Synthesis of novel fluorine-containing poly(aryl ether nitrile)s derived from 2,3,4,5,6-pentafluorobenzonitrile

2,3,4,5,6-Pentafluorobenzonitrile (PFBN) is a valuable intermediate and it is available as a commercial product. In this paper, synthesis and characterization of novel fluorinated poly(ether nitrile)s (PEN) derived from PFBN is reported. Novel fluorinated PENs containing fluorine atoms in the main chain and pendant phenoxy group (2F-PEN) are synthesized by aromatic nucleophilic substitution reaction, of which M_n ranges from 1.77×10⁴ to 5.16×10⁴. The obtained PENs show excellent solubilities in common solvents, and 2F-PEN(6FBA) and 2F-PEN(DPE) can be cast as tough transparent films. These polymers have high thermal stabilities with the 5% weight loss temperature in the range 509-562°C and the T_g of 142-235°C, which is highly dependent on the structures.