Boltorn-modified polyimide gas separation membranes

This paper describes the preparation, characterization and permeation properties of polyimide BTDA-AAPTMI (Matrimid 5218) and co-polyimide BTDA-TDI/MDI (P84) dense polymer films containing aliphatic hyperbranched polyesters, Boltorn (H40). The H40 are dispersed in the polymers at various concentrations. For Matrimid-H40 1.0 wt% membrane the nitrogen permeability increases but with significant loss in selectivity, while at higher H40 concentrations (5.0 and 10.0 wt%) the permeability becomes lower than of the pure polymer and the selectivity generally stays constant. The dispersion of various concentrations of H40 (1.0, 5.0 and 10.0 wt%) in P84 membranes decreases gas permeability in comparison to pure P84, while the selectivity generally stays constant. (C) 2007 Elsevier B.V. All rights reserved.