Physical, Mechanical, and Thermal Characterization of the Elastomer Response to High-Pressure CO2 for Use in Carbon Capture and Storage Applications

CO2 transport efficiency is vital for the success of carbon capture, utilization,and storage (CCUS) which is considered one of the most viable solutions to limit CO2release in the atmosphere, aiming to reach net-zero CO2 emissions. To increase transportefficiency, CO2 must be compressed and transported as a liquid or supercritical fluid,conditions that might affect the performance of the materials employed. In fact, polymersmay absorb CO2 molecules during their handling via pipelines and ships and this can lead toplasticization and the risk of rapid gas decompression (RGD) damage when the CO2 pressureis released. In this concern, elastomers comprise only a small portion of the CCS value chainbecause they are mainly used as seals and gaskets; however, they are essential elements forcontrolling leakage. This work presents the results of a comprehensive experimentalcharacterization of high-pressure CO2 compatibility in common elastomers, such as ethylenepropylene diene monomer (EPDM), natural rubber (NR), and butyl rubber (IIR), viathermal, mechanical, and transient-sorption experiments. From the results obtained, we sawthat CO2 solubility is always lower than 0.09 gCO2/gpol for all materials, while permeabilityreaches values higher that 100 Barrer at 45 °C for EPDM and NR. The role of reinforcing fillers incorporated into the polymermatrix has been also analyzed with a focus on evaluating their influence on mechanical properties and CO2 transport properties. Inthis concern, swelling decreases from 400 to 70% from NR to EPDM, as the filler content increases, suggesting a positive interactionbetween the two phases. The extent of the analysis has been then upgraded by performing a modeling description of the resultsthrough the use of a thermodynamic equation of state (EoS) approach, thanks to which the polymer−penetrant interaction can bepredicted in a wider range of pressure and temperature, down to cryogenic environments, as the one required for the CCS transport chain.