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Fluid Resistant, Electrically Resistive Foam

Description:

OBJECTIVE: Develop and demonstrate electrically resistive foam with improved fluid resistance characteristics. The final product shall be a drop-in replacement for the current foam parts and require no additional aircraft modification. 

DESCRIPTION: The Air Force currently uses electrically resistive, reticulated, open cell foam materials on aircraft in locations which are not isolated from aircraft oils and fuel. The current materials are not hydrocarbon resistant; upon exposure to fuel and oils, they absorb and retain the fluids and create a significant fire hazard to the aircraft. As a result, there is a compelling need for an innovative material solution. The replacement material must be durable, fuel-, oil-, coolant-, and water-resistant, and sufficiently flexible to allow for installation and surrounding aircraft deflection. Uniform, tailorable electrical resistivity is required. Foam properties must be maintained over a minimum temperature range of -40 to +300 °F. The resulting material must exhibit resistance to JP-8 aircraft fuel, MIL-PRF-5606 hydraulic oil, and silicate ester coolant (COOLANOL) penetration and retention (weight gain testing). Physical properties of the foam must not exceed a maximum weight of 5.5 pounds per cubic foot, minimum tear strength of 2.5 pounds per inch, and minimum tensile strength of 15 pounds per square inch. The electrical properties of the foam must exhibit reflection loss in the 2 to 18 gigahertz range. 

PHASE I: Demonstrate proof of concept on candidate electrically resistive foam(s). Produce lab scale foam samples to prove ambient and elevated temperature physical, mechanical, and electrical material property requirements are achievable across the full temperature range. Report fuel permeability according to SAE J2665 as well as hydrocarbon and coolant retention via weight gain testing. 

PHASE II: Produce three prototype sheets of foam to deliver for government electrical testing with minimum dimensions of 0.75 ± 0.1 inch x 24 inch x 24 inch to demonstrate consistent manufacturability and quality control. Demonstrate consistent reflection loss across each foam sample and between samples at required angles of incidence. Prove the physical and electrical property requirements from Phase I are met after fluid and temperature aging. Assess and quantify foam material cost and manufacturability. 

PHASE III: Perform remaining material testing to qualify for use on the targeted aircraft. Deliver three 0.75 ± 0.1 inch x 24 inch x 24 inch sheets of the final foam product as well as the transition plan to scale up production to meet continuing need. 

REFERENCES: 

1: Guoqing, Jian, Qingfeng Hou & Youyi Zhu. Stability of Polymer and Surfactant Mixture Enhanced Foams in the Presence of Oil Under Static and Dynamic Conditions. Journal of Dispersion Science and Technology. Volume 36 Issue 4, 2015.

2:  Fletcher, Alan, M.C. Gupta, K.L. Dudley, and E. Vedeler. Elastomer foam nanocomposites for electromagnetic dissipation and shielding applications. Composites Science and Technology. Volume 70 Issue 6 Pages 953-958, June 2010.

3:  Haupert, F. and B. Wetzel: Reinforcement of Thermosetting Polymers by the Incorporation of Micro- and Nanoparticles. Polymer Composites: From Nano- to Macro-Scale, Springer 2005.

4:  Osei-Bonsu, Kofi, et al. Foam stability in the presence and absence of hydrocarbons: From bubble- to bulk-scale. Colloids and Surfaces A: Physicochemical and Engineering Aspects. Volume 481 Pages 514-526, 20 September 2015.

KEYWORDS: Foam, Fluid-resistant, JP-8, Coolanol, Aircraft Fluids, Absorbing, Static Dissipation, Conductive 

CONTACT(S): 

Michelle Barga 

(937) 904-4378 

michelle.barga@us.af.mil 

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