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Vegetable oils have been largely used as healing agents for self-healing coatings, which in turn, can recover their physical integrity upon damage due to oil film formation resulted of its oxidative polymerization process. Linseed oil (LO) and chia oil (CO) are able to form films because of their air-drying properties and high polyunsaturated fatty acids content. In this work, drying properties of CO and LO with and without cobalt (II) octoate, as a catalyst for the oxidative polymerization, were quantitatively estimated over time by Fourier-Transform Infrared Spectroscopy (FTIR). The CO drying property showed 47% higher than LO and the catalyst has successfully accelerated the oxidative polymerization of both oils in 95%. Microcapsules containing both pure and catalyzed oils were prepared, mixed into epoxy resin, and applied onto AISI 1020 steel samples. Their healing effect was evaluated through a simulated scratch and submitted to electrochemical tests and imaging.

The drying properties and the performance of the chia oil (CO) as a novel healing agent for self-healing coatings are reported in this work, in comparison with linseed oil (LO). The drying properties of both oils were estimated by their respective drying rates (D.R.) between 0 and 500 h by Fourier-transform infrared spectroscopy. The D.R. of CO at 216 h was 47% higher than LO, which was attributed to its higher polyunsaturated fatty acids content. CO and LO were encapsulated in poly(urea–formaldehyde) microcapsules by in situ polymerization in oil-in-water emulsion, showing mean diameters of 20 and 23 µm, respectively. Coatings loaded with 10 wt% of microcapsules were applied onto AISI 1020 steel surfaces. The effect of these drying oils as healing agents for self-healing coatings was evaluated by artificial scratches and measured by potentiodynamic polarization test (PPT) and electrochemical impedance spectroscopy (EIS) techniques. Scratched samples showed an increasing corrosion potential of only 4 h after the scratch simulation, according to the PPT. EIS results showed that coatings containing CO as a healing agent had lower double-layer capacitance (QPE2-Q), suggesting a slight improved self-healing effect compared to LO.

In the past two decades, self-healing coatings have emerged as a potential alternative approach to enhance the life span of structural metal components constantly exposed to aggressive environments. In this work, we aimed to obtain capsules smaller than 1 µm containing an appropriate amount of oil seeking to provide efficient self-healing. A modification in the route of synthesis of self-healing coating capsules is proposed. This modification of a typical synthesis route, which consisted of introducing an additional mechanical agitation step before adding a formaldehyde aqueous solution, was used to entrap linseed oil as a healing agent in poly(urea–formaldehyde). Hence, two synthesis routes were investigated: one involving mechanical agitation at high-speed rotation and another which combines mechanical and ultrasonic agitation. The capsules obtained by agitation had average sizes of 0.35 ± 0.13 and 0.37 ± 0.19 µm and an oil content of 80 ± 2.2 and 77 ± 1.7 wt%, respectively. Both were incorporated, separately, into an epoxy resin matrix, and the composite was applied onto ASTM A36 steel plates for evaluation of healing crack filling performance and accelerated corrosion testing. Scanning electron microscope images showed that the two coatings had a similar healing effect, mainly due to their similar estimated oil content.

Cornstarch was processed on an extruder with glycerol and different contents of urea giving rise to samples named as SGU-0, SGU-1, SGU-5, and SGU-10. The gelatinization enthalpy ΔHgel, calculated by DSC, indicated that the mixture of glycerol and urea seems to better plasticize the starch than glycerol alone. XRD was used to identify the changes in the crystal structure of native starch after extrusion processing. XRD diffractograms indicated the presence of both residual native crystallinity and processing-induced crystallinity. The morphology observed by SEM was compatible with the presence of residual crystals and recrystallization, as suggested by XRD analysis. SAXS experiments pointed out the minute amount of B-type crystallites in the samples with urea, probably due to the hydrophilic character of urea, which contributes to starch hydration.

