Navegando por Palavras-chave "Celulose"

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    Aspectos morfologicos e morfometricos reacao tecidual a pelicula celulosica introduzida no plano muscular da parede abdominal de ratos
    (Universidade Federal de São Paulo (UNIFESP), 1988) Queiroz, Valdeir Fagundes de [UNIFESP]
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    Avaliação do desempenho das empresas benchmark no setor de papel e celulose no pré e pós pandemia da Covid-19
    (Universidade Federal de São Paulo, 2022-07-13) Santos, Gustavo de Lacerda [UNIFESP]; Miraglia, Simone Georges El Khouri [UNIFESP]; http://lattes.cnpq.br/6423311971848669
    A pandemia da COVID-19 trouxe diversas mudanças no modelo econômico de todos os países e no Brasil esse impacto da pandemia foi um dos maiores encontrados no mundo, pois o número de mortos pela doença passa de 600.000 mil até maio/2022. A indústria se deparou com a sua capacidade produtiva diminuída, queda de faturamento e aumento de custos da maneira nunca vista nos tempos recentes. Além disso, a demissão em massa, queda no consumo e falta de previsibilidade para a retomada econômica fizeram com que o clima de incerteza diminuísse o número de investimentos em todos os setores. Um dos setores-chave dentro desse contexto pandêmico foi o segmento de papel e celulose pois, ao mesmo tempo que sofreu todas as consequências da pandemia, também conseguiu ver seu consumo se manter à medida que o e-commerce se intensificou devido à utilização desse material nas embalagens e na própria composição de diversos produtos, como utensílios de limpeza para higienização de materiais e estabelecimentos. A indústria de papel e celulose é representada por dois grandes nomes: Klabin e Suzano; esse estudo usou das informações fornecidas pelas duas empresas para mensurar tais impactos e foi possível perceber que as dificuldades foram contornadas propondo mudanças no processo produtivo, buscando minimizar o impacto no forte aumento de custos e na dificuldade logística vivida pelo mundo. Atividades sociais também foram um dos pontos que mais passou por mudanças durante o período estudado, onde diversos programas de capacitação foram criados, buscando trazer novos talentos para o setor. Um dado importante que reforça essas observações é a queda da produção de celulose em 14% e 18% para a Klabin e Suzano respectivamente; porém, essa queda vem acompanhada de um aumento na receita líquida em 79% para a Klabin, chegando ao valor de R$1,7 bilhão e 104% para a Suzano, totalizando R$5,1 bilhões. Por fim, os investimentos continuaram a ser aplicados em expansão e aprimoramento da produção e em P&D (pesquisa e desenvolvimento), chegando a valores de R$1 bilhão investidos pela Klabin (+17%) no primeiro trimestre de 2022 e R$2,6 bilhões para a Suzano (+88%) no mesmo período.
