Effect of different synthesis conditions on the microstructure, crystallinity and solubility of Mg-substituted hydroxyapatite nanopowder

• Mg-n-HA was synthesized under different synthetic conditions.
• The morphology, microstructure, crystallinity and solubility were investigated.
• The crystallinity decreased with the introducing of macromolecules.
• The solubility was improved in comparison with n-HA in SBF soaking.

A series of the Mg-substituted nano-hydroxyapatite (Mg-n-HA) nanopowders were synthesized by chemical co-precipitation method under different conditions, including two reaction temperature of 70 °C and 40 °C, and two water-soluble macromolecules of carboxyl methyl cellulose and poly(acrylic acid). The influence of magnesium content, reaction temperature and macromolecules on the microstructure, crystallinity and solubility of Mg-n-HA were characterized using SEM, XRD, FTIR techniques and soaking in simulated body fluid (SBF) solution. The results showed that needle-like Mg-n-HA nanoparticle with Mg being successfully incorporated in HA lattice could be synthesized, and there was no obvious morphology difference among the Mg-n-HA nanoparticles synthesized under different conditions. However, the crystallite sizes, cell parameters and crystallinity evidently decreased with the increasing magnesium content, the lowering reaction temperature and the introducing of macromolecules. Moreover, the solubility in SBF soaking was greatly improved in comparison with n-HA due to their lower crystallinity.

The synthesis and characterization of Mg-n-HA with different Mg substitute amounts of 5 mol%, 10 mol%, 15 mol% and 20 mol% synthesized under different synthetic conditions were systematically and completely investigated, including two reaction temperature of 70 °C and 40 °C, and two water-soluble macromolecules of CMC and PAA. The influence of magnesium content, reaction temperature and macromolecules on the microstructure, crystallinity and solubility of Mg-n-HA were characterized. The results showed that the crystallite sizes, cell parameters and crystallinity evidently decreased with the increasing magnesium content, the lowering reaction temperature and the introducing of macromolecules.Figure optionsDownload as PowerPoint slide