Covalent and electrostatic incorporation of amines into hypercrosslinked polymers for increased CO 2 selectivity

Two methods of incorporating functional groups rich in nitrogen into low cost microporous hypercrosslinked polymers (HCPs) have been evaluated and the effects on the carbon dioxide CO 2 /N 2 IAST selectivity were measured. Electrostatic incorporation of an ammonium salt into a sulfonic acid‐containing HCP polymer afforded a static CO 2 uptake of 2.5 mmol g −1 with a CO 2 /N 2 IAST selectivity of 42:1 at 1 bar and 298 K. Using column breakthrough measurements with a 15:85 CO 2 /N 2 mixture at 298 K and 1 bar, a selectivity of 17:1 was obtained. However, varying the counterion resulted in polymers with lower CO 2 /N 2 selectivity values. Decoration of the parent polymer with CO 2 ‐philic imidazole followed by electrostatic ammonium salt incorporation blocked some of the micropores reducing the selectivity which re‐emphasizes the role and importance of pore width for CO 2 /N 2 selectivity. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2513–2521