Synthesis and characterization of soluble aromatic poly(ether amide amide ether ketone ketone)s by electrophilic Friedel–Crafts solution polycondensation

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°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.

Synthesis and properties of novel copolymers of poly(ether ketone ketone) and poly(ether ether ketone ketone) containing amide and sulfone linkages

N, N′-Bis(4-phenoxybenzoyl)-4,4′-diaminodiphenyl sulfone (BPBDAS) was prepared by the condensation of 4,4′-diaminodiphenyl sulfone with 4-phenoxybenzoyl chloride in N, N-dimethylacetamide. Novel copolymers of poly(ether ketone ketone) (PEKK) and poly(ether ether ketone ketone) containing amide and sulfone linkages (PEASAEKK) were synthesized by electrophilic Friedel–Crafts copolycondensation of terephthaloyl chloride with a mixture of diphenyl ether (DPE) and BPBDAS over a wide range of DPE/BPBDAS molar ratios, in the presence of anhydrous AlCl3 and N-methylpyrrolidone in 1,2-dichloroethane. The influences of the reaction conditions on the preparation of copolymers were examined. The copolymers obtained were characterized by different physicochemical techniques. The copolymers containing 10–25 mol% BPBDAS are semicrystalline and had remarkably increased Tgs compared to the commercially available poly(ether ether ketone) and PEKK due to the incorporation of amide and sulfone linkages in the main chains. The copolymer V with 25 mol% BPBDAS had not only high Tg of 187°C but also moderate Tm of 343°C, with good potential for melt processing. The copolymer V had a tensile strength of 102.7 MPa, Young’s modulus of 2.19 GPa, and elongation at break of 14.1%, and it also exhibited high thermal stability and good resistance to organic solvents.