Probe Into the Influence of Crosslinking on CO(2) Permeation of Membranes

Crosslinking is an effective way to fabricate high-selective CO(2) separation membranes because of its unique crosslinking framework. Thus, it is essentially significant to study the influence of crosslinking degree on the permeation selectivities of CO(2). Herein, we report a successful and facile synthesis of a series of polyethylene oxide (PEO)-based diblock copolymers (BCP) incorporated with an unique UV-crosslinkable chalcone unit using Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT) process. The membranes of as-prepared BCPs show superior carbon dioxide (CO(2)) separation properties as compared to nitrogen (N(2)) after UV-crosslinking. Importantly, the influence of different proportions of crosslinked chalcone on CO(2) selectivities was systematically investigated, which revealed that CO(2) selectivities increased obviously with the enhancement of chalcone fractions within a certain limit. Further, the CO(2) selectivities of block copolymer with the best block proportion was studied by varying the crosslinking time which confirmed that the high crosslinking degree exhibited a better CO(2)/N(2) (α(CO2/N2)) selectivities. A possible mechanism model revealing that the crosslinking degree played a key role in the gas separation process was also proposed.