RESUMO Empresas fornecedoras de Zamac reciclam sucatas de peças técnicas provenientes do processo produtivo de zamac injetado sob pressão e revestido por eletrodeposição. No entanto, somente 35% da sucata enviada para beneficiamento é reciclada e retorna para o processo produtivo como matéria-prima. Levando em consideração que a matéria-prima é um dos principais custos das empresas, o reaproveitamento de sucata representa uma oportunidade de economia para o processo fabril. Com isso, o objetivo desse trabalho foi verificar a viabilidade de fundição de sucatas de peças técnicas como matéria-prima para a fabricação de peças para o mercado da moda. A sucata foi analisada quanto à composição química, microestrutura e características térmicas. A sucata foi fundida sob pressão para produção de componentes para calçados e acessórios (elementos estéticos como fivelas e enfeites). Para comparação, enfeites e fivelas foram obtidos com matéria-prima virgem. Os enfeites e fivelas foram analisados quanto à microestrutura, resistência à corrosão e propriedades mecânicas. As amostras fundidas com uso de sucata responderam de forma satisfatória a todos os ensaios e, em alguns casos, de maneira superior às peças de controle, que foram fundidas com matéria-prima virgem. Assim, constatou-se que a sucata oriunda de peças técnicas pode ser usada como matéria-prima para produção de peças e acessórios para o setor de moda e, neste contexto, representa uma possibilidade de redução de custo de fabricação.

ABSTRACT Zamak supplier companies recycle scraps of technical parts from the production process of zamak injected under pressure and coated with electrodeposition. However, only 35% of the scrap sent for processing is recycled and returns to the production process as raw material. Taking into account that raw material is one of the main costs of companies, the reuse of scrap represents an opportunity to save the manufacturing process. With that, the objective of this work was to verify the viability of casting scraps of technical parts as raw material for the manufacture of parts for the fashion market. The scrap was analyzed for chemical composition, microstructure and thermal characteristics. The scrap was melted under pressure to produce components for shoes and accessories (aesthetic elements such as buckles and ornaments). For comparison, ornaments and buckles were obtained from virgin raw material. The ornaments and buckles were analyzed for microstructure, corrosion resistance and mechanical properties. Samples cast using scrap responded satisfactorily to all tests and, in some cases, better than control parts, which were cast with virgin raw material. Thus, it was found that scrap from technical parts can be used as raw material for the production of parts and accessories for the fashion sector and, in this context, it represents a possibility of reducing manufacturing costs.

RESUMO O descarte inadequado de pneus representa um grave problema ambiental, pois seu elevado tempo de decomposição, aliado ao seu descarte incorreto, o torna uma grande ameaça aos recursos naturais, causando contaminação de solos e rios, além de enfermidades provocadas pelo acúmulo de resíduos e água em seu interior, proliferando vírus e bactérias. Dentre as alternativas possíveis de reutilização deste resíduo é possível optar por sua incorporação em outros materiais, o que além de torná-lo um resíduo economicamente atrativo, possibilita que sejam desenvolvidas novas composições de materiais com propriedades diferenciadas. A proposta deste trabalho consiste na adição de resíduo de pneu em matriz de elastômero termoplástico SEBS (copolímero de estireno - etileno/butileno - estireno). Em um primeiro momento avaliou-se a influência do tamanho de grão do resíduo. Foram utilizados grãos de tamanhos de 12, 24 e 35 mesh. Após a realização de ensaios físicos, térmicos e mecânicos, que permitiram a escolha da melhor granulometria, variou-se a concentração de resíduo em 10, 20 e 30% em massa de SEBS. Os resultados mostraram que o composto desenvolvido com granulometria de 12 mesh, em concentração de 10% em massa de SEBS, mostrou-se a composição com melhores propriedades mecânicas, o que sugere sua vantagem em aplicação em pisos industriais.

