Aproveitamento da fibra do epicarpo do coco babaçu em compósito com matriz epóxi: estudo do efeito do tratamento da fibra

Nowadays the environmental issues are increasingly highlighted since the future of humanity is dependent on the actions taken by man. Major efforts are being expended in pursuit of knowledge and alternatives to promote sustainable development without compromising the environment. In recent years there has been a marked growth in the development of reinforced composite fiber plants, as an alternative for economic and ecological effects, especially in the substitution of synthetic materials such as reinforcement material in composites. In this current study the chemical- physical or (thermophysics )characteristics of the babassu coconut fiber, derived from the epicarp of the fruit (Orbignyda Phalerata), which the main constituents of the fiber: Klason lignin, insoluble, cellulose, holocellulose, hemicellulose and the content of ash and moisture will be determined. A study was conducted about the superficial modification of the fibers of the epicarp babassu coconut under the influence of chemical treatment by alkalinization, in an aqueous solution of NaOH to 2.5% (m/v) and to 5.0% to improve the compatibility matrix / reinforcement composite with epoxy matrix. The results of the changes occurred in staple fibers through the use of the techniques of thermogravimetric analyses (TG) and differential scanning calorimetry (DSC). The results found on thermal analysis on samples of fiber without chemical treatment (alkalinities), and on fiber samples treated by alkalinization show that the proposed chemical treatment increases the thermal stability of the fibers and provides a growth of the surface of area fibers, parameters that enhance adhesion fiber / composite. The findings were evaluated and compared with published results from other vegetable fibers, showing that the use of babassu coconut fibers has technical and economic potential for its use as reinforcement in composites

Utilização de resíduo lignocelulósico na obtenção de chapa de madeira aglomerada homogênea e compósito reforçado com fibra de vidro-E

This research is about the use of the coconut´s endocarp (nucifera linn) and the waste of derivatives of wood and furniture as raw material to technological use. In that sense, the lignocellulosic waste is used for manufacture of homogeneous wood sheet agglomerate (LHWS) and lignocellulosic load which take part of a polymeric composite with fiber glass E (GFRP-WC). In the manufacturing of the homogeneous wood sheet agglomerate (LHWS), it was used mamona´s resin as waste s agglutinating element. The plates were taken up in a hydraulic press engine, heated, with temperature control, where they were manufactured for different percentage of waste wood and coconuts nucífera linn. Physical tests were conducted to determine the absorption of water, density, damp grade (in two hours and twenty-four hours), swelling thickness (in two hours and twenty-four hours), and mechanical tests to evaluate the parallel tensile strength (internal stick) and bending and the static (steady) flexural. The physical test´s results indicate that the LHWS can be classified as bonded wood plate of high-density and with highly water resistant. In the mechanical tests it was possible to establish that LHWS presents different characteristics when submitted to uniaxial tensile and to the static (steady) flexural, since brittle and elasticity module had a variation according to the amount of dry endocarp used to manufacture each trace of LHWS. The GFRP-WC was industrially manufactured by a hand-lay-up process where the fiber glass E was used as reinforcement the lignocellulósic´s waste as load. The matrix was made with ortofitalic unsaturated polyester resin. Physical and mechanical tests were performed in presence of saturated humidity and dry. The results indicated good performance of the GFRP-WC, as traction as in flexion in three points. The presence of water influenced the modules obtained in the flexural and tensile but there were no significant alteration in the properties analyzed. As for the fracture, the analysis showed that the effects are more harmful in the presence of damp, under the action of loading tested, but despite this, the fracture was well defined starting in the external parts and spreading to the internal regions when one when it reaches the hybrid load

Avaliação de concretos reforçados por confinamento com manta de fibra de vidro estrutural e pré-impreganada

