Orientador: Carlos Henrique Scuracchio. / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós Graduação em Nanociências e Materiais Avançados, 2010.

Orientador: Everaldo Carlos Venâncio / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2012.

Orientador: Sandra Andrea Cuz / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2013

Foi preparado o nanocompósito de borracha natural/argila chocolate B modificada por sodificação via seca com variação no processo, utilizando silicato de sódio ao invés de carbonato de sódio e tratada com sal quaternário de amônio, cloreto hexadecil trimetil amônio. A argila no seu estado natural, após sodificação e após quaternização foi caracterizada pelas técnicas de microscopia estereoscópica, análise térmica, infravermelho, difração de raios X e microscopia eletrônica de varredura. Outras cargas orgânicas foram adicionadas, como celulose e piaçava e comparadas com cargas tradicionais, como o negro de fumo. As placas obtidas, após vulcanização, tiveram medidas as suas propriedades mecânicas e foram analisadas por DRX e MEV. Os nanocompósitos obtidos mostraram melhoria nas suas propriedades mecânicas em comparação com as placas sem a adição de argila. / The natural rubber/clay chocolate B nanocomposite modified by dry sodification process with variation processing was prepared using sodium silicate instead of sodium carbonate and treated with quaternary ammonium salt, hexadecyl trimethyl ammonium chloride. The clay in its natural state after sodification and after quaternization was characterized by the techniques of stereoscopic microscopy, thermal analysis, infrared, X-ray diffraction and scanning electron microscopy. Other organic fillers were added, such as cellulose and piaçava, and compared with traditional fillers such as carbon black. The plates obtained after vulcanization had their mechanical properties measured and were analyzed by XRD and SEM. The obtained nanocomposites showed improvement in their mechanical properties in comparison with the plates without the addition of clay.

Hidróxido de níquel é um material amplamente estudado principalmente devido às suas aplicações como cátodo de baterias secundárias de níquel, entretanto tal sistema ainda apresenta problemas devido à progressiva diminuição da capacidade de carga em função do número de ciclos de oxidação/redução. No presente trabalho são descritas a preparação, caracterização e propriedades de nanomateriais de hidróxido de níquel, obtidos pelo processo sol-gel; e também dos nanocompósitos obtidos por meio da interação do sol de Ni(OH)2 com argilas catiônica (hectorita) e aniônica (HDL similar a hidrotalcita). Os materiais foram caracterizados por análise térmogravimétrica, espectroscopia UV-Vis e infravermelho, difração de raios-X, microscopia eletrônica de varredura, voltametria cíclica e microbalança eletroquímica a cristal de quartzo. Os resultados obtidos são claramente consistentes com a forma α-Ni(OH)2, e apresentam uma maior reversibilidade eletroquímica que os nanomateriais análogos preparados por outros métodos. Além disso, essa característica foi melhorada por meio de tratamento térmico a 240 °C, ou por meio da incorporação nas matrizes lamelares hospedeiras, gerando nanomateriais com grande potencialidade para o desenvolvimento de dispositivos eletroquímicos, em particular baterias, dispositivos eletrocrômicos, catalisadores e sensores amperométricos. / Nickel hydroxide has been extensively studied because of its use as active material in the cathode of alkaline secondary batteries, but the main problem related to the progressive decrease of charge capacity as a function of the number of oxidation/reduction cycles still remains unsolved. In this work, the preparation, characterization and electrochemical properties of nickel hydroxide nanomaterials obtained by sol-gel method, and of nanocomposites materials prepared by the combination of nickel hydroxide sol and a cationic clay (hectorita) and an anionic clay (LDH like hydrotalcite) are described. The materials were characterized by thermogravimetric analyses, UV-Vis and IR spectroscopy, X-ray diffractometry, scanning electron microscopy, cyclic voltammetry and electrochemical quartz microbalance. The results were consistent with the α-Ni(OH)2 phase, but showing better electrochemical reversibility than that of similar materials obtained by others methods. Furthermore, this property was enhanced by thermal treatment at 240 °C or by Ni(OH)2 incorporation into the layered hosts. In conclusion nickel hydroxide nanomaterials with possible applications for the development of electrochemical devices such as batteries, electrochromic devices, catalysts and amperometric sensors were prepared and their exceptional electrochemical reversibility demonstrated