Antistatic packagings are very important for proper transportation and storage of electronic components since these components can be damaged with electric overloads generated through rubbing. Therefore, the purpose of this study was to develop an innovative material for antistatic packaging with a sustainable character. For this, a blend of recycled poly(ethylene terephthalate) (PET), polycarbonate (PC), and polyaniline (PAni) was prepared by melt extrusion. Samples have a final content of 68 wt% of PET, 29 wt% of PC, and 3 wt% of PAni doped with cobalt (PAni-Co). The properties were determined by differential scanning calorimetry, thermogravimetric analysis, tensile testing, electrical resistivity analysis, and Fourier transform infrared spectroscopy. To the best of our knowledge, no previous work studied the incorporation of PAni-Co in PET/PC blend.

Nanocrystals cellulose (CNC) has been used in studies as biotemplate to improve the electronic properties of conjugated polymers (CP) increasing their molecular orientation. This study demonstrates the in situ grafting of the CNC surface esterified with 3-thiophenetic acid (3TAA) during the oxidative polymerization of 3-hexylthiophene. The surface modification of the CNC was evidenced by the presence of the band with an absorption peak at 1737 cm−1 in the infrared region and the chemical displacement at 157 ppm of the 13C NMR, assigned to ester group carbon. The influence of cellulose nanocrystals in the molecular organization of the CP was studied by Ultraviolet-visible Spectroscopy (UV–vis) and Cyclic Voltammetry (CV). The lower band gap energy and anodic peak potential observed for the nanocomposite elaborated with 10 wt% CNC3TAA suggest the influence of nanocrystals on the increase in planarity of P3HT macromolecular chains, decreasing the energy expenditure in the oxidative process of the conjugated polymer.

The present study describes the influence of the concentration of lignin when used as a filler in polyurethane foam for crude oil sorption. The foams (lignin 0-20wt%) were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis, contact angle and density. The FTIR analysis confirmed urethane linkage formation, showing that the chemical structure of the polymer was preserved, despite the addition of different lignin concentrations. Thermogravimetric analysis showed that the presence of lignin has altered the onset temperature (Tonset) of the foams, decreasing as the concentration of lignin is increased. The contact angle analysis showed a decrease in the hydrophobicity of the foams with increasing lignin concentration. All modified foams showed an improvement in the oil sorption capacity in a PUF/oil/water system, and the PUF-10 showed an improvement of about 35.5% compared to the PUF-blank. The Langmuir isotherm showed a better fit to the data and predicted a maximum oil adsorption of 28.9gg-1 by the PUF-10. The ΔG° value of -4.4kJmol-1 indicated that crude oil adsorption process by PUF-10 was spontaneous. The results of reuse of the PUF-10 showed that oil removal efficiency remained greater than 95% after five consecutive cycles.

The work demonstrates an easy and simple method for obtaining a TiO2 porous ceramic coated with a CeO2 thin film (COTF) on the surface. Replica technique used a 30 PPI polyurethane sponge and TiO2 ceramic suspension. Dip coating technique was used to coat the material surface and cerium polymeric resin synthesis was obtained by polymeric precursors method. Thermal analysis indicated a thermostable material from 500 °C. X-ray diffraction analysis of calcined CeO2, at 600 to 900 °C, resulted in monophasic and crystalline with a fluorite type cubic structure. Scanning electron microscopy made it possible to monitor COTF formation and growth from islands shape to a more homogenous form over 10 depositions.