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    Caracterização molecular de resíduos florestais de diferentes espécies Eucalyptus por espectroscopia Raman
    (Universidade Federal de São Paulo, 2024-10-17) Schultz, Ciro de Almeida [UNIFESP]; Noda, Lucia Kiyomi [UNIFESP]; http://lattes.cnpq.br/0772763475537005; http://lattes.cnpq.br/9406190876760627
    A indústria de base florestal brasileira teve um desempenho notável em 2022, gerando 2,6 milhões de empregos e alcançando uma receita bruta de R$ 260 bilhões. Este setor, que se destaca como o quarto item nas exportações do agronegócio brasileiro, atingiu recordes de produção, totalizando 25 milhões de toneladas de celulose, 11 milhões de toneladas de papel e 8,5 milhões de m³ de painéis de madeira. Em 2022, a economia brasileira também se beneficiou do alívio das restrições relacionadas à pandemia, aumentando a demanda por bens e serviços. As plantações de eucalipto estão predominantemente nas regiões Sudeste (46%), Sul (18%) e Centro-Oeste (18%), com destaque para Minas Gerais, responsável por 29% dos plantios. Outros estados notáveis incluem Mato Grosso do Sul, com 15%, e São Paulo, com 13%. Essa distribuição geográfica evidencia a concentração estratégica dessas plantações em áreas específicas do país. Este projeto teve como objetivo coletar informações sobre a composição molecular de resíduos florestais de várias espécies de eucalipto, por meio da técnica de espectroscopia Raman. Após a colheita, materiais como cascas, ramos, raízes, ponteiras, tocos, toretes e permanecem no campo. Parte desses resíduos desempenha um papel essencial na reciclagem de carbono no solo, enquanto outra parcela pode ser considerada biomassa residual, passível de aproveitamento. A técnica Raman é caracterizada por sua alta especificidade, não exigindo preparação especial da amostra e permitindo medidas rápidas. A excitação das amostras ocorreu com um laser Nd: YAG, de 1064 nm, recomendado na literatura para reduzir a fluorescência. A área da lignina foi calculada entre 1500 cm⁻¹ e 1684 cm⁻¹, enquanto a da celulose variou de 980 cm⁻¹ a 1194 cm⁻¹. Após a obtenção dos dados, foram analisadas 30 árvores das espécies Eucalyptus urograndis, E. grandis, E. urophylla e E. saligna, com espectros coletados da casca e folhas de todas as amostras. As cascas das diferentes espécies apresentaram bandas espectrais distintas relacionadas à lignina, com picos em 1680 cm⁻¹, 1670 cm⁻¹, 1651 cm⁻¹, 1645 cm⁻¹,1618 cm⁻¹, 1611 cm⁻¹, 1604 cm⁻¹, 1601 cm⁻¹, 1583 cm⁻¹, 1562 cm⁻¹, 1550 cm⁻¹, 1531 cm⁻¹ e 1521 cm⁻¹. Essas bandas refletem a diversidade de compostos fenólicos e as variações nas estruturas moleculares. As regiões espectrais associadas à celulose mostraram padrões mais consistentes, com picos em 1151 cm⁻¹, 1121 cm⁻¹, 1096 cm⁻¹, 1063 cm⁻¹, 1033 cm⁻¹ e 1000 cm⁻¹, indicando características químicas mais constantes. O comparativo entre as espécies de eucalipto revelou padrões distintos na relação entre lignina e celulose. As espécies H546-Urograndis e H694-Urograndis, pertencentes à mesma espécie, apresentaram valores similares, com média de aproximadamente 2,35, sugerindo uma proporção média de lignina em torno de 27% e celulose em 73%. Em contraste, as espécies IPB21-Grandis e IPb7-Saligna mostraram valores mais baixos, com médias de 1,64 e 1,54, respectivamente, indicando uma média de lignina de aproximadamente 17% e celulose de cerca de 83% para IPB21-Grandis, e 16% de lignina e 84% de celulose para IPb7-Saligna. A espécie B414U-Urophylla apresentou uma relação intermediária, com um valor médio de 2,1, sugerindo uma composição de lignina em torno de 21% e 79% de celulose. Este projeto destaca-se no contexto acadêmico devido à abordagem inovadora na análise de resíduos florestais, em particular a casca de eucalipto, permitindo a avaliação in situ sem preparo prévio, potencializando a rapidez da análise. Os resultados obtidos direcionarão propostas para uma gestão mais eficaz dos resíduos, visando à otimização da produtividade por hectare e plantações mais sustentáveis.
