Synthesis, characterization and mechanic evaluation of dense bovine hydroxyapatite ceramics with TiO2 nanoparticles

• Ano de defesa: 2020
• Autor(a) principal: Silva, Lucas José de Azevedo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Biocompatible material; Cerâmica; Ceramics; Durapatita; Durapatite; Materiais biocompatíveis
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/25/25146/tde-26102021-102558/

Bovine bone can be considered a renewable source of hydroxyapatite (HA) for use as a raw material. Recycled bovine bone have the advantages of reducing costs and developing a safe material from a biological source, being a sustainable product, already used in medical and dental treatments. The study aimed to synthesize and characterize the microstructure and mechanical properties of dense bovine hydroxyapatite (HA) ceramics with addition of 5% or 8% of TiO2 nanoparticles in the rutile phase after the final sintering. The structural characterization was obtained from analysis by FTIR, XRD, SEM, EDS and relative density. The mechanical characterization was performed by measuring the fracture toughness after a threepoint flexural strength test. The results of the microstructural characterization show that there was no secondary phase formation and that there was a non-homogeneous dispersion of nanoparticles in the HA matrix. The relative density was 2.9 ± 0.09 g/cm3 for HA/8%TiO2np presenting higher density compared with pure HA (2.7 ± 0.03 g/cm3) (p = 0.011) and HA/5%TiO2np (2.7 ± 0.05 g / cm3) (p = 0.041) groups. Regarding mechanical properties, the flexural strength indicates that pure HA (51.7 ± 10.3 MPa) and HA/8%TiO2np (47.4 ± 6.4 MPa) presented statistically significant different higher results (p <0.001) relative to HA/5%TiO2np group (28.8 ± 3.1 MPa). Such results lead to a fracture toughness value with statistical significance difference between the groups. The pure HA (0.43 ± 0.01 MPa m1/2) and HA/8%TiO2np (0.40 ± 0.06 MPa m1/2) groups presented higher KIc, comparing with the HA/5%TiO2np group (0.23 ± 0.02 MPa m1/2) (p <0.003; p <0.007). It is concluded in this way, that the addition of TiO2 nanoparticles in the rutile phase, through the adopted synthesis methodology, did not manage to increase the fracture toughness results of dense hydroxyapatite ceramics.