Orientadores: Rubens Maciel Filho, Paulo de Tarso Vieira e Rosa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-18T13:48:41Z (GMT). No. of bitstreams: 1 RodriguezGuerrero_JulieKaterine_M.pdf: 4744317 bytes, checksum: 8df1bde5d893cdf55d7e26d1c72fc31d (MD5) Previous issue date: 2011 / Resumo: Neste trabalho, foram estudados três processos de síntese de ésteres etílicos: sem catalisador, com catalisador homogêneo (hidróxido de sódio) e com catalisador heterogêneo (difosfato ácido de lantânio), a partir de óleo de mamona em etanol sub e supercrítico. O estudo da influência das variáveis de operação na conversão nos processos não catalítico e usando catalisador homogêneo foi realizado por meio de planejamento experimental associado à metodologia de superfície de resposta, utilizando como variáveis independentes a temperatura, o tempo de reação, a razão molar etanol:óleo e, quando utilizado, a concentração de catalisador. No caso do processo com catalisador heterogêneo, foram feitas análises nas condições ótimas (temperatura e razão molar) determinadas a partir do planejamento experimental dos outros dois processos. Verificou-se que, usando 0,1 % m/m de NaOH (quantidade inferior à necessária para neutralizar o óleo), foi possível obter conversões elevadas e que o uso de difosfato ácido de lantânio apresenta uma atividade catalítica significante na produção de biodiesel, mesmo utilizando óleos com índice de acidez alto. A máxima conversão atingida foi 98,94 % no processo com catalisador homogêneo, 92,94 % no processo com catalisador heterogêneo e 56,17 % no processo não catalítico. Além disso, foi obtida a cinética das reações e as energias de ativação para os três processos, observando-se que as constantes de reação são de pseudo primeira ordem. As energias de ativação encontram-se dentro da faixa reportada na literatura. Além disso, verificou-se que, a opção de trabalhar com NaOH é a mais viável em termos operacionais, já que o custo do catalisador é baixo, a quantidade de catalisador empregada é pequena e, adicionalmente, não requer uma etapa de pré-tratamento do óleo de mamona usado como matéria-prima / Abstract: In this work, three processes of synthesis of ethyl esters were studied: non-catalytic, using homogeneous catalyst (sodium hydroxide) and using heterogeneous catalyst (acid lanthanum diphosphate), from castor oil and sub and supercritical ethanol. The influence of the operating variables on the conversion of both non-catalytic and using homogeneous catalyst processes was studied by means of a design of experiment associated to the surface response methodology, using temperature, reaction time, ethanol:oil molar ratio and, whenever used, catalyst concentration as independent variables. In the process with heterogeneous catalyst, several analysis were performed under the optimum conditions (temperature and molar ratio) calculated from experimental design of the other two processes. It was verified that, using 0,1% wt of NaOH (amount lower than the required to neutralize the oil), it was possible to obtain high conversions and that using acid lanthanum diphosphate presents a significant catalytic activity on the biodiesel production, even using oils with high acidity index. The maximum conversion reached was 98,94 % in the process with homogeneous catalyst, 92,94 % with heterogeneous catalyst and 56,17 % in the non-catalytic process. Additionally, the reaction kinetics and activation energies were obtained for the three processes, observing that the reaction rate constants are pseudo first order. The activation energies are within the range reported on literature. Besides, it was verified that the option of working with NaOH is the most interesting in operational terms since the catalyst cost is low, the amount of catalyst used is small and, in addition, it is not necessary a pretreatment stage of the castor oil used as raw material / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientador: Maria Regina Wolf Maciel / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T14:16:37Z (GMT). No. of bitstreams: 1 ParadaHernandez_NataliaLorena_D.pdf: 3619653 bytes, checksum: 89e5fe01b39a1e7b4df6202248e4f9c5 (MD5) Previous issue date: 2015 / Resumo: O objetivo desta pesquisa é sintetizar um biopolímero a partir do óleo de mamona usando um processo não tóxico, tanto na síntese da resina epoxídica quanto no processo da sua cura, visando obter assim um biomaterial com características adequadas para uso na área médica. Para isso, foi necessária a funcionalização do óleo de mamona, por meio do processo de epoxidação, para posterior utilização como monômero na síntese do biopolímero. O processo de epoxidação foi realizado utilizando um sistema catalítico verde (H2O2/Al2O3/acetato de etila). Inicialmente, foi realizada a epoxidação do ricinoleato de metila (componente modelo), para a avaliação da eficiência do processo de epoxidação. Neste estudo foi utilizada a metodologia de planejamento de experimentos, a qual possibilitou definir as variáveis significativas do processo de epoxidação. A epoxidação do componente modelo foi monitorada por meio de Cromatografia Gasosa acoplada a um Detector de Ionização de Chama (GC-FID). Os resultados mostraram alta conversão (99%), em poucas horas de reação (2h), e ausência de subprodutos (99% de seletividade). Com esses