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

The porous hydroxyapatite (HA) bioceramics were prepared through combination of sacrificial template and direct foaming techniques using PMMA granules (varied from 5 to 50wt% in content) as a template and H2O2 solution (varied from 5 to 30wt% 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 ?m, while H2O2 provided the larger pores with the diameter ranging from 100 to 1,000 ?m depending on concentration.