(659g) Investigating the Role of Competitive Sorption in Tertiary-Amine-Functional Poly(arylene ether)s for H2s- and CO2-Focused Separations

Polymer membranes are promising for CO₂-based gas separations due to their processability, mechanical strength, and manufacturability. Recent advancements in polymers with permanent porosity (termed “microporous”) have indicated that a phenomenon known as competitive sorption can be used to enhance separation performance. This presentation will focus on the fundamentals and practical implications of leveraging competitive sorption to enhance performance in application-relevant and multi-component gas mixtures.

Specifically, microporous polymers with primary amines have enhanced CO₂-based selectivities for mixture testing due to an emergent phenomenon known as competitive sorption. However, the strong secondary forces in these polymers through hydrogen bonding results in low solvent solubility, precluding standard solution processing approaches to form these polymers into membrane films. Herein, we circumvent these manufacturing constraints while maintaining competitive-sorption enhancements by synthesizing eight representative microporous poly(arylene ether)s (PAEs) with tertiary amines. High-pressure H₂S, CO₂, and CH₄ sorption isotherms were collected for these samples to demonstrate enhanced affinity for acid gases relative to the unfunctionalized control polymer. While competition sorption was observed for all samples, improvements were less pronounced than for primary-amine-functional analogs. For H₂S-based separations, the benefits of competitive sorption are largely offset by plasticization. This detailed study helps to elucidate the role of tertiary amines for acid gas separations in solution-processable microporous PAEs.