NAMS 2002 Workshop - ICOM 2008

Nanostructured Membranes I – 3
Monday July 14, 3:30 PM-4:00 PM, Moloka’i
Polymers of Intrinsic Microporosity: New Copolymers, Syntheses,
Properties and Applications.
D. Fritsch (Speaker), GKSS Research Centre Geesthacht GmbH, Germany, fritsch@gkss.de
K. Heinrich, GKSS Research Centre Geesthacht GmbH, Germany
G. Bengtson, GKSS Research Centre Geesthacht GmbH, Germany
J. Pohlmann, GKSS Research Centre Geesthacht GmbH, Germany
Since the discovery of polymers of intrinsic microporosity (PIM polymers) in 2004
[1] their superior properties and applicability in membrane separation processes
were detected [2, 3] . Besides very recently reported polyimides based on the PIM
concept [4] in this paper new copolymers of the PIM family with excellent film
forming properties will be reported. As detected by modeling of PIM-1 [5] the site
of contortion of the spirobisindane unit and the ether bonds attached to the
dicyanobenzene are somewhat deformed in the packed model, thus showing
more flexibility than expected. We concentrated our work on increasing the
stiffness of the site of contortion by synthesizing new tetrahydroxymonomers and
applying 2,3,5,6- tetrafluoro-4-cyanopyridine to introduce basic tertiary nitrogen
to eventually shift the properties. The syntheses and basic gas data, such as
permeability, diffusivity and solubility, will be reported for the first time. From
these properties the microporosity of the new polymers may be presumed. To
verify this hypothesis, a simple test applying PIM membranes for separation of
methanol/Ar mixtures fitted to a mass spectrometer as detector was performed.
Starting from gas/vapor-free thick membranes of about 100 µm, the pore filling
process could be monitored by (1) fast increase of the argon signal according to
the time-lag and (2) with increase of the methanol signal, accompanied by the
methanol condensation in the micropores, a marked decrease of the argon signal
was observed. This effect attributed to microporosity was validated further by
measuring well known high free volume, microporous polymers of the
polyacetylene family. In addition, thin-film composite membranes on different
polymeric supports were prepared and the properties measured, including
durability measurements for gases and in nanofiltration.
[1] P.M. Budd, B.S. Ghanem, S. Makhseed, N.B. McKeown, K.J. Msayib, C.E. Tattershall,
Polymers of intrinsic microporosity (PIMs): robust, solution- processable, organic nanoporous
materials, Chem. Commun., 2004, 230-231.
[2] P.M. Budd, E.S. Elabas, B.S. Ghanem, S. Makhseed, N.B. McKeown, K.J. Msayib, C.E.
Tattershall and D. Wang, Solution- processed, organophilic membrane derived from a polymer of
intrinsic microporosity , Adv. Mater., 2004, 16, 456-459.