Study on the pyrolysis behaviour of polytetrafluoroethylene polymer under cooking temperatures

Title : Study on the pyrolysis behaviour of polytetrafluoroethylene polymer under cooking temperatures

Abstract:

Non-stick cookware, coated with Polytetrafluoroethylene (PTFE) is recognized as a convenient choice for effortless cooking and cleaning. Cooking typically occurs at temperatures below the melting point of PTFE and is assumed to be putatively safe. This study evaluates the thermal stability of PTFE using single-shot thermogravimetric analysis (TGA) and stepwise TGA which mimics the real-life scenarios experienced during cooking, simulated with cycles of stepwise heating/cooling in a TGA. Further focusing on the by-products formed at these cooking temperature using Py-GC-MS. Raw-PTFE powder and various brands of non-stick Teflon pans were characterized using powder X-ray diffraction (PXRD) to determine crystalline phase, energy-dispersive X-ray spectroscopy (EDXS) for elemental composition and scanning electron microscopy (SEM) for surface morphology before and after heating. Results showed raw PTFE powder and all non-stick Teflon pans displayed similar surface morphology and elemental composition with a dominant fluorine fraction. Single-shot TGA confirmed that both Raw PTFE and Teflon Pan coatings showed stability till 400?. On contrary to this stepwise TGA of Raw PTFE powder showed degradation of  1.27%, 4.09%, and 7.64% at 220°C, 260°C, and 300°C, respectively, and Py-GC-MS revealed that at cooking temperatures (220? and 260?), PTFE breaks down into Perfluoro carboxylic acids (PFCAs) later on confirmed using UHPLC-HRMS on non-stick Teflon pans. PFCAs are forever chemicals known for their persistence and potential environmental toxicity. Our findings highlight the possible release of fluorinated compounds from non-stick cookware posing risk to human health and environment.

Biography:

Raveena Dhore, Indian Institute of Technology Indore, India: Miss Raveena Dhore is a Ph.D. scholar in the Mehta School of Biosciences and Biomedical Engineering at the Indian Institute of Technology Indore, India. She completed her master’s degree from SRM Institute of Science and Technology in 2019. Her research primarily focuses on Polytetrafluoroethylene (PTFE), a type of Per- and Polyfluoroalkyl Substances (PFAS), which are also classified as Contaminants of Emerging Concern (CEC). Specifically, she investigates the degradation of PTFE under cooking temperature conditions and toxicity analysis of compounds generated from PTFE, contributing to the understanding of their environmental and health risks.