Nanoparticulation methods of bovine hydroxyapatite, synthesis and structural/chemical characterization of an experimental SiO2/nanohydroxyapatite composite ceramic

• Ano de defesa: 2021
• Autor(a) principal: Ferrairo, Brunna Mota
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Cerâmica; Cerâmica composta; Ceramics; Composite ceramic; Hidroxiapatita; Hydroxyapatite; Silica; Sílica
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/25/25146/tde-03122021-094954/

Objectives: The aim of the study was to evaluate two methods of nanoparticulation methods of bovine hydroxyapatite (HA), synthesize an experimental SiO2/nano-hydroxyapatite composite ceramic and made a structurally and chemically characterization of them. Materials and Methods: Cortical of bovine femurs were selected and, after a pre-treatment, calcined and particulate. Sonication was performed with 40% of the maximum amplitude of 750W and 20Hz in aqueous solution added with HA and ammonia polyacrylate (4h of activation). Milling technique used a polyethylene jug (300 cm3) loaded with 40vol% (500g) milling elements (3Y zirconia balls, HA, isopropyl alcohol and para-aminobenzoic acid), placed in a rotatory mill (104rpm, 48h) followed by a vibratory mill (72h). Ball mill technique was used to mixture fumed silica and nano-HA from bovine bone source. Groups were divided into 3, 5 and 10% of HA addition, 1.2 and 2.4 wt.% of PVB, and 1100, 1200 and 1300 °C for maximum temperatures to firing plateau (4h). Characterization was performed by Transmission Electron Microscopy (TEM) / Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XDR) and Fourier Transform Infrared (FTIR). Results: The initial particle size is 75m and sonication (60 nm) and ball mill (40 nm) techniques, associated with prior calcination, were capable of producing nanosized bovine HA particles, maintaining an appropriate stoichiometry, morphology and purity. According to SH composite ceramic, the uniaxial/isostatic powder compression is an efficient method. The temperature of 1200 °C presented potentialized chemical bonds without the degradation of HA at XDR profile. SEM images suggests that 2.4 wt.% of PVB result in optimized compaction and a lower incidence of cracks and pores, and the SH composite ceramic with 5% of HA presents potential superior properties to biomaterial. Conclusion: The ball mill technique provided smaller particles of bovine hydroxyapatite and the experimental material SH composite ceramic with 5% of HA, 2.4 wt.% of PVB and sintered at 1200 °C presents potential superior properties to biomaterial.