Crystallization of poly(aryl‐ether‐ether‐ketone): Effect of thermal history of the melt on crystallization kinetics

Differential Scanning Calorimetry (DSC) and optical microscopy were used to investigate the effect of the thermal history of the melt on the crystallization of a commercial sample of poly(aryl‐ether‐ether‐ketone) (PEEK). Heating a film of PEEK at a temperature above the melt temperature for various periods of time changes the nucleation and crystal growth rate upon cooling the sample. Destruction of existing nuclei, formation of new nuclei, chain branching, cross linking, and chemical degradation of the macromolecular chains are all believed to take place at different times and to different extents during the thermal melt processing of the polymer. This study suggests that the thermal history of the melt plays an important role in the crystallization of PEEK samples.