(699e) Polybenzoxazole Copolymer Membranes Tuned for Enhanced Gas Permeability Via Thermal Rearrangement

Thermally-treated of acetate-containing polyimide at elevated temperature to convert aromatic polymer chain into polybenzoaxazole is well known for the enhancement in gas permeation performance due to the increase in fractional free volume and cavity sizes [1]. In the present work, a series of acetate-containing co-polyimide in various compositions were prepared, and subsequently rearranged to polybenzoaxazole copolymer membranes at 425 ^oC. The resulting polybenzoaxazole copolymer membranes were characterized by a number of physical and chemical techniques. All the copolymer membranes showed higher gas permeability than the homopolymer membranes and an increment of 420% were found in CO₂ permeability. CO₂ permeability as high as 1539 Barrer can be achieved without a significant loss in selectivity. The polybenzoaxazole copolymer membranes reported here show gas permeation performance surpassing the trade-off lines, mainly due to the improved of intrinsic membrane properties such as increase in rigidity of the chemical backbone.

Reference:

[1]  C. H. Jung, J. E. Lee, S. H. Han, H. B. Park, Y. M. Lee, Highly permeable and selective poly(benzoxazole-co-imide) membranes for gas separation. Journal of Membrane Science 350 (2010) 301–309.