Constructing continuous and fast transport pathway by highly permeable polymer electrospun fibers in composite membrane to improve CO2 capture

Electrospun fibers composite membrane shows an insufficient CO2 permeability due to the impermeable polymer fibers. In this work, highly permeable poly(1-trimethylsilyl-1-propyne) (PTMSP) electrospun fiber were utilized to construct continuous and fast transport pathway with low-resistance for gas molecules in PEO matrix. The PEO/PTMSP electrospun fiber composite membrane (EFCM) was obtained by the in-situ polymerization of polyethylene glycol (PEG) into the voids of PTMSP electrospun fibers, which is demonstrated by FTIR and XPS characterizations. Furthermore, the obtained EFCM is dense and defect-free, which is confirmed by SEM images. Specifically, the PTMSP fibers and PEO matrix present good interfacial compatibility, as revealed by DSC results. In addition, PTMSP electrospun fibers perform as skeleton for EFCM to reinforce the membrane mechanical properties. The PEO/PTMSP EFCM shows CO2 permeability of 281 Barrer and CO2/N2 selectivity of 32.94. The CO2 permeability is 280% higher than that of pure PEO membrane, which is resulted from the continuous and fast transport pathway provided by PTMSP electrospun fibers. The CO2/N2 selectivity is enhanced by 4 to 6 times in comparison with pure PTMSP membrane and PTMSP c-EFM, which can be attributed to the affinity between EO groups of PEO matrix and CO2 molecules and also the screening effect from the tortuous pathway of PTMSP fibers. This superior gas separation performance of PEO/PTMSP EFCM exceeds most reported PTMSP based membranes, especially its selectivity of CO2 over N2 is significantly high. Consequently, this proposed EFCM with continuous and fast transport pathway holds a competitive prospect for polymer based CO2 capture.