Matrimid-based carbon tubular membranes: the effect of the polymer composition

Abstract

In this article, we present a development study of new membrane materials and enhancements of productive membranes to improve the current performance of polymeric membranes. Carbon membranes are a promising material for this matter as they offer an improvement in the gas-separation performance and exhibit a good combination of permeability and selectivity. Carbon membranes produced from the carbonization of polymeric materials have been reported to be effective for gas separation because of their ability to separate gases with almost similar molecular sizes. In this study, a carbon support membrane was prepared with Matrimid 5218 as a polymeric precursor. The polymer solution was coated on the surface of a tubular support with the dip-coating method. The polymer tubular membrane was then carbonized under a nitrogen atmosphere with different polymer compositions of 5–18 wt %. The carbonization process was performed at 850°C at a heating rate of 2°C/min. Matrimid-based carbon tubular membranes were fabricated and characterized in terms of their structural morphology, thermal stability, and gas-permeation properties with scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and a pure-gas-permeation system, respectively. Pure-gas-permeation tests were performed with the pure gases carbon dioxide (CO2) and N2 at room temperature at a pressure of 8 bar. On the basis of the results, the highest CO2/N2 selectivity of 75.73 was obtained for the carbon membrane prepared with a 15 wt % polymer composition.