NAMS 2002 Workshop - ICOM 2008

Nanostructured Membranes I – 6
Monday July 14, 5:00 PM-5:30 PM, Moloka’i
An Efficient Method for Preparing High Molecular Weight Polymers of
Intrinsic Microporosity (PIM)s with Cyclic-Free Structure via Fast
Polycondensation
N. Du (Speaker), Institute for Chemical Process and Environmental Technology, National
Research Council, Ottawa, Ontario, Canada
G. Robertson, Institute for Chemical Process and Environmental Technology, National Research
Council, Ottawa, Ontario, Canada
J. Song, Institute for Chemical Process and Environmental Technology, National Research
Council, Ottawa, Ontario, Canada
S. Thomas, Membrane Technology and Research, Menlo Park, CA, USA
I. Pinnau, Membrane Technology and Research, Menlo Park, CA, USA
M. Guiver, Institute for Chemical Process and Environmental Technology, National Research
Council, Ottawa, Ontario, Canada, michael.guiver@nrc-cnrc.gc.ca
Recently, a British research group, reported on the syntheses of a number of
wholly aromatic glassy ladder polymers, referred to as Polymers of Intrinsic
Microporosity (PIM)s, via irreversible polycondensations at 65°C for 72 h. These
polymers have attracted great interest as an outstanding class of advanced
polymeric materials for membrane-based gas separation due to their rigid and
contorted zig-zag chain structure and loose chain packing that is capable of
generating very high free volume. In our work, a successful synthetic approach to
high molecular weight linear ladder polymers with few low molecular weight cyclic
species was carried out at elevated temperature and high monomer
concentration. In contrast with previously reported conditions for preparing these
PIM materials, the reaction could be completed within a few minutes. The
polymer properties were characterized by GPC, 1 HNMR, 13 CNMR, FNMR, FT-IR,
and MALDI-TOF MS. This procedure can also be used for the general synthesis
of other ladder polymers by irreversible polycondensation of tetraphenols with
activated tetrafluoro aromatics. Gas permeability coefficients (P) were measured
for helium, hydrogen, carbon dioxide, oxygen, methane and nitrogen. PIM-1
exhibits high gas permeability coupled with moderate selectivity. For example,
the oxygen permeability of PIM-1, made by the new synthetic method, is 1,650
Barrer coupled with an oxygen/nitrogen selectivity of 3.3.