Transformação de vidro de janela em biovitro-cerâmica

Abstract

The present work presents the elaboration and characterization of biovitro-ceramics (BVC) of the SiO2-CaO-Na2O-P2O5 system, which are based on glasses from recycling. In this way, the aim was to search for a BVC with lower cost and the consequent use of glass that would be discarded, generating a product with high added value. With the change in the percentage of recycled glass used, four groups of samples were developed. The following percentages of recycled glass were evaluated for the development of a BVC: 90, 80, 70 and 60% of the weight of the new material being recycled glass and the rest a mixture of CaCO3, Na2CO3 and P2O5. All variants were sintered in an oven with four different parameters. The first process took place at a heating rate of 5°C/min to a temperature of 800°C and maintained for 30min. The following three procedures were performed with a heating rate of 10°C/min and 30min stay at the final temperature, being 800°C, 850°C and 900°C. The change in their masses was verified, which decreased between 12% and 18%. Densities were measured by the Archimedes method and showed values from 4% to 20% lower than the theoretical density. The X-ray diffraction technique (XRD) was used to ascertain the phases present in the developed samples and confirm the formation of the BVC, verifying the presence, in its majority, of combeite phase, a silicate-based phase, as expected based on the compounds that were added. For the in vitro test, the samples were submerged in a simulated body fluid (SBF) solution for 7 days to check their bioactivity. The XRD technique performed after immersing the samples in the SBF showed the presence of compounds containing phosphate and calcium in their compositions. Fourier-transform infrared spectroscopy (FTIR) was used to confirm the presence of the functional groups P-O and PO43-. With the result of these characterizations there is an indication of the formation of an apatite layer on the surface of the BVC, that is, the material is bioactive. Keywords: Biomaterials; Bioglass; Biovitro-ceramics; Recycling; In vitro test.