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Biosynthetic PFAS Alternatives to Provide Omniphobicity

Description:

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Biotechnology, Advanced Materials

 

OBJECTIVE: Develop and scale production of biosynthetic materials for environmentally friendly, omniphobic technologies for Department of Defense clothing and equipment without use of fluorine or perfluorinated compounds (PFAS).

 

DESCRIPTION: The Department of Defense (DoD) uses finishes with perfluorinated compounds (PFAS) to provide essential properties for Warfighter protection and survival, including water, chemical, oil, and stain repellency for clothing and equipment items. PFAS, which are associated with cancer, reproductive health issues, and developmental delays, are being banned from use and manufacture worldwide. There are over 9,000 different PFAS compounds, used since 1940 in clothing, food packing, personal care products, water/stain resistant products, and non-stick cookware (1,2). Since PFAS have worked so well in providing water, liquid, oil, and omniphobicity, they have been the default chemicals used in the textile industry to provide the durable treatments needed to meet DoD clothing and equipment requirements.

 

The DoD is seeking new, biosynthetic and environmentally friendly non-PFAS technologies for clothing and equipment to impart omniphobicity. No PFAS-free alternative has been developed thus far which can provide the needed level of oil repellency, and while water repellency can be obtained, non-PFAS finishes struggle to meet military durability requirements over the expected life cycle of an item. Truly novel non-PFAS formulations/technologies are needed that can provide durable omniphobicity equivalent to those obtained using PFAS.

 

Biosynthetic materials are key to sustainable domestic production and offer new opportunities to discover and synthesize novel compounds (3,4). The goal of this topic is to solicit new biosynthetic material technologies that can replace PFAS compounds in DoD clothing and equipment, providing the needed level of oil repellency and durability. The developed non-PFAS bioinspired solution should target at least one of the following areas: textile-based systems clothing and equipment items (uniforms, shelters, sleeping bags, hydration systems), food packaging and/or protective clothing items (barrier materials) and be developed into a formfactor that can be integrated into an end item. The biosynthetic solution may be provided as an alternative coating or finish for an existing DoD item, or as an entirely new material or substrate with inherent repellency to replace and/or be integrated into existing materials within the DoD system. Integration into DoD end items must consider other requirements for the final product, such as retaining water repellency, flame resistant properties, or others.

 

Specific care must be taken to avoid “regrettable substitutions” such as siloxanes, which are under similar scrutiny as PFAS compounds from health and safety standpoints. Due to health, safety, and regulatory concerns, solutions should not contain any carbon-fluorine bonds, including partially fluorinated fluoropolymers, even those not defined as “PFAS” by the EPA. Thoroughly review state-of-the-art for non-PFAS substitutions and be familiar with environmental concerns for manufacture (such as the use of isocyanates or solvents) as well as feasibility of producing omniphobicity with the proposed system using environmentally friendly materials and processes (5).

(Suggested Reference: https://www.ri.se/en/popfree/pfas-substitution-guide-for-textile-supply-chains)

 

PHASE I: Feasibility Assessment: Demonstrate proof of concept for a biosynthetic solution with no fluorine-carbon bonds that can provide omniphobicity.

The objective is a small-scale demonstration of omniphobicity on a substrate to illustrate proof of concept.

 

Identify a biosynthetic system that can be synthesized and/or produced to provide omniphobicity. Achieving oil repellency is a greater challenge than water repellency using non-PFAS systems, but both qualities are critical for DoD clothing and equipment. Produce the bioinspired system at quantities over 10 grams (or milliliters), with an objective of 100 grams (or milliliters) and a purity over 80%.

 

For textile substrates, feasibility can be demonstrated on a swatch or coupon by achieving some level of oil repellency in accordance with the American Association of Textile Chemists and Colorists (AATCC) Test Method 118. Water repellency can be demonstrated through spray rating tests (AATCC Test Method 22), and at this stage should prove water repellency can be achieved in addition to oil repellency using the proposed omniphobic system. If a demonstration on a swatch or coupon cannot be performed during Phase I, a robust model demonstrating how the synthetic biology technology will impart omniphobicity must be provided, with a realistic path towards application on a DoD end item.

 

An assessment of scaling capability for the omniphobic technology will be made, with special consideration for industry standard practices and limitations, and any benefits of using biotechnology for environmentally friendly manufacture. At the completion of Phase I, a sample of the non-PFAS technology proposed must be made available for independent evaluation by the Government Technical Point of Contacts. If a small-scale demonstration was performed, a sample of these materials should be provided for independent evaluation as well.

 

Prior to moving into Phase II, the specific targeted application and/or properties expected of the solution should be identified.

 

PHASE II: Prototype Development: At the end of Phase II there should be a viable solution to provide durable omniphobicity to a DoD end item. The technology should be scalable to commercial levels.

 

Year 1: Optimization and application of the biosynthetic technology on the targeted substrate and/or application into a DoD end item.

 

The biosynthetic technology should be scaled to an appropriate level that it can be applied to a DoD end item. Partnership with a manufacturer is encouraged. The scaling method should consider environmentally friendly practices, including use of biotechnology and solvent-free systems. Application or integration of the biosynthetic solution into the DoD clothing or equipment should be determined based on the formfactor of the solution and requirements of the end item. Regardless of formfactor and integration/application method, end items should maintain the desired physical properties as determined by the end use application. For example, weight, thickness, air permeability, durability to abrasion and laundering, etc. for textiles used for personal clothing and equipment items, resistance to cold cracking for shelters application, durability to delamination in food packaging, no leaching etc. The omniphobic solution should not impart more than a 10% weight gain to the end item.