Esta tese apresenta um estudo detalhado das propriedades eletroquímicas dos nanocompósitos de V2O5.nH2O e poli(pirrol) sobre a superfície de eletrodos. Demonstramos aqui que pelo controle de parâmetros de síntese é possível alterar a composição das interfaces eletroquímicas dos eletrodos modificados, fazendo com que o poli(pirrol) esteja por cima, por baixo ou dentro do V2O5 que recobre os eletrodos. Esta diferenciação estrutural tem repercussão nas propriedades eletroquímicas e espectroscópicas dos eletrodos modificados. Desenvolvemos além disto um método para gerar matrizes de V2O5.nH2O, assim como nanocompósitos com poli(pirrol) que possuam anisotropia elétrica tridimensional, propriedade útil em eletrônica. Na última parte do trabalho, poli(pirrol) foi inserido em matrizes de intercalação do tipo BV (V2O5.nH2O estabilizado com esmectita) gerando materiais estáveis em meio aquoso e adequados modificadores de eletrodos, viabilizando a exploração das propriedades dos compósitos de V2O5/poli(pirrol) em água. / This thesis focuses on the electrochemical properties of V2O5.nH2O and its poly(pyrrole) nanocomposites over electrodes. We demonstrate that it is possible, by controlling synthetic procedures, to change the composition of the modified electrodes interfaces, leaving poly(pyrrole) over, under or inside the V2O5 films covering the electrodes. This structural differenciation repercutes on the electrochemical and spectroscopic properties of the modified electrodes. We have developed also a method to generate V2O5.nH2O matrices as well as their nanocomposites with poly(pyrrole) showing tridimensional electrical anisotropy, a useful property in electronics. Additionally, poly(pyrrole) has been inserted into BV (smectite stabilized V2O5.nH2O) matrices, generating stable materials in aqueous medium, conveying to this, the properties of V2O5/poly(pyrrole) nanocomposites modified electrodes.

As propriedades dielétricas dos materiais têm ganhado importância na aplicação industrial nas últimas décadas, estas propriedades fornecem informações úteis para melhorar o controle de processamento e qualidade dos produtos alimentícios e outros materiais. A espectroscopia dielétrica é amplamente utilizada para estudar a dinâmica molecular em diversos sistemas, nos quais é comum observar o fenômeno de relaxação dielétrica que tem sido associado por vários pesquisadores ao fenômeno de transição vítrea, importante na estabilidade e propriedades dos materiais. O objetivo da tese foi analisar as propriedades dielétricas de produtos alimentícios e filmes biopoliméricos, dando ênfase ao estudo da mobilidade molecular nos filmes; e ao estudo da dinâmica estrutural de alimentos e sua correlação com fatores de qualidade. O estudo foi dividido em várias etapas com objetivos específicos: A primeira consistiu na montagem e startup do equipamento adquirido para medida das propriedades dielétricas (E4980A com 16451B; E5061B com 85070E, Keysight Technologies); A segunda etapa foi dedicada à análise das propriedades dielétricas de goiabada em pasta e suco de laranja na faixa de frequência de 500-3000 MHz, em função do teor de sólidos solúveis e da temperatura visando a geração de correlações que permitiriam fazer um monitoramento durante o processo de produção; Na última etapa foi estudada a mobilidade molecular de filmes de gelatina e nanocompósitos através da análise dielétrica em função da umidade, temperatura, e teor de plastificante ou nanopartícula, na faixa de frequência de 20 Hz - 2 MHz. Análises de calorimetria diferencial de varredura (DSC) e dinâmica mecânica (DMA) foram realizadas para determinar a temperatura de transição vítrea e de relaxação mecânica nos filmes produzidos. A constante dielétrica e o fator de perda