Sorption and Diffusion of Methane, Carbon Dioxide, and Their Mixture in Amorphous Polyethylene at High Pressures and Temperatures

Molecular dynamics (MD) simulations are performed to study the sorption and transport properties of CH4 CO2 in amorphous polyethylene at temperatures from 350 600 K pressures up 500 bar. The uptake by generally increased with increasing pressure decreasing temperature. However, high pressures, for example, methane increases self-diffusion coefficients carbon dioxide increase pressure. These results are, general, consistent swelling behavior polymer. Interestingly, penetrants, activation barrier diffusion decreases MD also carried out CH4/CO2 mixture polyethylene. Here, overall were similar those reported pure selectivity CO2/CH4 temperature was mostly independent bulk mole fraction methane. Importantly, mobility found here is higher than that corresponding opposite trend observed case dioxide. might be due fact polymer presence significantly methane, especially pressures. membrane selectivities dioxide/methane show a data. Furthermore, simulation data good agreement theoretical calculations based on PC-SAFT equation state.