Semifluorinated, organo-soluble new aromatic poly(ether amide)s: Synthesis, characterization and gas transport properties

A series of processable fluorinated poly(ether amide)s (PAs) were synthesized from a new diamine monomer, 1,4-bis-[{2′-trifluromethyl 4′-(4″-aminophenyl)phenoxy}] phenyl with four different aromatic dicarboxylic acids. The polymers have been well characterized by GPC, FTIR, NMR, XRD and thermal techniques. The PAs showed excellent thermal stability (411–468 °C for 10% weight loss), high glass transition temperatures (243–290 °C), high tensile strengths up to 83.9 MPa and elongation at break up to 21%. PA ‘6a’ showed highest permeability in barrer for PCO2=55.41PCO2=55.41, PO2=14.09PO2=14.09, PN2=2.38PN2=2.38, PCH4=2.29PCH4=2.29. PA ‘6b’ showed highest permselectivities for CO2 and CH4 (PCO2/PCH4=36.83PCO2/PCH4=36.83) as well as for O2 and N2 gas pairs (PO2/PN2=8.05PO2/PN2=8.05) among the series. It has been attempted to draw a structure–property correlationship between the chemical structures of the polymers and their gas transport properties on the basis of their FFV, glass transition temperatures, and chain packing density.

► Processable poly(ether amide)s.
► Membrane preparation.
► High gas permeabilities.
► High ideal selectivity both for O2/N2 (PO2/PN2=8.05PO2/PN2=8.05) and CO2/CH4 (PCO2/PCH4=36.83PCO2/PCH4=36.83) gas pairs.
► Structure–property correlation.