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.
Micrograded ceramic-metal composites
2019 - RESTIVO, THOMAZ A.G.; BECCARI, RAFAEL F.; PADILHA, WELLINGTON R.; DURAZZO, MICHELANGELO; TELLES, VICTOR B.; COLETI, JORGE; YAMAGATA, CHIEKO; SILVA, ANTONIO C. da; SUZUKI, EDUARDO; TENORIO, JORGE A.S.; MELLO-CASTANHO, SONIA R.H.
The article shows new designed cermets and processes concerning primary to applications as thermal insulation materials with low emissivity. A new projected microstructure was obtained where dense regions (micropellets) rest inside the main porous pellet. The feature resembles a frozen hypercube, therefore such architecture is called hyper-pellet/ cermet. The processing method to obtain the hyper-cermet is based on sequential tape castings and sintering techniques. Ni-zirconia lamellae were prepared by a special mechanochemical process followed by sintering, which remain inside the main pellets as a dense region. The whole pellet is turned to be porous by employing pore-forming additives. All the constituents and porosity shapes are aligned along the disc/ flake planes. Thermal conductivity is estimated for the materials up to 800 °C by a flash diffusivimeter. Ceramographic analyses show graded density regions with directional constituents and pores. Applications of such materials are foreseen as temperature insulation materials and thermal radiation shields.
Micrograded ceramic-metal composites
2018 - RESTIVO, T.A.G.; BECCARI, R.; DURAZZO, M.; TELLES, V.; YAMAGATA, C.; SILVA, A.C.; TENORIO, J.A.S.; MELLO-CASTANHO, S.R.H.
Cermet materials are traditional materials for applications as catalysts and solid oxide fuel cell electrodes, i.e. zirconia-Ni and alumina-Ni. The paper shows new designed cermets and processes concerning primary to applications as thermal insulation materials with low emissivity. A new projected microstructure was obtained where dense regions (micropellets) rest inside the main porous pellet. The feature resembles a frozen hypercube (tesseract), therefore such architecture is called hyperpellet. In this way, the material shows both low thermal conductivity and emissivity. The processing method to obtain the hyperpellet cermet is based on 3-steps tape casting forming and 2-steps sintering technique. Metal (Ni) lamellae were prepared by a special mechanochemical process followed by sintering, which remain inside the main pellets as a dense region. The whole pellet is turned to be porous by employing pore former additives. All the constituents and porosity shapes are aligned along the flat disc plane. Micro pellets were also prepared into a rather regular flake morphology type through a suitable granulating process. The thermal conductivity is estimated for hyperpellet type discs and flake powders samples at 800oC by a flash diffusivimeter and compared with commercial ceramic insulation fiber blanked. Ceramography analyses show graded density regions and different constituents and pores with directional feature. Applications of such materials are foreseen as high temperature insulation materials and performant thermal radiation shields.
Structural reinforcement of Nb2O5 in soda-lime borosilicate glasses for nuclear waste immobilization
2018 - SILVA, D.L.C.; SILVA, A.C.; ARAUJO, M.S.; MELLO-CASTANHO, S.R.
The vitrification process has been used for high level nuclear waste (HLW) immobilization for more than 40 years around the word. However, there are still many difficulties involving the radiation effects in the glass matrixes as, for example, crackings that reduce their mechanical and chemical resistance. The impact of Nb2O5 addition in the CaO-Na2O-SiO2-B2O5 glass system was investigated. The glass samples, produced by melting method, were submitted to extreme chemical attacks like the alkaline ISO 695-1984 (E), the acid DIN 12116-1976 and characterized by X-ray diffraction (XRD), Fourier Transformed Infrared Spectroscopy (FTIR) and Raman Spectroscopy. XRD diffraction patterns obtained before the chemical attacks confirmed the vitreous character of the samples. Raman spectra and FTIR spectra obtained after the chemical attacks indicated that the Nb2O5 is well connected to the glass network, supported by the decrease in mass loss after the chemical attacks, as the the Nb2O5 content was raised in the samples. These results are indicative that the chemical resistance of the studied glasses can be improved by increasing the Nb2O5 content. These results show that the process is a promising alternative to produce new family of the appropriate glasses for nuclear wastes immobilization.
Variations of Qn distribution in bioactive glasses containing strontium oxide and alumina
2018 - ARAUJO, M.S.; SILVA, A.C.; SILVA, D.L.C. e; MELLO-CASTANHO, S.R.
