Abstract
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 CO2 release in the atmosphere, aiming to reach net-zero CO2 emissions. To increase transport efficiency, CO2 must be compressed and transported as a liquid or supercritical fluid, conditions that might affect the performance of the materials employed. In fact, polymers may absorb CO2 molecules during their handling via pipelines and ships and this can lead to plasticization and the risk of rapid gas decompression (RGD) damage when the CO2 pressure is released. In this concern, elastomers comprise only a small portion of the CCS value chain because they are mainly used as seals and gaskets; however, they are essential elements for controlling leakage. This work presents the results of a comprehensive experimental characterization of high-pressure CO2 compatibility in common elastomers, such as ethylene propylene diene monomer (EPDM), natural rubber (NR), and butyl rubber (IIR), via thermal, mechanical, and transient-sorption experiments. From the results obtained, we saw that CO2 solubility is always lower than 0.09 gCO2/gpol for all materials, while permeability reaches values higher that 100 Barrer at 45 °C for EPDM and NR. The role of reinforcing fillers incorporated into the polymer matrix has been also analyzed with a focus on evaluating their influence on mechanical properties and CO2 transport properties. In this concern, swelling decreases from 400 to 70% from NR to EPDM, as the filler content increases, suggesting a positive interaction between the two phases. The extent of the analysis has been then upgraded by performing a modeling description of the results through the use of a thermodynamic equation of state (EoS) approach, thanks to which the polymer–penetrant interaction can be predicted in a wider range of pressure and temperature, down to cryogenic environments, as the one required for the CCS transport chain.