The research team for this project will develop a robust and cost-effective approach based on ionic liquids (IL) to separate fluoropolymers from inorganic particulates. This one-year, proof-of-concept project has three major objectives:

1. Synthesis and characterization of specific IL with desirable physicochemical properties.
2. Separation of fluoropolymers by selected IL and IL recovery.
3. Life cycle analysis evaluating the costs of the IL approach against conventional combustion management. 

Fluoropolymers in fully dense and cohesively mixed polymer-metal composites have very low solubility in most solvents. ILs, as “designer” solvents, can dissolve many polymers. Building upon this, the proof-of-concept research seeks to tailor IL specifically for fluoropolymers separation from inorganic metal particles. This project will develop specific IL, particularly with fluorinated anions such as bis(trifluoromethylsulfonyl)imide, tetrafluoroborate, and hexafluorophosphate. The overarching hypotheses driving this project are: (i) the combination of different cations and anions will result in distinctive physicochemical properties of synthesized IL; (ii) the use of fluorinated anions enables IL to exhibit unique solvating properties and can effectively separate fluoropolymers from composites due to fluorine-to-fluorine (or ‘like dissolves like’) interactions; and (iii) the relatively mild fluoropolymer processing conditions render easy recovery of IL with chemical integrity, providing a suitable IL based approach for fluoropolymer treatment. The technical approach involves synthesizing and tailoring IL, investigating fluoropolymer separation, exploring IL recovery and reuse, and performing a techno-economic assessment. 

This project will provide fundamental insights into the interactions and separation mechanisms of fluoropolymers using IL which will advance knowledge on IL and polymer-metal composites. The findings will assess feasibility for developing an IL-based fluoropolymer separation technique. An IL-based approach to separating fluoropolymers from inorganic particulates will enable a resource efficient approach to managing polymer-metal composite wastes at Department of War facilities. (Anticipated Project Completion - 2026)