Plasticization-resistant Ni2(dobdc)/polyimide composite membranes for the removal of CO2 from natural gas

Abstract

We demonstrate that the incorporation of Ni₂(dobdc) metal–organic framework nanocrystals into various polyimides can improve the performance of membranes for separating CO₂ from CH₄ under mixed-gas conditions. Four upper-bound 6FDA-based polyimides, as well as the commercial polymer Matrimid®, show improved selectivity under mixed-gas feeds when loaded with 15–25 wt% Ni₂(dobdc), while the neat polyimides show diminishing selectivity upon increasing feed pressure. This approach presents an alternative to chemical crosslinking for achieving plasticization resistance, with the added benefit of retaining or increasing permeability while simultaneously reducing chain mobility.