Polyurethanes are polymers prepared from the reaction between polyfunctional isocyanates and polyols, containing intramolecular urethane bonds. The thermosetting polyurethane (PUR) is a non-biodegradable polymer, that cannot be reprocessed by melting, so that the waste generated becomes an environmental problem. The objective of this study was to produce and characterize thermoplastic polyurethane (TPU) composites incorporated with rigid polyurethane particles through the extrusion process, as an alternative for the reuse of the PUR and improvement of the TPU properties. Extruded composites with 10%, 20% and 30% in weight were thermopressed and had their morphological, thermal and mechanical properties analyzed. The composite with 20% of filler (TPU/PUR20%) presented the best results, with an increase of 117% in the elastic modulus and 79% in the yield stress when compared to the pure matrix (TPU/PUR0%). No additional increment of the mechanical properties was observed to the composite with 30% of PUR (TPU/PUR30%), probably because of the greater heterogeneity of this composite, related to the difficulty of dispersion and distribution of the high content of the PUR particles in the matrix. This study presented a viable alternative for the use and value aggregation of the thermoset polyurethane residue, contributing to minimize environmental impacts and to improve the properties of thermoplastic polyurethane.

A chemically modified tung oil was used as the main polyol component in the formulation of viscoelastic (low resilience) polyurethane foams. Rice Husk Ash (RHA), a residue from the rice process industry, was chosen to be incorporated as rigid filler in these materials because of its high silica content. Water was used as blowing agent in order to increase the green nature of the reinforced foams. Physico-chemical and thermal properties of the neat and reinforced foams were measured and analyzed. RHA addition leads to noticeable changes in several properties, mainly thermal conductivity, density and foam morphology, even at the low filler content used in this work. Although the thermal stability was almost unaffected by ash content, a stabilizing effect of the inorganic filler was identified, since the residual char was higher than predicted from theoretical calculations. Fil: Silva, Virginia Ribeiro da. Universidade Federal de Minas Gerais; Brasil Fil: Mosiewicki, Mirna Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Yoshida, Maria Irene. Universidade Federal de Minas Gerais; Brasil Fil: Silva, Mercês Coelho da. Universidade Federal de Minas Gerais; Brasil Fil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Marcovich, Norma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

In the aluminum industries, there are several steps involved in processing since the extraction of bauxite to obtain the final product (Al). During the development of these, various steps generated wastes. One of them, from the electrostatic filter of the calcination step of the Bayer process is a very fine black powder, rich in alumina (Al2O3) that does not meet industry specifications, and it is discarded in the industry yard. Alumina is a noble material and has high commercial value. This black powder has great prospects for recovery, recycling, and future applications. Therefore, it is important to perform characterization of tailings and to do that we have used XRD, SEM, EDS, FTIR, Raman, and thermal analysis.

This paper is a contribution of scientific knowledge on the characteristics of several by-product materials from a bleached eucalyptus kraft pulp mill. In fact, three industrial wastes arising from bleached hardwood kraft pulps, namely: unbleached screen rejects (USR), effluent treatment (ETW), and eucalyptus bark (EB) were analyzed with the aim of their possible valorization as an alternative source of cellulose. Pure powder cellulose, CEAL, from Aldrich was also analyzed, as a reference. The structural, thermal, and morphological study of these raw materials were carried out by Fourier transform infrared spectroscopy (FTIR), energy dispersion spectrometry (EDS), X-ray diffraction (XRD), thermogravimetry (TG), temperature modulated differential scanning calorimetry (TMDSC) and scanning electron microscopy (SEM). Their morphological properties were determined using MorFi apparatus. For this study the sample bleached kraft pulp, BKP, was analyzed as a reference. Lignin and carbohydrate contents were also quantified. These by-products were studied as such (i.e. without careful purification) because we intended to find rational and low-cost way of valorization. In fact any additional operation will induce an over cost. The results obtained indicate that these industrial wastes can be potential raw material in fibre-based applications (paper, composites, …), since they contain a high proportion of cellulose with preserved fibrillar morphology and good thermal stability. Some of these materials have low lignin and inorganic residue contents.

