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Polyurethanes are polymers produced from polyols and isocyanates. Commonly, aiming to modify physicochemical properties of the resulting material, other chemical species can be introduced in the polymeric structure, modifying its mechanical, thermal and electronic characteristics and conferring more stability and resistance to external factors. The rare earth chemical elements, composed of lanthanides, Y and Sc, can give the materials such improved characteristics, and are still less researched when compared to other chemical elements. In the present study, a systematic search was carried out on the Web of Science platform. No studies were identified with polyurethanes and Sc, Pr, Pm, Sm, Dy and Ho, showing room for unexplored studies. Most of the articles investigated the luminescent characteristics of the chemical elements that were used, but it was also possible to notice trends in changing mechanical and thermal properties.

Due to the environmental concerns, the conversion of lignocellulosic waste can be the key to produce bioproducts and biofuels such as butanol. This study aimed to present and evaluate orange bagasse pellets (OBP) as a carbon source to produce butan-1-ol production via ABE fermentation using Clostridium beijerinckii. These bagasse pellets were characterized, holocellulose (18.99%), alfacellulose (5.37%), hemicellulose (13.62%), lignin (6.16%), pectin (7.21%), protein (3.14%), and was tested under three different pretreatments, which were the following: (a) ultrasound, (b) autohydrolysis, and (c) acid-diluted hydrolysis followed by enzymatic hydrolysis to verify an amount of fermentable total reducing sugars. ANOVA was used and pretreatments followed by enzymatic hydrolysis do not enhance a significant amount of available sugars compared to raw bagasse. The ABE fermentation was carried out in batch reactors at 37 °C under agitation of 160 rpm and anaerobic conditions, using OBP without treatment followed by enzymatic hydrolysis. Using a non-mutant microorganism, the fermentation achieved butyric acid yields of 3762.68 mg L−1 for control and 2488.82 mg L−1 for OBP and the butanol production was 63.86 mg L−1 and 196.80 mg L−1 for OBP and the control (glucose) assay, respectively. The results of this solvent’s production have shown that OBP has the potential for ABE fermentation and a promising feedstock.

Cellulose is considered one of the most important renewable sources of biopolymers on Earth. It has attracted widespread attention due to its physical–chemical characteristics, such as biocompatibility, low toxicity, biodegradability, low density, high strength, stability in organic solvents, in addition to having hydroxyl groups, which enable its chemical modification. In this study, cellulose nanofibrils (CNFs) were functionalized with dicyanovinyl groups through nucleophilic vinylic substitution (SNV) and used as electrocatalyst in electrochemical of carbon dioxide (CO2) reduction. Results indicate that introducing dicyanovinyl groups into the structure of nanocellulose increases electrocatalytic activity as compared to that of pure nanocellulose, shifting the onset potential of the electrochemical CO2 reduction reaction to more positive values as compared to those for the reaction with argon. The atomic force microscopy (AFM) images show no changes in the morphology of CNFs after chemical modification.

