Hyperbranched poly(ether ether ketone)s (HPEEKs) that were suitable as rheology control agents for linear poly(ether ether ketone)s (LPEEKs) were first prepared via commercially available hydroquinone (A 2 monomer, HQ) and synthesized 3,4',5-trifluoro-benzophenone (BB' 2 monomer, TF) effortlessly. The polymerization mode of A 2 + BB' 2 was demonstrated by MS. Moreover, FTIR, 1 H NMR, 13 C NMR, and 19 F NMR spectroscopy revealed the structure and degree of branching (DB) of the resulting polymers. In comparison with A 2 + B 3 approach, HPEEK prepared using an A 2 + BB' 2 strategy possessed a higher molecular weight, and improved the melt processability of LPEEK. Remarkably, with the addition of HPEEK, the mechanical properties of LPEEK increased with a HPEEK content of 5%. The improved mechanical properties were attributed to the good miscibility. Moreover, the addition of HPEEK did not decrease the thermal stability of LPEEK.

A novel series of sulfonated hyperbranched poly(aryl ether ketone)s (S-HPAEKs) was synthesized based on different postsulfonation reactions of fluoro-terminated hyperbranched poly(aryl ether ketone). Moreover, the blend membranes of S-HPAEKs with sulfonated linear poly(aryl ether ketone) (S-LPAEK) (S-HPAEK/S-LPAEK) were prepared for proton exchange membrane. All the blends could be cast into tough membranes. The structure of S-HPAEKs was characterized and the thermal stability, water uptake, and proton conductivity of S-HPAEK/S-LPAEK membranes were investigated. The results showed that S-HPAEK/S-LPAEK membranes possessed good thermal stability, better water uptake, and good proton conductivity compared with the S-LPAEK membrane, and their properties depended on the ion exchange capacity and the content of S-HPAEK in the blend membranes.

An improvement in the processability of poly(ether ether ketone) (PEEK) and PEEK/carbon fiber (PEEK/ CF) composites with less influence on the other properties is important. A novel high temperature lubricant, GENIO-PLAST PELLETS (GPPS), was used to decrease the melt viscosity of PEEK and PEEK/CF composites. PEEK/ GPPS and PEEK/CF/GPPS compounds were characterized by dynamic rheometry, universal tester, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that a small amount of GPPS could decrease the melt viscosity of the compounds during processing, and improve the dispersion uniformity of the carbon fiber in the PEEK matrix, and further enhance the tensile strength of PEEK/CF composites, but have little effect the thermal stability of the compounds.

In this study, poly(ether ether ketone) (PEEK)/gadolinium oxide (Gd 2 O 3 ) composites were prepared by melt extrusion in combination with a Haake rheometer. Differential scanning calorimetry was used to investigate the crystallization behavior of PEEK and its corresponding composites. The microstructural features of the composites and the interfacial interactions between the filler and PEEK phases were viewed with a scanning electron microscope. Gd 2 O 3 powder was blended with PEEK, and sulfonated poly(ether ether ketone) (SPEEK) was used as the compatibilizer in the PEEK/Gd 2 O 3 composites. Isothermal crystallization exotherms showed that the addition of SPEEK increased the crystallization of PEEK in PEEK/Gd 2 O 3 composites. However, the PEEK crystallization rates decreased with increasing Gd 2 O 3 fractions, which probably resulted from the Gd 2 O 3 that had no heterogeneous nucleation effects on the matrix. The modified Avrami equation and Mo's equation were used to study the nonisothermal crystallization kinetics. The addition of Gd 2 O 3 did not change the nucleation process of PEEK, but it markedly decreased the crystal growth rate.

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