Abstract
ABSTRACT Carbon capture, utilization, and storage is a crucial short‐term strategy to mitigate climate change. Once captured, CO 2 needs to be transported to storage sites, and to ensure efficient transport, it is typically compressed into a liquid or supercritical fluid. These conditions can alter the properties of materials used during the transport stage. A HNBR, a commonly used elastomer in oil and gas applications, is investigated in this work in terms of its CO 2 permeation properties. The plasticization effect of CO 2 plays a key role, as it can shift the glass transition temperature, leading to peculiar permeability behavior at high‐pressure. Thermodynamic modelling is also effectively applied, describing the observed trends.