Testing will be performed based on the end use application and properties identified. Oil repellency on textile substrates should be determined in accordance with AATCC TM 118. A 5A oil rating should be achieved, with an objective of higher oil ratings up to 8A (per AATCC TM118). These oil rating values reflect lowered surface energy of the substrate that protects against fuels and battlefield contaminants such as F-24. Spray rating test AATCC TM 22 should be used to determine water repellency on textile substrates. As oil repellency presents the larger challenge, a demonstration that the omniphobic technology can provide water repellency in addition to meeting oil repellency metrics is sufficient.

 

At the end of year 1, at least 4 sample swatches a minimum of 6 x 6 inch, or one completed prototype incorporating the optimized omniphobic technology should be delivered to the Government Technical Point of Contacts for independent evaluation, along with a report detailing the technology development in detail, all test data and evaluations conducted to verify that the target performance criteria is met, and a feasibility assessment for scaling up the omniphobic technology.

 

Year 2: Ability to scale repellent technology.

Lab scale production to 1000 grams (or liters) for industry scale up should be achieved, prioritizing environmentally friendly practices. Work with a manufacturer to scale up the biosynthetic technology to commercial levels and determine a realistic pathway to integrate with the DoD end item. Special consideration should be made to maintaining the DoD end item functionalities – for example, water repellency, flame resistance, dyability. By the end of Year 2, pilot production level quantities of the biosynthetic solution will be achieved in a formfactor and purity level acceptable for manufacture (as determined by standard practices for the targeted DoD end item manufacture). Partnership with a manufacturer is encouraged.

 

Treated end items at a pilot or prototype scale level must be supplied to the Government Technical Point of Contacts for independent evaluation: 1 yard of a treated fabric substrate, laminate, membrane, or similar material; or 1 prototype of the treated end item (ex. shirts, gloves, sleeping bags, hydration systems). A cost analysis for producing the end items at full scale production is required at the end of Year 2, as well as a durability assessment for the lifecycle of the finished end item predicting durability to laundering, abrasion etc.

 

PHASE III DUAL USE APPLICATIONS: Commercialization: Proposals should establish a lifecycle framework that can mature as the technology or process advances through the acquisition process. Life cycle management is an important consideration when assessing the potential PFAS release into the environment from manufacturing through use (including abrasion during wear and laundering) and disposal. At end-of-use, any residual chemistry needs to be handled in the relevant material recovery method, regardless of whether it is recycling, incineration, or landfilling. Contamination can occur in:

  • Ground/Water - carpet and clothing are most likely sources of PFAS in landfill leachate.
  • Air - During manufacturing air emissions from volatile substances must be addressed. PFAS that is polymerized and integrated into the textile, when thermally decomposed such as in burn pits, could also be released into the environment. Burning waste in pits can create more hazards compared to controlled high-temperature burning - like in a commercial incinerator.
  • Water – The processing/manufacturing of textiles containing PFAS can lead to wastewater contamination (water emulsions during application to fabrics, effluent water).  Many textile manufacturers (Milliken, DuPont, 3M, and Mount Vernon Mills) have been sued for contaminating US public drinking water.

 

Synthetic biology systems using biomanufacturer for production may offer greener alternatives and reduce environmental contamination.

 

There are 100 plus DOD items which have been identified as using PFAS to meet omniphobicity requirements in end item applications including many cold weather clothing items.  In addition to supporting the Army’s Arctic Strategy and the Army’s Climate Strategy, the technology developed will be applicable to a variety of items currently in the supply chain.  Depending on the technology developed it could benefit clothing and equipment items the Army Overwhite program, ECWCS (Extended Cold Weather Clothing System) and CTAPS (Cold Temperature and Arctic Protection System,), clothing items and/or shelters used to provide chemical and biological protection and other items used for a specific MOS such as fuel handler coveralls etc. where omniphobicity is crucial to provide required protection or food packaging items

The developed technology would provide dual-use applications in the civilian sector in the high end outdoor retail clothing industry, but perhaps more importantly  in protective personal equipment for first responders and healthcare workers in addition to the possibility of replacing PFAS currently used in medical devices all of which have been impacted  by PFAS regulations and restrictions.

 

REFERENCES:

  1. Environmental Protection Agency. (December 21, 2021). Our Current Understanding of the Human Health and Environmental Risks of PFAS. EPA.gov.  https://www.epa.gov/pfas/our-current-understanding-human-health-and-environmental-risks-pfas;
  2. Gluge, J., et al. (2020). "An overview of the uses of per- and polyfluoroalkyl substances (PFAS)." Environ Sci Process Impacts 22(12): 2345-2373.;
  3. Pablo Cárdenas, Starting from scratch: a workflow for building truly novel proteins, Synthetic Biology, Volume 6, Issue 1, 2021, ysab005, https://doi.org/10.1093/synbio/ysab005;
  4. Tang, Tzu-Chieh & An, Bolin & Huang, Yuanyuan & Vasikaran, Sangita & Wang, Yanyi & Jiang, Xiaoyu & Lu, Timothy & Zhong, Chao. (2020). Materials design by synthetic biology. Nature Reviews Materials. 6. 10.1038/s41578-020-00265-w;
  5. RISE Research Institute of Sweden. (2022). “PFAS Substitution Guide for Supply Chains.” 2022.98. https://www.ri.se/en/popfree/pfas-substitution-guide-for-textile-supply-chains;
  6. Gibbons, H.S. and Feeney, B.B. (2023)  “Grow Your Own Supply Chain.” Army AL&ST. Fall 2023: 13-17.  https://asc.army.mil/armyalt/Fall2023/html/index.html

 

KEYWORDS: PFAS; Synthetic Biology; Bioinspired; Clothing and Equipment; Omniphobicity; Non fluorinated

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