ABSTRACT The inadequate disposal of tires represents a serious environmental problem, since its high decomposition time, together with its incorrect disposal, makes it a great threat to natural resources, causing contamination of soils and rivers, as well as diseases caused by to the accumulation of waste and water inside and the proliferating viruses and bacteria. Among the possible alternatives of reuse of this residue is its incorporation in other materials, which in addition to making it an economically attractive residue and allows the development of new compositions of materials with different properties. The purpose of this work is the addition of tires residue in SEBS thermoplastic elastomer matrix (styrene - ethylene / butylene - styrene block copolymer). In first step, the influence of the grain size of the residue was evaluated. Tires particles of 12, 24 and 35 mesh sizes were used. After physical, thermal and mechanical analysis, which allowed the choice of the best granulometry, the residue concentration was varied in 10, 20 and 30% by mass in SEBS matrix. The results showed that the compound developed with 12 mesh granulometry at a concentration of 10% by mass SEBS matrix showed the composition with better mechanical properties, which suggests its advantage in application on industrial floors.

RESUMO O corante azul de metileno, amplamente utilizado na indústria têxtil, é capaz de causar sérios danos, caso despejado nos corpos hídricos sem o devido tratamento. O objetivo deste trabalho foi estudar a eficiência do uso de bambu, in natura e carvão vegetal, como bioadsorvente na remoção do corante azul de metileno. Para isso, o bambu in natura e o bambu ativado termicamente foram produzidos e caracterizados por meio de análises de área superficial específica, termogravimétricas, microscopia eletrônica de varredura e espectroscopia no infravermelho. Ensaios de adsorção, em batelada, foram realizados com os bioadsorventes produzidos, utilizando planejamento experimental, do tipo fatorial 2³ e repetição do ponto central. Foram obtidas as condições do processo de adsorção para o bambu in natura, com 16 g/L de concentração de adsorvente, 50 mg/L de concentração de corante e pH =10, alcançando uma eficiência de remoção de 98,1%. As mesmas condições foram usadas com o bambu carvão, obtendo-se uma eficiência de remoção do corante de 92,2%. A diferença observada na porcentagem de remoção do corante deve-se às características de cada bioadsorvente. Os resultados demonstraram que o uso do bambu como bioadsorvente pode ser uma alternativa eficiente e sustentável para o tratamento de efluente com corantes pelo processo de adsorção.

ABSTRACT The methylene blue dye, widely used in the textile industry, is capable of causing serious damage if dumped into water bodies without proper treatment. The objective of this work was to study the efficiency of using bamboo, in natura and charcoal, as bioadsorbents in the removal of methylene blue dye. For this, fresh bamboo and thermally activated bamboo were produced and characterized by specific surface area, thermogravimetric, scanning electron microscopy and infrared spectroscopy. Batch adsorption tests were carried out with the bioadsorbents produced, using an experimental design, of the 23 factorial type and repetition of the central point. The conditions of the adsorption process for bamboo in natura were obtained, with 16 g/L of adsorbent concentration, 50 mg/L of dye concentration and pH =10, achieving a removal efficiency of 98.1%. The same conditions were used with charcoal bamboo, obtaining a dye removal efficiency of 92.2%. The difference in dye removal percentage is due to the characteristics of each bioadsorbent. The results demonstrate that the use of bamboo as a bioadsorbent can be an efficient and sustainable alternative for the treatment of effluent with dyes through the adsorption process.

Abstract The accumulation of polymeric residues has been one of the most impacting environmental problems in recent human history, coming, above all, from disposable artefacts, such as plastic bags. Processing polyolefins with pro-oxidant additives is an alternative to favour the abiotic degradation process of macromolecules, including thermooxidation, so that the oxygenated fragments produced can be assimilated by microorganisms. The objective of this work was to evaluate the process of thermomechanical oxidative degradation of polyethylene (PE) during tubular extrusion of HDPE/LDPE films, without and with 1% of two different pro-oxidants, d2wTM and benzoin. The results of viscosimetric and MFI analyses indicated smaller chain sizes in the additivated films. The FTIR spectra and contact angles indicate a higher presence of polar functional groups in the samples with pro-oxidants. The surface morphological analysis by SEM indicated difference of PE homogeneity in the films. Benzoin, however, proved to be a better pro-oxidant than d2wTM.

