Preparação de biomateriais cerâmicos para aplicações biomédicas com desenvolvimento de uma metodologia de caracterização.

Abstract

The loss of bone tissue is a serious problem that requires a different look both in human and veterinary medicine and, therefore calcium phosphates have been used as ceramic biomaterials for applications such as graft or bone implant. In this context, several calcium phosphates are studied because they present the main mineral constituents of bones. The synthesis of the ceramic biomaterials promotes the formation of different crystalline phases, which are necessary for their biomedical applications. However, the validation standard of the ceramic biomaterials ISO 13779- 3 2008 for the quantification of crystalline phases performs the calculation with only a certain crystallographic plane of each crystalline phase, which limits the result. The objective of this work was to obtain three types of calcium phosphate (Hydroxyapatite - HAp; tricalcium phosphate - ȕTCP and tricalcium phosphate - αTCP), after, uses refinement by Rietveld to obtain more accurate information of the material, constructing their standard curves. Calcium phosphates were obtained by precipitation (HAp and ȕTCP) and by combustion (αTCP), X-ray Fluorescence (FRX), Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), and then apply refinement by Rietveld. In the results by FRX were found and quantified the chemical elements (Ca and P) as main, in the FTIR was identified the presence of functional groups corresponding to the respective calcium phosphates, in the SEM it was possible to observe agglomerated particles with sizes smaller than 10ȝm, in XRD the crystalline phases of each phosphate were identified and, with the use of the refinement by Rietveld, the crystalline phases were quantified, determining also the amorphous phase of the material that does not diffract, consequently, when compared with the norm a more precise result of the crystalline phases present in the material was identified. Afterwards a study on the influence of the temperature for the calcium phosphate (ȕTCP) by precipitation, at the temperatures of λ00 ° C and λ50 ° C was carried out, and a binary phase (HAp / ȕTCP) was foundν with the elevation of the temperature from 1000 ° C to 1200 ° C, a single phase (ȕTCP) was identified. The calibration curves allow quantification of the phases (Hap / ȕTCP and HAp / αTCP), however, in the combustion synthesis to obtain αTCP, (HAp / αTCP) due to particle size, sample preparation, preferential orientation and the presence of amorphous material in the sample were observed. It was concluded that it was possible to synthesize the calcium phosphates, and that the application of the refinement by Rietveld proved to be a viable method, which is constituted in a simpler and more reliable way for the quantification of crystalline phases, so that this biomaterial can then be applied in the biomedical area.