The complexity in designing brand-new compositions as 45S5 Bioglass® is mainly due to the fact the more components you have, the more difficult it is to trace the relationship between composition, structure and bioactivity. Also, the properties of bioactive compositions reflect their ability to release a critical amount of different ions in the surrounding host tissue, creating or not favorable conditions to stimulate cellular processes. Since these properties and process of interaction are directly related to the glass network connectivity, which can be evaluated by Qn distribution and other medium-range structural techniques, the present research studied two series of compositions based on 45S5 however adding amounts of Al2O3 and SrO, to verify the impact of subtle compositional changes in the Qn distribution. The samples were obtained by melting (1500°C) and quenching and characterized by X-ray diffraction (XRD), differential thermal analysis (ATD), Fourier transform infrared (FTIR) and Raman spectroscopy. The initial results indicates that the matrix of typical bioactive phospho-silicate glasses which consists to be mostly Q², with some Q³, structures have been maintained in samples containing only SrO (0-2,7%mol). However, the samples containing both Al2O3 (2%mol) and SrO (0-2,7%mol) indicates that the addition of 1%mol SrO there is an increase of Q² in detriment of Q³, but then when the addition is up to 2,7%mol there is a decrease of Q² inversely proportional to Q³. Although these changes have been presented, none of the samples of both series presented cytotoxicity. Furthermore, studies on biocompatibility are being conducted to evaluate its impacts on their bioactivity.
Vitrificação de metais de transição: A estabilidade química no sistema quaternário Na2O-CaO-SiO2-RxOy
2017 - SILVA, A.C.; ARAUJO, M.S.; COSTA E SILVA, D.L.; MELLO-CASTANHO, S.R.H.
A estabilização de resíduos industriais contendo metais de transição por meio de processos de vitrificação é de relevância tanto para a saúde pública como a ambiental. O sucesso destas ações depende de que material resultante apresente a necessária estabilidade química frente a meios corrosivos. Uma vez dispersos na massa vítrea fundida, os metais de transição podem assumir coordenações que lhes permite tomar parte na estrutura vítrea resfriada. Desta forma os óxidos destes metais (Cr, Ni, Cu, Zn) considerados genericamente como RxOy, interagem com os óxidos do sistema CaO:Na2O:SiO2, resultando no sistema quaternário CaO:Na2O:SiO2:RxOy, no qual composições adequadamente formuladas podem apresentar apreciável resistência química. No presente trabalho uma composição de matriz vítrea CaO:Na2O:SiO2 (10:30:60 em massa percentual) recebeu adições de metais de transição RxOy provenientes de resíduos industriais (Lama Galvânica) entre 10 e 40 % em massa, de modo a iniciar a exploração da região na qual a incorporação de RxOy no sistema CaO:Na2O:SiO2:RxOy incremente a resistência química. Tal estudo visa iniciar a construção de uma adequada ferramenta para a formulação de vidros contendo metais de transição. Os vidros foram obtidos por fusão (1500°C) em cadinhos de alumina seguida de “Quenching” em molde de aço. A caracterização dos vidros foi realizada por difração de raios-x (DRX), por infravermelho na transformada de Fourier (FTIR) e resistência hidrolítica. Os resultados indicaram alterações na distribuição entre as espécies de sílica Q3 e Q2 na rede vítrea e o aumento da estabilidade química em função da incorporação do RxOy.
Multifunctional bioactive glasses for tissue regeneration: compositions modified with strontium oxide
2017 - ARAUJO, M.S.; SILVA, A.C.; SILVA, D.L.C. e; MELLO-CASTANHO, S.R.H.
The complexity in designing brand-new compositions as 45S5 Bioglass® is mainly due to the fact the more components you have, the more difficult it is to trace the relationship between composition, structure and bioactivity. Also, the properties of bioactive compositions should reflect directly their ability to release a critical amount of different ions in the surrounding host material, creating or not favorable conditions for the cellular processes. The present research was conducted by modifying the glass network of 45S5 by adding Al2O3 and SrO in order to obtain a multifunctional glass for biomedical applications, i.e. a not only with bioactive properties as osteoinductive and also biocidal. Three series of compositions were produced to optimized the amounts of both oxides, thus, minimizing undesirable effects and enhancing the mobility of Ca2+ cations due to the rearrangement of the glass network. The samples were obtained by melting (1500°C) and quenching and characterized by X-ray diffraction (XRD), differential thermal analysis (ATD), Fourier transform infrared (FTIR) and Raman spectroscopy. The initial results indicates that the vitreous network is predominantly of Q3 arrangements in detriment of the typical 45S5 Q2 structure. And, the FT-IR and Raman spectra are similar to glasses with adequate solubility and bioactivity for the interaction between the implant and the host.