dielétrica de suco de laranja e de goiabada em pasta foram dependentes da temperatura e concentração de sólidos solúveis. A temperatura de transição vítrea (Tg) e os tempos de relaxação dielétrica de filmes de gelatina diminuíram com o aumento da concentração de glicerol e com o aumento da umidade relativa de condicionamento. A temperatura de transição vítrea nos filmes nanocompósitos diminuiu com o aumento da umidade relativa de condicionamento. Filmes com 6% de laponita e sem adição de glicerol apresentaram os maiores valores de Tg. Os tempos de relaxação aumentaram ligeiramente com o aumento na concentração de laponita. Foram gerados dados úteis para estimar as propriedades dielétricas de suco de laranja e goiabada em pasta nas principais frequências de uso comercial, 915 e 2450 MHz, através de equações matemáticas em função da temperatura e concentração de sólidos solúveis. O glicerol e especialmente a água afetaram as propriedades dielétricas dos filmes de gelatina refletidas em menores tempos de relaxação, enquanto que as interações da laponita com a gelatina reduziram ligeiramente a mobilidade molecular nos filmes nanocompósitos proporcionando tempos de relaxação maiores. Este tema fez parte do Pilar 4 do projeto CEPID (2013/07914-8) \"Food Research Center\" (FoRC). / The dielectric properties of materials have gained importance in industrial application over the last decades; these properties provide useful information to improve processing and quality control of food products and related materials. The dielectric spectroscopy is widely used to study molecular dynamics in several systems, where it is common to observe the dielectric relaxation phenomenon that has been associated by many researchers to the glass transition phenomenon, important in stability and material properties. The objective of the thesis was to analyze the dielectric properties of food products and biopolymer films, emphasizing the study of molecular mobility in films; and the study of the structural dynamics of food and its correlation with quality factors. The study was divided into several stages with specific goals: The first was the installation and startup of the equipment for measurement of dielectric properties (E4980A with 16451B; E5061B with 85070E, Keysight Technologies); The subsequent step was dedicated to the analysis of the dielectric properties of guava paste and orange juice in frequencies between 500-3000 MHz, as a function of soluble solids content and temperature in order to generate correlations which allow to make a monitoring during the production process; In the last stage, the molecular mobility of gelatin biodegradable films and nanocomposites was studied through dielectric analysis as a function of moisture content, plasticizer or nanoparticle concentration and as a function of temperature, in frequencies between 20 Hz - 2 MHz. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were performed to determine the glass transition and mechanical relaxation temperatures of the films. The dielectric constant and the dielectric loss factor of orange juice and paste guava were dependent on the temperature and soluble solids concentration. The glass transition temperature (Tg) and the dielectric relaxation times of gelatin films decreased with increasing glycerol concentration and with increasing relative humidity of conditioning. The glass transition temperature of the nanocomposite films decreased with the increase of the relative humidity of conditioning. Films with 6% of laponite and without addition of glycerol had the highest values of Tg. Relaxation times increased slightly with increasing laponite concentration. Useful data were generated to estimate the dielectric properties of orange juice and guava paste in the main commercial frequencies, 915 e 2450 MHz, through mathematical equations as a function of temperature and soluble solids content. Glycerol and especially water affected the dielectric properties of gelatin films reflected in lower relaxation times, whereas laponite and gelatin interactions reduced slightly the molecular mobility of the nanocomposite films by providing longer relaxation times. This topic was part of the Pillar 4 of CEPID project (2013 / 07914-8) \"Food Research Center\" (FoRC).

