Synthesis, characterization, and gas transport properties of new semifluorinated poly(ether imide)s containing cardo moiety

Abstract

ABSTRACT A series of new semifluorinated poly(ether imide)s (PEI)s was synthesized from a diamine monomer, 9,9‐ bis ‐[3‐phenyl‐4‐{2′‐trifluoromethyl‐4′‐(4′′‐aminophenyl)phenoxy} phenyl]fluorene on reaction with three different aromatic dianhydrides namely, 4,4′‐(4,4′‐isopropylidenediphenoxy) bis (phthalic anhydride), 4,4'‐(hexafluoro‐isopropylidene)diphthalic anhydride, and 4,4'‐oxydiphthalic anhydride. The PEIs were well characterized by elemental analysis, spectroscopic, thermal, mechanical, electrical, and optical techniques. The synthesized PEIs showed high glass transition temperature ( T g up to 288 °C) and high thermal stability (T d ,10 up to 521 °C under synthetic air), high tensile strength, up to 76 MPa and low dielectric constant (ɛ) (2.35–2.61 at 1 MHz). The membranes prepared from these polymers were studied for their gas permeability for four different gases CO 2 , O 2 , N 2 , and CH 4 . The PEI membranes showed high gas permeability ( P CO2 up to 70.3 and P O2 up to 16.7 Barrer) and high permselectivity ( P CO2 / P CH4 up to 73.6 and P O2 / P N2 up to 13.4); for the O 2 /N 2 gas pair the PEIs surpassed the present upper boundary limit of 2008 drawn by Robeson. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45213.