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Breathable, Non-Fluorinated Chemical Barrier Materials


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Biotechnology OBJECTIVE: Develop a non-fluorinated chemical protective material that meets the Class 3 requirements set forth in National Fire Protection Association (NFPA) 1994 standard. DESCRIPTION: The Government requires ensembles that will meet the requirements for Class 3 protection as defined in NFPA 1994, Standard for Protective Ensembles for Hazardous Materials for First Responders to Hazardous Materials Emergencies and CBRN Incidents, 2018. Ensemble elements described in this standard include protective garments, protective gloves, protective hoods, and protective footwear with descriptions of all the properties and test methods required to meet Class 3 requirements. Of particular interest to this topic is the development of garment materials which are resistant to the chemical warfare agents (CWAs) and toxic chemicals listed in the standard. The threshold level of permeation resistance for Class 3 garment materials should be the cumulative permeation mass in one hour of less than 4.0 micrograms per square centimeter (µg/cm2) for distilled mustard, less than 1.25 µg/cm2 for Soman, and less than 6 µg/cm2 for toxic industrial chemicals when challenged with 10 grams per square meter (g/m2) of liquid challenge or with 40 ppm of vapor challenge. Also of particular interest to this topic is the breathability of garment materials, as indicated by thermal and water vapor resistance measurements, with evaporative heat transfer (total heat loss) not less than 200 watts per square meter (W/m2) and evaporative resistance not greater than 30 pascal square meter per watt (Pa m2/W). In addition to the requirements set forth in NFPA 1994, non-fluorinated ensemble materials are required. Environmental concerns with perfluoroalkyl and polyfluoroalkyl substances (PFAS) is leading to the discontinuation of numerous commercial products that have been utilized in chemical protective systems including ensemble components, coatings, and finishes. Non-fluorinated material alternatives are sought with this topic. PHASE I: Demonstrate a fluorine-free garment material candidate that shows the NFPA 1994 required chemical resistance for one CWA simulant and two toxic industrial chemical liquids. Breathability must also be demonstrated. NFPA 1994 specified testing (ASTM F1868 and ISO 11092) may require more material than possible in the Phase I effort. Alternative methods may be proposed to provide acceptable estimates for breathability. Other physical properties are specified in NFPA 1994 (viral penetration, burst strength, puncture resistance, low temperature performance) and measured or addressed as possible in the Phase I effort to strengthen the feasibility for a Phase II effort. Chemical resistance and breathability are the key Phase I topic goals. At the end of the Phase I effort the candidate material should be able to be produced at a 6 inch by 6 inch swatch level and swatches made available for independent testing by the government. A preliminary scale-up method and a cost assessment should also be provided. PHASE II: Optimize and scale candidate garment material to be able to produce enough material for prototype fabrication. Show chemical resistance to the CWAs and liquid and vapor challenges in NFPA 1994. Show breathability through the NFPA 1994 specified testing. Initiate garment fabrication and carry out all physical property testing (seam strength and closure strength in addition to those listed in Phase I). The Phase II effort should show a candidate garment material that meets the NFPA 1994 requirements and ready for scaling to production quantities. At the conclusion of Phase II, a sample of at least 12 inches wide and 5 yards in length of the optimized garment material should be delivered. A cost assessment for full scale production should also be provided. PHASE III DUAL USE APPLICATIONS: PHASE III: The successful Phase II material will be scaled to continuous production at full width (>40 inches) and integrated into Class 3 protective ensembles. PHASE III DUAL USE APPLICATIONS: In addition to military applications, Class 3 ensembles have a broad range of applications for the first responder for hazardous material and anti-terrorism situations. REFERENCES: 1. NFPA 1994, “Standard for Protective Ensembles for Hazardous Materials for First Responders to Hazardous Materials Emergencies and CBRN Incidents”, 2018 ; 2. ASTM F1868, “Standard Test Method for Thermal and Evaporative Resistance of Clothing Materials Using a Sweating Hot Plate” ; 3. ISO 11092, “Textiles - Physiological effects - Measurement of thermal and water-vapour resistance under steady-state conditions (sweating guarded-hotplate test)” KEYWORDS: chemical protective garment; permeation; breathable; chemical resistance; water vapor permeable; fluorine-free
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