resultados, procedeu-se com a epoxidação do óleo de mamona, cuja eficiência do processo foi avaliada por meio de Espectroscopia no Infravermelho por Transformada de Fourier (FTIR) e Espectroscopia Raman (FT-Raman) e Ressonância Magnética Nuclear de Prótons (1HNMR). Após epoxidação do óleo de mamona, foi avaliada a reação de polimerização do óleo de mamona epoxidado (ECO) usando ácidos carboxílicos (ácido cítrico) como comonômero, utilizando a técnica de Calorimetria Exploratória Diferencial (DSC), FTIR, Análise Termogravimétrica (TGA) e testes de capacidade de inchamento. Os resultados obtidos indicam que o processo de polimerização estudado é viável, obtendo-se um poliéster reticulado. Visando a possível aplicação do poliéster obtido na engenharia de tecidos e área médica, foi realizada a análise de citotoxicidade do polímero obtido, usando células Vero (fibroblastos). O resultado da análise de citotoxicidade mostrou a não toxicidade do polímero sintetizado em células Vero (fibroblastos) / Abstract: The target of this research is to synthesize a biopolymer from castor oil using a nontoxic process, not only in the epoxy resin synthesis but also in its curing process, aiming to obtain a biomaterial with suitable characteristics for medical applications. With this purpose, castor oil was functionalized using an epoxidation process in order to be used as monomer in the biopolymer synthesis. Epoxidation process was performed using a green catalytic system (H2O2/Al2O3/ethyl acetate). Initially, it was carried out the epoxidation of methyl ricinoleate (model compound) for evaluating the epoxidation process efficacy by using experimental design methodology, allowing in this way to define the significant epoxidation process variables. Model compound epoxidation was monitored by gas chromatography equipped with a flame ionization detector (GC-FID). The evaluation of the results showed high conversion (99%) in a few hours (around 2hs) without byproduct formation (99% selectivity). Taking into account these results, it was performed the castor oil epoxidation and the process efficacy was evaluated by Fourier transform infrared (FT-IR), Raman Spectroscopy and 1H NMR. After castor oil epoxidation, epoxidized castor oil (ECO) polymerization using carboxylic acids (citric acid) as comonomer was evaluated by Differential Scanning Calorimetry (DSC), FTIR, Thermogravimetric Analyses (TGA) and swelling tests. The obtained results showed that polymerization process is viable and it was obtained a cross-linked polyester. In order to evaluate the potential application of the obtained polymer in the medical field, it was performed a cytotoxicity assay using Vero cells (fibroblast type). Cytotoxicity results showed nontoxic effect of synthesized polyester on Vero cells / Doutorado / Engenharia Química / Doutora em Engenharia Quimica

Este trabalho tem por finalidade, o estudo do comportamento do adesivo poliuretano à base de mamona para o emprego em madeira laminada colada (MLC). A eficiência do adesivo foi avaliada por meio da resistência dos seguintes ensaios mecânicos: cisalhamento, tração normal e tração paralela às fibras. Os ensaios seguiram as recomendações da norma brasileira NBR 7190/97 \"Projeto de estruturas de madeiras\" e por meio de seus resultados foram determinados os parâmetros de colagem como: viscosidade (V), tempo de pressão de colagem (Tp), pressão de colagem (P) e tempo de cura (Tc) e avaliadas as influências dessas variáveis e de suas interações sobre as resistências. Duas espécies de madeira foram empregadas: o Pinus caribea hondurensis e o Eucaliptus grandis, geralmente empregadas em reflorestamento nas regiões Sul e Sudeste do Brasil, onde estão localizadas as indústrias de MLC. O adesivo estudado é do tipo bicomponente, o poliol B1640 e o prepolímero A249, oriundo de recurso natural e renovável, de cura a frio, não agressivo ao ser humano e nem ao meio ambiente e é uma tecnologia nacional. Os resultados mostraram que o adesivo à base de mamona é um boa alternativa para a utilização da madeira laminada colada em estruturas com espécies de reflorestamento. / The aim of this work is the study of the polyurethane adhesive based on castor oil in glued laminated timber structures (GLULAM). The efficiency of the adhesive was evaluated using the following mechanical tests: shear, perpendicular and parallel tension to the grain strengths. The Brazilian Code NBR 7190/97 \'\'Design of the timber structures\" was used to the tests and based on these results were determined the gluing parameters as: viscosity (V), gluing pressure (P), time of pressure (Tp) and the curing time (Tc) and evaluated the influence of these variables and interactions on the mechanical strengths. Two wood species Pinus caribea hondurensis and Eucaliptus grandis were chosen because they are used as reforestation in South and Southeast areas in Brazil where are located the glulam industries. The adhesive studied is of the two components, that is, the poliol B1640 and the prepolymer A249 and is made of a natural and renewable resource, cure in the environment conditions, not aggressive to man and the environment, and a national technology. The results showed a good performance of this adhesive, a good technical alternative for the technology utilization of GLULAM in timber structures with reforestation species.

