Estudo da influência do óxido de magnésio na bioatividade de vidros borofosfatos

• Autor(a) principal: SILVA, Andrea Ferraz
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFMA
• Texto Completo: https://tedebc.ufma.br/jspui/handle/tede/tede/5105
• topic: Bioatividade;; Vidros borofosfatos bioativos;; Fosfatos de cálcio;; Apatitas;; Óxido de magnésio; Bioactivity;; Bioactive borophosphate glasses;; Calcium phosphates;; Apatites;; Magnesium oxide; Química Bio-Inorgânica

The present study aimed to investigate the effect of adding magnesium oxide to borophosphate glasses of the 40B2O3–25P2O5–(20-x)Na2O–15CaF2–xMgO system (with x = 0, 2,5, 5, 7.5 and 10% in mol), analyzing the influence of the addition of MgO, in partial substitution of Na2O, on the physical and bioactive properties of these glasses. The samples were synthesized by melt-quenching method, submitted to bioactivity test in SBF solution for 28 days and characterized by X-ray diffraction (DRX), density and molar volume, DSC analysis and Fourier transform infrared spectroscopy (FTIR). During the immersion, daily measurements of pH were carried out and the mass loss of samples up to 28 days in SBF was checked. The replacement of Na2O by MgO caused an increase in the values obtained for density, a reduction in molar volume and an increase in the glass transition (Tg) as the MgO content in the glasses increased. The pH measurements performed up to 28 days of immersion showed a decrease in the pH values of the SBF solutions for all immersed samples, suggesting that a higher concentration of addition had made the surface of the samples less reactive. The mass loss data showed higher percentage of loss for the sample that does not contain MgO and smaller mass loss as the MgO was incorporated into the vitreous systems. XRD diffractograms before immersion confirmed the amorphous nature of the samples and after immersion peaks of crystalline calcium phosphates and apatites in the glasses was detected. The FTIR spectra before immersion indicated structural changes in the glasses with the addition of MgO and after immersion the new FTIR analysis exhibited absorption bands in the characteristic regions of calcium phosphates. The obtained results showed that the increase in the concentration of MgO made the glasses more chemically stable to the processes of dissolution of the vitreous network, with attention to the samples Mg_0, Mg_2,5 and Mg_5 that exhibited the best results for bioactivity up to 28 days. Finally, the analyzed samples containing up to 5% mol of MgO showed promising results for application as biomaterials.