In the past decade there has been increasing interest in exploring the use of nanocellulose in medicine. However, the influence of the physicochemical properties of nanocellulose on the material´s biocompatibility has not been fully investigated.  In this thesis, thin films of nanocellulose from wood (NFC) and from Cladophora algae (CC) were modified by the addition of charged groups on their surfaces and the influence of these modifications on the material´s physicochemical properties and on cell responses in vitro was studied. The results indicate that the introduction of charged groups on the surface of NFC and CC results in films with decreased surface area, smaller average pore size and a more compact structure compared with the films of unmodified nanocelluloses. Furthermore, the fibres in the carboxyl-modified CC films were uniquely aggregated and aligned, a state which tended to become more prevalent with increased surface-group density. The biocompatibility studies showed that NFC films containing hydroxypropyltrime-thylammonium (HPTMA) groups presented a more cytocompatible surface than unmodified NFC and carboxymethylated NFC regarding human dermal fibroblasts. Carboxymethyl groups resulted in NFC films that promoted inflammation, while HPTMA groups had a passivating effect in terms of inflammatory response.  On the other hand, both modified CC films behaved as inert materials in terms of the inflammatory response of monocytes/macrophages and, under pro-inflammatory stimuli, they suppressed secretion of the pro-inflammatory cytokine TNF-α, with the effects of the carboxylated CC film more pronounced than those of the HPTMA CC material.  Carboxyl CC films showed good cytocompatibility with fibroblasts and osteoblastic cells. However, it was necessary to reach a threshold value in carboxyl-group density to obtain CC films with cytocompatibility comparable to that of commercial tissue culture material.  The studies presented here highlight the ability of the nanocellulose films to modulate cell behaviour and provide a foundation for the design of nanocellulose-based materials that trigger specific cell responses. The bioactivity of nanocellulose may be optimized by careful tuning of the surface properties. The outcomes of this thesis are foreseen to contribute to our fundamental understanding of the biointerface phenomena between cells and nanocellulose as well as to enable engineering of bioinert, bioactive, and bioadaptive materials.

Orientadora: Prof. Dra. Márcia Aparecida da Silva Spinacé / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2016. / Nos ultimos anos, varios metodos tem sido desenvolvidos para obtencao de nanocristais de celulose. Dentre eles, destaca-se o por ultrassom de alta intensidade, utilizado neste trabalho para fibra de bambu. Foram avaliadas diferentes condicoes de extracao de celulose por ultrassom, alterando tempo de reacao, densidade de massa e de potencia em relacao ao volume e tipo de pre tratamento. As amostras foram caracterizadas por microscopia optica, teor de umidade, espectroscopia de infravermelho, microscopia eletronica de varredura, espalhamento de luz dinamico, microscopia de forca atomica, analise termogravimetrica e difracao de raio X. A fibra de partida apresentou razao de aspecto de 2,33, com comprimento medio de 35 ¿Êm e diametro medio de 15 ¿Êm. Os nanocristais obtidos apresentaram dimensao entre 3 nm a 1 ¿Êm, com geometria elipsoidal. Concluiu-se que maior densidade de potencia e maior quantidade de massa conferiram maior reprodutibilidade ao processo e maior grau de cristalinidade a amostra (75 %), sendo indicado para aplicacao em nanocompositos polimericos . / In the last years, a lot of methods have been developed to obtain cellulose nanocrystals. Among them, there is high intensity ultrasound, used in this work to bamboo fiber. Different conditions of extraction of cellulose by ultrasound were evaluated, changing reaction time, mass and power density in relation to volume and pretreatment type. The samples were characterized by optics microscopy, moisture content, infrared spectroscopy, scanning electronic microscopy, dynamic light scattering, atomic force microscopy, thermogravimetric analysis and X ray diffraction. The original fiber showed aspect ratio of 2,33, with medium length of 35 ìm and medium diameter of 15 ìm. The nanocrystals showed dimensions between 3 nm and 1 ìm, with ellipsoidal geometry. It was observed that higher power density and higher mass allow better reproducibility of the process and higher crystallinity to the sample (75 %), it is indicated to applications in polymeric nanocomposites.

