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

Abstract

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°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°C and 232°C and 10% weight loss temperatures ranging from 443°C to 496°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.