Synthesis and properties of fluorine-containing poly(aryl ether oxadiazole)s

Fluorine-containing poly(aryl ether 1,3,4-ozadiazole)s were synthesized by the nucleophilic aromatic substitution reaction of 2,5-bis(2,3,4,5,6- pentafluorophenyl)1,3,4-oxadiazole and various bisphenols in the presence of potassium carbonate. The polymerizations were carried out at 30°C in l-methyl-2-pyrrolidinone to avoid the gelation caused by a crosslinking reaction at para and ortho carbons to the 1,3,4-oxidiazole ring. The obtained polymers were all pom-connected linear structures. The obtained fluorine-containing poly(aryl ether 1,3,4-ozadiazole)s showed excellent solubility and afforded tough, transparent films by the solution-casting method. They also exhibited a high glass transition temperature depending on the molecular structure, and the glass transition temperature could be controlled by the bisphenols in the range of 157-257°C. They showed good thermal stability and excellent hydrophobicity due to the incorporation of the 2,3,5,6-tetrafluoro-l,4-phenylene moiety.