RESUMO A laminação é um processo de conformação por deformação plástica amplamente utilizado na indústria para o processamento de ligas metálicas semi-acabadas, pois, além de dar a forma comercial desejada ao produto, proporciona o aumento das propriedades mecânicas em um processo contínuo e de grande produtividade. Desta forma, é importante que o acadêmico de engenharia compreenda como funcionam os equipamentos utilizados na laminação e quais são as variáveis que influenciam este processo. Dentro deste contexto, e pensando que habilidades obtidas através de experimentos que relacionem a teoria com a prática são fundamentais para a formação de um engenheiro, a proposta deste trabalho foi projetar e adaptar um laminador didático do tipo duo, para metais não ferrosos que, empregado no decorrer da graduação, promova maior proximidade dos alunos de engenharia com este processo industrial. A adaptação deste dispositivo se deu com base em um laminador de joias manual já existente, o qual foi acoplado a um motor elétrico que promovesse a potência necessária para o processo. O resultado deste trabalho foi a adaptação de um laminador que atendesse as expectativas de laminação, estando disponível para a elaboração de atividades que propulsionam o entendimento acadêmico sobre o tema. Em relação aos metais que foram laminados, diversas características do processo de laminação a frio e de seus produtos descritos pela literatura e pela indústria da transformação mecânica foram observadas durante a execução dos testes de funcionamento e dos ensaios, validando, desta forma, a adaptação do equipamento e o alcance de seu principal objetivo.

ABSTRACT Lamination is a plastic deformation forming process widely used in the industry for the processing of semi-finished metal alloys, as it not only gives the desired commercial shape to the product, but also provides increased mechanical properties in a continuous and high productivity process. In this way, it is important that the engineering academic understand how the equipment used in the lamination works and what are the variables that influence this process. In this context, and thinking that skills obtained through experiments that relate theory to practice are fundamental for the formation of an engineer, the purpose of this work was to design and adapt a didactic laminator of the duo type, for nonferrous metals that, employee during the graduation, promote greater proximity of engineering students with this industrial process. The adaptation of this device was based on an existing manual jewelry mill, which was coupled to an electric motor that promoted the power needed for the process. The result of this work was the adaptation of a rolling mill that met the lamination expectations, being available for the elaboration of activities that propel the academic understanding on the subject. In relation to the metals that were rolled, several characteristics of the cold rolling process and its products described in the literature and in the mechanical transformation industry were observed during the execution of the tests of operation and of the tests, thus validating the adaptation of the equipment and the achievement of its main objective.

ABSTRACT Titanium and its alloys are the most popular metals applied on end osseous implants manufacturing. Commercially pure titanium (Ti c.p.) has been successfully used as a biomaterial because of its mechanical and chemical properties, excellent corrosion resistance and biocompatibility. In order to improve and accelerate the osseointegration process after implantation, superficial treatments are performed aiming properties that stimulate the growth of the newly-formed bone. In this work, self organized titanium dioxide (TiO2) nanotubes were obtained by anodic oxidation on Ti c.p. (grade 2). Also, it has been shown that the process is industrially reproducible for this purpose. As parameters for the anodizing process, it was concluded that the optimal electrolyte was H3PO4 solution + 0.15% HF under potentiostatic mode for 30 minutes. Potentials of 1, 5, 10, 15 and 20 V were tested in order to verify the best conditions to obtain nanotubes. In this case, potential was set at 10V. The morphology of the samples was characterized by Scanning Electron Microscopy (SEM), Scanning Electron Microscopy with Field Emission (SEM-FEG) and Atomic Force Microscopy (AFM). The results showed the nanotubes formation throughout the titanium samples surface. In accordance to the obtained roughness, it was observed that the formed nanotubes film is thin, however, the literature indicates that the film thickness is not relevant on the performance of nanostructures as optimizers of the osseointegration process, unlike the nanotubes morphology and diameter. In the wettability analysis, the nanotubes behaved as hydrophilic. Therefore, it is possible to obtain TiO2 nanotubes for using in implants by a superficial treatment, allowing a better osseointegration quality.