Few investigations have examined the structural controls of bark on its water storage and influence on stemflow, despite the bark being considered a critical component that determines the time and magnitude of this process. This study seeks to answer the question: Do bark water absorbability and wettability estimates correlate with stemflow yield? We hypothesized that (1) the absorbability and wettability are correlated, that is, greater water absorbability implies greater wettability, and (2) high rates of bark water absorbability and wettability has a strong and negative correlation with stemflow generation. Stemflow yield (Sy) was monitored over 12 months for 31 trees, representing 9 species common to the Brazilian savanna ecosystem known as Cerrado. Bark absorbability, per unit dry weight, changes over time of the water absorbability (BWA - by submersion methodology), bark drying (BWD), bark absorbability rate (BWArate), bark drying rate (BWDrate), and wettability (initial contact angle – CAin and CA rate - CArate) were determined under laboratory conditions. As insoluble lignin may also act to alter bark water storage dynamics, for each species, the bark insoluble lignin content was characterized. Stemflow variability was significant across the study species. Funneling ratios (FR) indicates that all species’ canopies diverted enough rainfall as stemflow to concentrate rainwaters at the surface around their stem bases (FR > 1). Differences in bark water absorbability were notable some of tree species. A decrease in the CA value as a function of time was not observed for all barks, which in association with stemflow yields, allowed a novel classification method of wettability, based on CAin and it’s rate of change: highly wettable (CAin ≤ 75.3° and CArate ≥ 0.26°h–1) and non-wettable (CAin ≥ 93.5° and CArate ≤ 0.13°h–1). So, only from the wettability classification could be observed that the non-wettable bark species presented higher Sy, FR, BWA, and BWArate than highly wettable bark species. The stemflow from species with highly wettable bark had a strong and positive correlation with BWA. On the other hand, non-wettable bark stemflow yield has a strongly and negative correlation with FR, CAin, and BWArate. Thus, bark wettability properties showed to deserves special attention. This novel classification of bark wettability had a substantial effect on stemflow yield comprehension and proved to be an important variable to link laboratory and field investigation for understanding the stemflow yield. These findings will improve our understanding of the stemflow dynamics, water balance and the ecohydrology processes of forest ecosystems.

Made available in DSpace on 2018-11-29T12:37:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01. Added 1 bitstream(s) on 2019-10-09T18:27:34Z : No. of bitstreams: 1 S1516-14392017000800842.pdf: 3614732 bytes, checksum: d77bf6d3c6073fcae24ced575e5a0a2c (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Cellulose is a polymer widely available in nature, however its applications may be restrict due to its hydrophilic character. The creation of hierarchical structures on the surface is one of the required factors to obtain the hydrophobicity of this material. In order to compare the morphological and chemical effects caused by the action of different gases in the creation of nanostructures on the cellulose surface, samples were exposed to oxygen (O-2) and sulfur hexafluoride (SF6) plasma treatments. The changes in morphology after treatment prove that both the gases were able to create similar nanostructures in the material. The analysis of elemental composition and identification of functional groups on the sample surface showed that chemical modifications occurred differently for each treatment. Contact angle measurements revealed that samples treated by O-2 plasma remained hydrophilic, whereas low receptivity to polar (theta > 120 degrees) and non- polar (theta > 100 degrees) liquids was observed for samples exposed to SF6 plasma. Univ Fed Sao Carlos, Ctr Ciencias & Tecnol Sustentabilidade, Rod Joao Leme dos Santos,Km 110, BR-18052780 Sorocaba, SP, Brazil Univ Estadual Paulista, Lab Plasmas Tecnol, Campus Expt Sorocaba,Av Tres de Marco 511, BR-18087180 Sorocaba, SP, Brazil Univ Estadual Paulista, Lab Plasmas Tecnol, Campus Expt Sorocaba,Av Tres de Marco 511, BR-18087180 Sorocaba, SP, Brazil

International audience; This paper investigates the use of an aqueous dispersion of polyethylene copolymer with a relatively high content of acrylic acid as a compatibilizer and as an alternative medium to obtain polyethylene CNF nanocomposites. The CNF content was varied from 1 to 90 wt% and the appearance, optical, thermal, mechanical and rheological properties, as well the morphology of the films were evaluated. The PE/CNF films are transparent up to 20 wt% of NFC indicating a good dispersion of CNF, but a poor distribution, with PE-rich and CNF-rich regions observed by SEM. Improved mechanical properties were achieved, with a 100% and 15,900% increase in the Young’s modulus with 1 wt% and 90 wt% NFC, respectively. The rheological behavior indicated good melt processability. According to these results, aqueous polyolefin dispersions seem to be a promising, easy and relatively fast route for obtaining cellulose/polyolefins nanocomposites with low to high contents of cellulose nanofibrils.