Cellulose fiber waste from the white cellulose pulp purification process produced by the company Nipo Cellulose-Brazil (CENIBRA) was used in the preparation of composites with polyurethane. An elastomeric polyurethane based on polyether poly(tetramethylene glycol) and 4,4-diphenylmethane diisocyanate was used as polymeric matrix. Structural, thermal, and morphological characterization of the composites was carried out by infrared spectroscopy, thermogravimetry, differential scanning calorimetry, and scanning electron microscopy. The results indicate that interfacial interaction between the cellulose fiber residue and the polyurethane matrix occurs and that cellulose waste is a promising reinforcement for polyurethane composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 336–340, 2005

The present work reports a simple route to prepare tin(II) sulfide semiconductor nanometric particles by thermal decomposition in air of the easily prepared organotin sulfur-containing precursors R4Sn4S6 [R = Me, Bun and Ph]. Thermogravimetric (TG) analyses showed that Me and Bun derivatives decompose in a single sharp step at relatively low temperatures to produce the pure SnS phase, which was confirmed by powder X-ray diffraction (XRD). Temperature programmed decomposition-mass spectrometry (TPD/MS) experiments suggested that the decomposition occurs ia reductive elimination steps involving the –R and –S groups. The ring structured R6Sn3S3 [R = Me, Bun, But and Ph] compounds were also studied. However, during thermal decomposition in nitrogen or air tin is partially lost to the gas phase due to sublimation, leaving Sn or SnO, with only traces of SnS.

Viscoelastic polyurethane (PU) foams based on modified tung oil, ethylene glycol and polymeric MDI, and reinforced with rice husk ash (RHA), were prepared by a free-rise pouring method and characterized in terms of density, compression and dynamic mechanical behavior. The density of foams ranged between 50 and 90 kg/m3, depending on the position of the sample with respect to the foam rise direction and filler content. As revealed by dynamic mechanical tests, the foams exhibited two different and broad thermal transitions, the temperature of their maxima depending on filler concentration. Compression modulus, compressive strength and storage modulus increase as foam density increases but decreases as rice husk ash concentration increases due to the detrimental changes induced by the filler in the foam cellular structure. However, densification strain exhibits the opposite behavior, indicating that reinforced foams can sustain slightly higher deformations without collapsing, probably due to a reduced reactivity of the components induced by the filler. © 2013 Elsevier Ltd. All rights reserved. Fil: Ribeiro Da Silva, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidade Federal de Minas Gerais; Brasil. Ministry of Education of Brazil. CAPES Foundation; Brasil Fil: Mosiewicki, Mirna Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Yoshida, Maria Irene. Universidade Federal de Minas Gerais; Brasil Fil: Coelho Da Silva, Mercês. Universidade Federal de Itajubá; Brasil Fil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Marcovich, Norma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

Today the management of solid waste and wastewater is a major concern for humanity. In the last decade, traces of pharmaceuticals have been reported in the water cycle and have raised concerns among regulators, water suppliers and the public regarding the potential risks to human health. This study evaluated solid waste management in the state of Minas Gerais and concluded that the main fate of hazardous waste has been incineration, while the non-hazardous waste has been recycled or sent to landfills. However, complaints to the Environmental Agency - FEAM have indicated that a significant number of companies just send their hazardous wastes to landfills or even to garbage dumps, thus highlighting the urgent need for adequate waste management in Minas Gerais. Most of the pharmaceutical companies in Minas Gerais use conventional wastewater treatment. Mass spectrometry with electrospray ionization (ESI-MS) showed that the treatment routes adopted by the two 2 selected pharmaceutical industries were not effective enough since residues and degradation products of antibiotics were detected. The physicochemical analysis of the effluents showed variability in their characteristics, which may influence their treatability. The degradation assay with Fenton's reagent stood out as a promising route in achieving a higher removal capacity compared to the conventional treatment. This study contributes to enhancing our knowledge of the management of wastewater as well as of solid waste from the pharmaceutical industry in Minas Gerais and points out the need for further research.Atualmente, a gestão de resíduos sólidos e águas residuais é uma grande preocupação para a humanidade. Na ultima década, a detecção de traços de medicamentos no ciclo da água tem sido reportada e tem gerado preocupação entre os agentes reguladores, fornecedores de água e público devido os riscos potenciais para a saúde humana. As empresas farmacêuticas, em Minas Gerais, aplicam tratamentos convencionais para as águas residuais e não há praticamente avaliação sobre a eficiência de remoção de resíduos de antibióticos. Este estudo avaliou a gestão de resíduos sólidos e concluiu que o destino principal foi, para o caso de resíduos perigosos, a incineração e, para os não perigosos, a reciclagem e o aterro sanitário. No entanto, denúncias apresentadas à Agência Ambiental - FEAM indicam que número significativo de empresas envia seus resíduos perigosos para aterros sanitários e até mesmo para lixões, ressaltando, assim, a necessidade urgente de adequada gestão dos resíduos gerados. A espectrometria de massas com ionização electrospray (ESI-MS) mostrou que a rota de tratamento convencional adotada por duas empresas do setor selecionadas não foi suficientemente eficaz, uma vez que resíduos e fragmentos de antibióticos foram detectados. Os resultados da caracterização físico-química de efluentes evidenciaram suas características variáveis, que podem influenciar a sua tratabilidade. O ensaio de degradação com o reagente Fenton destaca-se como caminho promissor para alcançar maior remoção. Este estudo contribuiu para elevar o nível de conhecimento no gerenciamento de águas residuais e resíduos sólidos da indústria farmacêutica no estado de Minas Gerais e evidenciou a necessidade de estudos mais detalhados.