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-05-12T13:09:47Z No. of bitstreams: 1 DissTJB.pdf: 4566630 bytes, checksum: 5702ce61ab78e32583b82b3d119c75b6 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-18T20:28:49Z (GMT) No. of bitstreams: 1 DissTJB.pdf: 4566630 bytes, checksum: 5702ce61ab78e32583b82b3d119c75b6 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-18T20:28:56Z (GMT) No. of bitstreams: 1 DissTJB.pdf: 4566630 bytes, checksum: 5702ce61ab78e32583b82b3d119c75b6 (MD5) / Made available in DSpace on 2017-05-23T18:32:29Z (GMT). No. of bitstreams: 1 DissTJB.pdf: 4566630 bytes, checksum: 5702ce61ab78e32583b82b3d119c75b6 (MD5) Previous issue date: 2016-02-29 / Não recebi financiamento / The use of eucalyptus kraft as biomass for an integrated production of sugars and new added-value products such as nanocellulose, stands out a potential strategy for the implementation of a forest biorefinary, that can contribute to the diversification of the paper and cellulose sector. In this process configuration, amorphous cellulose is converted into sugars that can be used for second generation ethanol (2G) production, leaving a residual fraction of nanocellulose that can be applied in various sectors as a high-value product. In this context, the objective of this study was to evaluate the viability of integration of 2G ethanol production with nanocellulose, using eucalyptus kraft pulp as raw material. In the enzymatic hydrolysis step, the experimental central composite design (CCRD) was used as a tool evaluate the effects of solids loading (SL) from 5 to 22% (w/v), and enzymatic loading (EL), from 3 to 17 mg protein/g of cellulose, on the glucose released and cellulose conversion. Glucose concentrations from 45 to 130 g/L with conversions from 40 to 95% were obtained after 24 hours of enzymatic hydrolysis. The validation of the statistical model was performed at SL 20% and EL 10 mg/g cellulose, defined using desirability function as the optimum condition for obtaining high concentrations of sugars associated with residual material to favor the production of nanocelulose. The sugars released using the selected optimum condition (134 g/L) were used to produce 2G ethanol by fermentation using Saccharomyces cerevisiae, resulting in 62.14 g/L ethanol after 8 h (yield 95.5%). For all of the conditions evaluated, the residual solids presented cellulose nanofiber (NFC) characteristics, according to analysis by Scanning Electron Microscopy with Field Emission (SEM - FEG). Nanocellulose presented crystallinity index between 76% and 83% with initial degradation temperature around 320ºC. The use of a temperature reduction strategy from 50 to 35 ° C after 24 hours of enzymatic hydrolysis allowed to obtain cellulose nanocrystals (NCC) after 144h reaction. The crystallinity index of this material confirmed the presence of highly crystalline cellulose with initial degradation temperature around 330°C. The NCC showed length of 260 nm and diameter 15 nm, with aspect ratio L/D 15. Such characteristics are adequate for application as reinforcement in polymeric materials. Finally, enzymatic hydrolysis experiments were made in a stirred tank reactor (5L) using SL of 10 and 15% and EL of 5 and 10 mg/g cellulose, in order to obtain the parameters required to scale-up. The impeller used was the up-pumping and down-pumping Elephants Ears. The rotation of 470 rpm, defined by performing mixing time test, was used to evaluate the power consumption and apparent viscosity during of hydrolysis reaction. The residual solids of the hydrolysis at 5L scale presented nanocelulose with similar characteristics to the smaller scale (100 mL). In conclusion, the results obtained here showed that the integration of the processes for nanocellulose and 2G ethanol production is very promising and could contribute to implementation of the forest biorefineries and diversification of cellulose and pulp sector. / A utilização da polpa de celulose de eucalipto como biomassa para produção integrada de açúcares fermentescíves e novos produtos de alto valor agregado, como a nanocelulose, se destaca como uma potencial estratégia para a implementação de biorrefinarias