Solvation Effects on the Permeation and Aging Performance of PIM-1-Based MMMs for Gas Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Polymer Science

Background:

• Membranes offer energy-efficient separations by avoiding phase changes, but polymer limitations hinder development.
• Mixed-matrix membranes (MMMs) integrate polymers with additives to overcome selectivity and stability issues.
• Polymers of intrinsic microporosity (PIMs) exhibit excellent intrinsic gas transport properties.

Purpose of the Study:

• To develop and characterize a novel mixed-matrix membrane (MMM) based on PIM-1 with porous additives.
• To investigate the impact of intimate polymer-additive mixing on membrane performance and physical aging.
• To explore solvent effects on MMM properties and gas selectivity.

Main Methods:

• Fabrication of a scalable, hyper-cross-linked porous polymer (pDCX) and its subsequent hydroxylation.
• Creation of an intimate MMM by mixing hydroxylated pDCX with polar PIM-1.
• Gas transport measurements and physical aging studies under varied solvent conditions.

Main Results:

• The MMM demonstrated improved gas transport properties and enhanced resistance to physical aging compared to neat PIM-1.
• Intimate mixing between PIM-1 and pDCX was crucial for eliminating nonselective transport pathways.
• Solvent selection enabled control over aging rates and improved selectivity for smaller gas molecules.

Conclusions:

• The developed MMM effectively enhances the performance and stability of PIM-1 for gas separations.
• This approach offers a practical and scalable method for stabilizing porous polymers in separation applications.
• Direct elucidation of MMM interactions provides insights for future material design.