Effects of Trifluoromethyl Side Groups on Gas Permeability and Permselectivity in Polyimides.

Polyimides [N(CO) 2 Ar(CO) 2 N-R-] n (Ar= Ph(CF 3 ), Ph, Ph-C(CF 3 ) 2 -Ph; R= Ph(CF 3 )-Ph(CF 3 ), Ph(Me) 2 -Ph(Me) 2 , Ph-C(CF 3 ) 2 -Ph, PhOPh) were synthesized and permeation properties of H 2 , CO, CO 2 and CH 4 were measured