Fabrication of Porous Hydroxyapatite through Combination of Sacrificial Template and Direct Foaming Techniques

Abstract

The porous hydroxyapatite (HA) bioceramics were prepared through combination of sacrificial template and direct foaming techniques using PMMA granules (varied from 5 to 50 wt% in content) as a template and H₂O₂ solution (varied from 5 to 30 wt% in concentration) as a foaming agent, respectively. The effects of PMMA content and H₂O₂ concentration on final porosity, microstructure and mechanical strengths were studied. The porous samples using PMMA provided the porosity ranging from 52% to 75%, the samples using H₂O₂ had the porosity ranging from 82% to 85%, and the sample using both pore formers provided the porosity ranging between 84% and 90%. The higher content of PMMA and concentration of H₂O₂ led the porosity increased, leading to a decrease in the compressive and flexural strengths. Furthermore, this combination technique allowed interconnected pores having two levels of pore size, which were come from PMMA and H₂O₂. The PMMA formed the small pores with the diameter ranging between 100 and 300 μm, while H₂O₂ provided the larger pores with the diameter ranging from 100 to 1,000 μm depending on concentration.