The effects of manganese ions on rheology and thermal properties of polyether ether ketone

Polyether ether ketone (PEEK) mixed with manganese (Mn) of different valences was prepared to simulate conditions of impurity. The melt flow rate (MFR) and rheological behaviour were systematically studied to characterize the mobility from different angles. MFR test was used for the preliminary exploration of mixtures of Mn ions. The results showed that Mn, Mn(II), and Mn(IV) had little impact on the mobility of PEEK contrary to Mn(VII) and that long chain branching or cross-linking was suspected. Mn(VII) was determined to be the main object of this research. Capillary rheometer test demonstrated that the apparent shear viscosity constantly reduced with the increase of apparent shear rate, and that the addition of Mn(VII) could worsen the mobility of PEEK. Similarly, parallel plate rheometer studies proved that the complex viscosity increased along with the content of Mn(VII) and LCB was confirmed. Thermal analysis revealed that LCB occurred internally and that thermal stability was worse.