Synthesis and characterization of poly(phthalazinone ether phosphine oxide)s by N-C coupling reaction

Based on several unsymmetrical, twist, noncoplanar phthalazinone-containing monomers 2a–2e and an active bis(4-fluorophenyl)phenyl phosphine oxide (BFPPO) monomer, a series of novel poly(phthalazinone ether phosphine oxide)s (PPEPO) was synthesized by anhydrous K2CO3 mediated N-C coupling reaction in DMAc. The polymers exhibited good thermal properties with Tgs ranging from 267°C to 306°C and 5% weight loss temperatures in nitrogen higher than 430°C, together with high char yield upon prolonged heating at 800°C (35%–56%). Moreover, the polymers were readily soluble in common organic solvents, such as N-methyl-2-pyrrolidone, chloroform and m-cresol. These polymers had inherent viscosities in the range of 0.45–0.72 dL/g and could be cast into flexible and colorless films by spin coating or casting approach.