Homogeneous and asymmetric membranes were fabricated from the mixture of polytrimethylvinylsilane (PTMVS) and polydimethylsiloxane (PSIO). The ratio of the PSIO content to that of the PTMVS was varied.
A scanning electron microscope was used to observe the surface and the cross section of the membranes. X-ray diffraction of the membrane and the permeability of N
2, O
2 and CO
2 through the membrane were measured to characterize the PTMVS-PSIO blend in the membranes.
Electron microphotographs of the asymmetric membranes showed that the thickness of the dense surface layer decreases, and the pore diameter of the porous substructure becomes larger as the PSIO content increases.
X-ray diffraction reveals that the PTMVS and PTMVS-PSIO blend membranes have amorphous structures, and that their interplanar distances become shorter with the increase of PSIO content. This indicates that PSIO molecules are inserted into the structure of PTMVS and are mixed homogeneously at the molecular level.
The permeability coefficients of the blend membranes become higher as the PSIO content increases. Moreover, the separation factors are intermediate between those of the pure PTMVS and PSIO membranes.
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