Rigid polyurethane composite foams were prepared with cellulose fibers as a filler. The cellulose fibers were an industrial residue of blanched cellulose pulp production. The influence of the cellulose fiber concentration on the structural, thermal, mechanical, and morphological properties of the foams was investigated. We also studied the influence of the cellulose fibers on the foam's resistance to fungal attack by placing a suspension of known fungus in contact with the surface of the foam and following the morphological evolution as a function of time (for 60 days). The increase in the cellulose filler concentration in the foams, up to 16% w/w with respect to the polyol, changed their properties as follows: (1) the cell size decreased, (2) the thermooxidative stability and mechanical properties remained approximately constant, (3) the thermal conductivity decreased slightly, and (4) fungal growth was observed. Therefore, a cellulosic fibrous industrial residue was rationally valorized as a filler in classical rigid polyurethane foams; this yielded materials with mechanical resistance and a susceptibility to fungi in a wet environment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Nesse trabalho, as principais variáveis reológicas que influenciam o processo de impressão 3D do tipo Modelagem por deposição de fundido (FDM) foram parametrizadas. Para isso foram produzidas blendas poliméricas com dois polímeros com propriedades reológicas distintas sendo um deles amplamente utilizado no processamento por impressão FDM, o poli(etilenoglicol-co-ciclohexano-1,4-dimetanol tereftalato) (PETG) e o Surlyn 8940® um poli(etileno-co-ácido metacrílico estabilizado com íons sódio) (PE-co-AMA), que demonstra propriedades de autorreparo. Foram preparadas blendas com composição 30%, 50% e 70% em massa de PE-co-AMA. Filamentos foram produzidos em larga escala e possibilitaram a impressão de peças de alta qualidade e com elevadas propriedades mecânicas. As blendas produzidas foram caracterizadas de forma térmica, mecânica, morfológica, reológica e autorreparo. Danos criados nas blendas por indentadores ligados a técnicas de microdureza foram reparados seja parcialmente ou totalmente. As blendas obtidas foram identificadas como blendas imiscíveis e compatíveis, tendo sido relatadas de forma pioneira na literatura, encaixando-se como um produto inovador que poderá, além da impressão 3D FDM, ser usado em diversas aplicações. In this work, the main rheological variables that influence the 3D printing process, Fused Deposition Modeling (FDM), were be parameterized. For this, polymeric blends with two polymers with distinct rheological properties were prepared, one of them being widely used in FDM printing processing, poly(ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate) (PETG) and the other Surlyn 8940® a poly(sodium ion stabilized methacrylic acid co-acid) (PE-co-AMA), which has self-healing properties. New polymeric blends PETG / PE-co-AMA containing 30%, 50% and 70% by weight of PE-co-AMA were prepared. Filaments were prepared in a large scale with the blends and enabled a successful printing of high quality parts with high mechanical properties. The prepared blends were characterized by thermal, mechanical, morphological, rheological and self-healing tests. Damages created in the blends by an indentation derived from a microhardness test were partially or totally repaired. The obtained novel blends were identified as immiscible and compatible, and can be considered an innovative product that can, in addition to FDM 3D printing, be used in many applications.