Due to the occurrence of diseases in the use of structural reinforcements in composites, with presentation of concrete blanket detachment, has been identified the need to evaluate the performance of concrete reinforced with glass fiber. This study aims to evaluate these concretes by means of testing methodologies, using concrete with low resistance with structural reinforcement for confinement by preimpregnated glass fiber and traditional fiberglass blanket. The first stage of work was the development of methodologies for analysis, opting for four types, such as the acoustic survey, strength to compressive, the pull-off and ultrasound. Next, tests were carried out using the four selected methodologies in 30 of proof-of-specimens by 5x10 cm, 15 were reinforced with the traditional fiberglass blanket with 5specimens exposed to test a marine environment of marine coastline of Natal-RN and 15 were reinforced with a pre-impregnated glass fiber blanket, as well as 5specimens exposed to a test environment of the marine coastline of Natal-RN. After conducting the acoustic survey, it has been verified a lack of delaminating and air bubbles in the samples, confirming the absence of gross shortcomings in the implementation of the ribs both the traditional fiberglass blanket and in the preimpregnated fiber glass blanket. After carrying out methods of pull-off and compressive strengthening test it was observed that the reinforced proof-bodies with pre-impregnated glass blanket showed maximum stresses higher than the traditional fiberglass blanket; consequently a greater grip with the formation of a smaller area of . fracture, unlike traditional glass mat, which showed lower maximum stresses, with a greater area of fracture. It was also found that the traditional fiberglass blanket presented detachment of blanket-concrete interface, unlike the pre-impregnated fiberglass blanket, which showed a better grip on the blanket-concrete interface. In the trial of ultrasound there was no presence of cracks in the blanket-concrete interface, yielding to both blankets good compactness of the concrete. At the end of this work, they were developed and proposed two methods of testing for evaluation of reinforced concrete structures with composites, for standardization, the acoustic survey and pull-off

Estudo comparativo de pás para aerogeradores de grande porte fabricadas em materiais compósitos reforçadas com fibra de carbono ou fibra de vidro

The research and development of wind turbine blades are essential to keep pace with worldwide growth in the renewable energy sector. Although currently blades are typically produced using glass fiber reinforced composite materials, the tendency for larger size blades, particularly for offshore applications, has increased the interest on carbon fiber reinforced composites because of the potential for increased stiffness and weight reduction. In this study a model of blade designed for large generators (5 MW) was studied on a small scale. A numerical simulation was performed to determine the aerodynamic loading using a Computational Fluid Dynamics (CFD) software. Two blades were then designed and manufactured using epoxy matrix composites: one reinforced with glass fibers and the other with carbon fibers. For the structural calculations, maximum stress failure criterion was adopted. The blades were manufactured by Vacuum Assisted Resin Transfer Molding (VARTM), typical for this type of component. A weight comparison of the two blades was performed and the weight of the carbon fiber blade was approximately 45% of the weight of the fiberglass reinforced blade. Static bending tests were carried out on the blades for various percentages of the design load and deflections measurements were compared with the values obtained from finite element simulations. A good agreement was observed between the measured and calculated deflections. In summary, the results of this study confirm that the low density combined with high mechanical properties of carbon fibers are particularly attractive for the production of large size wind turbine blades

Efeito da adição do poli(etileno acrilato de metila) (ema) e da fibra de linter de algodão nas propriedades do poli(tereftalato de etileno) reciclado (petrec)

The development of new materials to fill the demand of technological advances is a challenge for many researchers around the world. Strategies such as making blends and composites are promising alternatives to produce materials with different properties from those found in conventional polymers. The objective of this study is to evaluate the effect of adding the copolymer poly(ethylene methyl acrylate) (EMA) and cotton linter fibers (LB) on the properties of recycled poly(ethylene terephthalate) (PETrec) by the development of PETrec/EMA blend and PETrec/EMA/LB blend composite. In order to improve the properties of these materials were added as compatibilizers: Ethylene - methyl acrylate - glycidyl methacrylate terpolymer (EMA-GMA) and maleic anhydride grafted polyethylene (PE-g-MA). The samples were produced using a single screw extruder and then injection molded. The obtained materials were characterized by thermogravimetry (TG), melt flow index (MFI) mensurements, torque rheometry, pycnometry to determinate the density, tensile testing and scanning electron microscopy (SEM). The rheological results showed that the addition of the EMA copolymer increased the viscosity of the blend and LB reduces the viscosity of the blend composite. SEM analysis of the binary blend showed poor interfacial adhesion between the PETrec matrix and the EMA dispersed phase, as well as the blend composite of PETrec/EMA/LB also observed low adhesion with the LB fiber. The tensile tests showed that the increase of EMA percentage decreased the tensile strength and the Young s modulus, also lower EMA percentage samples had increased the elongation at break. The blend composite showed an increase in the tensile strength and in the Young`s modulus, and a decrease in the elongation at break. The blend formulations with lower EMA percentages showed better mechanical properties that agree with the particle size analysis which showed that these formulations presented a smaller diameter of the dispersed phase. The blend composite mechanical tests showed that this material is stronger and stiffer than the blend PETrec/EMA, whose properties have been reduced due to the presence of EMA rubbery phase. The use of EMA-GMA was effective in reducing the particle size of the EMA dispersed phase in the PETrec/EMA blend and PE-g-MA showed evidences of reaction with LB and physical mixture with the EMA

