Epoxy Cross-Linked Polyamine CO2 Sorbents Enhanced via Hydrophobic Functionalization

Optimizing sorption capacity and amine efficiency are among the major challenges in developing solid carbon dioxide sorbents. Such materials frequently feature polyamines impregnated onto supports adding weight to the sorbents. This work presents the cross-linking of polyethyleneimine (PEI) by the industrially available epoxy resin, bisphenol-A diglycidyl ether (DER) to form support-free sorbent materials. Prior to cross-linking, the polyamine chain is functionalized with hydrophobic additives; one material modified with the branched chain hydrocarbon 2-ethylhexyl glycidyl ether displays a CO2 uptake of 0.195 g/g, 4.43 mmol CO2/g (1 atm single component CO2, 90 °C). The additive loading affects the cross-linking, with the lesser cross-linked materials showing more favorable sorption capacities and higher amine efficiencies. The type of additive also influences sorption, with the larger, longer and bulkier additives better able to free the amines from their hydrogen bonding network, generally promoting bet...