Novos materiais obtidos a partir de polímeros biodegradáveis são uma alternativa para a redução do impacto ambiental causado pelo uso excessivo de polímeros derivados do petróleo. Atualmente, vários estudos têm sido realizados na busca de matéria-prima para o desenvolvimento de filmes biodegradáveis, com boa viabilidade técnica e econômica. Dentre estas matérias-primas, destacam-se as que são provenientes de fontes renováveis, de baixo custo e que tenham grande importância econômica e ambiental, como, por exemplo, o amido, as argilas, e a quitosana. Nos filmes que preparamos, adicionamos como plastificante a glicerina, um subproduto do biodiesel, e que contribui para maior estabilidade térmica dos filmes, em conjunto com o amido. O propósito deste trabalho foi o preparo de um biopolímero a base de quitosana e argila com propriedades de nanocompósitos, pois estes materiais costumam exibir propriedades físico-químicas diferenciadas em relação a outros materiais, devido à redução no seu tamanho. Sendo assim, através do estudo e comparação de duas argilas esmectíticas sódicas naturais, Bentogel e Corral, pôde-se observar o comportamento dos filmes formados em presença de amido e glicerina. Os filmes obtidos, através do método de dispersão em solução do polímero, foram caracterizados através das técnicas de DRX, MEV, IV, TG e DSC. Os resultados obtidos mostraram a formação de filmes nanocompósitos esfoliados de boa estabilidade térmica. / New materials made from biodegradable polymers are an alternative to reducing the environmental impact caused by excessive use of polymers derived from petroleum. Currently, several studies have been conducted in search of raw material for the development of biodegradable films, with good technical and economic feasibility. Among these materials, we highlight those that are from renewable resources, low cost and have great economic and environmental importance, such as, starch, clays, and chitosan. In preparing films, we added glycerol as a plasticizer, a byproduct of biodiesel, and contributes to better thermal stability of the films, together with starch. The purpose of this study was the preparation of a biopolymer based on chitosan and clay nanocomposites properties, because these materials tend to display different physico-chemical properties compared to other materials because of the reduction in size. Thus, through the study and comparison of two natural sodium smectite clays, Bentogel and Corral, it was observing the behavior of films formed in the presence of starch and glycerol. The films obtained by the method of dispersion in the polymer solution, were characterized by techniques of XRD, SEM, FTIR, TG and DSC. The results obtained showed the formation of exfoliated nanocomposites films and good thermal stability.

Neste trabalho, pós magnéticos nanoestruturados de PrxFe94-xB6 (x = 6, 8, 10 e 12) foram preparados a partir da combinação do processo de hidrogenação, desproporção, dessorção e recombinação (HDDR) e moagem de alta energia entre uma liga em estado bruto de fusão (Pr14Fe80B6) e Fe-α em pó. As nanopartículas produzidas apresentaram propriedades magnéticas e microestruturais comparáveis aos estudos realizados em hipertermia. O tempo ideal para obtenção de nanopartículas magnéticas é de 5 horas (a 900 rpm). Foi constatado que quanto maior o tempo de moagem, maior o percentual de carbono nas partículas (0,05 - 3,43 % C). O carbono é proveniente do ácido oléico adicionado como surfactante na etapa de moagem. Os nanocompósitos obtidos exibiram forças coercivas entre 80 Oe (6,5 kAm-1) e 170 Oe (13,5 kAm-1), e momentos magnéticos variando entre 81 - 129 Am2kg-1. A partir da difração de raios X foram identificadas apenas duas fases em todas as amostras: Fe-α e a fase magnética Pr2Fe14B. Nanopartículas isoladas com diâmetro aproximado de 20nm foram analisadas. Todas as composições estudadas apresentaram aquecimento proveniente da exposição a um campo magnético alternado (f = 222 kHz e Hmax ~3,7 kAm-1) comparáveis aos reportados na literatura. As variações de temperaturas (ΔT) dos pós foram: 51 K referente à composição de Pr6Fe88B6, 41 K para Pr8Fe86B6, 38 K no composto com 10% at. Pr (Pr10Fe84B6) e 34 K em Pr12Fe82B6. As taxas de absorção específicas estimadas foram de 201 Wkg-1 para a composição Pr6Fe88B6, 158 Wkg-1 para a composição Pr8Fe86B6 e 114 Wkg-1 para as composições Pr10Fe84B6 e Pr12Fe82B6. / In