

Material degradation at fuel:medium interface

1 mm

25 mm

30 mm

Jet A inoculated

9 Distribution Statement A. Approved for public release. Distribution unlimited.

Results: Materials Testing

PR 1440 Polysulfide Mn cure Sealant

0

100

200

300

400

500

600

Unaged Jet A Jet A Inoc Jet A:HRJ Jet A:HRJInoc

PSI

0

100

200

300

400

Unaged Jet A Jet A Inoc Jet A:HRJ Jet A:HRJInoc

Pe

rce

nta

ge

0

5

10

15

20

25

30

Jet A Jet A Inoc Jet A:HRJ Jet A:HRJ Inoc

Pe

rce

nta

ge

Tensile (stress)

Elongation (strain)

Volume swell

FAIL

FAIL

FAIL

10 Distribution Statement A. Approved for public release. Distribution unlimited.

Materials Testing Results: Pass/Fail relative to uninoculated Jet A

SEALANTS BLADDERS HOSE WIRING

INSULATION

Polysulfide Mn cure

Polysulfide Polysulfide DiCr cure

Fluorosilicone Nitrile Polyurethane Acrylic Nitrile Nylon

inoculated

TENSILE

Jet A + FAIL PASS PASS PASS PASS PASS PASS PASS

JetA/HRJ - PASS PASS PASS FAIL FAIL PASS PASS PASS

JetA/HRJ + PASS PASS PASS FAIL FAIL PASS FAIL PASS

ELONGATION

Jet A + FAIL FAIL FAIL PASS PASS PASS PASS PASS

JetA/HRJ - PASS PASS PASS PASS PASS PASS PASS FAIL

JetA/HRJ + FAIL FAIL FAIL PASS PASS FAIL PASS FAIL

VOL SWELL

Jet A + FAIL FAIL PASS PASS FAIL FAIL PASS NA

JetA/HRJ - PASS PASS PASS PASS PASS FAIL FAIL NA

JetA/HRJ + FAIL FAIL PASS PASS PASS FAIL FAIL NA

11 Distribution Statement A. Approved for public release. Distribution unlimited.

Microbiome Analysis

• DNA extracted from biofilms formed on materials — 4 sealants (3 polysulfide, 1 polythioether) — polysulfide electrical potting compound — 2 coatings (nitrile and polyimide epoxy) — nitrile bladder material

• Amplification of 16S rDNA, 454 seq, QIIME

QIIME analysis by Dr. Brad Stevenson and Blake Stamps, OU

Inoculum

Fuel type dictates community membership

Jet A Jet A/HRJ

Micrococcales; Georgenia Propionibacteriales; Tessaracoccus

Proteobacteria; Other Rhizobiales; Other

Rhizobiales; Rhizobium Rhodospirillales; Azospirillum

Sphingomonadales; Other Sphingomonadales; Sphingobium

Burkholderiales; Other Burkholderiales; Achromobacter

Burkholderiales; Gks98_freshwater_group Burkholderiales; Massilia

Burkholderiales; Pseudorhodoferax Burkholderiales; Variovorax

Pseudomonadales; Azomonas Pseudomonadales; Pseudomonas

Ino

culu

m

Nitrile co

ating-JetA

PS sealan

t-JetA/H

RJ

PTE sealan

t-JetA/H

RJ

PS-M

n sealan

t-JetA

PS sealan

t-JetA

PS-C

r sealant-JetA

Epo

xy coatin

g-JetA

Nitrile b

ladd

er-JetA

PTE sealan

t-JetA

PS p

ottim

g cmp

d -JetA

Nitrile co

ating-JetA

/HR

J

PS-M

n sealan

t-JetA/H

RJ

Nitrile b

ladd

er-JetA/H

RJ

PS-C

r sealant-JetA

/HR

J

Epo

xy coatin

g-JetA/H

RJ

PS p

ottin

g cmp

d -JetA

/HR

J

12 Distribution Statement A. Approved for public release. Distribution unlimited.

What’s Next?

Achromobacter piechaudii

• Are Achromobacter piechaudii. and/or Pseudomonas stutzeri necessary and sufficient to cause material degradation?

− 2 polysulfide sealants will undergo further analysis − Inocula:

− A. piechaudii alone − P. stutzeri alone − A. piechaudii/P. stutzeri co-inoculum − Original soil enrichment

• Mechanism of degradation to be investigated by FTIR, XPS

Pseudomonas stutzeri

13 Distribution Statement A. Approved for public release. Distribution unlimited.

Summary

• Rates and frequency of biocorrosion in the AF are poorly understood.

− field studies underway − increasing awareness amongst maintainers

• ‘Green’ initiatives in alternative fuels and non-Cr material systems have the

potential affect biocorrosion rates.

• AFRL is taking proactive approach to understanding the potential impact of these initiatives.

− Of 22 polymeric materials tested, at least 3 were negatively affected by inoculated fuel; 5 more were negatively affected by HRJ/Jet A and/or microbes.

− Fuel type, not material type, determined microbial community associated with the material.

− Mechanism of polymer degradation will be investigated. − Metals in phase II

14 Distribution Statement A. Approved for public release. Distribution unlimited.

Acknowledgments

AFRL/Mat’ls and Manufacturing Directorate Microbial Contamination of Materials Team – Carrie Drake – Tyler Huelsman – Pamela Lloyd – Lloyd Nadeau – Lt. David Thurber – Dr. Sandra Zingarelli

AFRL/Aerospace Systems Directorate Fuel Microbiology Team – Dr. Oscar Ruiz – Susan Mueller – Lisa Brown

University of Dayton Research Institute – Bill Fortener – David Claiborne

University of Oklahoma – Dr. Bradley Stevenson – Blake Stamps

Funding: AFRL Materials and Manufacturing Directorate Corrosion IPT