Synthesis and Characterization of Novel Soluble Aromatic Polyesters with Pendant Cyano Groups

Abstract

Bis (4-carboxyphenoxy) benzonitrile was first synthesized by condensation of 2, 6-difluorobenzonitrile with p-Hydroxybenzoic acid in the presence of KOH and DMSO. And then the reaction of 2, 6-bis (4-carboxyphenoxy) benzonitrile with sulfur oxychloride yieded 2, 6-bis (4-chloroformylphenoxy) benzonitrile (BClPOBN). A series of novel soluble aromatic polyesters with pendant cyano groups were prepared by polycondensation of different aromatic diphenols and 2,6-bis (4-chloroformylphenoxy) benzonitrile (BClPOBN) using 1,2-dichoroethane (DCE) as solvent and pyridine as the absorbent of HCl. The resulting polymers were characterized by different physico-chemical techniques, such as FT-IR, Thermogravimetric analysis (TGA), Wide angle X-ray diffraction (WAXD), and so on. All the polymers had the proposed structure and were amorphous. Thermogravimetric studies showed that the thermal decomposition temperatures (Tds) at 5% weight loss of polymers were 391~406 ℃ in N2 atmosphere, indicating they had good thermal stabilities. The prepared polyesters exhibited good solubility in some common solvents, such as CHCl3, ethylene dichloride (DCE), CH2Cl2, tetrahydrofuran (THF) as well as aprotic polar organic solvents such as N-methyl pyrrolidone (NMP), N, N-dimethylacetamide (DMAC) and N, N-dimethylformamide (DMF), and so on.