this work, PrxFe94-xB6 (x = 6, 8, 10 and 12) nanostructured powders were prepared by a combination of hydrogenation, disproportionation, desorption and recombination (HDDR) process with high energy milling applied to the mixture of an as-cast alloy (Pr14Fe80B6) and α-Fe. The produced nanoparticles showed magnetic properties comparable to those reported in hyperthermia studies. The optimal time to obtain the magnetic nanoparticles is 5 hours (at 900 rpm). It was verified that longer milling times cause an increase in carbon percentage on the particles. The carbon is derived from oleic acid added as a surfactant in the milling step. The nanocomposites exhibit coercive force ranging from 80 Oe (6.5 kAm-1) to 170 Oe (13.5 kAm-1) and magnetic moments in the range of 81 129 Am2kg-1. From the x-ray diffraction analyses, only two phases were found in all samples: α-Fe and the magnetic phase Pr2Fe14B. Individual nanoparticles with diameter of about 20 nm were verified. The samples studied presented heating when exposed to an alternating magnetic field (f = 222 kHz e Hmax ~3.7 kAm-1) comparable to reported in literature. Temperature variations (ΔT) of the powders were: 51 K for Pr6Fe88B6, 41 K for Pr8Fe86B6, 38 K for Pr10Fe84B6 and T = 34 K for Pr12Fe82B6. The specific absorption rates (SARs) of the powders were 201 Wkg-1 for Pr6Fe88B6 composition, 158 Wkg-1 on the composition Pr8Fe86B6, and 114 Wkg-1 for Pr10Fe84B6 and Pr12Fe82B6 compositions.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Tese (Doutorado) / Abstract: Since this thesis presents two independent studies on cellulose nanocrystals (CNCs), the abstract was divided in two sections referring to chapters II and III, respectively. Comprehensive morphological and structural investigation of cellulose I and II nanocrystals prepared by sulfuric acid hydrolysis Cellulose has several polymorphs. These polymorphs differ by crystal packing (i.e. unit cell parameters), polarity of the constituting chains and hydrogen bond patterns established between them. Most of cellulose polymorphs result from chemical treatments of the native polymorph, the so-called cellulose I (Cel-I) (Wada et al., 2008). In Cel-I, the chains are parallel and can be packed into two allomorphs, namely Iα and Iβ. Among the cellulose polymorphs, cellulose II (Cel-II), in which the chains are antiparallel, can be prepared from Cel-I by two distinct processes: Mercerization or Regeneration. Mercerization is an essentially solid-state process during which cellulose fibers are swollen in concentrated alkali media and recrystallized into cellulose II upon washing and drying (removal of the swelling agent). Unlike the mercerization process, in process known as regeneration, cellulose is first dissolved in an appropriated solvent and subsequent reprecipitated by adding a non-solvent, leading the chains to recrystallize into into Cel-II polymorph. The Cel-I to Cel-II transition is irreversible, which suggests that Cel-II is thermodynamically more stable (Habibi et al., 2010). Cell-II is the second most extensively studied polymorph due to its technical relevance. Nevertheless, so far, most of investigations involving Cel-II have focused on fibers and only a few recent studies have been carried out on CNCs. Cel-II nanocrystals have been prepared either by acid hydrolysis of mercerized fibers (Hirota et al., 2012; Kim et al., 2006; Yue et al., 2012), mercerization of Cel-I CNCs (Jin et al., 2016), or after recrystallization of fractions of short cellulose chains in solution (Dhar et al., 2015; Hirota et al., 2012; Hu et al., 2014; Sèbe et al., 2012). However, while these studies have generally combined the data from several imaging, diffraction and spectroscopic techniques, a complete structural picture of the nanocrystals has not been reported so far. In this context, the purpose of the research work presented in chapter II was to produce, characterize and compare CNCs obtained from eucalyptus wood pulp using three different methods: i) classical sulfuric acid hydrolysis (CN-I), ii) acid hydrolysis of cellulose previously mercerized by alkaline treatment (MCN-II), and iii) solubilization of cellulose in sulfuric acid and subsequent recrystallization in water (RCN-II). The morphology, crystal structure, crystallinity index, surface charge and degree of polymerization of these nanocrystals were characterized by complementary techniques, namely