Improving CO separation performance of the polyethylene glycol (PEG)/polytrifluoropropylsiloxane (PTFPMS) blend composite membrane.

Polyethylene glycol (PEG) as a promoting material for CO separation performance of a composite membrane is introduced into the polytrifluoropropylmethylsiloxane (PTFPMS) network to form a blend selective layer coated on a porous polyetherimide (PEI) support membrane. The maximum blend ratio of PEG to PTFMS in mass is determined for PEG-400, PEG-600, and PEG-1000 at 0.5, 0.2 and 0.2 from the blend solution status observed by an optical microscope. The miscibility of PEG and PTFPMS is verified from one peak of the blend film in DSC characterization. Furthermore, the interaction between PEG and PTFPMS is van der Waals force from the decreasing strength of ether group in ATR-FTIR analysis. The stability of the PEG/PTFPMS blend composite membrane is investigated with pure N, O, and CO permeation experiments under the transmembrane pressure difference up to 1.0 MPa. The N permeation rate of the PEG400/PTFPMS blend composite membrane with a blend ratio of 0.2 is 2.11 GPU, while the O/N and CO/N selectivities are improved to 2.67 and 26.67, respectively, which are higher than those of pure PTFPMS composite membrane that is 2.2 and 13.79, respectively. [ABSTRACT FROM AUTHOR]