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    Dispersões altamente concentradas de nanopartículas de prata em meio aquoso: preparação, caracterização, imobilização em celulose não modificada e aplicações
    (Universidade Federal de São Paulo, 2023-07-31) Nunes, Rodolfo Pedro Pereira [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; http://lattes.cnpq.br/6334598937296642; http://lattes.cnpq.br/3948517654608176
    Atualmente, ainda há uma escassez na literatura de trabalhos que se concentrem na obtenção de dispersões com altas concentrações de nanopartículas de prata (AgNPs). Portanto, este trabalho apresenta um novo método de síntese de AgNPs por redução química para obter dispersões com concentrações de 5, 10, 25, 50 e 100 mM em meio aquoso, na presença do agente estabilizante polivinilpirrolidona (PVP). As dispersões produzidas consistem em partículas esféricas com diâmetros inferiores a 100 nm, baixa polidispersividade e estabilidade razoável ao longo do tempo. Com o objetivo de aumentar a estabilidade das AgNPs, elas foram imobilizadas em filmes de celulose em duas etapas. Na primeira etapa, a celulose microcristalina foi dissolvida em um líquido iônico chamado 1-butil-3-metilimidazólio (BMlmCl), e na segunda etapa, o filme foi formado usando um anti-solvente para a celulose. Foram obtidos cinco filmes por meio do contato dos filmes de celulose com as dispersões contendo 5, 10, 25, 50 e 100 mM de prata. As análises indicam que os filmes obtidos eram amorfos, contendo celulose do tipo 2, com superfície lisa e homogênea, e uma porcentagem de prata variando de 1% a 5%, dependendo da dispersão utilizada. A atividade catalítica dos filmes produzidos com diferentes concentrações de prata foi avaliada em relação à degradação do 4-nitrofenol. Os filmes utilizados resultaram na redução do 4-nitrofenol em 25 a 40 minutos, dependendo do filme utilizado. Embora a atividade catalítica diminua após o primeiro ciclo de uso, os filmes podem ser utilizados com atividade parcial por pelo menos cinco ciclos. A grande vantagem do uso de filmes em vez de dispersões de AgNP é que o filme pode ser facilmente removido do meio racional e possui um maior potencial de reutilização. Esses resultados contribuem para o avanço na obtenção de dispersões de AgNPs concentradas e sua aplicação catalítica. Estudos futuros podem otimizar as condições de síntese e imobilização, bem como explorar outras aplicações desses filmes de celulose com AgNPs.
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    Estudo de filmes híbridos de celulose e polímeros sintéticos para imobilização de nanopartículas de prata
    (Universidade Federal de São Paulo, 2018-06-27) Barroso, Bruno Lupi [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Microcrystalline cellulose and hydropropylmethylcellulose (HPMC) films, added with two synthetic polymers, polyvinylalcohol (PVA) and polyvinylpyrrolidone (PVP), were produced on the present study. The aim of PVA and PVP addition was to manufacture more transparent cellulose films with better mechanical properties. Microcrystalline cellulose films containing PVA and PVP were prepared by two methods. In method A, all polymers were solubilized in an ionic liquid, 1-butyl-3- methylimidazolium (BMImCl), while in method B the synthetic polymers were dissolved in dimethyl sulfoxide (DMSO) and then mixed in the dissolved cellulose, using BMImCl as solvent. HPMC films containing PVA and PVP were prepared by mixing the aqueous solutions of all the polymers and subsequent water removal. Cellulose films containing PVA or PVP, prepared by methods A and B, were obtained by the addition of water in the cellulose solution containing the synthetic polymers. Although they are soluble in water, both PVA and PVP remain in the cellulose film due to the interactions, via hydrogen bonds, that they establish with cellulose. The PVA addition generates more transparent films than the cellulose one. The PVP addition generates more transparent films only when DMSO is used in the process. In general, the cellulose films containing PVA and PVP are amorphous and exhibit similar thermal stability than the cellulose film. The mechanical properties of films containing cellulose and PVA/PVP have not been markedly improved over the cellulose film. HPMC films are colorless and their transparency increase as the concentration of PVA or PVP increases. The films are amorphous and there is good miscibility between the biopolymer and the synthetic polymers within the different proportions tested. HPMC establishes hydrogen bonds with PVA and PVP. The thermal stability of the films is high. The elongation capacity of the films also increases as the concentration of synthetic polymer increases. Aiming to use HPMC films with greater transparency and better mechanical properties as curatives for second degree burns, 2.5% by mass of silver nanoparticles were added to these films. They exhibited microbicidal activity against S. aureus and E. coli.
