Berlin 2008 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 14: Membranes
CPP 14.1: Talk
Tuesday, February 26, 2008, 15:00–15:15, C 230
Free Volume and Permeability in Boltorn-modified Gas Separation Membranes — •Klaus Rätzke1, Jan Kruse1, Franz Faupel1, Dana Sterescu2, Dimitrios Stamatialis2, Matthias Wessling2, and Eduardo Mendes3 — 13. Technische Fakultät Universität Kiel, Germany — 21. University of Twente, The Netherlands — 32. Delft University of Technology, The Netherlands
This paper describes the the permeation properties of poly (2, 6-dimethyl-1,4-phenylene oxide) (PPO) dense polymer films containing aliphatic hyperbranched polyesters, Boltorn (H40) which are dispersed at various concentrations. Focus is on the correlation between permeation and free volume, which was determined by positron annihilation lifetime spectroscopy, using a well established correlation between orthopositrionium lifetime and average free volume size. The gas permeability of PPO with 1.0 wt % of Boltorn is 2-3 times higher than the pure polymer, while at higher concentration (9.1 wt %) of Boltorn the permeability becomes almost 50 % of the pure polymer. The gas pair selectivity, however, stays constant. The increase in permeability at low concentration of Boltorn is due to the increase of the free volume, probably due to hydrogen bonds between Boltorn and the oxygen of PPO backbone. The decreased permeability of PPO containing higher concentration of Boltorn (9.1 wt %) is due to two reasons: decrease in free volume as determined by PALS as well as phase separation. D. Sterescu, D. Stamatialis, E. Mendes, J. Kruse, K. Rätzke, F. Faupel, M. Wessling Macromolecules, 40 (2007) 5400.