A Low-Temperature Regenerative Porous Amine–Epoxy Polymer for Direct Air Capture

The polymerization of triethylenetetramine (TETA) with epoxy resin produced a porous amine–epoxy polymer (AEP). Polypropylene glycol, used as the porogen, was subsequently removed. This industrially viable method yielded an AEP with a high amine density (10.4 mmol/g), a specific surface area of 7.5 m 2 /g, and a cocontinuous porous structure. Scanning electron microscopy confirmed the three-dimensional network skeleton and through-hole morphology, with pore sizes below 1 μm. Thermogravimetric analysis revealed that although TETA has limited thermal stability, the synthesized AEP exhibits significantly enhanced thermal resistance. CO 2 adsorption experiments, conducted using 400 ppm of CO 2 /N 2 gas at 20 °C and 50% relative humidity, demonstrated that increasing the regeneration temperature moderately increased CO 2 desorption. Notably, CO 2 desorption at 65 °C reached 1.81 mmol/g, demonstrating excellent low-temperature regeneration performance and working capacity under mild regeneration conditions. These results indicate that the porous AEP is a promising candidate for energy-efficient direct air capture applications.