Porous poly-ether ether ketone (PEEK) manufactured by a novel powder route using near-spherical salt bead porogens: Characterisation and mechanical properties

•Porous PEEK has been made by tapping fine powder into a network of spherical salt beads.•Excellent repeatability and homogeneity of density, pore size and connectivity are demonstrated.•Good connectivity leads to faster salt removal rates and lower levels of residual salt.•A good balance between structure and compressive strength has been achieved.

Porous PEEK structures with approximately 85% open porosity have been made using PEEK-OPTIMA® powder and a particulate leaching technique using porous, near-spherical, sodium chloride beads. A novel manufacturing approach is presented and compared with a traditional dry mixing method. Irrespective of the method used, the use of near-spherical beads with a fairly narrow size range results in uniform pore structures. However the integration, by tapping, of fine PEEK into a pre-existing network salt beads, followed by compaction and “sintering”, produces porous structures with excellent repeatability and homogeneity of density; more uniform pore and strut sizes; an improved and predictable level of connectivity via the formation of “windows” between the cells; faster salt removal rates and lower levels of residual salt. Although tapped samples show a compressive yield stress > 1 MPa and stiffness > 30 MPa for samples with 84% porosity, the presence of windows in the cell walls means that tapped structures show lower strengths and lower stiffnesses than equivalent structures made by mixing.

Graphical abstractPorous PEEK with excellent repeatability and homogeneity of density and uniform pore and strut sizes made by tapping fine PEEK into a pre-existing network of near spherical salt beads.Figure optionsDownload full-size imageDownload as PowerPoint slide