Mechanical performance and in vivo bioactivity of functionally graded PEEK–HA biocomposite materials

A functionally graded material (FGM) of polyetheretherketone (PEEK)–hydroxyapatite (HA) with a symmetrical three-layer structure containing 8.7, 2.6 and 8.7 vol% HA, respectively, is successfully fabricated by hot pressing and evaluated by scanning electron microscopy and tensile testing. A good bonding between the HA particles and the PEEK matrix is achieved by virtue of an in situ method in fabricating each PEEK–HA composite layer. There are no apparent microcracks and microscopic interfaces within each layer of the FGM. The symmetrical PEEK–HA FGM does not fall apart or delaminate during loading with a tensile strength of 86.2 MPa, and its fracture energy is 56.5 kJ/m 2 . Furthermore, in vivo bioactivity of the FGM sample is also evaluated, showing that it has sound biocompability and bioactivity. Accordingly, the FGM in the future may be a promising biomaterial to be used as replacement implant of human bone through a proper design to balance mechanical properties and bioactivity.