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

Abstract

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°C for 10% weight loss in air, glass transition temperatures in the ranges of 252–278°C, tensile strengths up to 99MPa). PA ‘I’ having tert-butyl group showed highest permeability in barrer for PCO2=42.60, PO2=10.00, PN2=2.10, PCH4=1.80. PA ‘II’ containing hexafluroisopropylidene linkage showed highest permselectivity for O2 and N2 gas pair (PO2/PN2=7.08) whereas PA ‘IV’ showed highest permselectivity towards CO2 over CH4 (PCO2/PCH4=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.