Constructing a CO2-Philic and Highly Permeative Transmission Pathway in Electrospun Fiber Composite Membranes by Introduction of Ether-Oxygen Groups

Polyethylene glycol dimethyl ether (PEGDME) is proposed to incorporate into PTMSP fibers to prepare an electrospun fiber composite membrane (EFCM) to break the trade-off limit. The abundant ether-oxygen groups in PEGDME can enhance CO2 affinity, improving its selective permeation. Meanwhile, PEGDME has a similar chemical structure with the pore-filled polymer PEO, resulting in intensified interfacial affinity between PTMSP fibers and PEO. Moreover, the high permeability and continuous structure of PTMSP fibers can provide a fast transmission channel for CO2, leading to elevated CO2 permeability. The EFCM exhibits a dense and defect-free structure with fibers distributed uniformly in PEO. The CO2 separation performance increases with the increase in the PEGDME content, and EFCM-30 presents the best CO2/N2 selectivity of 45.46 and CO2 permeability of 753 Barrer, which are increased by 31.5 and 58.5%, respectively, in comparison with EFCM-0. This excellent performance exceeds the 2008 Robeson upper bound.