This study aimed at the production of biosurfactants from yeasts under acidic conditions using residual soybean oil as a carbon source, as well as the biosurfactant produced in the solubilization of metals in sewage sludge. The yeast Meyerozyma guilliermondii was considered the best producer in both pH 4.0 and 2.0; therefore, the product obtained by this yeast was characterized by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (NMR) spectroscopy. Moreover, it was applied in metal removal assays in anaerobic sewage sludge. The spectra obtained in FT-IR suggested that M. guilliermondii's biosurfactant had a similar structure to glycolipids from the sophorolipid class, and it was confirmed by 1H NMR spectroscopy. In the bioleaching assays, the application of biosurfactant (2%) produced by M. guilliermondii with pH adjusted to 2.0 was able to solubilize 15.9% of cadmium from the sewage sludge.

In this work the macrophyte Typha domingensis was characterized. Cellulose nanocrystals (CNCs) were extracted and pretreated with alkali at 80 °C followed by hydrolysis with sulfuric acid 34 % (w/w) at 80 °C for 15 min. The plants were separated into two groups: the young and senescent. Then each plant was sectioned into three parts (top, bottom and middle). The middle and the bleached middle fibers were characterized using thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and the chemical composition. The CNCs from the young middle part show values of 593 ± 482 nm in length and 12.6 ± 4.4 nm in diameter and the senescent part 704.4 ± 316 nm in length and 7.4 ± 3.5 nm in diameter. The results were obtained using an atomic force microscope and show the great potential of this fiber as a source of CNCs to reinforce polymeric material.

In the work presented in this article surface chemical modifi cation was applied to ramie cellulose nanocrystals by grafting organic acid chlorides presenting different lengths of the aliphatic chain. The objective of this surface chemical treatment was to enhance the nonpolar nature of the grafted nanocrystals and improve their dispersibility in a nonpolar polymeric matrix. The occurrence of the chemical modifi cation was evaluated by Fourier transform infrared (FTIR) spectroscopy, the degree of crystallinity by X-ray diffraction, and the morphology by scanning electron microscopy with fi eld emission gun (FEG-SEM) and atomic force microscopy (AFM). The morphology and crystallinity provided by different experimental methods were carefully compared.

RESUMO O isolamento de nanocristais de celulose (CNCs) de fibras vegetais é uma alternativa promissora para sua aplicação como reforço em matrizes poliméricas. A caracterização dos CNCs é fundamental para a confiabilidade da técnica, além de determinar as aplicações possíveis a partir de cada tipo de fibra. A partir da técnica de microscopia de força atômica, um estudo da morfologia e distribuição dos CNCs de semente de manga, vagem de algaroba, pseudocaule da bananeira e fibra do mesocarpo de dendê foi realizado neste trabalho. Os CNCs foram obtidos via reação hidrolítica com ácido sulfúrico em concentrações que variaram de acordo com a fonte da fibra. Os resultados obtidos revelaram dimensões variando de 300 a 500 nm em comprimento e 4 a 16 nm em diâmetro. A apresentação morfológica em forma de agulha demonstrou que o isolamento das fibras de celulose em CNCs foi efetiva. A razão de aspecto associada à formação cilíndrica em agulha dos CNCs isolados evidenciou o alto potencial das fontes de dendê e de vagem de algaroba para o reforço de bionanocompósitos. ABSTRACT The isolation of vegetables fiber in cellulose nanocrystals (CNCs) comprises a promising alternative for application as reinforcement in polymer matrices. The characterization of the CNCs is essential to evaluate the reliability of this technique and to determine the possible applications from each vegetable fiber type. Therefore it is proposed here a study with atomic force microscopy technique to analyze the morphology and distribution of CNCs from mango seed, mesquite pods, banana pseudostem and fiber palm mesocarp. CNCs were obtained by acid hydrolysis with sulfuric acid in concentrations that varied according to the fiber sources. The results showed dimensions ranging from 300 to 500 nm in length and 4 to 16 nm in diameter. The morphology obtained needle-like show that the isolation of cellulose fibers to CNCs was. The aspect ratio related to the cylindrical needle organization of the isolated CNCs indicate the high potential of the palm mesocarp and mesquite pods as reinforcement on bionanocomposites.

