Polyamine-Functionalized Porous Organic Polymer Nanoparticles for High-Performance PIM-1 Mixed-Matrix Membranes toward CO2/N2 Separation

Abstract

Porous organic polymer nanoparticles bearing polyamine functionalities offer an effective platform for designing mixed-matrix membranes with improved CO2 separation performance. Herein, a series of amine-functionalized porous polymer nanoparticles, referred to as PP-x, was synthesized via Friedel–Crafts alkylation and subsequent post-synthetic functionalization with different polyamines. These fillers were embedded into PIM-1 to prepare mixed-matrix membranes for CO2/N2 separation. By controlling the amine functionality and pore accessibility of the fillers, the CO2/N2 separation behavior could be tuned through the combined effects of enhanced CO2 affinity, modified gas diffusivity, and suppressed N2 sorption. The improved interfacial compatibility between the fillers and PIM-1, together with uniform filler dispersion, contributed substantially to the enhanced separation properties. The membrane containing 10 wt % PP-DETA showed a CO2 permeability of 23,555 Barrer and a CO2/N2 selectivity of 17.1, whereas the 10 wt % PP-TEPA membrane achieved a higher selectivity of 20.1 while retaining high gas permeability. Furthermore, incorporation of the functionalized nanoparticles mitigated physical aging by 34% relative to the pristine PIM-1 membrane. Overall, this work demonstrates that polyamine-functionalized porous polymer nanoparticles are attractive filler materials for high-performance CO2 separation membranes.