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    Identificação e caracterização de promotores foliares de cana-de-açúcar para fins biotecnológicos
    (Universidade Federal de São Paulo, 2022-07-28) Martins, Alice Loureiro [UNIFESP]; Brito, Michael dos Santos [UNIFESP]; http://lattes.cnpq.br/1357542636768944; http://lattes.cnpq.br/9381119054784288
    Atualmente, a demanda energética mundial está levando à busca por novas tecnologias de biocombustíveis, como o biodiesel e o bioetanol, a fim de substituir os combustíveis fósseis limitados. O bioetanol tem origem sumariamente vegetal, com a fermentação de açúcares mais acessíveis – como o amido e a sacarose –, advindos de gramíneas (milho e cana-de-açúcar, principalmente); e outros menos usuais, de elevada complexidade, como os de origem lignocelulósica, também conhecidos como etanol de segunda geração (E2G). Tal complexidade se origina da recalcitrância celular, com uma elevada presença de lignina, que impede o acesso à celulose, que é um dos principais alvos para a expansão da produção de bioetanol. Logo, a engenharia genética e a biotecnologia vegetal têm ganho espaço nas pesquisas na área de energias renováveis, de modo a compreender processos envolvidos com o acúmulo de matéria fermentável, mas também a estrutura e a síntese e degradação de elementos da parede celular, em regiões ricas em celulose, para produção de E2G. Dentre as ferramentas genéticas disponíveis, uma das mais relevantes são os promotores, que tem a capacidade de regular a expressão gênica de maneira dúbia, promovendo ou inibindo-a. Além disso, a identificação de promotores para uso na biotecnologia vegetal de monocotiledôneas (especialmente gramíneas) por si só já possui uma grande relevância dado a baixa disponibilidade de promotores efetivos para tal, principalmente com capacidade de regulação tecido-específica. Assim, este trabalho teve como objetivo identificar, caracterizar e amplificar regiões promotoras tecido-específicas de folha de cana-de-açúcar, para futuras aplicações biotecnológicas. Utilizando-se de metodologias in sílico e informações de banco de dados, obteve-se 10 supostos promotores de cana-de-açúcar, milho e sorgo, devidamente caracterizados em relação à sua conservação e sítios de ligação para fatores de transcrição e, através do desenho de primers, também foi possível realizar a amplificação via PCR de fragmentos em cana, que possivelmente correspondem às sequências desejadas. Consequentemente, este trabalho atendeu às expectativas e aos objetivos previamente fixados, e abriu caminho para novos projetos e metodologias voltadas a caracterização molecular e utilização desses promotores para fins biotecnológicos.
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    Identificação e verificação de atividade celulolítica de microrganismos isolados de compostagem
    (Universidade Federal de São Paulo, 2016-02-29) Paganini, Thais Pires Martins [UNIFESP]; Vallim, Marcelo Afonso [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The composting process is an effective and economical way of treating organic waste, mainly by microbial decomposition. The Fundação Parque Zoológico de São Paulo (FPZSP) has a compost production unit (UPCO) that takes organic matter from various sources, and one of the waste more used in the process are vegetable scraps, and consequently cellulose is the largest source of carbon present. This study explored the diversity in order to obtain cellulose-degrading microorganisms. Thus, a total of 54 microorganisms were isolated in medium supplemented with carboxymethyl cellulose as sole carbon source. Among them, a specie never described before as cellulose degrading, identified as Gordonia paraffinivorans, showed a high specific activity in enzymatic assays. Further, this microorganism had their genomes sequenced and the analysis of the genome identified sequences encoding two families (GH1 and GH3) of β-glucosidases.
