The objective of this SEED statement of need (SON) is to develop and test the feasibility of a proposed technology(ies) to separate fluoropolymers from particulate filler using an environmentally friendly process. 

• Specifically, methods are sought to mechanically or chemically separate polymer-metal composites comprised of micron-scale low-density metals compounded with Viton and Teflon polymers. 
• Although the use of any combustion methods is precluded, thermal treatment methods may be considered.
• Proposals that use surrogate materials as alternatives to commonly used fluoropolymers and metal powders, discussed herein, are allowable.  However, all surrogate materials must be translatable to relevant fluoropolymer/metal materials and choice of surrogates must be thoroughly explained in the proposal, and if possible, validated within the work.
• Methods to oxidize metal particulates embedded within a hydrophobic polymer matrix would be considered, but only non-oxidizing surrogate polymers should be used.   
• The proposed methods should have the potential to generate products with reduced hazard classification.
• The proposed separation technologies should be safe, scalable, cost effective, and minimize environmental hazards, including use of organic solvents and other reagents. 
• This SON is not focused on recycling or reuse of the components or any products formed.   

Proposals should include a plan to conduct a Sustainability Analysis[1] of appropriate proportion to the proposed research and development. Proposals should establish a lifecycle framework that can mature as the technology or process advances through the acquisition process. This tiered approach aims to develop and document a minimum data set at each stage of research and development that can be used to make informed decisions and streamline transition to an acquisition program. The Sustainability Analysis may include varying depths of data and information that can inform: the goal and scope of an analysis; the identity and quantity of relevant inputs and outputs to the system; and the estimation of life cycle impacts and costs.
 

[1] https://www.denix.osd.mil/esohacq/home/dod-guidance/dod-sustainability-analysis-guidance/OSD-AS%20SA%20Guidance%20v7%20-%20final%20June%202020.pdf

A cost-effective means of separating fluoropolymers and metal powders would reduce DoD costs for hazardous waste treatment or disposal and reduce potential environmental impacts. 

Fluoropolymers, such as Viton (vinylidene difluoride/hexafluoropropylene copolymer) and Teflon (polytetrafluoroethylene) are the polymers of interest.  The polymers and metal powders are typically mixed and processed into fully dense and cohesive mixtures to maximize surface area between the fluoropolymer and filler.  The fluoropolymers have very low solubility in most solvents and the high degree of mixing prevent easy extraction of metal particles from the fluoropolymer.  The proportion of metal powders in the fluoropolymers ranging from 10 to 50 weight percent is of interest.  The particle size of the metal powders of interest is 60 to 350 microns. Metals of interest include those with a density less than 3.0 g/cm³. Given the low density of the metals and high density of the subject polymers, density-based separations are not recommended unless they are capable at separating materials with less than 10% density difference. 

Although it is possible to recover the metal and/or fluoropolymer, the waste streams are not typically generated in significant quantities and their pre-existing use decreases their value substantially.  As a result, this SON is not focused on recycling or reuse of the components or any products formed.  The hazardous characteristics of the separated products will be of interest due to their impact on disposal costs.  Waste materials that do not meet the criteria of hazardous, as defined within the Resource Conservation and Recovery Act regulations, are particularly advantageous given the lower cost and management requirements associated with their disposal.     

Metal oxides are effectively non-reactive with fluoropolymers.  Similarly, mixtures of fluoropolymers with most ceramics, glasses, and other polymers form non-reactive mixtures.  Such mixtures could be used to eliminate safety hazards associated with metal-fluoropolymer mixtures to more easily develop separation processes.

A preliminary life cycle analysis (LCA) would help indicate the economic and environmental cost benefit associated with the proposed process relative to current processes. Thus, it is highly recommended that some work within the project focuses on a preliminary LCA.

To meet the objectives of this SEED SON, proposals should not exceed $250,000 in total cost and approximately one year in duration. Work performed under the SEED SON should investigate innovative approaches that entail high technical risk and/or have minimal supporting data. At the conclusion of the project, sufficient data and analysis should be available to provide risk reduction and/or a proof-of-concept. SEED projects are eligible for follow-on funding if they result in a successful initial project.