The in-depth oxypropylation of different types of cellulose fibers, namely Avicel, Rayon, Kraft, and Filter Paper, was investigated. New biphasic mono-component materials were obtained, which could be hot-pressed to form films of cellulose fibers dispersed into a thermoplastic matrix. The success of this chemical modification was assessed by FTIR spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis and contact angle measurements. The optimization of this process led to the establishment of the optimal molar ratio between the cellulose OH groups and propylene oxide, which varied as a function of the specific morphology of the fibers.

This work describes the partial oxypropylation of filter paper cellulose fibers, employing two different basic catalyst, viz., potassium hydroxide and 1,4-diazabicyclo [2.2.2] octane, to activate the hydroxyl groups of the polysaccharide and thus provide the anionic initiation sites for the “grafting-from” polymerization of propylene oxide. The success of this chemical modification was assessed by FTIR spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis and contact angle measurements. The study of the role of the catalyst employed on the extent of the modification and on the mechanical properties of the ensuing composites, after hot pressing, showed that both the Bronsted and the Lewis base gave satisfactory results, without any marked difference.

Bulk oxypropylation limited to the outer layer of cellulose fibres constitutes a straightforward approach to the preparation of a novel type of composite material made up of a thermoplastic sleeve (matrix) surrounding the unreacted core of the fibres (reinforcing elements).

International audience; The surface of ramie cellulose whiskers has been chemically modified by grafting organic acid chlorides presenting different lengths of the aliphatic chain by an esterification reaction. The occurrence of the chemical modification was evaluated by FTIR and X-ray photoelectron spectroscopies, elemental analysis and contact angle measurements. The crystallinity of the particles was not altered by the chain grafting, but it was shown that covalently grafted chains were able to crystallize at the cellulose surface when using C18. Both unmodified and functionalized nanoparticles were extruded with low density polyethylene to prepare nanocomposite materials. The homogeneity of the ensuing nanocomposites was found to increase with the length of the grafted chains. The thermomechanical properties of processed nanocomposites were studied by differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) and tensile tests. A significant improvement in terms of elongation at break was observed when sufficiently long chains were grafted on the surface of the nanoparticles. It was ascribed to improved dispersion of the nanoparticles within the LDPE matrix.

The thermodynamic compensation effect plot derived from Eyring rate process theory was applied to the thermal and UV ageing of LDPE/Carbon Black composites containing commercial carbon black (CB) and carbon black surface oxidized with nitric acid. Correlations were tested among compensation effect, electrical threshold field and volumetric electrical conductivity. Compensation plots from OIT measurements correlate with thermal and UV ageing effect on activation ΔS and ΔH values, giving a good linear correlation for all samples studied. The relative changes in dc conductivity and electrical threshold field are consistent with the OIT compensation plot, demonstrating that this analysis can be used to monitor LDPE/CB composite degradation under thermal or UV ageing. It can also be used to evaluate, quite accurately, the effect of oxidizing the surface of the CB on the electrical properties (dc conductivity and electrical threshold field) of the LDPE/CB composites.

