Characterization of PFAS Air Emissions from Thermal Application of Fluoropolymer Dispersions on Fabrics
Wickersham et al.
Journal of the Air & Waste Management Association
DOI: 10.1080/10962247.2023.2192009
Alongside our partner, Aerodyne Research, we continuously support the operation of our mass spectrometers for new, groundbreaking research. This publication aims to understand PFAS emissions and provide emission factor estimates for thermal transformation products using TOFWERK Vocus technology.
Fluorinated coatings are applied to various surfaces to enhance durability and resistance to mechanical, thermal, chemical, and UV degradation. These coatings, often used on fabrics, involve liquid dispersions of fluoropolymers, additives, water, and surfactants, including PFAS. Historically, PFOA was a common polymer processing aid (PPA), but it has been replaced by alternatives like GenX.
The coating process includes dipping textiles in dispersions, followed by drying and sintering in a three-furnace system at temperatures up to 400°C. This thermal treatment vaporizes water, surfactants, additives, and residual PPAs, potentially leading to the degradation and emission of fluoropolymers. Studies have shown that high temperatures cause PTFE to decompose, emitting various toxic substances. However, most research focuses on the fluoropolymer alone, not the complex mixture in industrial dispersions. Few studies have characterized air emissions from fabric coating facilities, indicating that dispersion components can transform during processing, producing new compounds.
This study used a bench-scale furnace tower to simulate industrial coating and thermal processing, analyzing gas-phase emissions and degradation products from model mixtures and commercial dispersions. The study found that 6:2 FTOH and commercial fluoropolymer dispersions transform into multiple PFAS during thermal processing, particularly in the highest temperature sintering furnace. Despite different fluoropolymer species in the dispersions, similar PFAS emissions were observed, with E1 concentrations peaking after the baking furnace and decreasing after the sintering furnace. This suggests the presence of HFPO-DA or GenX, leading to E1 formation and further degradation into other PFAS. Emission factors for E1 were highest at 475 ÎĽg/g dispersion in low-temperature experiments. The study highlights that industrial fabric coating conditions can alter PFAS and produce various decomposition products, impacting air quality and health without pollution control technologies. Bench-scale experiments replicated industrial processes, enabling detailed analysis and suggesting future field studies and development of catalytic thermal oxidizers.
This study showcases the broad, real-time capabilities of the Vocus CI-TOF to detect PFAS emissions, for example from fabrics. Learn more about Vocus capabilities for PFAS detection in the whitepaper, Revolutionizing PFAS Detection in Air: High Sensitivity and Versatility with the Vocus Aim Reactor. Additionally, off-gassing information can be found in application notes on consumer products and tubing material.
