Tuning the morphology of segmented block copolymers with Zr-MOF nanoparticles for durable and efficient hydrocarbon separation membranes

Abstract

Microphase separation of block copolymers is a critical parameter to control the mechanical–physical properties. Zr-Metal–organic frameworks (MOFs) display high potential for the development of mixed matrix membranes. Here, the effect of UiO66 and amine-functionalized UiO66 (UiO66-NH₂) nanocrystals on the phase separation and gas transport properties of polyurethane (PU) membranes is investigated. In addition to considerable gas adsorption on MOFs, tuning the phase separation of PU by the incorporation of UiO66-NH₂ particles generates more accessible adsorption sites for gas molecules and increases the selectivity. The PU/UiO66-NH₂ membrane exhibits high C₄H₁₀/CH₄ selectivity (∼70), which is far beyond the separation performance of typical polymers (e.g. PDMS, PTMSP, etc.) for hydrocarbon separation. The increase in the phase separation is verified by FTIR, DSC and AFM measurements. C₄H₁₀ plasticization of the PU MMMs is significantly suppressed, and the mechanical properties are improved by more than 600% for PU/UiO66-NH₂ composites. Additionally, the Maxwell model reliably predicts the transport properties of the membranes.