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    Imobilização de nanopartículas de dióxido de titânio e de prata em celulose não modificada
    (Universidade Federal de São Paulo, 2018-03-19) Garcia, Arthur Matsudo [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The Development Of Methods Using Biopolymer As Matrix For Immobilization Of Inorganic Nanoparticles (Metal And Oxide) Is Increasing. Among The Biopolymers, The Cellulose Is One Of The Most Interesting, Because It Is Natural, Abundant And Non-Toxic. On The Other Hand, Its Insolubility And Hard Processability Are Obstacles To Overcome. In This Study, We Developed A New Method To Prepare Non-Modified Cellulose Films (Cel) Containing Titanium Dioxide Nanoparticles (Tio2np) And Silver Nanoparticles (Agnp) Silver Nanoparticle Dispersions Pure And Containing Stabilizers, Such As Polyvinylalchool (Pva) And Polyvynilpyrrolidone (Pvp) Were Prepared. The Dispersion Obtained Without Pva Or Pvp Contains Agnp With Diameter Around 7 To 33 Nm And They Are Stabilized By The Bh4- Anions, Via An Electrostatic Stabilization. The Microbicide Effect Of Silver Nanoparticles With Low Concentration Of Pva And Pvp Against E. Coli Is Similar To The Naked Silver Nanoparticles, Indicating That The Use Of These Polymers Is Low ConcentratiThe development of methods using biopolymer as matrix for immobilization of inorganic nanoparticles (metal and oxide) is increasing. Among the biopolymers, the cellulose is one of the most interesting, because it is natural, abundant and non-toxic. On the other hand, its insolubility and hard processability are obstacles to overcome. In this study, we developed a new method to prepare non-modified cellulose films (CEL) containing titanium dioxide nanoparticles (TiO2NP) and silver nanoparticles (AgNP) Silver nanoparticle dispersions pure and containing stabilizers, such as polyvinylalchool (PVA) and polyvynilpyrrolidone (PVP) were prepared. The dispersion obtained without PVA or PVP contains AgNP with diameter around 7 to 33 nm and they are stabilized by the BH4- anions, via an electrostatic stabilization. The microbicide effect of silver nanoparticles with low concentration of PVA and PVP against E. coli is similar to the naked silver nanoparticles, indicating that the use of these polymers is low concentration doesn´t decrease its microbicide effect. Distinctly, in the test using S. aureus, only the dispersions containing 0,5 e 1,0% of PVA or PVP showed notable microbicide effect. Films of cellulose containing silver nanoparticles with or without PVA or PVP were prepared by the simple impregnation of the AgNP dispersions in a regenerated cellulose film. The films have cellulose type II and the distribution of silver nanoparticles is homogeneous along the fibers. When it was used the AgNP dispersions containing PVA and PVP, the presence of both stabilizers also was observed in the films. Titanium dioxide nanoparticles (TiO2NP) were also prepared successfully. They have mainly the anatase form, bandgap around 3,28 eV and diameter under 100 nm. Cellulose films containing the titanium dioxide nanoparticles synthesized in this study and commercial TiO2, called P25, were also prepared. The cellulose films showed cellulose type II and the titanium dioxide nanoparticles are homogenously distributed along the film. It was performed a photocatalytic test using indigo carmime as a dye under a mercury lamp. We noted that photocatalytic effect of the TiO2NP is more effective than that using P25. The powders showed superior photocatalytic effect compared to the cellulose film containing P-25. However, it worth to mention that the use of the film Cel_P25 shows the advantage to be easily removed from the reaction medium, fact that is not possible using titanium dioxide nanoparticles as a powder. The method to produce cellulose films presented in this dissertation is distinct of those described in the literature, since it involves the use of non-modified cellulose and the impregnation of the nanoparticles is homogenous and it is not superficial. Therefore, it was observed that the lixiviation process of the nanoparticles did not occur significantly.