RESUMO O nióbio é um metal que forma óxido aderente e protetor em contato com o ar, possuindo a propriedade de se autoproteger. O método utilizado para acelerar o crescimento do óxido é conhecido como anodização, no qual o óxido formado pode ser do tipo barreira ou poroso. O óxido poroso é amplamente estudado e pode ser utilizado em células solares, sensores de gás, como biomaterial, entre outros. No entanto, óxidos porosos em nióbio têm sido obtidos com uso de F-, o que provoca intenso processo de dissolução do óxido. Com intuito de minimizar essa reação, eletrólitos contendo glicerina tem favorecido o processo de anodização formando superfícies porosas uniformes. Nesse sentido, o objetivo deste trabalho é obter estruturas nanoporosas em nióbio por anodização a partir de parâmetros conhecidos. A partir de (12,73 mA.cm-2, 100 V), tempos (5 e 30 minutos), concentração de HF (2,24%) e uso de cátodo de platina, já utilizados em estudo anterior, foi inicialmente testada a influência do cátodo de aço inoxidável em substituição à platina, visando promover uma futura transferência tecnológica. A partir disso, a fim de minimizar o processo de dissolução que ocorreu com o uso de HF (2,24%), apenas a HF (1%) foi testada. Finalmente, para obter uma estrutura de óxido mais uniforme, adicionou-se glicerina ao eletrólito de HF (1%). O uso do cátodo de aço inoxidável, apesar de influenciar os resultados dos transientes de anodização, devido a sua provável dissolução química, mostrou-se eficaz no processo. Amostras anodizadas com menores concentrações de HF e com adição de glicerina, como esperado, apresentaram menor dissolução durante a formação dos óxidos, originando estruturas nanoporosas, além de microcones.

ABSTRACT Niobium is a metal that forms adherent protective oxide in contact with the air, which has the property of self-protection. The method used to accelerate the growth of the oxide is known as anodizing, in which the oxide formed may be barrier or porous. Porous oxide is widely studied and can be used in solar cells, gas sensors, as biomaterial, among others. However, porous oxides in niobium have been obtained with the use of F-, which causes an intense dissolution process of the oxide. In order to minimize this reaction, electrolytes containing glycerine have favored the anodizing process forming uniform porous surfaces. In this sense, the objective of this study is to obtain nanoporous structures in niobium by anodization from known parameters. From (12.73 mA.cm-2, 100 V), times (5 and 30 minutes), HF concentration (2.24%) and platinum cathode use, already used in a previous study, was initially tested the influence of the cathode of stainless steel in substitution to the platinum, aiming to promote a future technological transference. From this, in order to minimize the dissolution process that occurred using HF (2.24%), only HF (1%) was tested. Finally, in order to obtain a more uniform oxide structure, glycerin was added to the HF electrolyte (1%). The use of the stainless steel cathode, although influencing the results of the anodizing transients, due to its probable chemical dissolution, proved effective in the process. Anodized samples with lower concentrations of HF and with addition of glycerine, as expected, presented lower oxide dissolution during oxide formation, originating nanoporous structures, besides microcones.

