Cross-Linked Mixed-Matrix Membranes Using Functionalized UiO-66-NH₂ into PEG/PPG-PDMS-Based Rubbery Polymer for...

Area of Science:

• Materials Science
• Chemical Engineering
• Polymer Science

Background:

• Fabricating mixed-matrix membranes (MMMs) with optimal polymer-filler interfaces for gas separation is challenging due to material incompatibility.
• Achieving high gas permeability and selectivity simultaneously in MMMs remains a significant hurdle in the field.

Purpose of the Study:

• To develop a simple technique for preparing cross-linked MMMs (xMMM@n) with covalently attached metal-organic frameworks (MOFs).
• To investigate the gas separation performance, stability, and antiplasticization properties of these novel MMMs.

Main Methods:

• Utilized ring-opening metathesis polymerization and in situ membrane casting to create MMMs with norbornene-modified UiO-66 MOFs in a PEG/PPG-PDMS matrix.
• Homogeneously dispersed MOFs within the polymer matrix via strong covalent interactions and fast polymer formation.
• Evaluated gas permeability and selectivity (CO2/N2) and assessed antiplasticization and antiaging performance.

Main Results:

• Achieved significant gas permeability improvement in xMMM@n membranes with up to 5 wt% MOF loading without compromising selectivity.
• CO2/N2 separation performance of xMMM@1, xMMM@3, and xMMM@5 surpassed the 2008 Robeson upper bound.
• The best-performing membrane (xMMM@3) approached the 2019 upper bound, demonstrating excellent CO2 separation potential.
• Demonstrated outstanding antiplasticization up to 25 atm and stable antiaging performance for 11 months.

Conclusions:

• The developed cross-linked MMMs (xMMM@n) offer a promising pathway for efficient CO2 separation from flue gas.
• The covalent attachment strategy ensures homogeneous MOF dispersion and enhances membrane performance and stability.
• These MMMs exhibit superior performance characteristics, including high permeability, selectivity, antiplasticization, and antiaging properties.