Porous foams based hydroxyapatite prepared by direct foaming method using egg white as a pore promoter

Stoichiometric hydroxyapatite (Ca₁₀(PO)₆(OH)₂, HAP) foams have been produced. The porous parts were prepared from a calcined HAP powder and egg white as a bio and non-toxic pore promoter. The colloidal slurry was prepared, poured into cylindrical molds, dried, unmolded, and sintered at 1200 °C. The effects of the concentration of the solid loading, of the dispersing agent, and the foaming agent on the ceramic preparation were examined. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) were used to evaluate the composition and the structure of the sintered HAP ceramics. Scanning electron microscopy (SEM) was used for microstructural analysis. The XRD analysis of the porous parts, prepared under optimized conditions, showed the presence of crystallized HAP (JCPDS 9-432) as a single phase. SEM images showed existence of open and interconnected micro and macropores in the ceramics. The use of the egg white protein as pore former provides a total porosity of 86 vol% and a foam-structure that allows to a microporous wall.