Direct observation of the fracture behavior of the polyether ketone ketone (PEKK) spherulites

Vanessa Marinosci, Kuan Chen, Nick G. J. Helthuis, Wouter J. B. Grouve, Erik G. de Vries, Ningzhong Bao, Remko Akkerman, Matthijn B. de Rooij, Liangyong Chu*

*Corresponding author for this work

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This article reports the direct observation of the fracture of individual poly‐ether‐ketone‐ketone (PEKK) spherulites. A single layer of PEKK spherulites was obtained by bonding a PEKK film in‐between two sandblasted Ti alloy plates using an autoclave. The crack of an individual PEKK spherulite was achieved by opening the Ti/PEKK/Ti sandwich using a double cantilever beam test. The fracture morphology of the PEKK spherulite was characterized using scanning electron microscopy and atomic force microscopy. It was found that under tensile stress the crack of the individual spherulite propagates along the middle plane and crosses the nucleation core. This is due to the symmetric radial structure of the spherulite. Moreover, it was found that the fracture surface morphology at the core of the spherulite is strongly influenced by the local crystalline structure, which is anisotropic and determined by the initial nucleation growth direction. As a result, the area fraction experiencing plastic deformation during the fracture of PEKK spherulites at different orientations may vary by an order of 10. Our results show the important role of the initial nucleation growth direction on the mechanical properties of the polymer crystals and may provide a new approach to the design of high‐performance polymer materials with tailored crystalline structures.
Original languageEnglish
Article numbere54764
Number of pages11
JournalJournal of applied polymer science
Issue number1
Early online date8 Oct 2023
Publication statusPublished - 5 Jan 2024


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