The gas separation properties of new aromatic polyoxadiazole (POD) and
polytriazole (PT) membranes have been investigated. A wide range of p
ermeability and selectivity was found for polymers with 4,4'-diphenyl-
ether unit (POD-DPE and PT-DPE), 4,4'(2,2'-diphenyl)hexafluorisopropan
e (POD-HF), 1,1',3-trimethyl-3-phenylindane (POD-PIDA) and 5-tert-buty
lisophthalic (POD-TBI) units incorporated into the backbone. The diffe
rences found in permeability and selectivity, as well as the dual sorp
tion parameters of POD-PIDA and POD-DPE polyoxadiazoles are discussed
in terms of their free volume determined by group contribution.