Unusual crystalline morphology of Poly Aryl Ether Ketones (PAEKs)

The crystal structure of Poly Aryl Ether Ketones (PAEKs) fabricated using a range of manufacturing processes has been investigated by high resolution electron microscopy. The study has revealed a hierarchical spherulitic crystal structure, different from the common spherulite morphology with lamellae grown in a radial direction. The results show that spherulites in laser sintered PAEKs are built of granular crystal blocks of 75-145 nm in size self-assembled along the radial direction. The study also showed that the granular crystal blocks are composed of small primary crystals approximately 20-30 nm in size combined together with a secondary structure. The secondary structure was found to be less ordered and was preferentially removed during chemical etching whereas the primary crystals remained intact.