The overall objective of this project is to quantify and characterize gas- and particle-phase per- and polyfluoroalkyl substances (PFAS) during the thermal degradation of fluoropolymeric materials including Teflon®, Viton®, and Kel-F^®, the Plastic Bonded Explosive (PBX), and Magnesium/Teflon^®/Viton^® (MTV) pyrotechnics, while also accounting for mass balance, and to understand the mechanisms that control the release of thermal byproducts. The specific objectives of this project are to 1) characterize the PFAS thermal degradation products formed from neat fluoropolymers and to characterize fluoropolymer phase as a function of temperature and time, 2) characterize the PFAS thermal degradation products formed from fluoropolymers mixed with explosives like PBX, 3) to characterize the residue and PFAS thermal degradation pathway of fluoropolymers in MTV, 4) to characterize the PFAS degradation products emitted during small-scale open burn of neat fluoropolymers and fluoropolymers mixed with explosives, 5) conduct technology transfer, and 6) perform requisite reporting to SERDP.

The overall objective of this project is to quantify and mechanistically understand the PFAS that evolve from the thermal degradation of fluoropolymeric materials including Teflon®, Viton®, and Kel-F® in neat form and when mixed with explosives in plastic-bonded explosive (e.g., PBXN-5), and in MTV pyrotechnics. The interdisciplinary team consists of analytical chemists, a physical chemist, and engineers with expertise in PFAS (Dr. Field, Simonich), polymers (Dr. Rochefort), munitions/explosives (Drs. Bahaghighat, Beal, Nagelli), and chemical computations (Dr. Vyas). The overall approach of this multi-disciplinary research project is to conduct detailed laboratory thermal degradation studies (Objectives 1-3) evaluated using state-of-the-art PFAS analytical methods. Small-scale open burn experiments will be conducted with neat fluoropolymers, PBX and other combinations of fluoropolymers and explosives, and MTV (Objective 4). Objectives 5 and 6 are to conduct technology transfer and requisite SERDP reporting, respectively.

Growing health and environmental concern surrounding PFAS is increasing pressure on Department of Defense operations, including range operations and the demilitarization mission for conventional ammunition. This work addresses emerging questions on the thermal breakdown products of fluoropolymers in munitions by utilizing experimental and modeling approaches to encompass the wide range of environmental conditions and combustion processes that occur in the field. By combining academic PFAS experts with military researchers, the team is poised to transition research results effectively through existing relationships with ammunition and demilitarization stakeholders. Specifically, this work will transition directly into an integrated project team with these stakeholders that seeks to solve environmental issues associated with the demilitarization mission. In addition, this work will provide novel mechanistic data on the thermochemical breakdown of fluoropolymers that will advance the state of knowledge on PFAS in the environment. Overall, this project addresses major gaps in the understanding of the fate of fluoropolymers used in military operations, and it delivers robust data and mechanistic understandings to the stakeholders who can then act to mitigate environmental impacts and sustain operations.