RESUMO Metais sanitários são objetos que, segundo as exigências vigentes do mercado consumidor, devem ser, ao mesmo tempo, resistentes à corrosão e bonitos, com aspecto espelhado brilhante. Estes são geralmente produzidos em latão fundido devido às suas características de fácil processamento e eletrodeposição. No entanto, para reduzir custos de produção, o latão tem sido substituído por ligas de zinco na fabricação destes componentes. O Zamac possui propriedades como baixo ponto de fusão em comparação ao latão, o que permite a obtenção de peças de paredes finas e geometrias complexas. A injeção sob pressão para obtenção de peças de ligas hipoeutéticas de zinco (Zamac 5) permite maior produtividade associada a melhores características dimensionais, com custo cerca de 30% menor do que o do latão. Este estudo apresenta a caracterização macro e microestrutural do Zamac 5 injetado sob pressão, relacionando-as com a resistência à corrosão da liga. Para tanto, foram realizados ensaios de névoa salina e análises por meio de microscopia eletrônica de varredura, ensaios de microdureza e ensaios eletroquímicos de corrosão. O Zamac 5 injetado sob pressão apresentou corrosão não-uniforme em regiões distintas da peça quando submetido à atmosfera agressiva. Os resultados também mostraram que este fato está associado aos defeitos de porosidade oriundos do processo de fabricação da liga. A microdureza da liga foi associada também aos defeitos oriundos do processo de fabricação. Por fim, evidenciou-se que o comportamento eletroquímico da liga é pouco influenciado pela presença dos defeitos.

ABSTRACT Sanitary metals are objects that, according to the current requirements of the consumer market, must be both corrosion resistant and beautiful, with a shiny mirror appearance. These are usually produced in cast brass because of their easy processing and electrodeposition characteristics. However, to reduce production costs, brass has been replaced by zinc alloys in the manufacture of these components. Zamac has properties such as low melting point compared to brass, which allows the production of thin-walled parts and complex geometries. Pressure injection to obtain zinc hypoeutec alloys (Zamac 5) allows higher productivity associated with better dimensional characteristics, costing about 30% less than brass. This study presents the macro and microstructural characterization of Zamac 5 injected under pressure, relating them to the corrosion resistance of the alloy. For this, saline fog tests and analyzes were performed by scanning electron microscopy, microhardness tests and electrochemical corrosion tests. The Zamac 5 injected under pressure presented non-uniform corrosion in distinct regions of the part when subjected to the aggressive atmosphere. The results also showed that this fact is associated with porosity defects from the alloy manufacturing process. The microhardness of the alloy was also associated with defects from the manufacturing process. Finally, it was evidenced that the electrochemical behavior of the alloy is little influenced by the presence of the defects.

ABSTRACT In many places, charcoal production, using Australian Blackwood, is still a rudimentary process, generating huge environmental impact, due to the release of pyrolysis smoke into the atmosphere. Both the society and governmental agencies is pushing the factories to condense the smoke, generating byproduct known as pyroligneous liquor. Although it's largely used for agricultural purpose, as a fertilizer and phytosanitizer, its chemical composition presents hydrogen and oxygen rich compounds, making it a potential electrolyte in the surface treatment industry, especially for anodization. Organic alternatives are being used to replace these electrolytes to make the anodizing process cleaner. Then, for the first time, Australian Blackwood pyroligneous liquor was used as an anodizing electrolyte for titanium TICP-G2, to obtain oxides for protection and coloring of the metal. For such, suitable parameters to execute the process were determined (dilution, current density, temperature, agitation, pH, conductivity) and an analysis of the transient potential over time was made. The anodized surfaces were characterized using top view Scan Electronic Microscopy (SEM) and Grazing Incidence X-ray Diffraction (GIXRD). Based on the results presented, it can be concluded that the best parameters to anodize the titanium were obtained with 50% pyroligneous liquor diluted in water, obtaining colored surfaces and promoting the formation of oxide crystallites clusters mainly in longer process times (3600s).