No presente trabalho foram preparados onze distintos supercapacitores (nas configurações simétrica e assimétrica) contendo diferentes materiais ativos de eletrodos e eletrólitos do tipo ionogel. O principal foco da pesquisa foi a construção de dispositivos flexíveis que fornecessem altas capacitância e densidades de energia (superiores a 10 Wh.Kg-1), sem comprometimento da ciclabilidade, isto é, que operassem por um grande número de ciclos. As escolhas dos ionogéis foram feitas de modo a possibilitar a construção de supercapacitores (SCs) flexíveis. Foram avaliados três diferentes ionogéis, os quais foram preparados a partir da adição de líquidos iônicos (LIs) a matrizes de poli (liquidos iônicos) -PLIs. Três matrizes de PLIs e três diferentes LIs foram selecionados por possuírem o mesmo ânion e cátions parecidos, a fim de melhorar a compatibilidade desses compostos. Os ionogéis de concentração de 50% (em massa) de LI foram escolhidos por fornecer boas condutividades iônicas e janelas de potencial (2,5V), sem comprometimento da estabilidade mecânica dos géis, permitindo com isso a construção de SCs na configuração tipo sanduíche (eletrodo ¿ ionogel ¿ eletrodo), sem a necessidade de uso de separadores. Para o preparo do ionogel 1 foi usado o PLI [EPIm][FSI] e o LI [EMIm][FSI]. Já para o ionogel tipo 2, usou-se o PIL [EPIm][TFSI] e o LI [EMIm][TFSI]. Por sua vez, no ionogel tipo3, foram empregados o PLI [A2M2Am][TFSI] e o LI [MPPy][TFSI]. O ionogel tipo 1 foi o que forneceu maiores valores de condutividade iônica. Os ionogeis 1 e 2 exibiram aspecto gelationoso, proporcionando boa aderência aos materiais dos eletrodos e assim, possibilitando o preparo de SCs flexíveis. Em contrapartida, o ionogel 3, um filme de aspecto ceroso, promoveu o descolamento dos materiais do eletrodo dos coletores correntes, sendo portanto, inadequado para a construção de dispositivos flexíveis. Os materiais ativos dos eletrodos foram: (i) nanotubos de carbono de paredes múltiplas funcionalizados (f-MWCNT), (ii) óxidos de grafeno reduzido (r-GO) e (ii) nanocompósitos (r-GO:f-MWCNT), sendo estes dois últimos sintetizados via redução com hidrazina. A composição dos nanocompósitos baseou-se em dados da literatura que indicava que nesta concentração, os CNT atuariam como espaçadores entre as folhas de r-GO, proporcionando uma maior área superficial para a formação da dupla camada elétrica na interface eletrodo/eletrólito. Os SCs foram preparados com esses eletrodos na configuração simétrica, isto é, ambos os eletrodos de mesmo material e também assimétrica com eletrodos distintos (um eletrodo de r-GO e outro de f-MWCNT). Os dados da caracterização eletroquímica mostraram que o supercapacitor assimétrico (r-GO ¿ Ionogel 1 ¿ f-MWCNT) apresentou o melhor desempenho eletroquímico fornecendo altos valores de capacitância, densidade de energia e de potência, com pouco variação desses parâmetros ao longo de 2000 ciclos de operação. Neste trabalho, destaca-se duas contribuições inéditas importantes ao estado da arte de supercapacitores: (i) desenvolvimento de eletrólitos géis do tipo PLI/LI (ionogéis tipo 1 e 2) de alta aderência aos materiais do eletrodo (contribuindo para diminuição da resistência de contato) e (ii) descrição completa do comportamento dos diferentes supercapacitores sólidos e flexíveis desenvolvidos