Fluorinated poly(arylene ether)s with aliphatic chain appended cardo moiety: Synthesis and gas transport properties

• New bisfluoro monomer containing 9-alkylated fluorene moiety was synthesized.
• Poly(arylene ether)s (PAEs) were synthesized by using the new bisfluoro monomer.
• PAEs showed good thermal stability and low dielectric constant (ϵ=2.33).
• PAEs showed very high permeability and permselectivity.

The effect of cardo moiety together with long aliphatic chain in the poly(arylene ether)s (PAEs) on gas transport properties has been investigated. Accordingly, this article reports the synthesis of a new cardo bisfluoro monomer with long aliphatic chain; 9,9-bis(2-ethylhexyl)-2,7-bis[4-fluoro-3-trifluoromethylphenyl]-9H-fluorene and its polymerization with six different bishydroxy monomers. The monomer and the PAEs were characterized by elemental analysis, NMR, and FTIR techniques. The molecular weights of the PAEs were determined by GPC. Thermal and mechanical properties of the PAEs were also investigated. The polymers showed Tg up to 189 °C, 10% degradation temperature up to 427 °C and 420 °C under nitrogen and air atmosphere respectively, tensile strength up to 64 MPa and dielectric constant (ϵ) as low as 2.33. Gas transport properties of these PAE membranes were investigated at 35 °C using four different gases (e.g., CH4, N2, O2 and CO2). The PAEs showed high gas permeability [P(CO2)=74.65P(CO2)=74.65] and permselectivity [α(CO2/CH4)=61.69α(CO2/CH4)=61.69] in comparison with many other previously reported PAEs.

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