Avaliação do efeito da adição de resíduo de borracha de pneu e brita calcária na formulação de compósitos cimentíceos

Researches have shown that the introduction of rubber in concrete improves the features of its deformability, as well as contributes to environmental disposal of waste generated in the tire retreading process. Furthermore, there is a high availability of limestone within RN and CE country. Ignorance about this stone, does not allow its wide use as aggregate, leaving, this abundant supply idle. A composite of limestone gravel, with proportions of tire rubber waste which could be used as concrete would be an alternative to concrete for low applications. Therefore, this research aims to evaluate the characteristics of concrete containing limestone gravel and proportions of little aggregate replacement (sand) by tire rubber waste. To this goal, the material components of the concrete were characterized, concrete specimens with limestone gravel were made, from the dash 1.0: 2.5: 3.5, varying the water/cement ratio, and inserting a commercial plasticizer, without a proportion of residue, known as reference. From this, concrete with and without the presence of the additive in the same proportions were chosen, as well as these with the use of granite gravel, for being the most used. Selected the references, to these, replacements of little aggregate (sand) were added replaced by rubber waste from the tire retreading process, treated with 1M NaOH in proportions from 5.0 to 20.0 % by mass, cured and exposed to the semiarid environment. The results indicate the possibility of using limestone gravel in the concrete composition with workability correction using plasticizer. There was a decrease in the mechanical properties of the concrete with increments of waste rubber, but there is an improvement in toughness and deformability of the composite, which makes it interesting for the construction of non-structural concrete floors, as well as, the rubber waste delayed the hardening process, continuing to gain resistance after 28 days

Pirólise termoquímica de pós da fibra de coco seco em um reator de cilindro rotativo para produção de bio-óleo

This master thesis aims at developing a new methodology for thermochemical degradation of dry coconut fiber (dp = 0.25mm) using laboratory rotating cylinder reactor with the goal of producing bio-oil. The biomass was characterized by infrared spectroscopy with Fourier transform FTIR, thermogravimetric analysis TG, with evaluation of activation energy the in non-isothermal regime with heating rates of 5 and 10 °C/min, differential themogravimetric analysis DTG, sweeping electron microscopy SEM, higher heating value - HHV, immediate analysis such as evaluated all the amounts of its main constituents, i.e., lignin, cellulose and hemicelluloses. In the process, it was evaluated: reaction temperature (450, 500 and 550oC), carrier gas flow rate (50 and 100 cm³/min) and spin speed (20 and 25 Hz) to condensate the bio-oil. The feed rate of biomass (540 g/h), the rotation of the rotating cylinder (33.7 rpm) and reaction time (30 33 min) were constant. The phases obtained from the process of pyrolysis of dry coconut fiber were bio-oil, char and the gas phase non-condensed. A macroscopic mass balance was applied based on the weight of each phase to evaluate their yield. The highest yield of 20% was obtained from the following conditions: temperature of 500oC, inert gas flow of 100 cm³/min and spin speed of 20 Hz. In that condition, the yield in char was 24.3%, non-condensable gas phase was 37.6% and losses of approximately 22.6%. The following physicochemical properties: density, viscosity, pH, higher heating value, char content, FTIR and CHN analysis were evaluated. The sample obtained in the best operational condition was subjected to a qualitative chromatographic analysis aiming to know the constituents of the produced bio-oil, which were: phenol followed by sirigol, acetovanilona and vinyl guaiacol. The solid phase (char) was characterized through an immediate analysis (evaluation of moisture, volatiles, ashes and fixed carbon), higher heating value and FTIR. The non-condensing gas phase presented as main constituents CO2, CO and H2. The results were compared to the ones mentioned by the literature.