Modificações químicas foram aplicadas às fibras celulósicas e ao amido com o objetivo de obter produtos com uma camada termoplástica externa, preservando a parte interna desses substratos (não modificada). O produto final deveria se comportar como um material compósito onde a parte interna não modificada é o agente de reforço e a camada termoplástica a matriz. As modificações foram realizadas através da inserção de pequenas cadeias de óxido propileno a cadeia carbônica do polissacarídeo (celulose e amido). As cadeias de poli(oxido propileno) enxertadas proporcionará uma camada termoplástica em torno da porção de polissacarídeo não modificada. A obtenção destes materiais pode dispensar as etapas de mistura e permitir o processamento térmico sem a necessidade de utilização de um segundo componente (matriz), uma vez que a própria capa polimérica desempenharia este papel. A construção da capa polimérica envolvente foi conduzida através da reação da celulose ou amido pré-ativados com o óxido de propileno. A etapa de ativação foi realizada com o tratamento dos substratos com KOH ou DABCO e a reação de enxertia foi realizada em sistema heterogêneo. Os materiais obtidos utilizando esses tratamentos foram caracterizados por diferentes técnicas (FTIR, Raios-X, MEV, TG, DSC, Ângulo de contato e ensaios de Resistência à Tração). Os resultados obtidos demonstraram que é possível de produzir materiais com características termoplásticas reforçadas através da reação em uma única etapa, sem a necessidade de laboriosos procedimentos sintéticos. Chemical modifications were applied to cellulosic materials and starch with the objective to obtain products with an external thermoplastic layer while preserving the inner part of these substrates. The final products should behave as composite materials where the unmodified inner part is the reinforcement agent and the thermoplastic layer the matrix. The modifications were performed by grafting polypropylene oxide short chains to the polysaccharide backbone (cellulose and starch). The grafted polypropylene oxide chains will render a thermoplastic layer around the unmodified polysaccharide portions. The attainment of these materials can excuse the stages of mixture and allow the thermal processing without the necessity of use the second component (matriz), a time that the proper polymeric layer would play this role. The construction of the involving polymeric layer was conducted by reacting pre-activated cellulose (or starch) and propylene oxide (PO). The activation step was performed with KOH (or DABCO) treatment and the grafting reaction was carried through in heterogeneous system. The materials obtained following these treatments were characterized by different techniques (FTIR, X-Ray, MEV, TG, DSC, Contact Angle and Mechanical Analyses). The results had demonstrated that it is possible to produce materials with strengthened thermoplastic characteristics through the reaction in an only stage, without the necessity of laborious synthetic procedures.

Devido à preocupação com o meio ambiente e o volume crescente de resíduos plástico em aterros sanitários, os polímeros biodegradáveis estão sendo estudados extensivamente. Um deles é o PLA. Apesar de possuir propriedades comparáveis a polímeros commodities e polímeros de engenharia, ainda é necessário melhorar certas características do PLA, como resistência ao impacto. Para isso, a nanocelulose (NC) pode ser usada sem alterações significativas na biodegradação polimérica. Este estudo teve como objetivo obter a nanocelulose, caracteriza-la e incorpora-la ao poli(ácido láctico) (PLA), assim como, estudar as propriedades térmicas, morfológicas e mecânicas do compósito obtido. A NC foi obtida por hidrólise ácida utilizando ácido fosfórico e posteriormente foi silanizada com três silanos distintos. As nanopartículas foram caracterizadas por Birrefringência, Microscopia Eletrônica de Transmissão (MET), Termogravimetria (TG), Potencial Zeta, Espectroscopia Vibracional de Absorção no Infravermelho com Transformada de Fourier (FTIR) e Difração de Raio X (DRX). Com as imagens obtidas pelo MET foi possível medir o tamanho das partículas de NC. E então obter a razão de aspecto de 82 e o limite de percolação de 1,1% em massa, confirmando a morfologia de nanofibra. De acordo as analises TG\'s, a presença de NC silanizada aumentou o início da degradação térmica. Os compósitos, contendo 3% em massa de NC, foram obtidos por fusão em câmara de mistura e moldados por injeção. Os compósitos foram caracterizados por FTIR, Cromatografia de Permeação em Gel (GPC), TG, Calorimetria Exploratória Diferencial (DSC), Microscopia Eletrônica de Varredura (MEV-FEG), Impacto e Tração. As análises dos compósitos mostraram que a NC atuou como agente de nucleação, facilitando a cristalização do PLA, além de a NC ter atuado como reforço na matriz polimérica melhorando as propriedades mecânicas. Due to concern for the environment and the growing volume of plastic waste in landfills, biodegradable polymers are being studied extensively. One of them is the PLA. Despite properties comparable to commodities polymers and engineering polymers, it is still necessary to improve certain characteristics of PLA, such as impact resistance. For this, the nanocelulose (CN) can be used without significant changes on the polymeric biodegradation. This study aimed to obtain nanocelulose, characterizes it and incorporates it to polylactic acid (PLA), even as, studies of thermal, morphological and mechanical properties of the composites processed. The CN was obtained by acid hydrolysis using phosphoric acid and it was, subsequently, silanized with three different silanes. The nanoparticles were characterized by Birefringence, Transmission Electron Microscopy (TEM), Thermogravimetry (TG), Zeta Potential, Spectroscopy Absorption Vibrational Infrared Fourier Transform (FTIR) and X-Ray Diffraction (XRD). By images taken by TEM was possible to measure the size of particles CN. So, obtain the aspect ratio of 82 and the percolation limit of 1.1 wt%, demonstrating morphology of nanofiber. According to TG analysis, the beginning of thermal degradation increased when CN Pure was compared with modified CN. The composite, containing 3 wt% CN, were obtained by melt in mixing chamber and then injection molded. The composites were characterized by FTIR, Gel Permeation Chromatography (GPC), TG, Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Impact and Tensile Strength. The results showed that the CN acts as a nucleating agent in PLA, facilitating the crystallization and acts as reinforcement in polymer matrix to improve the mechanical properties.