RESUMO A elevada resistência à corrosão dos revestimentos decorativos de cromo hexavalente obtidos nos processos de galvanoplastia é bem conhecida pela sua grande utilização e alta eficiência. Esse revestimento tem sido amplamente utilizado na indústria moveleira e de calçados, obtido por eletrodeposição em peças de zamac. No entanto, o processo galvânico apresenta alto grau poluidor devido à quantidade de efluentes geradas e à toxicidade dos produtos químicos utilizados no processo. Sabe-se que o cromo hexavalente é um agente cancerígeno e os resíduos associados são perigosos e difíceis de serem tratados. Neste contexto, o desenvolvimento de novas tecnologias tem visado à obtenção de processos resistentes à corrosão, ambientalmente corretos e economicamente viáveis. A tecnologia alternativa que pode ir ao encontro desta necessidade é o PVD - physical vapor deposition, com o processo de sputtering. Neste sentido, este estudo tem como objetivo avaliar e comparar o desempenho de revestimentos de cromo aplicados por sputtering com verniz em relação ao desempenho do revestimento de cromo eletrodepositado. Para tanto, os revestimentos foram aplicados em zamac e foram caracterizados morfologicamente, eletroquimicamente e físico-quimicamente. Os resultados mostraram que os acabamentos de cromo depositados por sputtering apresentam características equivalentes quanto ao desempenho eletroquímico se comparados ao revestimento cromado no processo convencional, podendo ser uma alternativa de substituição com âmbito sustentável.

ABSTRACT The high corrosion resistance of decorative hexavalent chromium coating, obtained thru electroplating processes, is well known for its wide usage and elevated efficiency. This coating has been used all throughout furniture and shoe’s industries, obtained via electrodeposition in Zamac pieces. However, the galvanic process presents a high pollution degree, due to the amount of generated waste, and the toxicity of the chemicals used. It is well known the hexavalent chromium is a carcinogenic agent, and how its residues are dangerous and hard treat properly. Because of this, the development of new technologies is aiming towards ecofriendly, economically viable, with a high corrosion resistance. The alternate technology that might be heading in this direction is PVD (Physical Vapor Deposition), with the sputtering process. In this sense, this paper’s main objective is to evaluate and compare the development of varnished sputtering applied chromium coatings, in relation to the performance of electrodeposited chromium coatings. For such, they were applied in Zamac and morphologically, electrochemically, and physically-chemically characterized. The results showed that the sputtering deposited chromium coatings presented similar characteristics to the conventional coating method, so it might be a suitable and clean alternative in those regards.

Abstract Squeeze casting is the most industrially advantageous process for producing zamak 5 parts. However, this process generates porosity defects in parts, compromising their corrosion resistance. Therefore, this work aims to minimize defects and improve zamak 5 corrosive performance through the anodizing process. For this purpose, zamak 5 was anodized in 300 mol.m-3 oxalic acid and analyzed by ATR-FTIR, SEM, wettability and EIS techniques. The anodizing process promoted the formation of oxalate and oxide layers of Zn and Al, thereby reducing porosity defects. Although the anodized layer has fragile behavior, being porous and permeable, the immersion time of anodized zamak 5 in NaCl forms corrosion products in the alloy that exhibit better protection.

RESUMO A indústria de calçados emprega em seus produtos diversas matérias primas derivadas do setor de plásticos. Um dos mais utilizados é o laminado sintético de PVC, utilizado na construção de cabedais devido à grande versatilidade de cores, estampas e espessuras. O laminado é composto de PVC e de fibra têxtil, normalmente na proporção mássica de 60/40. O corte das peças gera uma grande quantidade de aparas que normalmente são descartadas ou depositadas em aterros sanitários ou ARIPs (Aterros de Resíduos industriais Perigosos). O presente trabalho avalia a viabilidade de incorporação destes resíduos em forma de pó em matriz de PVC virgem para uso em solados nas proporções de 0, 5, 15, 25, 35 pcr (partes por cento de resina), bem como seu desempenho mecânico. Foram avaliadas propriedades físico-mecânicas com tração, dureza shore A e colagem, microscopia eletrônica de varredura (MEV) e espectroscopia no infravermelho (FTIR). Os resultados dos ensaios de dureza e tração demonstraram um decréscimo no desempenho na medida em que a concentração de resíduo no compósito aumentou. A força de colagem também apresentou queda na resistência final obtida pelo efeito pull out, confirmado pelas micrografias da superfície de fratura. Pode-se dizer que as misturas com resíduos de laminados em pó apresentam características aceitáveis, segundo as normas indicadas e os padrões especificados para a utilização como material para solado. Além disso, a incorporação deste resíduo diminui a quantidade de material descartado reduzindo o impacto ambiental.

