Characterization of β-tricalcium phosphate-clay mineral composite obtained by sintering powder of apatitic calcium phosphate and montmorillonite

Abstract

Calcium phosphates and clay minerals have taken great attention by researchers for medicals applications. Recently, numerous researchers have been developed the calcium phosphate/ montmorillonite composites as a synthetic bone graft substitutes. In this study, β-tricalcium phosphate (Ca3(PO4)2,β-TCP)/Montmorillonite(MNa) composites were developed by sintering powder at 900 °C of apatitic tricalcium phosphate (Ca9(HPO4)(PO4)5(OH), TCPa) and unmodified MNa at various amounts (2, 5, and 10 wt.%). The composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR) and thermal analysis (TG / DSC). XRD results show that the sintering of TCPa with and without MNa lead to the formation of a single crystallized β-TCP phase and that the addition of the MNa causes a change in his crystalline lattice. The results of XRD, FT-IR and the structural refinement indicate the insertion of the clay ions in the β-TCP structure. This ionic substitution leads to a decrease in lattice parameters and an increase in index distortion. The low percentages of MNa lead to an increase in crystallite size while the high values (10 wt.%) lead to an opposite effect. The change of the composition leads to the stabilization of the β-TCP phase, and the temperature of the allotropic transformation of β to α-TCP shifts toward the higher temperature.