Highly porous hydroxyapatite (HA) scaffolds containing calcium phosphate glass-ceramics with large pore size and improved compressive strength have been prepared using a combined processing route of polymer sponge and freeze/gel-casting. Tertiary-butyl alcohol (TBA) was used as a solvent. The sintered scaffolds were characterized in terms of microstructure, physical and mechanical properties. A reticulated structure with large pore size of 220-300 μm was formed on burn-out of polyurethane foam where the struts consisted of a few intergranular small-sized pores (< 2 μm) formed by freeze/gel-casting. The addition of glass-ceramics seemed to lead a matrix phase to partial liquid phase sintering and thus the strut structure became more dense with the small size reduction of coarsened pores consisting of reticulated structure. As a consequence, the compressive strength was improved. Also, with the addition of 10 wt.% glass-ceramics the in vitro bioactivity of the scaffolds was further enhanced.

Keywords: Hydroxyapatite scaffolds, Calcium phosphate glass ceramics, Tertiary-butyl alcohol, Polymer sponge, Freeze/gel-casting.