Thesis (M.Sc. (Microbiology)) -- University of Limpopo, 2015 / Antioxidants play an important role in living organisms to control level of free radicals and other reactive molecules in the body to reduce oxidative damage. Synthetic antioxidant compounds are used in food industries as food additives to boost our immune systems. These compounds are associated with a number of critical side effects including liver damage and carcinogenesis. Scientists are also concerned about microorganisms that have developed resistant genes against current antibiotics used in hospitals. The aim of the study was to isolate and characterize bioactive compounds from Ricinus communis leaves with activity against Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853). Consequently, medicinal plants are studied and considered for their efficacy and safety, because they possess bioactive compounds with various biological activities. Leaves of R. communis were collected at the University of Limpopo, Turfloop campus in Limpopo province, South Africa. The leaves were dried and milled to a fine powder. A number of trial extraction methods were employed using various solvents of different polarities on a fine powder leaves to identify the best extraction method. Plant extracts were analyzed by thin layer chromatography (TLC) developed in four mobile phases. To detect separated phytochemical compounds, TLC plates were sprayed with vanillin- sulphuric acid in methanol and heated at 110oC for optimal colour development. Qualitative antioxidant activity was determined by using 2, 2–diphenyl-1-picrylhydrazyl (DPPH) assay on TLC plates. Quantitative antioxidant activity was determined by measuring percentages scavenging activity of DPPH and 2, 2’-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) free radical molecules by plant extracts. Antibacterial activity of all extracts was quantified by a serial microbroth dilution method while bioautography was used in qualitative analysis of the active compounds. Cytotoxicity effect of R. communis extracts was evaluated using tetrazolium-based calorimetric assay on human Caucasian skin fibroblast (Bud-8) cell line. Anti-inflammatory activity was assessed using phagoburst kit on Raw 264.7 macrophages cell line. Pure compounds were subjected to nuclear magnetic resonance spectroscopy for 1H, 13C and DEPT experiments to elucidate structures of compounds. 2 During extraction process, methanol was the best extractant, extracting greater amount of extracts than any of the other solvents. Serial exhaustive extraction method was selected as the best extraction method for extracting compounds from ground plant materials. In quantitative antioxidant assays, chloroform and methanol extracts had highest percentage scavenging activity against DPPH free radicals compared to other extracts and vitamin C. Methanol extract had the highest percentage scavenging activity of ABTS free radicals and minimum percentage scavenging activity was in hexane extract. Acetone, ethyl acetate and ethanol extracts showed strong antioxidant activity against DPPH free radicals in qualitative antioxidant assay on TLC plates. In quantitative antibacterial assay, crude extracts showed lowest minimum inhibitory concentration value of 0.13 mg/ml against all tested organisms and the highest was 1.05 mg/ml. Hexane extracts revealed potent antibacterial activity against all tested microorganisms on bioautograms. Hexane and acetone extracts also revealed anti-inflammatory activity and have ability to reduce oxidative stress. In cytotoxicity effect of plant extracts, Methanol extracts had lethal concentration for 50% of the cells (Lc50) of 784 μg/ml on Human Caucasian skin fibroblast (Bud-8) cell line while hexane extracts had Lc50 of 629 μg/ml. Plant extracts with high Lc50 are low toxic to normal cell line and preferable to work with for drug development. Bioassay-guided fractionations results in successful isolation of three antioxidant and two antibacterial compounds from R. communis using column chromatography. Isolated compounds were tested for their biological activities using qualitative DPPH assay on TLC plates for antioxidant activity and bioautography for antibacterial activity. Antioxidant compounds showed strong antioxidant activity after spraying with DPPH in methanol and antibacterial compounds showed less activity compared to the crude extracts. The study suggests the use of crude extracts to fight against pathogenic microorganisms compared to pure compounds. Compound 4 was successful identified as the mixture of stigmasterol and β-sitosterol. The present study recommends the use of R. communis leaves as the potential source of antioxidant, antibacterial and anti-inflammatory compounds. The study serves as a scientific proof for use of this plant in traditional medicine for treatment of various ailments.