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    Nanopartículas de ouro em líquidos iônicos: preparação, caracterização e imobilização em celulose não modificada
    (Universidade Federal de São Paulo (UNIFESP), 2021) Cabreira, Camila Rodrigues [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo
    Gold nanoparticles (AuNPs) are attractive due to their interesting properties and applications such as therapeutic agents, sensors and catalysts. In view of these numerous applications, this thesis focused on the synthesis of AuNPs in ionic liquids (ILs), and their use in two different areas. The first goal was the study of the effects of AuNPs on cell membrane models, due to its application in medicine. The second aim was to immobilize AuNPs on cellulose and evaluate the catalytic activity of the material in the reduction of 4-nitrophenol. Thus, in this thesis AuNPs were prepared by Au3+ reduction using tetrabutylammonium borohydride (TBABH4) in different ILs containing imidazolium cations, such as 1-butyl-3- methylimidazolium (BMIm) or 1-octyl-3-methylimidazolium (OMIm) or 1-dodecyl-3- methylimidazolium (DMIm) chloride (Cl- ) and bis(trifluoromethanesulfonyl)imide (Tf2N- ). Dispersions of AuNPs at 3 mM, 10 mM and 20 mM concentrations were obtained in 1-butyl-3-methylimidazolium chloride (BMImCl) and 1-octyl-3-methylimidazolium chloride (OMImCl), and showed good stability over time. The dispersions contain nanoparticles with diameters around 5-20 nm. Increasing the alkyl chain length of the imidazolium cation from butyl to octyl led to the formation of smaller and more monodisperse AuNPs. Due to its high viscosity, AuNPs synthesis using 1-dodecyl-3- methylimidazolium chloride (DMImCl) was not performed. Also, stable dispersions were not obtained in ionic liquids containing Tf2Nanion. AuNPs synthesized in ILs and pure ILs were incorporated in monolayers of dipalmitoylphosphatidylcholine (DPPC) at the air-water interface as cell membrane model in a Langmuir trough. All the samples led to monolayer condensation and presented a homogeneous pattern, suggesting that both pure ILs and AuNPs in ionic liquids interact with the cell membrane model. A film of cellulose containing AuNPs synthesized in aqueous media was prepared efficiently by impregnation of an aqueous AuNPs dispersion in a regenerated cellulose film. It has cellulose type II structure and nanoparticles around 10 nm are homogeneously dispersed along the polymeric matrix. Cellulose films containing AuNPs prepared in BMImCl and OMImCl were also obtained by a simpler methodology than the one using AuNPs in aqueous medium. This method allowed the incorporation of higher concentrations of Au into the films. They have cellulose type II and spherical nanoparticles well distributed along the films. The films of cellulose and AuNPs were applied as heterogeneous catalysts for 4-nitrophenol reduction. The film containing AuNPs prepared in water showed great efficiency during 5 cycles. Films containing AuNPs prepared in ionic liquids were efficient for around 8 cycles, and the catalysts containing AuNPs in OMImCl showed the highest kapp values. The ease of removal of the films from the reaction medium makes the hybrid material very appealing in application as a catalyst.
