| Abstract [eng] |
Most people have some diseases, bones injuries and their deformations. Scientists are trying to synthesize synthetic materials which could be used in bone regeneration. Calcium phosphates are materials that have similar properties to natural human bone. Calcium phosphates can be synthesized in many ways and have different phases and crystal structures. Each phase can be applicable in different fields of uses. Doping of calcium phosphates with metal ions is one of the promising modification ways. Each metal ion has certain biological and physical properties, which calcium phosphate has not, thus, doped synthetic materials can gain these properties and be used in wider application fields. In the present work, different calcium phosphates were synthesized through the phase transformations and the influence of synthesis conditions was investigated was investigated in detail. The influence of Fe3+ ions on the crystallization process of ACP was investigated. Also, in this work, Mn2+ doped CPP polymorphs were synthesized and characterized. Finally, the influence of annealing conditions on the transformations of calcium phosphates was investigated, when the temperature and time were the same. The crystal structure and phase purity of the obtained products were determined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and solid-state nuclear magnetic resonance (NMR). The lattice parameters were calculated using the Rietveld method using the FullProf program. The morphology was characterized using a scanning electron microscope (SEM). Thermal degradation was analyzed using thermogravimetric and differential scanning calorimetric (TG DSC) analysis. The obtained results showed that doping ACP with Fe3+ ions affect the intermediate products of phase transformations and reduces the crystallization temperature. Normally, upon heating ACP crystallizes in α TCP followed by β TCP at higher temperature, but in the presence of Fe ions the CDHA was produced followed by β TCP. Three different CPP polymorphs were obtained by annealing Mn2+ doped brushite at different temperatures. Their structural properties were studied, and the calculated lattice parameters confirmed that Mn2+ is doped in the CPP structure. The measurements of optical properties confirmed that all doped CPP are optically active. Finally, results of the influence of annealing conditions showed, that this is a very important factor in the synthesis procedure and that calcium phosphates with different structures can be obtained in different cases. In the air atmosphere and N2 flow, the main phase was α CPP with the Ca/P ratio of 1, whereas when the same material was annealed in a vacuum, the main phase was α TCP with the Ca/P ratio of 1.5. |
