Synthesis and characterization of 1,3,4-oxadiazole-containing polyethers from 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole and various aromatic diols

✍ Scribed by Yasuo Saegusa; Takeshi Iwasaki; Shigeo Nakamura

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 458 KB
• Volume: 198
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1997.021980609

✦ Synopsis

Abstract

Six 1,3,4‐oxadiazole‐containing polyethers with reduced viscosities of 0,65–1,17 dL · g^−1^ were synthesized by high‐temperature solution polycondensation of an activated difluoride, 2,5‐bis(4‐fluorophenyl)‐1,3,4‐oxadiazole, with aromatic diols possessing a variety of ring structures. The expected chemical structures were confirmed by IR and ^1^H NMR spectroscopy and elemental analysis. Of all the polymers, two polyethers were highly crystalline and soluble only in limited solvents such as o‐chlorophenol and conc. sulfuric acid. The other polyethers were amorphous and dissolved readily in a variety of organic media including polar aprotic solvents, phenols and chlorinated hydrocarbons. Colorless to slightly yellow‐colored, transparent and tough films could be cast from the N‐methyl‐2‐pyrrolidone or o‐chlorophenol solutions. The mechanical properties were excellent and their tensile strength, elongation at break and tensile moduli were in the ranges of 53–80 MPa, 4–12% and 1,3–2,0 GPa, respectively. The amorphous polyethers had high glass transition temperatures of 195–259°C. All the polyethers were highly thermally and thermooxidatively stable and exhibited no weight loss up to 400°C, with 10% weight loss being recorded at 464–514°C in air.