The influence of phosphorus precursors on the synthesis and bioactivity of SiO2-CaO-P2O5 sol-gel glasses and glass-ceramics

Autor(es)

Siqueira, Renato Luiz ^{[1, 2]} ; Zanotto, Edgar Dutra ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Engn Mat, Lab Mat Vitreos, BR-13565905 Sao Carlos, SP - Brazil

^[2] Ctr Fed Educ Tecnol Minas Gerais, Grp Pesquisas Nanotecnol & Nanomat, BR-35183006 Timoteo, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE; v. 24, n. 2, p. 365-379, FEB 2013.
• Citações Web of Science: 27

Resumo

Bioactive glasses and glass-ceramics of the SiO2-CaO-P2O5 system were synthesised by means of a sol-gel method using different phosphorus precursors according to their respective rates of hydrolysis-triethylphosphate (OP(OC2H5)(3)), phosphoric acid (H3PO4) and a solution prepared by dissolving phosphorus oxide (P2O5) in ethanol. The resulting materials were characterised by differential scanning calorimetry and thermogravimetry, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and by in vitro bioactivity tests in acellular simulated body fluid. The different precursors significantly affected the main steps of the synthesis, beginning with the time required for gel formation. The most striking influence of these precursors was observed during the thermal treatments at 700-1,200 A degrees C that were used to convert the gels into glasses and glass-ceramics. The samples exhibited very different mineralisation behaviours; especially those prepared using the phosphoric acid, which had a reduced onset temperature of crystallisation and an increased resistance to devitrification. However, all resulting materials were bioactive. The in vitro bioactivity of these materials was strongly affected by the heat treatment temperature. In general, their bioactivity decreased with increasing treatment temperature. For crystallised samples obtained above 900 A degrees C, the bioactivity was favoured by the presence of two crystalline phases: wollastonite (CaSiO3) and tricalcium phosphate (alpha-Ca-3(PO4)(2)). (AU)

• Processo FAPESP: 07/08179-9 - Processos cinéticos em vidros e vitrocerâmicas
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Temático