On the interlayer toughening of carbon fibre/epoxy composites using surface-activated ultra-thin PEEK films

Dong Quan, Guilong Wang, Guoqun Zhao*, René Alderliesten

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review


The exceptional mechanical properties of Polyether-ether-ketone(PEEK) polymers make them ideal candidates for interlayer toughening of carbon fibre/epoxy composites. Herein, ultra-thin PEEK films with a thickness of 8μm, 18μm and 25μm were used for interlayer toughening of an aerospace-grade carbon fibre/epoxy composite. The mode-I and mode-II fracture behaviour of the interleaved laminates were investigated, with the fracture mechanisms being investigated. The surfaces of the PEEK films were treated by a UV-irradiation technique to enhance their intrinsically low surface activities. This significantly increased the adhesion at the interface between the PEEK interlayers and the composite matrix. A topography analysis on the fracture surfaces revealed extensive damage of the PEEK interlayers during the fracture process of the laminates. Owing to the exceptional properties of the PEEK films, significant enhancements in the mode-I and mode-II fracture properties of the laminates were obtained, i.e. the mode-I and mode-II fracture energies were significantly increased by 227% and 441%, respectively. Overall, the UV-treated PEEK films proved superior effectivenesses for laminate toughening when compared to the other state-of-the-art interlayer materials.

Original languageEnglish
Article number116309
Number of pages11
JournalComposite Structures
Publication statusPublished - 2023

Bibliographical note

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  • Fracture toughness
  • Interlayer toughening
  • Polymer-matrix composites (PMCs)
  • Ultra-thin films


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