High oxygen permeable Zeolite-4A poly(dimethylsiloxane) membrane for air separation

High oxygen permeability with optimal selectivity of the membrane is required for advancement in air separation membrane technology. Zeolite 4A-PDMS composite membranes were prepared by incorporation of Zeolite 4A nanoscale crystals during the polymerization process of PDMS membrane using toluene and n-heptane solvents, and their oxygen gas permeability and selectivity were explored. Small angle neutron scattering (SANS) technique was further used to study the polymer chain conformation and structure of membranes influenced by Zeolite 4A loading. The intersegmental distance between polymer chains and polymer chain aggregation or clustering were found to be increased on increasing the Zeolite 4A content in the membranes. Increment in the O-2 permeability and O-2/N-2 selectivity were observed for both type of membranes (toluene and n-heptane) with 1 wt% Zeolite 4A loading. The best performance result with O-2/N-2 selectivity of 2.6, and O-2 permeability of 1052 Barrer was exhibited by PDMS/toluene membrane loaded with 1 wt% Zeolite 4A. The PDMS/toluene membranes with 10 wt% Zeolite 4A loading exhibited increased O-2 permeability of 1245 Barrer with a fair O-2/N(2)selectivity of ~1.7, while the PDMS/n-heptane membrane with the same loading exhibited excellent O-2 permeability of 6773 Barrer but lesser O-2/N-2 selectivity of ~1.2. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48047.