Sipra Ghosh

Synthesis, characterization and gas transport properties of cardo bis(phenylphenyl)fluorene based semifluorinated poly(ether amide)s

Here we report the synthesis and properties of a series of processable poly(ether amide)s (PAs) having the bis(phenylphenyl)fluorene moiety prepared from a new diamine monomer, 9,9-bis-[3-phenyl-4-{2′-trifluoromethyl-4′-(4′′-aminophenyl) phenoxy}phenyl]fluorene. Analogous PAs having the bis(phenyl)fluorene moiety have also been prepared from the diamine 9,9-bis-[4-{2′-trifluoromethyl-4′-(4′′-aminophenyl) phenoxy} phenyl]fluorene for comparative purposes. The synthesized PAs exhibited high thermal stability (up to 517 °C and 539 °C in air and nitrogen respectively, for 10% weight loss), high glass transition temperature (272–299 °C) and high tensile strength up to 117 MPa. The optically transparent membranes (λcut-off ≥ 368 nm) from these PAs showed high gas permeability in barrer (PCO2 up to 67.42 and PO2 up to 15) and high permselectivity (PCO2/PCH4 up to 88.37 and PO2/PN2 up to 10.84); especially for the O2/N2 gas pair the PAs surpass or touch the present upper boundary limit of 2008 drawn by Robeson. The effect of the bis(phenylphenyl)fluorene moiety and diacid moieties in PAs on the dielectric values, thermal, mechanical, optical and gas transport properties were correlated.

Fluorinated Poly(Arylene Ether)s: Synthesis, Properties, and Applications

Abstract Poly(arylene ether)s consisting of aromatic rings and ether linkages form an important class of high-performance polymeric material with an excellent combination of thermal and mechanical properties. Poly(ary1ene ether)s are generally synthesized via nucleophilic aromatic substitution of an activated dihalide with an aromatic bisphenol. Fluorinated poly(arylene ether)s containing bulky –CF 3 groups are especially interesting because they enhance the solubility of the polymers and increase the glass transition temperature without reducing thermal stability. The bulky –CF 3 group also serves to increase the free volume of the polymer, thereby improving various properties of the polymer including its application as a membrane material and in microelectronic applications by endowing a low dielectric constant. The first part of the chapter deals with the synthetic strategies, characterization, and general properties of fluorinated poly(arylene ether)s. The second part deals with the application of fluorinated poly(arylene ether)s in gas separation and pervaporation and as proton exchange membranes for fuel cell application.