com determinação simultânea da voltagem das células e dos potenciais de cada eletrodo. In the present work, eleven different supercapacitors (in the symmetric and asymmetric configurations) were prepared containing different active materials for the electrodes and ionogel type electrolytes. Themain focus of the research was the construction of flexible devices that provide high capacitances and energy densities (greater than 10 Wh Kg-1), without compromising the cyclability. The ionogels choicewas made in order to allows the construction of flexible supercapacitors (SCs). Three different ionogels were evaluated, which were prepared with the addition of ionic liquids (ILs) to poly (ionic liquids) matrices - PILs. Three matrices of PILs and three ILs were selected to have the same anion and similar cations in order to improve the compatibility between these compounds. The ionogels with 50wt% of IL were chosen once they provide good ionic conductivities and potential windows (2.5V), withoutcompromising the mechanical stability of the gels, thus allowing the construction of SCs in the sandwich configuration (electrode|ionogel|electrode) without the need of separators. For the preparation of ionogel 1 the PIL [EPIm] [FSI] and the IL [EMIm] [FSI] were used. For type 2 ionogel, the PIL [EPIm] [TFSI] and the IL [EMIm] [TFSI] were employed. In the type 3 ionogel, the PIL [A2M2Am] [TFSI] and the IL[MPPy] [TFSI] were chosen. The type I ionogel provided the highest values of ionic conductivity. The ionogels 1 and 2 exhibited gelationous appearance, providing good adhesion to the electrode materialsand thus, making possible the preparation of flexible supercapacitors. In contrast, ionogel 3, a waxy-like film, promoted detachment of electrode materials from current collectors, and it is therefore unsuitablefor the construction of flexible devices. The active materials of the electrodes were: (i) functionalized multi-walled carbon nanotubes (f-MWCNT), (ii) reduced graphene oxides (r-GO) and (ii) nanocomposites (r-GO: f-MWCNT). The composition of the nanocomposites was based on data from the literature that indicates that in this concentration the CNTs would act as spacers between the sheets of rGO, providing a larger surface area for the formation of the electrical double layer in theelectrode/electrolyte interface. The supercapacitors were prepared with these electrodes in the symmetrical configuration, ie both electrodes of the same material, and also in the asymmetric one with different electrodes (one electrode of r-GO and another electrode of f-MWCNT. The electrochemical characterization data showed that the asymmetric supercapacitor (r-GO|Ionogel 1|f-MWCNT) presented the best electrochemical performance providing high capacitance, energy and power densities, with little variation of these parameters over 2000 operating cycles. In this work, two important new contributionsto the state of the art of supercapacitors are highlighted: (i) the development of gel electrolytes of type PIL/IL (ionogels types 1 and 2) with high adhesion to the electrode materials (decreasing the contactresistances) and (ii) complete description of the behavior of the different solid and flexible supercapacitors with simultaneous determination of the voltage of the cells and the potentials of each electrode.