florestais, podendo contribuir para a diversificação do setor de papel e celulose. Nessa configuração de processo, enquanto a celulose amorfa é convertida a açúcares fermentescíveis que podem ser utilizados para a produção de etanol de segunda geração (2G), a fração residual de nanocelulose pode ser aplicada em diferentes setores, como um produto de alto valor agregado. Nesse contexto, o objetivo deste trabalho foi estudar a viabilidade de integrar a produção de etanol 2G com a produção de nanocelulose, utilizando como matéria-prima a polpa de celulose de eucalipto. Na etapa de hidrólise enzimática da celulose foi utilizado o planejamento experimental delineamento composto central rotacional (DCCR), para avaliar os efeitos do teor de sólidos (TS), de 5 a 22% (m/v), e carga enzimática (CE), de 3 a 17 mg de proteína/g de celulose, tendo como resposta concentração de glicose e conversão de celulose. Concentrações de 45 a 130 g/L glicose foram obtidas, com conversões de celulose variando de 40 a 95%, após 24 h de hidrólise. A validação do modelo estatístico foi realizada para a condição de TS 20% e CE 10 mg/g de celulose, definida com auxílio da função desirability como sendo a condição ótima para obtenção de altas concentrações de açúcares fermentescíveis, associadas a um material residual para favorecer também a obtenção de nanocelulose. Os açúcares liberados na condição validada (134 g/L) foram utilizados para a produção de etanol 2G pela levedura Sacharomyces cerevisiae, resultando em 62,14 g/L de etanol após 8 h (rendimento de 95,5 %). O sólido residual da hidrólise enzimática apresentou características de nanofibras de celulose (NFC), de acordo com a análise por Imagens de Microscopia Eletrônica de Varredura com Emissão de Campo (MEV – FEG). A nanocelulose resultante de todas as condições apresentou índice de cristalinidade entre 76 e 83% e temperaturas iniciais de degradação de aproximadamente 320ºC. A aplicação de uma estratégia de redução de temperatura de 50 para 35ºC após 24 h de hidrólise enzimática na condição de validação levaram a obtenção de nanocristais de celulose (NCC) após 144h de reação. O monitoramento do índice de cristalinidade deste material comprovou a presença de celulose altamente cristalina e com temperatura inicial de degradação em torno de 330°C. O NCC obtido apresentou comprimento de 260 nm, diâmetro de 15 nm e razão de aspecto L/D 15, características favoráveis para aplicação como reforço em materiais poliméricos. Por fim, foram realizados experimentos de hidrólise enzimática em biorreator de mistura (5L) para condições de TS 10 e 15% e CE 5 e 10 mg/g de celulose, visando à obtenção dos parâmetros para a análise do aumento de escala. Os impelidores usados foram do tipo orelhas de elefante com escoamento ascendente (EEUP) e descendente (EEDP). A rotação de 470 rpm, definida a partir da análise do tempo de mistura, foi utilizada para a determinação do consumo de potência e da viscosidade aparente no decorrer da hidrólise. O sólido residual da hidrólise na escala de 5L apresentou características de nanocelulose compatíveis com os resultados em menor escala (100 mL). Como conclusão, os resultados obtidos indicam que a integração dos processos de obtenção de etanol 2G e nanocelulose é bastante promissora e poderá contribuir para a implementação de biorrefinarias florestais e diversificação do setor de papel e celulose.

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-06-01T13:37:05Z No. of bitstreams: 1 LIMA_Vitor_2016.pdf: 32934263 bytes, checksum: 69e1bbf4b33f79b2d38a4bf1801eb46c (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-06-01T13:37:13Z (GMT) No. of bitstreams: 1 LIMA_Vitor_2016.pdf: 32934263 bytes, checksum: 69e1bbf4b33f79b2d38a4bf1801eb46c (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-06-01T13:37:43Z (GMT) No. of bitstreams: 1 LIMA_Vitor_2016.pdf: 32934263 bytes, checksum: 69e1bbf4b33f79b2d38a4bf1801eb46c (MD5) / Made available in DSpace on 2017-06-01T13:37:52Z (GMT). No. of bitstreams: 1 LIMA_Vitor_2016.pdf: 32934263 bytes, checksum: 69e1bbf4b33f79b2d38a4bf1801eb46c (MD5) Previous issue date: 2016-04-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The industrial waste usage