Synthesis, characterization and thermal degradation of phosphorus–nitrogen containing poly(aryl ether ketone)s

A series of high-molecular-weight poly(aryl ether ketone)s with phosphorus and nitrogen on their side and main chains was synthesized by a nucleophilic substitution polycondensation of 6-(4-hydroxyphenyl)pyridazin-3(2H)-one (HPZ) with 1,1′-bis(4-hydroxyphenyl)-metheylene-bispheny-1-oxophosphine oxide (DOPO-PhOH) and 4, 4′-difluorobenzophenone (DFBP) at various molar ratios. The structures of the poly(aryl ether ketone)s were characterized by means of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR, 31P NMR) and elemental analysis. The influence of the nitrogen- and phosphorus-containing monomer ratio on their thermal stability was investigated by adjusting the proportion of the HPZ and DOPO–PhOH from 0:10 to 8:2. The polymers were readily soluble in polar organic solvents, such as N-methylpyrrolidone (NMP), N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF) and chloroform. Differential scanning calorimetry (DSC) demonstrated that these polymers have an amorphous morphology.