Synthesis, characterization and gas transport properties of semifluorinated new aromatic polyamides

This manuscript describes the synthesis, characterization and gas transport properties of a series of poly(ether amide)s (PAs) prepared from a new diamine monomer 4,4-bis-[2'-trifluromethyl 4'-(4 ''-aminophenyl)phenoxy]-biphenyl on reaction with five different aromatic dicarboxylic acids. The polyamides exhibited very good film forming ability, thermal and mechanical properties (448-479 degrees C for 10% weight loss in air, glass transition temperatures in the ranges of 252-278 degrees C, tensile strengths up to 99 MPa). PA 'I' having tert-butyl group showed highest permeability in barter for P-CO2 = 42.60, P-O2 = 10.00, P-N2 = 2.10, P-CH4 = 1.80. PA 'II' containing hexafluroisopropylidene linkage showed highest permselectivity for O-2 and N-2 gas pair (P-O2/P-N2 = 7.08) whereas PA 'IV' showed highest permselectivity towards CO2 over CH4 (P-CO2/P-CH4 = 30.25) among the series. Attempt has been made to draw structure-property co-relationship in terms of thermal, mechanical and gas transport properties vs. the polymer repeat unit structures. (c) 2012 Elsevier B.V. All rights reserved.