Solid-state foaming of poly(ether-ether-ketone)/hydroxyapatite composites

Poly(ether-ether-ketone) (PEEK) is a high strength and high temperature-resistant plastic with good potential for medical use. The addition of hydroxyapatite (HA) can improve the mechanical performance and biocompatibility of PEEK. However, little study has been done on solid-state foaming of PEEK or PEEK- based composites due to the semicrystalline nature and high processing temperature requirement. In this study, the solid-state foaming behavior of PEEK/HA composite is studied using supercritical CO2. A quenching process is applied to reduce the crystallinity and improve the gas saturation behavior. The mechanical properties of foamed PEEK/HA composite are characterized. The results show that quenching substantially improved the foamability of PEEK/HA composite. Foamed PEEK/HA regained crystallinity and exhibit a compressive strength comparable to human trabecular bone.