for technological application has been gaining ground in different segments and applications. One of the prominent sectors is Material technology, where these residues can be used to obtain the raw material for obtaining polyols, which, later on, will be used in the process for obtaining polymeric materials or as fillers and reinforcement in thermoplastic polymeric materials. The cellulose, which is a natural polymer and the material generated in greater amounts in nature, is been used as a source of study and has several applications in materials, such as reinforcement, load or chemical surface modifications. The nanocellulose, which is obtained from different chemical, mechanical and biological processes, may be in the form of cellulose nanofibrils (NFCs), which are present in crystalline and amorphous regions along it, and cellulose nanocrystals (NCCs) where it reveals only the crystal region. The material in this work is malt bagasse, which is currently the waste generated in the beer industry by bulk and shows no alternative reuse and application in Material technology. It was determined the chemical composition of the fibers and applied chemical bleaching process to remove components such as lignin and hemicellulose in preparation of the fibers for obtaining nanocellulose through acid hydrolysis. Hydrolysis was performed using H2SO4 at two concentrations, 44% (w / w) and 64% (m / m), with the temperature at 40 ° C and 50 ° C for the samples subjected to the acid solution 44%, besides that, it was used 40 ° C, 50 ° C and 60 ° C for samples with 64% solution. For the samples 44/40 and 44/50 it were obtained NFCS and for the 64% the result obtained was NCCs. Natural and bleached fibers, along with nanocellulose, obtained through different concentrations of H2SO4 and temperature variations were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (X-RD) and Thermogravimetric Analysis (TGA). / A utilização de resíduos industriais para aplicação tecnológica vem ganhando espaço em diferentes segmentos e aplicações. Um dos setores de destaque é o de Ciência e Tecnologia em Materiais, onde, esses resíduos podem ser utilizados para a obtenção de matéria prima para obtenção de polióis que, posteriormente, serão utilizados no processo de obtenção de materiais poliméricos. Outra alternativa é a utilização destes resíduos como agentes de carga e reforço nos compósitos poliméricos termoplásticos. A celulose, que é um polímero natural e o material gerado em maior quantidade na natureza, tem sido utilizada como fonte de estudo e diferentes aplicações na área de materiais, seja como reforço, carga ou para modificações químicas de superfície. A nanocelulose, que é obtida a partir de diferentes processos químicos, mecânicos e biológicos, pode se apresentar na forma de nanofibrilas de celulose (NFCs), onde estão presentes regiões cristalinas e amorfas ao longo destas, e também, nanocristais de celulose (NCCs), onde, observa-se apenas a região cristalina. O material utilizado neste trabalho é o bagaço de malte, que é atualmente o resíduo gerado em maior volume pelo setor cervejeiro e não apresenta nenhuma alternativa de reutilização ou aplicação tecnológica em materiais. Foi determinada a composição química das fibras e aplicado processo o químico de branqueamento para a remoção de componentes como lignina e hemicelulose como preparação das fibras para obtenção da nanocelulose via hidrólise ácida. A hidrólise foi realizada utilizando H2SO4 em duas concentrações, 44% (m/m) e 64% (m/m), variando a temperatura em 40°C e 50°C para as amostras submetidas à solução ácida 44%, e 40°C, 50°C e 60°C para as amostras onde foi utilizada solução 64%. Para as amostras 44/40 e 44/50 obteve-se NFCs e para 64% o resultado foi a obtenção de NCCs. As fibras brutas e branqueadas, e a nanocelulose obtida através de diferentes concentrações de H2SO4 e variações de temperatura foram caracterizadas através das técnicas de espectroscopia na região do infravermelho com transformada de Fourier (FTIR), microscopia de força atômica (AFM), microscopia eletrônica de varredura (MEV) e com emissão de campo (FESEM), difração de raios-x (DR-X) e análise termogravimétrica (TGA).

