Desilylation of copolymer membranes composed of poly[1-(-trimethylsilyl)phenyl-2-(-trimethylsilyl)phenylacetylene] for improved gas permeability

Efficient gas-separation systems comprising gas-permeable membranes are important for energy conservation in various industrial applications. Herein, high-molecular-weight copolymers ( 2ab and 2ac ) were synthesized in good yields by the copolymerization of 1-( p -trimethylsilyl)phenyl-2-( p -trimethylsilyl)phenylacetylene ( 1a ) with 1-phenyl-2-( p-tert -butyl)phenylacetylene ( 1b ) and 1-phenyl-2-( p -trimethylsilyl)phenylacetylene ( 1c ) in various monomer feed ratios using TaCl 5 - n -Bu 4 Sn. Tough membranes were obtained by solution casting. The copolymers exhibited very high gas permeabilities ( P O 2 : 1700-3400 barrers). Desilylation of 2ac membranes decreased the gas permeability, but desilylation of 2ab membranes resulted in a significant increase in the gas permeability. The highest oxygen permeability coefficient obtained was 9300 barrers, which was comparable to that of poly(1-trimethylsilyl-1-propyne), a polymer known to have the highest gas permeability. Enhancement of oxygen permeability by desilylation of diphenylacetylene copolymer membranes.