This diploma thesis deals with ultrasound attenuation measurement methods. Variety of methods are developed and tested . Castor oil was used as reference material. Different kinds of ultrasound transducers, hydrophone and ultrasound scanner GE Vingmed SystemFive were used for measurement. Data was processed by scripts developed in matlab.

<p>Hydrogenated castor oil (HCO) crystals as a rheology modifier have been widely used in paints, cosmetics and household products. In this thesis, we are interested in the effect of crystal morphology on the suspension rheology of products. Three major types of micron-sized crystal morphologies have been observed: fiber, rosette and irregular crystal. Fibers show a high aspect ratio with the length ranging from 5 to 33 µm and width around 1~3 µm. The rosette (2~50 µm) is a three-dimensional spherulitic structure with nano-fibrous arms extruding from a heterogeneous central point. Irregular crystals with equivalent diameter ranging from 4 to 84 µm are hard solid and show irregular shapes. There is an additional fourth type of crystal morphology which is a nano-sized fibrous structure that is assumed to be broken down from arms of micron-sized rosettes and fibers. Due to the relatively small amount, the effects of nano-fibrous fragments on rheology were not considered separately in this work.</p> <p>The effect of temperature and shear history on the HCO crystal morphology has been studied. The energy barrier to nucleation for fibers is suggested to be higher than that of rosettes. Irregular crystals are thermodynamically less stable and tend to transform into stable polymorphs. A non-isothermal crystallization study showed that the formation of rosettes and fibers was favored by a slow cooling rate (1°C/min) while the formation of irregular crystals was favored by a fast cooling rate (5°C/min). Shear rates from zero to 100 s^-1 have been applied at cooling rates from 1°C/min to 5°C/min. Nucleation has been found to be promoted with the increase of shear rate. Morphological analysis indicated that the formation of fibers was favored by gentle shear (e.g., 1 s^-1), but fibers can be broken with the increase of shear time.</p> <p>Kinetics of isothermal crystallization of hydrogenated castor oil in water emulsions exhibiting multiple crystal morphologies has been studied in the temperature range of 55°C to 70°C. The induction time of nucleation increases with the increase of the isothermal temperature under which crystallization occurred. A linear increase in induction time with increased temperature was found for both fibers and rosettes. A modified Avrami model was developed by introducing the volume fraction of each type of morphology into three dimensional and one dimensional full Avrami models. It was found that the experimental trends for mixed crystal morphologies could be captured by the modified Avrami model.</p> <p>Due to the difficulty of obtaining samples with a single crystal morphology, rheological studies of suspensions containing mixtures of the three morphologies in a surfactant solution have been undertaken. The viscometry of dilute suspensions has shown that the magnitude of intrinsic viscosity is dominated by the fraction of a crystal morphology type, i.e. fiber > rosette > irregular crystal. A modified Farris model was fitted to the rheology data from mixtures of crystal morphology with interacting particles. A yield stress exists for concentrated suspensions followed by a shear thinning behavior with the increase of shear rate. A power-law relation has been found between yield stress and total particle volume fraction with a constant exponent of 1.5 regardless of crystal morphology.</p> / Doctor of Philosophy (PhD)

No / The influence of surfactants on the stability of cyclodextrin (CD) Pickering emulsions is not well understood. In this study, we report two-way effects of Tween 80 and soybean lecithin (PL) on the long term stability of Pickering emulsions stabilized by the self-assembled microcrystals of alpha-CD and medium chain triglycerides (MCT). The CD emulsions in the absence and presence of Tween 80 or PL at different concentrations were prepared and characterized by the droplet size, viscosity, contact angle, interfacial tension and residual emulsion values. After adding Tween 80 and PL, similar effects on the size distribution and contact angle were observed. However, changes of viscosity and interfacial tension were significantly different and two-way effects on the stability were found: (i) synergistic enhancement by Tween 80; (ii) inhibition at low and enhancement at high concentrations by PL. The stability enhancement of Tween 80 was due to the interfacial tension decrease caused by the interaction of Tween 80 with CD at the o/w interface at lower concentrations, and significant viscosity increase caused by the Tween 80-CD assembly in the continuous phase. For PL at low concentrations, the replacement of alpha-CD/MCT by alpha-CD/PL particles at the o/w interface was observed, leading to inhibitory effects. High concentrations of PL resulted in an extremely low interfacial tension and stable emulsion. In conclusion, the extensive inclusion of surfactants by CD leads to their unique effects on the stability of CD emulsions, for which the changes of viscosity and interfacial tension caused by host-guest interactions play important roles.