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-05-11T11:30:22Z No. of bitstreams: 2 Tese - Thaís Moraes Arantes - 2018.pdf: 12865431 bytes, checksum: 833a4469f3024d3214408e3e279efef6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-05-11T11:41:10Z (GMT) No. of bitstreams: 2 Tese - Thaís Moraes Arantes - 2018.pdf: 12865431 bytes, checksum: 833a4469f3024d3214408e3e279efef6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-05-11T11:41:10Z (GMT). No. of bitstreams: 2 Tese - Thaís Moraes Arantes - 2018.pdf: 12865431 bytes, checksum: 833a4469f3024d3214408e3e279efef6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-04-02 / Polyurethane nanocomposites were prepared with nanoparticles of hydroxyapatite and/or nanocellulose in order to obtain biocompatible materials. The nanocelluloses were obtained from sugarcane bagasse, seeking to evaluate their use as a source of cellulose nanofibers. The conditions of extraction and separation of the nanocelluloses were investigated. The effect of time and concentration of sulfuric acid was studied, resulting in particles with reduced size and homogeneity in the size distribution without cellulose degradation. The cellulose nanocrystals that presented the best results regarding suspension staining, crystallinity index, thermal properties, particle size and Zeta potential were those hydrolyzed in 50% H2SO4 at 45 ° C for 2 hours. For the synthesis of the hydroxyapatite (HA) nanoparticles, a multivariate statistical analysis was carried out using a factorial design with resolution 23 . From which an empirical model was created that allows the control of the shape and size of the hydroxyapatite nanoparticles. HA nanoparticles with sizes varying from 8 nm to 600 nm were formed by oriented coalescence growth mechanism. The structure was confirmed by images of Electron Transmission Electron Microscopy and Scanning Electron Microscopy. The hydroxyapatite nanoparticles presented a well-defined nanorod shape with a narrow size distribution. It was observed that the model was statistically significant and the main parameter for the growth of crystals in the hydrothermal process was the temperature. Polyurethanes derived from castor oil were synthesized without residues of their monomers. The insertion of the nanoparticles into the polymer matrix improved the thermal stability of the composite. Finally, the cell viability assay showed that polyurethane nanocomposites with hydroxyapatite are biocompatible and in this way can be used as biomaterial. / Foram preparados nanocompósitos de poliuretana com nanopartículas de hidroxiapatita e/ou nanocelulose buscando obter materiais biocompatíveis. As nanoceluloses foram obtidas do bagaço de cana-de-açúcar, buscando avaliar a sua utilização como fonte de nanofibras de celulose. Foram investigadas as condições de extração e separação das nanoceluloses. Estudou-se o efeito do tempo e da concentração de ácido sulfúrico, que resultassem em partículas com tamanho reduzido e homogeneidade na distribuição de tamanho, sem que houvesse degradação da celulose. Os nanocristais de celulose que apresentaram os melhores resultados quanto à coloração da suspensão, índice de cristalinidade, propriedades térmicas, dimensão das partículas e potencial Zeta foram aqueles hidrolisados em H2SO4 50%, a 45 °C por 2 horas. Para a síntese das nanopartículas de hidroxiapatita (HA) foi realizada uma análise estatística multivariada usando um planejamento fatorial com resolução 23 . A partir do qual criou-se um modelo empírico que permite o controle da forma e tamanho das nanopartículas de hidroxiapatita. Foram sintetizadas nanopartículas de HA com tamanhos variando entre 8 nm e 600 nm, formados por mecanismo de crescimento por coalescência orientada. A estrutura foi confirmada por imagens de Microscopia Eletrônica de Transmissão e Microscopia Eletrônica de Varredura. As nanopartículas de hidroxiapatita apresentaram formato de nanorod bem definidas e com estreita distribuição de tamanho. Observou-se que o modelo foi estatisticamente significativo e o parâmetro principal para o crescimento de cristais no processo hidrotérmico foi à temperatura. Poliuretanas derivadas do óleo de mamona foram sintetizadas sem resíduos de seus monômeros. A inserção das nanopartículas na matriz polimérica melhorou a estabilidade térmica do compósito. Por fim, o ensaio de viabilidade celular mostrou que nanocompósitos de poliuretana com hidroxiapatita são biocompatíveis e desta forma podem ser utilizados como biomaterial.