ABSTRACT The footwear industry uses in its products various raw materials derived from the plastics sector. One of the most used is the synthetic PVC laminate, used in the construction of leather because of the great versatility of colors, prints and thicknesses. The laminate is composed of PVC and textile fiber, usually in the mass ratio of 60/40. Cutting of parts generates a large amount of shavings that are normally discarded or deposited in landfills or ARIPs (Hazardous Industrial Waste Landfills). The present work evaluates the feasibility of incorporating these residues in the form of powder in virgin PVC matrix for use in soils in proportions of 0, 5, 15, 25, 35 pcr (parts per cent of resin), as well as their mechanical performance. Physical-mechanical properties with traction, shore A hardness and bonding, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) were evaluated. The results of the hardness and tensile tests showed a decrease in performance as the concentration of residue in the composite increased. The bond strength also showed a decrease in the final resistance obtained by the pull out effect, confirmed by fracture surface micrographs. Mixtures with powdered laminate residues may be said to have acceptable characteristics, in accordance with the standards indicated and the standards specified for use as flooring material. In addition, the incorporation of this residue reduces the amount of material discarded reducing the environmental impact.

ABSTRACT The fouling formation in the EVA production leads to an increase in the residence time of the material. This result is a favorable condition to generation of the crosslinks during the polymerization. The crosslinking allows raising the molar mass of the polymer, which after the polymerization reaction are characterized as gels, thus generating problems in the product quality during production due to contamination of the resin. This paper describes the fouling process in the reactor, the defouling mechanism, the crosslinking, the scission of chain and presents a study on the influence of the reaction temperature in relation to the formation of gels by quantitative analysis by Optical Controller System -OCS. The average temperature rise of the reaction at 10 ºC, helped to reduce the generation of gels due to the viscosity reduction over the reactor, which reduces the polymer residence time in the walls of the tube and consequently the formation of fouling.

Acacia mearnsii de Wild (black wattle) is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with mass spectrometry (GC/MS). Branches of black wattle were thermally degraded at controlled ambient and temperature conditions. Overall, a higher variety of compounds were obtained under atmospheric air pressure than under synthetic air pressure. Most of the tentatively identified compounds, such as carboxylic acids, phenols, aldehydes, and low molecular mass lignin fragments, such as guayacol, syringol, and eugenol, were products of lignin thermoconversion. Substituted aromatic compounds, such as vanillin, ethyl vanillin, and 2-methoxy-4-propeny-phenol, were also identified. At temperatures above 200 ºC, furan, 2-acetylfuran, methyl-2-furoate, and furfural, amongst others, were identified as polysaccharide derivatives from cellulose and hemicellulose depolymerization. This study evidences the need for adequate management of the condensable by-products of charcoal production, both for economic reasons and for controlling their potential environmental impact.

A high performance liquid chromatographic-diode array detection method for the determination of busulfan in plasma was developed and validated. Sample preparation consisted of protein precipitation followed by derivatization with sodium diethyldithiocarbamate and liquid-liquid extraction with methyl-tert-butyl ether. Chromatograms were monitored at 277 nm. Separation was carried out on a Lichrospher RP 18 column (5 µm, 250 x 4 mm). The mobile phase consisted of water and acetonitrile (20:80, v/v). The method presented adequate specificity, linearity, precision and accuracy and allowed reliable determination of busulfan in clinical plasma samples, being applied to three patients submitted to bone marrow transplantation.