O presente trabalho tem por objetivo avaliar o desempenho físico-mecânico e a durabilidade de painéis de partículas de bagaço de cana-de-açúcar com resina bicomponente a base de mamona (BCP) e compará-los com painéis de partículas de madeira comerciais (Medium Density Particleboard - MDP). Os painéis de bagaço de cana de açúcar foram fabricados com um teor de resina poliuretana a base de óleo de maona de 15%. O desempenho físico e mecânico dos painéis particulados foi analisado com base nas prescrições dos documentos normativos vigentes. Ambos os materiais foram revestidos superficialmente com resina poliuretana bicomponente à base de óleo de mamona. Avaliou-se a influência do tratamento das bordas na deterioração e no desempenho dos painéis. O acompanhamento das propriedades físico-mecânicas foi realizado antes e após os ensaios de envelhecimento por exposição natural durante 3, 6 e 12 meses, envelhecimento acelerado e de intemperismo artificial. Foi feita a avaliação, da suscetibilidade ao crescimento gerada pelo ataque de fungos emboloradores e apodrecedores nos materiais durante o envelhecimento natural e no ensaio acelerado. Foi realizada a análise colorimétrica para a identificação de mudanças de cor e brilho nos materiais após os ensaios de deterioração. Foram utilizadas as técnicas de densitometria de raios X, espectroscopia por infravermelho próximo (NIR). Os resultados obtidos indicaram a selagem lateral permitiu avaliar a superfície exposta do material permitindo a entrada da água pela superfície avaliando o efeito dos agentes de deterioração. A porcentagem de retenção para o Módulo de ruptura após o ensaio de envelhecimento por imersão em agua e secagem (APA D1) foi de 87% e 3% para BCP e MDP sem revestimento respectivamente e de 90% e 3% para BCP e MDP com revestimento. A porcentagem de retenção das propriedades mecânicas em ambos os submetidos à exposição natural diminuiu em função do tempo. Entretanto o porcentagem de retenção para os materiais BCP e MDP com revestimento superficial foi de 76% e 60% para MOR. A exposição natural mostrou que os fungos emboloradores foram predominantes em ambos os materiais. Ambos os materiais com revestimento superficial apresentaram entre 1-10% de colonização com um 70% de probabilidade. Revestimento de resina de óleo de mamona reduz o crescimento de fungos em ambos os materiais no ensaio acelerado. O perfil de densitometria permitiu analisar o processo de fabricação dos painéis e permitiu identificar a deterioração gradativa do ambos os materiais após os ensaios de envelhecimento. A intepretação mediante a analise de componentes principais (ACP) na aplicação do NIR comportou a classificação das características relacionadas a cada ensaio de deterioração de ambos os materiais sem revestimento superficial. Com base nos resultados deste trabalho, foram propostas contribuições para ajustes de metodologias para a avaliação da durabilidade e do desempenho físico e mecânico dos painéis particulados, tendo em vista a sua viabilidade técnica, em sistemas construtivos da construção civil. / This work aimed to evaluate the physical-mechanical support and durability of sugarcane bagasse particle boards with a castor oil based bicomponent resin (BCP), and compare them to commercial wood particle boards (Medium Density Particleboard - MDP). The sugarcane bagasse boards were produced with a 15% castor oil based polyurethane resin. The physical and mechanical performance of the particle boards were analyzed based on the requirements of existing standardization documents. Both materials were superficially coated with castor oil based bicomponent polyurethane resin. The influence of treated edges on the decay and performance of the boards were evaluated. Monitoring the physical and mechanical properties was carried out before and after the aging tests by natural exposure during 3, 6, and 12 months, accelerated aging, e artificial weathering. An evaluation was made of the susceptibility to growth generated by the attack of moldy and rotting fungi in materials during the natural aging and accelerated tests. A colorimetric analysis was performed to identify the changes in color and brightness in the materials after the deterioration tests. X-rays densitometry and infra-red spectroscopy (NIR) techniques were used. The results obtained indicated that the lateral sealing allowed for an evaluation of the material surface exposed, permitting the entrance of water by the evaluating the effect of the deterioration agents. The retention percentage for the Module of rupture after the aging test by immersion in water and drying (APA D1) was 87% and 3% for BCP and MDP without coating, respectively, and 90% and 3% for BCP and MDP with coating. The retention percentage of the mechanical properties in both samples submitted