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / A utilizaÃÃo de materiais polimÃricos oriundos do petrÃleo na fabricaÃÃo de produtos de difÃcil decomposiÃÃo leva a estudos e desenvolvimento de materiais parcialmente ou completamente biodegradÃveis e de fontes renovÃveis. A celulose à um grande alvo destas pesquisas, nÃo somente por suas diversas fontes, mas tambÃm pela vasta aplicabilidade, principalmente em nanocompÃsitos. O Brasil, um paÃs do agronegÃcio, possui uma grande fonte de biomassa proveniente dos resÃduos do setor agroindustrial. Uma dessas fontes à a fibra do pseudocaule da bananeira, que à utilizada como adubo e cobertura de solo no prÃprio bananeiral. Tendo a grande geraÃÃo de resÃduos no bananeiral como oportunidade, o desenvolvimento de novas alternativas de aproveitamento amplia as opÃÃes de agregaÃÃo de valor e contribui para reduzir os seus impactos negativos. No presente trabalho, fibras do pseudocaule da bananeira (PCB), variedade Pacovan, foram avaliadas como possÃvel fonte para obtenÃÃo de nanocelulose para elaboraÃÃo de nanocompÃsitos em matriz de poli(Ãlcool vinÃlico) (PVOH), um polÃmero hidrofÃlico e biodegradÃvel. Inicialmente, o PCB foi dividido em quatro fraÃÃes: fraÃÃo externa, central, interna e nÃcleo para posterior caracterizaÃÃo quÃmica, tÃrmica e morfolÃgica. Em razÃo do maior conteÃdo de celulose e cristalinidade, utilizaram-se as fraÃÃes externas como matÃria-prima para a obtenÃÃo de nanocelulose. ApÃs branqueamento em meio alcalino, a fibra foi submetida à hidrÃlise Ãcida (H2SO4 62% m/m, 70 min, 45 ÂC) para obtenÃÃo dos nanocristais de celulose. A nanocelulose obtida do PCB apresentou-se como uma suspensÃo estÃvel de coloraÃÃo marrom. Tipicamente, os nanocristais apresentaram comprimentos (L) de 135,0 nm e diÃmetros (d) situados em torno de 7,2 nm; o que reproduziu razÃes de aspecto (L/d) de 21,2. A nanocelulose foi aplicada em uma matriz polimÃrica biodegradÃvel e solÃvel em Ãgua, o poli(Ãlcool vinÃlico), para obtenÃÃo de filmes nanocompÃsitos de diferentes concentraÃÃes (0, 1, 3 e 5% em base seca de matriz). A adiÃÃo de nanocelulose melhorou as propriedades mecÃnicas dos filmes atà a concentraÃÃo de 3%, diminuiu as propriedades tÃrmicas em todas as concentraÃÃes, melhorou a propriedade de barreira ao vapor de Ãgua gradualmente, com pequenas mudanÃas nas propriedades Ãpticas evidenciando uma oportunidade de aplicaÃÃo desse filme nanocompÃsito para embalagem. AlÃm disso, representando uma alternativa de agregaÃÃo de valor a um relevante resÃduo do agronegÃcio. / The use of polymeric materials from petroleum in the manufacture of difficult decomposition products leads to studies and development of partially or completely biodegradable materials from renewable sources. Cellulose is a major target of this research, not only for its various sources, but also by the wide applicability, especially in nanocomposites. Brazil, a country of agribusiness, has a large source of waste biomass from the agribusiness sector. One such source is the fiber from the banana pseudostem , which is used as fertilizer and soil cover in bananeiral own. Having a big residue generation in banana crop as an opportunity, the development of new alternative utilization expands the options of adding value and helps to reduce the negative impacts. In the present work, fibers from the banana pseudostem (PCB), Pacovan variety, were evaluated as a possible source for obtaining nanocelulose for preparation of nanocomposites in matrix of polyvinyl alcohol (PVOH), a hydrophilic and biodegradable polymer. Initially, the PCB was divided into four fractions: external fraction, central fraction, inner fraction and core for subsequent chemical, thermal and morphological characterization. Because of the higher cellulose content and crystallinity, we used the external fractions to obtain nanocelulose. After bleaching in alkaline environment, the pulp was subjected to acid hydrolysis (H2SO4 62% m / m, 70 min, 45  C) and reduced to cellulose nanocrystals. The nanocelulose extracted from the PCB appeared as a stable brown suspension . Typically, the crystals exhibited lengths (L) of 135.0 nm, and diameters (d) situated around 7.2 nm, which reproduces aspect ratios (L/d) 21.2. The nanocellulose was applied to a biodegradable polymeric matrix and water-soluble polyvinyl alcohol, to obtain nanocomposite films of different concentrations (0, 1, 3 and 5% on dry basis matrix). The addition of nanocellulose improved the mechanical properties of the films to 3% concentration, diminished the thermal properties at all concentrations, improved barrier property to water vapor gradually with small changes in the optical properties evidencing an opportunity to apply this nanocomposite film for packaging. Moreover, representing an alternative of adding value to a relevant agribusiness residue.