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    Preparação de filmes de celulose contendo nanopartículas de prata produzidas em meio de líquido iônico
    (Universidade Federal de São Paulo, 2018-05-10) Silva, Douglas Santos da [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The development of methods that use biopolymers as a support for the immobilization of metallic nanoparticles is of growing interest. Among biopolymers, cellulose is the most indicated because it is natural, abundant and non-toxic, but its insolubility and its poor processability are obstacles to be overcome. This study developed a new method for producing cellulose films (CEL) containing silver nanoparticles (AgNPs) produced in ionic liquid medium, called hexadecylpiridinium salicylate (HDPSal). The cellulose used in this work was a unmodified polymer, which was dissolved in an ionic liquid, 1-butyl-3-methylimizadiole chloride (BMImCl) 2.5% (w/w). This solution was regenerated by the addition of water, affording a transparent and resistant film. In this process of dissolution and regeneration of cellulose, it was transformed from type I to type II. The silver nanoparticles (AgNPs) were produced from the chemical reduction of silver nitrate dissolved in water with tetrabutylammonium borohydride (TBABH4) in the presence of different concentrations of HDPSal. Obtaining of AgNPs in all the samples was proved by the presence of the surface plasmon resonance (SPR) band of silver in nanometric scale around 415 nm. The assays for determination of minimum inhibitory concentrations showed that the microbicidal action of these dispersions was due to the ionic liquid (HDPSal), which surrounds the silver nanoparticles, stabilizing them by electrostatic effect. All prepared AgNPs in HDPSal were impregnated at cellulose films. It was possible to confirm the impregnation of the AgNPs, in the films, by the presence of the SPR band around 420 nm in all films. The AgNP impregnation process did not cause any change in the primary structure of the cellulose, although it modified to type II. In addition to the AgNPs, HDPSal was also impregnated in the film during the process. From the recorded images on a scanning electron microscope, AgNPs smaller than 100 nm were distributed homogeneously throughout the film. All films showed antimicrobial action against E. coli and S. aureus, and higher concentration of silver films showed activity against C. albicans. In this sense, the microbicidal action at films was attributed to the silver nanoparticles.
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    Preparação e avaliação de membranas de celulose com propriedades condutoras e microbicidas
    (Universidade Federal de São Paulo (UNIFESP), 2020-06-02) Oliveira, Roselaine Da Silva [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo
    There is a growing interest in developing methods that allow the immobilization of different types of materials (polymers and nanomaterials) in biopolymers. Among them, cellulose (CEL) is of the most indicated because it is natural, abundant, and non-toxic. In this thesis, new methods of immobilizing a conductive polymer and silver nanoparticles on cellulose membranes were developed. In order to overcome the insolubility and difficult processing of cellulose, in these procedures the biopolymer was dissolved in an ionic liquid called 1-butyl-3-methylimidazolium chloride (BMImCl). To simplify the comprehension of this thesis, it was divided into three chapters. In the first chapter (CHAPTER 1), the preparation of electrically conductive cellulose membranes, containing silver nanoparticles and polyaniline (PANI), which is a conductive polymer, will be shown. These membranes (CEL / PANI / Ag) showed high electrical conductivity and catalytic activity toward the reduction of p-nitrophenol. In the second chapter (CHAPTER 2), the preparation of several aqueous and non-aqueous dispersions (1-butanol) of silver nanoparticles (AgNP) with high metal concentration will be presented. A simple and fast method was developed, under mild reaction conditions. The dispersions presented excellent microbicidal activities. In the third chapter (CHAPTER 3) a new method of immobilizing the dispersions of AgNP produced in chapter 2 on cellulose membranes will be presented. These membranes will have their microbiological activity evaluated. An illustration of the chapters of thesis is in Figure 1.
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    Preparação e avaliação de propriedades de materiais híbridos de celulose com polianilina e polióxido de etileno
    (Universidade Federal de São Paulo, 2017-12-11) Maeda, Vinicius Cavalheiro [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    In recent years, there has been a growing interest in the development of methods which employ biopolymers as support to immobilize other polymeric materials. Among the biopolymers, cellulose is one of the most used due to its abundance, non-toxicity, and because it is obtained from a natural resource. Nevertheless, due its insolubility in common solvents, the biopolymer is not easily processed. Therefore, the search for new methods to overcome this problem is very required. In this Project, it was showed new methods to prepare films of a modified cellulose, called hydroxypropyl methylcellulose (HPMC) and polyaniline (PANI) to be used as conductive papers (GOAL 1) and to obtain films of non-modified cellulose (CEL) and poly(ethylene oxide) (PEO) for lithium-ion batteries (GOAL 2). The films of HPMC and PANI were prepared in homogeneous medium (aqueous medium), where both HPMC and PANI were soluble. It was obtained self-supported and green films. The green color is characteristic of polyaniline on the most conductivity form, the emeraldine form. The films have showed electroativity characteristic of polyaniline and conductivity around 10-3Scm-1 . Therefore, they can be classified as conductive papers. It was also noted that the addition of HPMC in PANI, enhanced the mechanical properties of the films. Films of PEO containing different amounts of non-modified cellulose (CEL) were also prepared by a new method, where cellulose is dissolved in ionic liquid. The addition of cellulose decreased PEO crystallinity, as desired. However, the conductivity of the film of PEO containing 5% of cellulose and lithium salt showed values around 10-5Scm-1, which is not enough to be employed as electrolyte for lithium-ion battery.