A celulose é o polímero natural renovável disponível em maior abundância atualmente. Por possuir estrutura semicristalina, é possível extrair seus domínios cristalinos através de procedimentos que ataquem sua fase amorfa, como a hidrólise ácida, obtendo-se assim partículas cristalinas chamadas nanopartículas de celulose (NCs). Estas nanopartículas têm atraído enorme interesse científico, uma vez que possuem propriedades mecânicas, como módulo de elasticidade e resistência à tração, semelhantes a várias cargas inorgânicas utilizadas na fabricação de compósitos. Além disso, possuem dimensões nanométricas, o que contribui para menor adição de carga à matriz polimérica, já que possuem maior área de superfície, quando comparadas às cargas micrométricas. Nanocompósitos formados pela adição destas cargas em matrizes poliméricas podem apresentar propriedades comerciais atraentes, como barreira a gases, melhores propriedades térmicas e baixa densidade, quando comparados aos compósitos tradicionais. Como se trata de uma carga com dimensões nanométricas, obtida de fontes renováveis, uma das principais áreas de interesse para aplicação deste reforço é em biopolímeros biodegradáveis. O poli(ácido lático) (PLA), é um exemplo de biopolímero com propriedades mecânicas, térmicas e de processamento superiores a de outros biopolímeros comerciais. No presente trabalho foram obtidas nanopartículas de celulose (NCs), por meio de hidrólise ácida, utilizando-se três métodos distintos, com o objetivo de estudar o método mais eficiente para a obtenção de NCs adequadas à aplicação em compósitos de PLA. Os Métodos I e II empregam extração das NCs por meio do H2SO4, diferenciando-se apenas pela neutralização, a qual envolve diálise ou neutralização com NaHCO3, respectivamente. No Método III a extração das NCs foi realizada com H3PO4. As NCs foram caracterizadas por diferentes técnicas, como difração de raios X (DRX), análise termogravimétrica (TG), espectroscopia vibracional de absorção no infravermelho (FTIR), microscopia eletrônica de transmissão (MET) e microscopia de força atômica (MFA). Os resultados de caracterização das NCs indicaram que, a partir de todos os métodos utilizados, há formação de nanocristais de celulose (NCCs), entretanto, apenas os NCCs obtidos pelos Métodos II e III apresentaram estabilidade térmica suficiente para serem empregados em compósitos preparados por adição da carga no polímero em estado fundido. A incorporação das NCs em matriz de PLA foi realizada em câmara de mistura, com posterior moldagem por prensagem a quente. Compósitos obtidos por adição de NCs obtidas pelo Método II foram caracterizados por calorimetria exploratória diferencial (DSC), análise termogravimétrica, microscopia óptica, análises reológicas e microscopia eletrônica de varredura (MEV). A adição de NCs, extraídas pelo Método II, em matriz de PLA afetou o processo de cristalização do polímero, o qual apresentou maior grau de cristalinidade. Além disso, a adição de 3% em massa de NCs no PLA foi suficiente para alterar seu comportamento reológico. Os resultados reológicos indicaram que a morfologia do compósito é, predominantemente, composta por uma dispersão homogênea e fina da carga na fase matriz. Micrografias obtidas por MEV corroboram os resultados reológicos, mostrando, predominantemente a presença de partículas de NC em escala nanométrica. Compósitos de PLA com