elemental analysis, zetametry, viscometry, transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier-transform infrared and solid-state nuclear magnetic resonance spectroscopies (FTIR and NMR, respectively). The three types of prepared CNC exhibit different morphologies and crystalline structures. When the acid hydrolysis conditions are set-up in such a way that the crystalline domains in the initial wood pulp and mercerized cellulose (WP and MWP, respectively) are preserved (60 wt% H2SO4, 45°C, 50 min), the resulting nanocrystals retain the fibrillar nature of the parent fibers (i.e., the chain axis is parallel to the long axis of the acicular particles) and their initial allomorphic type (I for WP and II for the MWP). In both cases, the particles are mostly composed of a few laterally-bound elementary crystallites, in agreement with what was shown for cotton CNCs by Elazzouzi-Hafraoui et al. (2008). The unit nanocrystals in CNCs from mercerized cellulose (MCN-II) are shorter but broader than those prepared from cellulose I fibers (CN-I). If harsher conditions are used (64 wt% H2SO4, 40°C, 20 min), resulting in the depolymerisation and dissolution of native cellulose, the short chains (with degree of polymerization DP ≈ 17) recrystallize into Cel-II ribbons upon regeneration in water at room temperature. In these somewhat tortuous ribbons, the chain axis would lie perpendicular to the long axis of the nanocrystal and parallel to its basal plane. In addition, these nanoribbons are very similar in shape and molecular orientation to mannan II nanocrystals prepared by recrystallization of mannan (Heux et al., 2005), a linear polymer of β-(1,4)-D-mannosyl residues, suggesting that this mode of crystallization may be a feature of short-chain linear β-(1,4)-linked polysaccharides. Although similar ribbons of recrystallized cellulose II have been reported by other authors, to our knowledge, it is the first time that a detailed morphological and structural description is proposed in terms of particle morphology, crystal structure and chain orientation. By comparison with the fibrillar nanocrystals prepared by acid hydrolysis of native or mercerized cellulose fibers, the unique molecular and crystal structure of the nanoribbons imply that a higher number of reducing chain ends are located at the particle surface, which may be important for subsequent chemical modification and specific potential applications such as biosensing and bioimaging agents. Therefore this study offers scope to a better understanding of crystalline structure and morphology of CNC obtained by regeneration process with sulfuric acid. Mechanical properties of natural rubber nanocomposites reinforced with high aspect ratio cellulose nanocrystals isolated from soy hulls At present, the most promising application of CNCs is as reinforcement material in the field of polymer nanocomposites.The incorporation of CNCs in polymer matrices generally leads to polymer-based nanocomposite materials with higher mechanical and barrier properties than the neat polymer or conventional composites. Among various factors that influence the efficiency of the reinforcing effect of CNCs, their intrinsic characteristics, including crystallinity and aspect ratio, play a key role (Dufresne, 2012; Favier et al., 1995; Mariano et al., 2014). It is also well-known that these characteristics depend on the source of the original cellulose, on the extraction method and its conditions (including pretreatment). However, it is widely accepted that the raw starting material is the most important factor (Beck-Candanedo et al., 2005; Dufresne, 2012; Elazzouzi- Hafraoui et al., 2008). The reinforcement capability of CNCs is therefore directly linked to the source of cellulose as well as its biosynthesis. Thus, the optimization of the extraction procedure and further characterization of CNCs from different sources of cellulose are crucial for an efficient exploitation of these sources, allowing the selection of the appropriate source (i.e. with targeted morphology) to suit specific end user applications (Brinchi et al., 2013). Natural rubber (NR) is a perfect polymer matrix to be used as a model system to study the effect of filler reinforcement, owing to its high flexibility and low stiffness. Its properties can be tailored by the addition of reinforcing fillers of various surface chemistries and aggregate size/aspect