to natural exposure decreased in relation to time. Meanwhile, the retention percentage for the BCP and MDP with a superficial coating was 76% and 60% MOR. Natural exposure showed that mold were predominant in both materials. Both of the materials with superficial coatings presented between 1-10% colonization with a 70% probability. Castor oil based resin decreased mold in both materials. The densitometry profile to analyze the production of the boards and allowed the identification of the gradual degradation of both materials after the aging tests. The interpretation through Principal component analysis (PCA) in the NIR application permitted the classification of characteristics related to each deterioration test for both materials without superficial coating. Based on the results of this work, contributions were proposed to adjust methodologies for the evaluation of durability and physical and mechanical performance of the particle boards, having in view its technical viability, in structural systems of construction.

Este trabalho teve como objetivo o estudo da espuma rígida de poliuretano (PU) derivada de óleo de mamona para aplicação como forro na isolação térmica de sistemas de cobertura. Dentro deste objetivo foram caracterizadas as suas propriedades termomecânicas e avaliado o seu comportamento térmico quando aplicada como forro em células de teste em quatro situa-ções diferentes. As caracterizações termomecânicas da espuma rígida de poliuretano derivada de óleo de mamona foram realizadas utilizando as técnicas Termogravimétrica (TGA), Dinâ-mico-Mecânica (DMA), e Método do Fio Quente Paralelo. A técnica Termogravimétrica (TGA) possibilitou o estudo da decomposição da espuma e uma avaliação de sua cinética. A cinética de decomposição foi realizada em quatro diferentes razões de aquecimento e os resul-tados foram avaliados utilizando o método baseado no modelo de Ozawa-Flynn-Wall no qual foi possível estimar o tempo de vida da espuma rígida de poliuretano para vários valores de temperatura constante. Por meio da utilização da técnica Dinâmico-Mecânica (DMA) foi pos-sível determinar a temperatura de transição vítrea da espuma e os módulos viscoelásticos de armazenamento (E) e de perda (E) assim como os valores de Tan Delta. O Método do Fio Quente Paralelo proporcionou a determinação do valor da condutividade térmica da espuma, que a classificou como um material muito isolante (1).A espuma rígida de poliuretano apre-sentou propriedades termomecânicas compatíveis para utilização como isolante térmico em temperaturas abaixo da ambiente, e em temperaturas acima de 100 oC. O estudo comparativo entre quatro células de teste para análise do comportamento térmico do forro foi feito com a coleta de dados em canteiro experimental. Os resultados obtidos comprovaram a eficiência da espuma rígida de poliuretano derivada do óleo de mamona na redução da entrada de calor durante o período de radiação solar global máxima e a atenuação da perda de calor no período sem influência da radiação solar / This work aimed to study the rigid foam polyurethane (PU) derived from castor oil for appli-cation as lining in thermal insulation systems coverage. Within this objective we have charac-terized the thermomechanical properties and assessed its thermal behavior when applied as lining cells testing in four different situations. The rigid foam polyurethanes thermo characte-rizations, derived from castor oil, were performed using the Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), and Hot Parallel Wire Method. The Thermo-gravimetric Analysis (TGA) has enabled the study of the foams decomposition and an evalu-ation of its kinetics. The decomposition kinetics was carried out in four various heating rea-sons and the results were evaluated using the method based on Ozawa-Flynn-Wall model which it was possible to estimate the rigid foam polyurethanes lifetime for various constant temperature values. By Dynamic Mechanical Analysis (DMA) has been possible to determine the foams glass transition temperature and the viscoelastics modules, storing module (E\') and loss module (E) well as the values of Tan Delta. The Hot Parallel Wire Method provided the valuation of foams thermal conductivity which ranked as a very insulating material (1). The rigid foam polyurethane has been shown to thermomechanical compatible for used as an insu-lator heat at temperatures below ambient, and temperatures above 100 oC. The four test cells comparative study for linings thermal behavior analysis was made with the collecting data from experimental plot. Results obtained proved the rigid foam polyurethane efficiency, de-rived from castor oil, in reducing the input heat during the maximum solar radiation and at-tenuation of heat loss in the period with no influence of solar radiation.