NCs obtidas pelo Método III apresentaram aglomerados de partículas de NC em escala micro e milimétrica, ao longo da fase matriz, e não foram extensivamente caracterizados. Cellulose is the renewable natural polymer currently available in greatest abundance. Cellulose is a semicrystalline polymer, and it is possible to extract its crystalline domains through a procedure that destroys its amorphous phase, such as acid etching, so obtaining crystalline cellulose particles called cellulose nanoparticles (NC). These nanoparticles have attracted great scientific interest because they have mechanical properties similar to those of many inorganic types of filler used in polymer matrix composites, like elastic modulus and tensile strength. Moreover, they have nanometric dimensions, which contribute to lower filler contents in the polymer matrix, due to its increased surface area when compared to the one of micrometric fillers. Nanocomposites formed by adding these fillers into polymeric matrices can present attractive commercial properties such as gas barrier, improved thermal properties, and low density, when compared to traditional composites. As NC are nanometric scale fillers, obtained from renewable sources, there is a great interest in their application into biodegradable biopolymer matrixes. Poly (lactic acid), PLA, is an example of biopolymer that presents improved thermal, mechanical and processing properties, when compared to the ones of other commercial biopolymers. In this work, cellulose nanoparticles (NC) were obtained, via acid hydrolysis, using three different methods, in order to study the most efficient method to obtain NC suitable to be used in polymer matrix composites. NC obtention methods I and II employ extraction by H2SO4. Methods I and II differ only in the neutralization step, which involves dialysis, for Method I, and neutralization with NaHCO3, for Method II. In Method III, the extraction of the NCs was performed using H3PO4. The NC were characterized by different techniques such as X-ray diffraction (XRD), thermogravimetric analysis (TG), infrared absorption spectroscopy (FTIR), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The characterization results indicated that all methods yielded cellulose nanocrystals. However, only NC obtained by methods II and III showed sufficient thermal stability to be used in composites prepared by melt mixing. The NC/PLA composites were prepared in a mixing chamber, followed by hot press molding. The composites with addition of NC obtained by Method II were characterized by differential scanning calorimetry (DSC), TG, optical microscopy, rheological analysis and scanning electron microscopy (SEM). The cellulose nanoparticles extracted by Method II affected the crystallization process of the PLA. The composite presented a higher degree of crystallinity than the pure matrix. Furthermore, the addition of 3 wt% of the NC in PLA was enough to change its rheological behavior. The rheological results indicated that the morphology is predominantly composed by a fine and homogeneous dispersion of the filler in the matrix. The SEM micrographs corroborate the rheological data, showing, predominantly, NC particles in nanometric scale. Composites with NC obtained by Method III presented micro and milimetric scale clusters of NC particles in the matrix phase and were not extensively characterized.

