Development of highly gas-permeable polymers by metathesis copolymerization of 1-( p -trimethylsilyl)phenyl-1-propyne with tert -butyl and silyl group-containing diphenylacetylenes.

The development of highly gas-permeable membranes is required for gas separation applications. In this study, 1-( p -trimethylsilyl)phenyl-1-propyne (SPP) was copolymerized with diphenylacetylenes bearing tert -butyl (BDPA) and SiMe 3 (SDPA) groups at various feed ratios to obtain poly(SPP- co -BDPA) and poly(SPP- co -SDPA) copolymers, respectively. Free-standing membranes were fabricated from toluene solutions of the copolymers, the gas permeability of which increased as the SPP ratio decreased ( P O 2 : 550-2100 barrers). Interestingly, poly(SPP- co -BDPA) and poly(SPP- co -SDPA) at a 1 : 4 ratio of SPP:BDPA and SPP:SDPA, respectively, showed higher permeabilities than the respective homopolymers. Desilylation of the poly(SPP- co -BDPA) membrane increased the gas permeability, whereas desilylation of the poly(SPP- co -SDPA) membrane had the opposite result.