Mechanochemical Defluorination of Polytetrafluoroethylene (PTFE) With Base Metals

ABSTRACT

We report highly efficient mechanochemical redox reactivity between polytetrafluoroethylene (PTFE) and base metals, enabling simultaneous polymer decomposition, fluorination of metals without F ₂ or HF, and mechanochemical dealloying. While milling with metals has recently emerged as a mechanochemical platform for PTFE defluorination, most such work has relied on highly reactive, air‐sensitive metals, such as alkali elements. We now demonstrate a proof‐of‐principle for direct and efficient transformation of PTFE into a mixture of sp ² ‐carbon and a metal fluoride by ball‐milling with stoichiometric amounts of safe‐to‐handle, abundant, inexpensive metals such as zinc. The reactivity is applicable to other metals, as shown by aluminum, lead and cadmium, and the process is also extendable into a two‐step, one‐pot mechanochemical strategy to generate NaF as a recycled fluorine source, along with a ZnO/carbon mixture which can undergo carbothermal reduction to recover zinc, suggesting an opportunity to develop a zinc‐based PTFE defluorination cycle. Moreover, ball‐milling with PTFE is shown to transform brass into a mixture of copper metal and ZnF ₂ , providing a proof‐of‐principle for mechanochemical dealloying of mixed‐metal materials using fluoropolymer waste as a reagent. This work introduces a different, mechanochemistry‐based paradigm for straightforward, atom‐economic, and potentially more sustainable PTFE defluorination, presenting its valorization as a mechanochemical fluorinating agent.