Naphthalene-based poly(aryl ether)s. I. Synthesis and characterization of poly(ether sulfone)s and poly(ether ketone)s containing one 1,4-naphthylene moiety in the repeat unit

The effect of insertion of one 1,4-naphthylene unit into several PEEK-like and Udel®-like commercial polymers is examined. Two series of poly(ether ketone)s and poly(ether sulfone)s were made from the polycondensations of 1-chloro-4-(4-fluorobenzoyl)naphthalene and 1-chloro-4-(4-fluorobenzenesulfonyl)naphthalene with phenolphthalein (PP), 2,2′,6,6′-tetramethyl-4,4′-biphenol (TMBP), and 4,4′-biphenol (BP). Each polymer was soluble in chloroform, from which dense films could be cast. Glass transition temperatures increased 14-19 °C with TMBP, 30–43 °C with BP, and 39–60 °C in the case of PP. The 1,4-naphthylene insertion reduced the crystallinity of the biphenol-based polymers. The onset temperatures for 5% weight loss ranged from 390 to 536 °C in nitrogen, as assessed by thermogravimetry. Young's moduli varied from 0.54 to 2.1 GPa. In the case of the poly (ether ketone) containing TMBP, incorporation of the 1,4-naphthylene moiety increased gas permselectivity at the cost of decreased permeability, whereas there seemed only to be a decrease in permeability with its poly(ether ketone) counterpart. Keywords: naphthalene, poly(ether sulfone)s, poly(ether ketone)s, glass transition temperature, gas permeability.