Characterization and Modeling of CO₂ Transport through Fluorinated Thermoplastics

Carbon capture and storage (CCS) is one of the most viable solutions to limit the CO₂ emission in the atmosphere, with the potential to be applied at short-medium time scales. In this concern, polymeric materials play a relevant role in protecting equipment in the CO₂ transport value chain (such as pipelines, pumps, vessels, or compressors). Among the various classes of polymers, fluorinated materials look promising for such application due to their excellent thermal and chemical resistance, combined with a favorable interaction with CO₂ in its supercritical or in a liquid state. This work explores the sorption, diffusion, and permeation properties of various fluorinated thermoplastic polymers when exposed to high-pressure carbon dioxide. Furthermore, the obtained results are analyzed by a thermodynamic equation of state (EoS) to describe the solubility behavior, while the standard transport model (STM) provides a reliable representation of gas transport. That allows the understanding of the penetrant–polymer interaction and the effect of dense phase CO₂ on polymer-based materials in a wide range of temperatures and pressures. The comparison of sorption and transport data by means of the dedicated model allows the reliable prediction of the effects of CO₂ on such fluorinated polymers at all desired temperature and pressure ranges, relevant for CO₂ transport (e.g., dense phase CO₂, up to supercritical conditions).