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

Abstract

ABSTRACTA 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 (Tg up to 288 °C) and high thermal stability (Td,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 CO2, O2, N2, and CH4. The PEI membranes showed high gas permeability (PCO2 up to 70.3 and PO2 up to 16.7 Barrer) and high permselectivity (PCO2/PCH4 up to 73.6 and PO2/PN2 up to 13.4); for the O2/N2 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.