For the last two decades, the possibility of using synthetic membranes for
industrial gas separations has attracted considerable interest since membrane
separation technologies have the advantages of energy efficiency, simplicity and
low cost. However, for wider commercial utilization there is still a need to develop
membranes with higher permeant fluxes and higher transport selectivities.
Conductive polymers, due to their high gas transport selectivities, give rise
to a new class of polymeric materials for membrane based gas separation though poor mechanical properties obstruct the applications for this purpose of use. This
problem led researches to a new idea of combining the conducting polymers with
insulating polymers forming mixed matrix composite membranes.
In the previous studies in our group, polypyrrole was chosen as the
conductive polymer, and different preparation techniques were tried and optimized
for membrane application. As the insulating polymer, previously poly(bisphenol-Acarbonate)
was used to support the conductive polymer filler in order to constitute a
conductive composite membrane. For this study, as the polymer matrix,
hexafluorobisphenol A based poly(arylene ether ketone) was targeted due to its
physical properties and temperature resistance which can be important for industrial
applications.
First of all, permeabilities of N2, CH4, Ar, H2, CO2, and H2 were measured at
varying temperatures ranging from 25° / C to 85° / C through a homogenous dense
membrane of chosen polymeric material to characterize its intrinsic properties.
Measurements were done using laboratory scale gas separation apparatus which
makes use of a constant volume variable pressure technique. The permeability
results were used for the calculations of permeation activation energies for each gas.
These permeation activation energies were found to be differing slightly for each
gas independently from the kinetic diameters of gases.
In this study, mixed matrix membranes of conducting polymer, polypyrrole
(PPy) and insulating polymer, hexafluorobisphenol A based poly(arylene ether
ketone) (PAEK) were also prepared. It was observed that PAEK and PPy form a
composite mixed matrix structure, which can function as permselective membrane.
The effect of conducting polymer filler content was investigated with two different
filler ratios. When comparing with the pure PAEK membranes, meaningful
increases for both permeability and selectivity were obtained for some of the gases.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/1045798/index.pdf |
| Date | 01 January 2003 |
| Creators | Mergen, Gorkem |
| Contributors | Toppare, Levent |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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