Synthesis of poly(ether ketone amide)s by a heterogeneous palladium-catalyzed polycondensation of aromatic diiodides, diamines, and carbon monoxide

A series of novel aromatic poly(ether ketone amide)s (PEKAs) were synthesized by the heterogeneous palladium-catalyzed carbonylative polycondensation of aromatic diiodides with ether ketone units, aromatic diamines, and carbon monoxide in N,N-dimethylacetamide (DMAc) at 120 degrees C using 6 mol% of a magnetic nanoparticles-supported bidentate phosphine palladium complex (Fe3O4@SiO2-2P-PdCl2) as catalyst and 1,8-diazabicyclo[5,4,0]-7-undecene as base. The PEKAs had inherent viscosities ranging from 0.61 dl g(-1) to 0.75 dl g(-1). All the PEKAs were soluble in strong dipolar organic solvents. These PEKAs showed glass transition temperatures between 178 degrees C and 232 degrees C and 10% weight loss temperatures ranging from 443 degrees C to 496 degrees C in nitrogen. These PEKAs could be cast into transparent, flexible, and strong films from DMAc solutions with tensile strengths of 72.8-82.6 MPa, tensile moduli of 2.19-2.84 GPa, and elongations at break of 5.4-7.5%. Importantly, the heterogeneous palladium catalyst can be conveniently recovered from the reaction mixture by simply applying an external magnet and recycled up to eight times without significant loss of activity.