Effects of Hydrophobic Modifications and Phase Transitions of Polyvinylamine Hydrogel Films on Reversible CO2 Capture Behavior: Comparison between Copolymer Films and Blend Films for Temperature‐Responsive CO2 Absorption

The separation of CO2 from large emission sources is essential to both mitigate the greenhouse effect, as well as generate carbon‐based energy. However, energy consumption of conventional CO2 separation processes, which using aqueous amine solution as absorbent, is too large. It is has been previously reported that hydrogel films that are consisting of temperature‐responsive amine‐containing polymers can be energy efficient CO2 absorbent—the films can reversibly capture and release large amount of CO2 via temperature‐induced phase transition of hydrogels. However, the study is limited to the films consisting of gel particles of polyacrylamides. In this study, a series of hydrogel films consisting of a mass‐produced amine‐containing linear polymer, polyvinyl amine (PVAm), are prepared, and the efficiencies of their reversible CO2 capture are tested. The effects of hydrophobic modifications and the temperature dependent phase transition behaviors of the films on the reversible CO2 capture efficiency are studied in detail. The function of hydrogel films containing modified PVAm (copolymers), as well as blend films of nonmodified PVAm and 100% modified PVAm, are compared for the first time. The results reveal that the reversible CO2 capture efficiency of polyamine films can be improved just by blending with temperature‐responsive polymers. The behaviors of polyvinylamine‐based blended and copolymer hydrogel films are compared as temperature‐responsive CO2 absorbents. The phase transitions of polymer chains in the film improve reversible CO2 capture efficiency both in the blended and copolymer films.