Per- and polyfluoroalkyl substances (PFAS) are a category of compounds whose industrial manufacture can result in environmental contamination that, due to the chemical stability and oleophobic and hydrophobic nature of most PFAS, is challenging to remediate. Fluoropolymers such as polytetrafluoroethylene (PTFE) are a type of PFAS that are not clearly known to be directly toxic, but there is concern that their disposal may lead to subsequent release of more toxic compounds. As such, there is increasing interest in evaluating potential disposal mechanisms, such as incineration, by developing methods to detect and quantify PFAS contamination. In this study, we performed thermal degradation studies on PTFE using thermogravimetric analysis (from 20 to 1000 °C) coupled with mass spectrometry (TGA-MS). Based on the observed TGA-MS experiments conducted on PTFE in open air combustion conditions, a proposed mechanism using a C16 molecule, CF3(CF2)14CF3, was developed. The kinetic and thermodynamic parameters were evaluated by density functional theory (DFT) and microkinetic models to compare and verify the proposed reaction mechanisms from the experimental TGA-MS data. In addition, process design models were developed using kinetic and thermodynamic reactors before and after the determined gel point for PTFE. The TGA-MS data provides an understanding of the potential gaseous degradation products during the thermal breakdown of PTFE. Ongoing studies aim to investigate potential reaction pathways for degradation of PTFE, other fluoropolymers, and fluoropolymer blends through correlating kinetic and thermodynamic parameters with DFT mechanistic modeling.