Em todo o mundo, as redes aéreas de distribuição de energia elétrica levam energia a todos os consumidores. Parte destas redes utilizam cruzetas como meio de sustentação mecânica para cabos. Estas cruzetas podem atualmente ser produzidas em fibra de vidro, plásticos reciclados (Polietileno, Polipropileno de primeira produção) e outros materiais híbridos, usando polímeros e barras de aço para inserir resistência mecânica. Os custos destes materiais ainda são elevados e o seu processo de reciclagem ainda apresenta problemas no processo de logística reversa, impondo custos elevados. Alguns países, como Noruega e Estados Unidos, usam cruzeta de madeira laminada com sucesso, como material alternativo em suportes de linhas de transmissão e de distribuição. A cruzeta tradicional de madeira nativa é ainda empregada no Brasil, com uso restrito às redes de distribuição de energia elétrica. A aplicação contínua da madeira é atribuída principalmente ao baixo custo comparado com o de outros materiais empregados nos elementos do sistema de energia elétrica. Entretanto, considerações ambientais e baixa estimativa de vida da madeira têm mudado esta situação, conduzindo ao aumento de pesquisa nesta área. Neste trabalho foram discutidas duas espécies de madeira de reflorestamento, Pinus elliottii e Eucalyptus citriodora, impregnadas com resinas poliuretanas derivadas do óleo de mamona e revestidas com manta geotêxtil. Durante a execução dos trabalhos, foi detectada fragilidades mecânicas na madeira Pinus elliottii. Apenas a madeira Eucalyptus citriodora atende plenamente as necessidades do produto final. É importante observar que a resina empregada é uma matéria prima totalmente nacional, e que esta pesquisa contribui para a sua aplicação no desenvolvimento de um novo produto (cruzetas de madeiras resinadas revestidas com geotêxtil), com tecnologia totalmente brasileira, utilizando-se madeiras de reflorestamento, tipo Eucalyptus Citriodora. Estas cruzetas, além de respeitarem as leis ambientais, também apresentaram um excelente desempenho mecânico e elétrico, com ótimas perspectivas de instalações na rede de distribuição de energia elétrica, a um custo competitivo. Este trabalho apresenta avanço significativo no aumento da vida útil destas madeiras, ampliando o tempo para substituições de cruzetas nas redes de distribuição de energia e contribuindo com a preservação da natureza. / Aerial distribution networks take energy to consumers worldwide. Part of these networks use cross arms as a means of mechanical support for cables. These cross arms can be currently produced on glass fiber, recycled plastics (polyethylene, polypropylene first production) and other hybrid materials, using polymers and inserting steel bars for mechanical strength. The costs of these materials are still elevated and its recycling process also presents problems in the reverse logistics process, imposing high costs. In some countries, like Norway and USA, wood laminated cross arms have been used as an alternative material to support transmission and distribution lines with success, whereas traditional native wood cross arms are still used in Brazil restricted to energy distribution networks. Wood application is continued mainly due to its low cost compared to other materials applied in the electric energy system. However, environmental considerations and low wood life time estimate have changed this situation leading to increased research in this area. In this work we discussed two types of wood reforestation, Pinus elliottii and Eucalyptus citriodora, impregnated with polyurethanes resins derived from castor oil and coated with a geotextile blanket. It is important to observe that the resin employed is a national raw material, and that this research contributes to its application in the development of a new product (cross arms of resinous woods lined with a geotextile blanket) with complete Brazilian technology, using reforested wood, type Eucalyptus citriodora. These cross arms not only comply with environmental laws, but also present an excellent mechanical and electrical performance with great installation perspectives in the electricity distribution network at a competitive cost. This paper presents a significant step forward in increasing the life of these woods, extending time to cross arm replacements in power distribution networks, and contributing to nature preservation.