This study aims to examine the throughput of nanoparticles through a Cladophora cellulose based virus removal filter. The effect of Brownian motion and flow velocity on the retention of 5 nm gold nanoparticles, 12.8 nm dextran nanoparticles and 28 nm ΦX174 bacteriophages was examined through MATLAB simulations and filtration experiments. Modeling of Brownian motion at different flow velocities was performed in MATLAB by solving the Langevin equation for particle position and velocity for all three types of particles. The motion of all three particle types was shown to be constrained at local flow velocities of 1∙10-2 m/s or greater. The constraint was greatest for ΦX174 bacteriophages, followed by dextran particles and then gold particles as a result of particle diameter. To verify the effect experimentally, virus removal filters were prepared with a peak pore width of 23 nm. Filtration experiments were performed at different flux values where gold and dextran particles did not exhibit any difference in retention between fluxes. However, a significant amount of gold and dextran particles were removed by the filter despite being smaller than the measured pore size. A decrease in retention with filtrated volume was observed for both particle types. Filtration of ΦX174 bacteriophages exhibited a difference in retention at different fluxes, where all bacteriophages where removed at a higher flux. The results from both simulations and experiments suggest that the retentive mechanism in filtering is more complex than what can be described only by size exclusion sieving, Brownian diffusion and hydrodynamic constraint of particles.

Cellulose, a sustainable raw material derived from nature, can be used for various applications following its functionalization and oxidation. Nanocellulose, inheriting the properties of cellulose, can offer new properties due to nanoscale effects, in terms of high specific surface area and porosity. The oxidation of cellulose can provide more active sites on the cellulose chains, improving its functionalization and broadening applications. Two kinds of oxidation and their corresponding applications are described in this thesis: periodate oxidation and Oxone® oxidation. 2,3-dialdehyde cellulose (DAC) beads were prepared from Cladophora nanocellulose via periodate oxidation, and were further modified with amines via reductive amination. Several diamines were selected as possible crosslinkers to produce porous DAC beads, which showed higher porosity, stability in alkaline solution and enhanced thermal stability. After functionalization of DAC beads with L-cysteine (DAC-LC), thiol, amine and carboxyl groups were introduced into the DAC beads, endowing the DAC-LC beads with high adsorption capacity for palladium. The synthesized DAC-LC beads were character­ized with SEM, FTIR, XPS, TGA, BET and XRD and the palladium adsorption process was investigated. Chitosan was employed as a crosslinker in functionalization of DAC beads (DAC-CS). The conditions for the synthesis of DAC-CS beads were screened and verifying the stability of the beads in alkaline solution. The DAC-CS beads produced were investigated using SEM, FTIR, XPS, TGA and BET, and the adsorption and desorption capacity of Congo red was studied, indicating DAC-CS beads have potential as sorbent. Oxone oxidation of cellulose is a novel one-pot oxidation method in which mainly the hydroxyl groups on C6 are oxidized to produce carboxylic acid groups on the cellulose chains. To increase the efficiency of Oxone oxidation, several reaction parameters were studied. Cellulose pulp and Cladophora nanocellulose were chosen as prototypes to investigate the effects of oxidation, and the physico­chemical properties of the oxidized products were characterized. Cellulose pulp, pretreated with Oxone oxidation, was disintegrated by homogenization to prepare cellulose nanofibers (CNF). The effect of pre­treat­ment on the preparation of CNF was studied, and the results indicated that Oxone oxidation was efficient in the production of CNF.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22081号 / 農博第2373号 / 新制||農||1073(附属図書館) / 学位論文||R1||N5235(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 矢野 浩之, 教授 和田 昌久, 教授 辻井 敬亘 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

This diploma thesis focuses on the optimization of bacterial cellulose production by Komagateibacter xylinus DSM 46604. The theoretical part of this thesis describes the properties of bacterial cellulose, its production and application possibilities. The experimental part aimed to assess the effect of different cultivation conditions on the production yields of bacterial cellulose. The effects of several cultivation strategies have been studied such as: (1) effect of acetate buffer used as a medium, (2) impact of oil added into the medium, (3) fed-batch cultivation, (4) variation of the volume of cultivation vessel and cultivation media and (5) aeration. In addition to the production of relatively thin samples, up to 100 µm was synthesized unique 3D structured bacterial cellulose in the form of cylinders, with a height up to 2 cm. The growth of bacterial cellulose in the form of cylinders was achieved by dynamically cultivating K. xylinus in combination with fed-batch approach.