PIM-1 membrane incorporated cPIM-1 grafted PP-DETA for high-efficiency CO2/N2 separation

Abstract

Mixed-matrix membranes (MMMs), developed through the combination of solid fillers with polymer matrices, represent an effective approach addressing the persistent challenge of balancing permeability and selectivity in polymer membrane. Diethylenetriamine-functionalized porous material of PP-DETA, which is synthesized from porous organic polymer of PP via one-step diethylenetriamine grafting, is an ideal material for MMMs production. However, designing and optimizing PP-DETA for high-performance CO₂ separation membranes remains a challenge. Herein, we develop an improved PP-DETA material, designated as PP-DETA-cPIM-1, by covalently attaching a carboxylated polymer of intrinsic microporosity (cPIM-1) network layer onto the PP-DETA surface. Membranes prepared from this PP-DETA-cPIM-1 filler and PIM-1 matrix demonstrate enhanced interfacial adhesion and stronger mechanical properties in comparison to the counterparts with the same loading of PP-DETA. The incorporation of PP-DETA-cPIM-1 into MMMs establishes an enhanced filler/polymer interface that facilitates the selective transport of CO₂ through the filler, while simultaneously improving membrane stability and suppressing physical aging. Specifically, with 5 wt% loading of PP-DETA-cPIM-1 filler, the MMM is able to enhance the CO₂/N₂ selectivity and CO₂ permeability by 52.3 % and 25.3 %, respectively, exceeding the upper bound established in 2008. Furthermore, PP-DETA-cPIM-1/PIM-1 MMMs display superior anti-aging ability for 180 days of aging.