New poly(aryl ether ketone)s containing 2,6-diphenylpyridyl units and diphenylphosphinophenyl pendant groups

Abstract

4-(4-Diphenylphosphino)phenyl-2,6-bis(4-hydroxyphenyl)pyridine, as a new bisphenol monomer, was prepared from 4-(diphenylphosphino)benzaldehyde and 4-hydroxyacetophenone and used in the preparation of several aromatic poly(ether ketone)s (PEKs) containing 2,6-diphenylpyridyl units and diphenylphosphinophenyl pendant groups via a nucleophilic aromatic substitution polycondensation with difluorinated aromatic ketones. The polycondensation proceeded quantitatively in tetramethylene sulfone in the presence of anhydrous potassium carbonate and afforded the polymers with high molecular weights. The resulting PEKs are amorphous and exhibit high glass transition temperatures of 209–255°C and 5% weight loss temperatures of 536–554°C with char yields of 57–62% at 800°C in nitrogen. Their high char yields and good limited oxygen index values ranging from 39 to 43 indicated these polymers exhibited good thermal stability and flame-retardant property. All new PEKs were soluble in common organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and chloroform and could form tough, flexible, and strong films with tensile strengths of 74.6–86.8 MPa, tensile moduli of 2.9–3.6 GPa, and elongations at break of 5–9%.

Synthesis and Characterization of a Self-Polycondensation Diazaphthalanone Monomer and Its Polymers from Polycondensation Reactions

“…With the development of science and technology, the high-tech field has put forward higher requirements for materials, such as molecular weight [17], glass temperature [18], heat resistance [19], solubility [20], mechanical properties [21], and other aspects for the requirements of higher performance. The aromatic heterocyclic structure containing nitrogen atoms has a conjugated system [22], which not only retains the overall rigidity of the main chain but also inhibits the free rotation of chain segments, endowing the polymer with excellent thermal and mechanical properties.…”