Measurement and modeling of solubilities and diffusion coefficients of carbon dioxide in poly(ethylene-co-acrylic acid)

We measured and modeled the solubilities and diffusion coefficients of carbon dioxide (CO2) in poly(ethylene-co-acrylic acid) (PEAA) over temperatures of 373-473 K and pressures of up to 20 MPa. The measured solubilities of CO2 in PEAA obeyed Henry's law and decreased with an increase in the acrylic acid content of the copolymer. The Sanchez-Lacombe equation of state could be applied to correlate the measured solubilities. The temperature dependence of the CO2 solubilities in PEAA was found to be similar to that in polyethylene with analysis using Henry's law. Further, the gas solubility and acrylic acid content were the influential factors for determining the diffusivity of CO2, which could be modeled based on the free volume theory. (C) 2019 Elsevier B.V. All rights reserved.