ratios to suit the targeted application. CNCs extracted from different sources have already been studied as nanoreinforcement in NRbased nanocomposites, including CNCs isolated from capim dourado (Siqueira et al., 2010), rachis of palm date tree (Bendahou et al., 2009), sugarcane bagasse (Pasquini et al., 2010; Bras et al., 2010), sisal (Siqueira et al., 2011), and bamboo (Visakh et al., 2012). So far, little results have been reported in the literature on the isolation of CNCs from soy hulls or their use in nanocomposites (Flauzino Neto et al., 2013, Silvério et al., 2014). In this study, CNCs were isolated from soy hulls by sulfuric acid hydrolysis treatment. The resulting CNCs, referred to as CNCSH in the following, were characterized using transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), wide-angle X-ray scattering (WAXS). These CNCSH were used as a reinforcing phase in a NR matrix to prepare nanocomposite films by casting/evaporation at 1, 2.5 and 5 wt% (dry basis) loading levels. The effect of CNCSH on the structure, as well as thermal and mechanical properties of NR, was investigated by means of scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), tensile tests and thermogravimetric analysis (TGA). For the acid hydrolysis treatment, were chose milder conditions compared to those described in Flauzino Neto et al. (2013) in order to avoid as much as possible the hydrolysis of crystalline cellulose domains. The CNCSH was found to have a type I crystal structure, high crystallinity (crystallinity index ≈ 80%), large specific surface area (estimated to be 747 m2.g-1 from geometrical considerations) and high aspect ratio (around 100). This aspect ratio is the largest ever reported in the literature for a plant cellulose source. Futhermore, from microscopic observations it is clearly seen that CNCSH does not consist of partially hydrolyzed microfibril since it displays the classical rod-like morphology of CNC. Thus, soy hull was found to be an interesting source of raw material for the production of CNC, due to the characteristics of the obtained nanocrystals associated with low lignin content and wide availability of this agro-industrial residue. In the meantime, the reuse of this agro-industrial residue goes towards sustainable development and environment-friendly materials. To tailor the dimensions of CNC and take full advantage of this source, special care needs to be paid to the extraction process and its conditions. A milder acid hydrolysis is preferable to improve the extraction yield, preserve the crystallinity of native cellulose and obtain high aspect ratio CNC. As expected, a high reinforcing effect is observed even at low filler contents when using this nanofiller (CNCSH) to prepare nanocomposites with a natural rubber (NR) matrix by casting/evaporation. For instance, by adding only 2.5 wt% CNC, the storage tensile modulus at 25°C of the nanocomposite was about 21 times higher than that of the unfilled NR matrix. This reinforcing effect was higher than the one observed for CNCs extracted from other sources. It may be assigned not only to the high aspect ratio of these CNCs but also to the stiffness of the percolating nanoparticle network formed within the polymer matrix. Moreover, the sedimentation of CNCs during the film processing by casting/evaporation was found to take place and play a crucial role on the mechanical properties. Thus, both the high aspect ratio of the CNC and sedimentation due to the processing technique are involved in the good mechanical results obtained. Indeed, if sedimentation occurs, then a multilayered film results and the CNC content in the lowest layers is higher than the average CNC content. It means that CNC mechanical percolation can occur in the lowest layers for an average CNC content which is lower than the percolation threshold. Hence, the system can be considered as constituted of parallel layers in the direction of the mechanical solicitation (tensile mode), and the CNC-rich layers can support a higher stress leading to a higher modulus value. Moreover, if high aspect ratio CNC is used, then percolation can occur in the lowest layers for lower average CNC contents. An important contribution of this work is to highlight the importance of the sedimentation of CNC during the evaporation step on the mechanical properties of the nanocomposites which is rarely mentioned in the literature.