As questões ambientais relacionadas à produção industrial, a busca de produtos renováveis para produção de materiais, tanto conhecidos como inéditos, e o aproveitamento/reciclagem de resíduos têm sido temas de diversos estudos, tanto em ciências como em áreas afins. Neste trabalho, são apresentadas formulações para espumas rígidas de poliuretano (ERPU), partindo-se de reagentes alternativos, de origem não petroquímica. As espumas foram sintetizadas a partir de polióis de óleos vegetais de rícino e tungue, materiais de fonte renovável, que se apresentaram como boa alternativa para a substituição de polióis de origem petroquímica. Às espumas rígidas sintetizadas, foram adicionadas cargas inorgânicas oriundas de rejeitos industriais, com o intuito de se estudar aplicações para estes resíduos e na tentativa de contribuir para a diminuição do impacto ambiental causado por eles. Às espumas produzidas a partir de poliol derivado de óleo de rícino, foi utilizado um pó preto (rejeito P3) que é um rejeito do processo Bayer de produção de alumina. Este rejeito, caracterizado através de diversas técnicas, mostrou-se rico em alumina (Al2O3) e hidróxido de alumínio (Al(OH)3). Devido à alta concentração destas duas substâncias, este material apresenta grande potencial como retardante de chamas para as espumas. Para as espumas produzidas a partir de poliol derivado de óleo de tungue, foi utilizada como carga a cinza de casca de arroz (CCA), rejeito industrial do beneficiamento do arroz, rico em sílica (SiO2) e com potencial de retardância de chamas para as espumas. As espumas obtidas foram caracterizadas por FTIR, análise térmica (TG, DTG e DTA) e MEV. Foram também medidas as densidades dos materiais e realizados ensaios mecânicos, de condutividade térmica e testes de chama, para se avaliar a influência das cargas nas diversas propriedades das espumas. Os resultados encontrados indicam que, para as porcentagens de cargas utilizadas, não há modificações morfológicas significativas nos compósitos, em relação às espumas matrizes. Observou-se um ganho em propriedade de retardância de chamas e não houve perda significativa de propriedades térmicas. Há indicativos de haver interação química secundária do rejeito P3 com o material poliuretânico sintetizado a partir de poliol derivado de óleo de rícino. O mesmo não foi observado para as espumas sintetizadas com poliol derivado de tungue, utilizando-se cinza de casca de arroz como carga inorgânica. Environmental issues related to industrial production, to a search for renewable products for the production of new materials, and recovery / recycling of waste have been subjects of several studies, both in science and in related areas. In this work are presented formulations for rigid polyurethane foams (PURF), using alternative and no petrochemical reactants. The foams were synthesized from vegetables based polyols (castor oil and tung oil based polyols), materials from renewable source, which showed a good alternative for the replacement of petrochemical polyols. Inorganic fillers, derived from industrial waste, have been added to rigid foam, with the intention of study applications for these residues and in an attempt to contribute to reducing the environmental impact caused by them. For the foams produced from polyol derived fromcastor oil, was used a black powder (reject P3) which is a waste from the Bayer process alumina production. This waste was characterized by various techniques and is rich in alumina (Al2O3) and aluminum hydroxide (Al(OH)3). Due to the high concentration of these two substances, this material has great potential as a flame retardant for foam. For the foams produced from tung oil based polyol, was used rice husk ash as the load. This is an industrial waste from the riceprocessing, rich in silica (SiO2), and also with flame retardance potential for the foam. The foams were characterized by FTIR, thermal analysis (TG, DTG and DTA) and SEM. Were also measured densities of materials and are performed mechanical, thermal conductivity and flame tests, to evaluate the load influence in the different foams properties.The results indicate that, for the loads percentages used, there were no morphological changes in the composites, compared to foam matrices. We observed an increment in the property of flame retardance and there was no significant loss of thermal properties. There are indications that there are secondary chemical interactions with the material waste P3 and the polyurethane synthesized castor oil based polyol. The same was not observed for the foams synthesized with tung oil based polyol, where rice husk ash as inorganic filler.