SONIA REGINA HOMEM DE MELLO CASTANHO

SONIA REGINA HOMEM DE MELLO CASTANHO

(Fonte: Lattes)

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Graduada em Engenharia de Materiais (UFSCar, Universidade Federal de São Carlos), Mestre em Tecnologia Nuclear (IPEN/USP, Universidade de São Paulo) e Doutora em Ciências Químicas-Cerâmicos (UAM/ES -ICV/CSIC, Universidad Autónoma de Madrid, Espanha e Instituto de Ceramica y Vidrio/CSIC de Espanha). Ela é Pesquisadora Senior e atualmente Gestora Adjunta em Pesquisa e Desenvolvimento do Centro de Ciências e Tecnologia de Materiais (CCTM) do Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP). É Professora da Universidade de São Paulo (USP), no programa de posgraduação Tecnologia Nuclear - Materiais. Coordenadora do grupo de pesquisas (GP/CNPq) em Materiais e Meio Ambiente. Principais áreas de atuação: - Energias Renováveis (células a combustível, catalizadores e biomassa), - Ambiental (mitigação, inertização e requalificação de efluentes e subprodutos de processos extrativistas e industriais, diretivas ambientais (RhOS, WEEE)), - Cerâmicas Biocompatíveis (vidros, compósitos multifuncionais para a implantologia). Experiência em gestão de Centro de Pesquisas, gestão ambiental, gestão de projetos, planejamento composicional de materiais, processamento coloidal, reologia, vidros e vitroceramicos, compósitos multifuncionais e nanoestruturas naturais. (Texto extraído do Currículo Lattes em 27 dez. 2021)

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Structural and thermal influence of niobia in aluminoborosilicate glasses
2022 - COSTA-SILVA, D.L.; BARTOLOME, J.F.; SILVA, A.C.; MELLO-CASTANHO, S.
The addition of small amounts of niobia (Nb2O5) in borosilicate glasses was explored. By analysis on thermal and structural changes, we found evidences that niobium integrates the glass structure in octahedral NbO6 coordination. Adding up to 8.0 mol% of Nb2O5, the oxide partially ruptured the glass structure, interfering in the BO3/ BO4 ratio, but the predominant network configuration was maintained. Thermally, there was an increase in the processing interval and the glasses became more resistant against crystallization, with the presence of niobia. Also, the oxide contributed to a notable decrease in the viscosity of the melts. The improvement of such properties were obtained by the controlled dispersion of the oxide in the glass network structure, avoiding large areas of phase-to-phase separation to preserve the desired ability of these glasses to incorporate a wide range of elements.
In vitro bioactivity and antibacterial capacity of 45S5 Bioglass®-based compositions containing alumina and strontium
2021 - ARAUJO, M.S.; SILVA, A.C.; CABAL, B.; BARTOLOME, J.F.; MELLO-CASTANHO, S.
A modified 45S5 Bioglass® containing 2 mol% alumina and 2 mol% strontium oxide was prepared. In vitro bioactivity in powder and monolithic samples was conducted. Fourier transform infrared analysis and pH change in simulated body fluid were investigated for powder samples after 480 min of immersion. Additionally, X-ray diffraction and scanning electron microscopy after 7 and 14 days of immersion in simulated body fluid were investigated for monolithic samples. The formation of phosphate and carbonate phase precursors of hydroxycarbonate apatite was observed after 480 min for powder samples, and the hydroxycarbonate apatite pattern and morphology were confirmed after 7 days of immersion for monolithic samples. It seems that changes in composition did not affect reactivity but caused a decrease in the maxima of pH. Cytotoxicity and cell viability obtained by using the NCTC clone 929 cell line did not show any significant loss of cell viability or cytotoxicity. Moreover, after overnight incubation, the samples demonstrated safe disinfection for Escherichia coli. For these reasons, the use of these new bioactive glasses can be considered a promising alternative for the reconstruction of bone defects and even for the treatment and suppression of bone infections.
Structural and thermal behavior of 45S5 Bioglass®-based compositions containing alumina and strontium
2020 - ARAUJO, MARIANA S.; SILVA, ANTONIO C.; BARTOLOMÉ, JOSÉ F.; MELLO-CASTANHO, SONIA
The present research exposes the influence of 2 mol% of Al2O3 and 2 mol% SrO in 45S5 Bioglass®-based compositions. Four compositions were produced to elucidate the difference in how both oxides influence structure and thermal behavior separately and their synergy when together. Thermal properties, crystallization tendency, and sintering behavior was evaluated by differential scanning calorimetry, hot stage microscopy, and dilatometry. Changes of medium-range structures were characterized by Qn distribution of Raman spectroscopy and evaluation of 31P, 27Al, 23Na, and 29Si environment obtained by magic angle spinning nuclear magnetic resonance. Despite Qn distribution was predominantly Q2 in all samples, the composition criteria used enabled improved processing and stabilibity characteristics. The addition of Al2O3 and SrO promoted larger sinterability parameter (Sc) which indicates better sintering behavior, the glass stability against crystallization doubled (KH) compared to 45S5 and the processing window enlarged from 106 to 171.
Niobium modified glass for nuclear waste immobilization
2019 - SILVA, D.L.C. e; SILVA, A.C.; RAMBO, C.R.; CASTANHO, S.
The impact of Nb2O5 addition to glasses belonging to the system SiO2-Na2O-CaO-B2O5-Al2O3 were investigated for nuclear waste immobilization applications. The glass samples, produced by the traditional melting method, were characterized by XRD, Differential Thermal Analysis (DTA) and Fourier-Transform Infrared Spectroscopy (FT-IR). The XRD results confirmed the amorphous state of the glasses and the thermal and FT-IR analyses revealed that Nb2O5 was dispersedly incorporated to the glass structure and that higher contents of the oxide result in a niobate network growth. The glasses showed good resistance to devitrification and are applicable for nuclear waste vitrification processes. These results show that the process is a promising alternative to produce a new family of glasses with optimized thermal resistance for the immobilization of nuclear wastes.