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    Síntese de nanopartículas de óxidos de manganês em líquidos iônicos e sua imobilização em celulose
    (Universidade Federal de São Paulo (UNIFESP), 2021) Oliveira, Larissa Verena Figueiredo De [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo
    The development of synthetic methodologies for manganese oxide nanomaterials has been the subject of several studies due to the improved physical and chemical properties of these materials compared to those in micro and macro scales and their wide applicability. In this thesis, it was developed a new preparation method of MnO 2 nanoparticles in an exclusive medium of different ionic liquids, which acted simultaneously as a solvent, structure-directing agent, and reducing agent of a permanganate salt, the tetramethylammonium permanganate (TMAMnO 4 ). The synthesis was performed in a single step and under mild conditions. It was obtained, for all ionic liquids tested, MnO 2 in nanoscale with lamellar structural organization and with the cations of the ionic liquids in the interlamellar space. These materials were immobilized on non-modified cellulose films and used in discoloration tests of Indigo Carmine dye (IC). The immobilization of the nanoparticles at the films prevented the aggregation and/or agglomeration of the particles during use and it facilitated its recovery from the reaction medium and reuse for several cycles. The obtained films were amorphous and had around 5 wt.% of MnO 2 nanoparticles distributed homogeneously in the cellulosic film. These films were capable of efficiently discoloring an Indigo Carmine dye solution, decolorizing 5.00 mL of a 20 ppm IC solution between 35-50 minutes, depending on the film used. Besides, they could be reused for at least 5 cycles without significant loss of efficiency. These materials were easily removed from the solution using a tweezer. The use of a film instead of dispersion or powdered material allows straightforward isolation from treated water, avoiding the need for more complex separation methods, such as centrifugation or filtration.
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    Síntese, caracterização e aplicações de materiais híbridos de óxido de nióbio (Nb2O5)
    (Universidade Federal de São Paulo (UNIFESP), 2021) Santos, Marconi Da Cruz [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; Universidade Federal de São Paulo
    The objective of this thesis was to propose new methods of producing hybrid materials of niobium oxide. In the first chapter, the preparation of hybrid materials of niobium oxide and conducting polymers was investigated using an unconventional niobium precursor, the niobium peroxo-oxalate complex. The hybrid materials obtained from the oxidation of aniline are composed of polyaniline in its most conductive form (the emeraldine salt form), containing oxalate as a doping anion, with Nb2O5 nanoparticles homogeneously dispersed in the polymeric matrix. The electrical conductivity ranged from 10-2 to 10-3 S cm-1 , which is three orders of magnitude greater than that observed for pure Nb2O5. The photocatalytic activity was investigated using the standard decolorization reaction of the methylene blue dye (MB) in aqueous solution. The hybrids showed better MB adsorption capacity and were more effective in discoloring the solution under visible light than pure Nb2O5. In the second chapter, the preparation of nonmodified cellulose membranes containing niobium oxide nanoparticles was proposed. In this approach, ionic liquids were used in the nanoscale synthesis of niobium oxide and in the immobilization of these particles in cellulose membranes. Using a simple methodology, transparent cellulose membranes containing nanostructured niobium oxide without segregation of organic and inorganic phases were obtained. The hybrid membranes were evaluated as photocatalysts for degradation of methylene blue dye in aqueous medium, showing a greater capacity for adsorption of the dye and later the discoloration of the solution under UV light irradiation.