Adsorção de cobre e cromo utilizando fibra de sisal visando o tratamento da água produzida pela indústria petrolífera

Currently, the oil industry is the biggest cause of environmental pollution. The objective was to reduce the concentration of copper and chromium in the water produced by the oil industry. It was used as adsorbent natural sisal fiber Agave sp treated with nitric acid and sodium hydroxide. All vegetable fibers have physical and morphological properties that enablies the adsorption of pollutants. The basic composition of sisal is cellulose, hemicellulose and lignin. The features are typically found in the characterization of vegetable fibers, except the surface area that was practically zero. In the first stage of adsorption, it was evaluated the effect of temperature and time skeeking to optimize the execution of the factorial design. The results showed that the most feasible fiber was the one treated with acid in five hours (30°C). The second phase was a factorial design, using acid and five hours, this time was it determined in the first phase. The tests were conducted following the experimental design and the results were analyzed by statistical methods in order to optimize the main parameters that influence the process: pH, concentration (mol / L) and fiber mass/ metal solution volume. The volume / mass ratio factor showed significant interference in the adsorption process of chromium and copper. The results obtained after optimization showed that the highest percentages of extraction (98%) were obtained on the following operating conditions: pH: 5-6, Concentration: 100 ppm and mass/ volume: 1 gram of fiber/50mL solution. The results showed that the adsorption process was efficient to remove chromium and copper using sisal fibers, however, requiring further studies to optimize the process.

Períodos de interferência das plantas daninhas em algodoeiro de fibra colorida ‘BRS Safira’

This study aimed to determine the late-season presence of weeds in reddish brown cotton (cultivar BRS Safira) and the critical times for removing weeds. The experiment was carried out in the area of Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) in Missao Velha-CE, Brazil, located at 7 degrees 42'07" S latitude and 39 degrees 24'18" WGr. longitude, during the 2007/2008 season. The treatments consisted of two control groups: weed-free crop during the initial period after crop emergency, and crop kept with weeds during initial period after plant emergency. Both consisted, 0; 20; 40; 60; 80 e 120 days after crop emergency (DAE), the weed community was evaluated by two phytosociological indices (relative dominance and relative importance). Regression analysis was performed as the model of sigmoidal Boltzman, using data from productivity separately within each type of competition, to identify the critical periods of competition, considering 2; 5 and 10% reduction in yield. The community of weeds was composed by 21 species, standing out among them: Richardia grandiflora, Amaranthus deflexus, Eleusine indica, Merremia aegyptia, Eragrotis pilosa, Cenchrus echinatus and Waltheria indica. Considering 2; 5 and 10% reduction in yield fiber as acceptable, the critical period before weed interference were, respectively, 8; 14 and 20 DAE. The critical period of weed interference, for those same levels of losses, were respectively, 100; 82 and 60 days.

Fontes de fibra na alimentação do pacu: desempenho, composição corporal e morfometria intestinal

O objetivo deste estudo foi avaliar os efeitos da utilização de diferentes ingredientes fibrosos nas dietas sobre o desempenho, a composição corporal e a morfometria intestinal de juvenis de pacu. Foram avaliadas cinco dietas isoproteicas (23% de proteína digestível), isoenergéticas (3250kcal de energia digestível/kg) e isofibrosas (9% de fibra bruta), sendo a principal fonte fibrosa de cada constituída por farelo de soja, casca de soja, farelo de girassol e polpa cítrica; esta última em dois níveis de inclusão (30 e 45%). Foram utilizados 300 juvenis de pacu (25,12±0,78 gramas), alojados em 25 aquários (200 litros). Os melhores resultados de crescimento e conversão alimentar foram obtidos com as dietas contendo farelo de soja e farelo de girassol. As dietas contendo casca de soja e polpa cítrica prejudicaram o desempenho dos juvenis de pacu, e o efeito negativo foi acentuado com o aumento da inclusão de polpa cítrica. Além disto, somente nos peixes alimentados com a dieta com 45% de polpa cítrica foi observada diminuição na densidade de vilosidades por área no epitélio intestinal. A partir dos resultados obtidos, pode-se concluir que alguns ingredientes fibrosos podem afetar negativamente o desempenho e as características do epitélio intestinal de juvenis de pacu.

Cultivo de híbridos de pimentão amarelo em fibra da casca de coco

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Consumo e dinâmica ruminal da fibra em detergente neutro em bovinos em pastejo no período das águas recebendo suplementação com nitrogênio não-proteico e/ou proteína verdadeira

Objetivou-se avaliar o efeito de diferentes relações entre proteína verdadeira e nitrogênio não-proteico sobre o consumo e a dinâmica de trânsito e degradação ruminal da fibra em detergente neutro (FDN) da forragem em bovinos em pastejo durante o período das águas. Foram utilizados cinco novilhos mestiços Holandês × Zebu, castrados, com peso corporal inicial de 335±35 kg fistulados no rúmen e no abomaso. Os tratamentos foram: controle (somente pasto); e suplementos com ureia; com 2/3 de compostos nitrogenados oriundos da ureia e 1/3 de compostos nitrogenados oriundos da albumina; com 1/3 de compostos nitrogenados oriundos da ureia e 2/3 de compostos nitrogenados oriundos da albumina; e com albumina. Foram fornecidos 200 g/dia de proteína bruta (PB) a partir dos suplementos. O experimento foi conduzido segundo delineamento em quadrado latino 5 × 5, com cinco períodos experimentais de 15 dias. Não foram observados efeitos da suplementação sobre o consumo voluntário, com exceção do consumo de PB, que aumentou com a suplementação. A substituição da ureia por albumina nos suplementos teve efeito linear sobre o consumo de PB. Os consumos dos demais componentes da dieta não foram afetados pela composição dos suplementos. Nenhum efeito foi observado sobre a taxa de passagem ruminal de compostos fibrosos. O fornecimento de suplementos ampliou, em média, a estimativa da taxa comum de latência e degradação da FDN. Contudo, não houve efeito da alteração na composição dos suplementos sobre este parâmetro. A suplementação de bovinos com fontes de compostos nitrogenados degradáveis no rúmen proteicos ou não-proteicos durante o período das águas não afeta o consumo voluntário de pasto.

Avaliação da determinação da fibra em detergente neutro e da fibra em detergente ácido pelo sistema ANKOM

O objetivo do trabalho foi comparar os valores de fibra em detergente neutro (FDN) e os de fibra em detergente ácido (FDA) obtidos com o equipamento ANKOM e pelo método convencional (Van Soest). No primeiro ensaio foram analisados cinco materiais diferentes (cana-de-açúcar, capim-braquiária, silagem de milho, polpa cítrica e fezes bovina) e testados quatro tipos de saquinhos para filtragem de amostra. O delineamento experimental foi em blocos casualizados, em um fatorial 5x4 (cinco materiais diferentes e quatro tipos de saquinhos de filtragem), com três repetições. As médias obtidas foram comparadas àquelas obtidas com método convencional. No segundo ensaio procurou-se avaliar o efeito da quantidade de amostra por saquinho (0,5; 0,8 e 1,0 g) sobre os teores de FDN e FDA em três tipos de alimentos, utilizando o ANKOM. Neste ensaio, o delineamento experimental foi em blocos casualizados em esquema fatorial 3x3 (três alimentos x três quantidades), com três repetições. Os tipos de saquinhos de filtragem utilizados não influenciaram os teores de FDN nos diferentes alimentos, com exceção das fezes, cujos saquinhos de náilon resultaram em concentrações de FDN inferiores. Não houve diferença entre os valores de FDN e FDA, obtidos pelo equipamento ANKOM ou pelo convencional, para os alimentos estudados, com exceção da polpa cítrica, cujo valor médio de FDA pelo ANKOM foi inferior àquele obtido pelo método convencional. A quantidade não exerceu efeito sobre a concentração de FDN dos alimentos analisados no equipamento ANKOM.

Efeitos de fontes nitrogenadas com distintas degradabilidades sobre o aproveitamento da fibra, do nitrogênio e do amido em rações para bovinos

O objetivo do experimento foi avaliar os efeitos da utilização do farelo de soja ou da glutenose sobre a degradabilidade ruminal in situ dos constituintes de dietas compostas por feno, milho e as fontes nitrogenadas fornecidas para bovinos adultos com 650 kg de peso. A glutenose foi considerada fonte nitrogenada de baixa degradabilidade e o farelo de soja, de média degradabilidade ruminal. As degradabilidades potenciais obtidas para o nitrogênio foram 39,7 e 90,3% e as degradabilidades efetivas 35,7 e 62,9%, respectivamente, para glutenose e farelo de soja. Utilizou-se a fibra mordente para determinar a taxa de passagem das dietas e obtiveram-se 6,6%/h para dietas com farelo de soja e 2,4%/h para dietas com glutenose. Não houve diferença na degradabilidade potencial da matéria seca do feno, nas frações A, B, C e na taxa de degradação, mas a degradabilidade efetiva da matéria seca foi inferior para as dietas com farelo de soja (29,3 vs 40,6%). Os demais ingredientes, à exceção do milho, apresentaram acentuadas diferenças entre as dietas nas variáveis de degradabilidade, na taxa de degradação e na degradabilidade efetiva do nitrogênio, com inferioridade na dieta com glutenose. O milho diferiu apenas quanto à degradabilidade efetiva do nitrogênio, superior na dieta com glutenose (68,7 vs 56,3%). O amido do milho apresentou menor degradabilidade efetiva na dieta com farelo de soja (52,5 vs 68,0%), sendo a degradabilidade efetiva da fibra do feno também inferior para essas dietas (27,3 vs 43,2%). Concluiu-se que fontes nitrogenadas com distintas degradabilidades podem afetar tanto a degradabilidade da fibra do volumoso quanto à do amido da própria fonte nitrogenada e do milho das dietas.

Degradabilidade da Matéria Seca e Fibra em Detergente Neutro da Cana-de-açúcar (Saccharum spp) com Diferentes Fontes de Proteína

Foram utilizados cinco bovinos fistulados no rúmen para se determinar a degradação da cana-de-açúcar em dietas com diferentes fontes de proteína degradável, por meio do método de incubação de sacos de náilon. Os tratamentos estudados foram: cana e uréia; cana e farelo de soja; cana, farelo de soja e uréia; cana e glúten de milho; cana, glúten de milho e uréia. Após um período de adaptação de 14 dias, iniciou-se a incubação dos sacos de náilon, nos tempos de 3, 6, 12, 24, 48, 72, 96 e 120 horas. Após o período de incubação, foram determinados o pH e a concentração de amônia no fluido ruminal, em amostras retiradas 0, 3, 6, 9, 12, 15, 18 e 21 horas após a alimentação. O delineamento estatístico utilizado foi o de blocos casualizados, com tratamentos como parcelas e tempos como subparcelas. A concentração de amônia foi mais elevada nos tratamentos com maior quantidade de proteína degradável, porém não houve efeito significativo para os tratamentos. Para os valores de pH, houve significância, apresentando valores mais elevados para os tratamentos com maior quantidade de proteína degradável. Não se observou efeito significativo das diferentes fontes de nitrogênio sobre a degradação da matéria seca e da fibra em detergente neutro da cana-de-açúcar, sendo que a degradabilidade dessas duas frações variou apenas com o tempo de incubação. Os resultados do experimento não comprovaram o princípio de que a maior quantidade de proteína degradável no rúmen possa induzir maior degradação da FDN da dieta.