Neste trabalho, foram sintetizados filmes de amido termoplástico (TPS) e blendas de TPS e polietileno de baixa densidade (PEBD), com uma metodologia de decoração para alterar o caráter hidrofílico exibido pela superfície do polímero biodegradável utilizado. Inicialmente foram processados os filmes de amido e as blendas com 25%, 50% e 75% de amido em peso com o polietileno de baixa densidade (PEBD). Em seguida, depositou-se micro/nanocomponentes nas superfícies destes substratos, como: espongilito, fibra de vidro, microesfera de vidro, microesferas de poliestireno 2- aminoetil (MPS) e nanofibras de policaprolactona (PCL) puro e com incorporação de sulfadiazina de prata (SULFA), dexametasona (DEXA), polianilina (PANI) e vidro bioativo. As deposições foram realizadas por aspersão de dispersões alcoólicas e por electrospinning. A caracterização dessas superfícies permitiu verificar a estruturação dos micro/nanocomponentes na superfície do material levando em consideração os modelos propostos para superfícies super-hidrofóbicas de Wenzel e Cassie/Baxter. A microscopia eletrônica de varredura (MEV), microscopia ótica (MO) e a microscopia de força atômica (AFM) foram utilizadas para visualizar a distribuição dos micro/nano componentes sobre as superfícies TPS/PEBD. Os processos de deposição, assim como os tipos de componentes depositados possibilitaram o controle do ângulo de contato dos substratos, com a obtenção de valores elevados de ângulo de contato (AC) e baixos valores de histerese de ângulo de contato, incluindo AC superiores a 150° e histereses do ângulo de contato menores que 10°. Assim sendo, provou-se que a superfície de polímeros biodegradáveis naturais e blendas polietileno/amido, que são intrinsicamente hidrofílicos, podem ter as características de suas superfícies alteradas via criação de padrões topográficos através da decoração com micro/nanocomponentes para gerar superfície hidrofóbicas e super-hidrofóbicas úteis para minimizar a absorção de água por estes materiais. In this research, films of thermoplastic starch (TPS) and blends of TPS/ LDPE (low density polyethylene) were prepared and had their surfaces decorated to alter the hydrophilic character of these biodegradable polymers. Initially, films of starch and blends with LDPE containing 25%, 50 % and 75 % of starch by weight were produced. Then, micro and nanocomponents were deposited on the surface of these substrates, such as: spongolite, short glass fibers, glass beads, polystyrene microspheres 2 - aminoethyl (MPS) and the polycaprolactone (PCL) nanofibers with silver sulfadiazine (SULFA), dexamethasone (DEXA), polyaniline (PANI) and bioactive glass nanoparticles. The deposition processes were performed by aspersion of alcoholic dispersions and electrospinning. The characterization of the prepared surfaces were done to show the structure of micro / nano components on the surface of the material taking into account the proposed models for superhydrophobic surfaces by Wenzel and Cassie/Baxter. Scanning electron microscopy (SEM), optical microscopy and atomic force microscopy (AFM) were able to visualize the distribution of micro / nano components on the surfaces of TPS/LDPE. The deposition processes as well as the types of components enabled the manipulation of the contact angle of the substrates. High values of contact angle (AC) and low values of contact angle hysteresis were measured for the modified surfaces, including AC higher than 150° and hysteresis lower than 10°. Therefore, it was proved that the intrinsically hydrophilic surfaces of biodegradable natural polymers can be altered by creating topographical patterns through the decoration with nano/microcomponents to generate hydrophobic and even superhydrophobic features that can be useful in minimizing the water absorption of these materials.

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

Nesta tese de doutorado, nanocristais de celulose (NCCs), preparados a partir de polpa de eucalipto, foram utilizados como material de reforço em bionanocompósitos poliméricos com o biopolímero quitosana e na preparação de nanoestruturas de carbono, através de pirólise controlada. As nanoestruturas de carbono obtidas foram usadas para modificar a superfície de vermiculita expandida (VE). Os NCCs foram obtidos por meio da hidrólise da polpa de eucalipto com H2SO4 e caracterizados com diferentes técnicas incluindo MET, DRX, FT-IR e titulação potenciométrica. Os NCCs obtidos apresentaram em média 145+-25 nm de comprimento e 6+-1,5 nm de diâmetro e uma superfície negativamente carregada, com 141mmol.Kg-1 de grupos funcionais ácidos na superfície dos nanocristais.Para preparação dos bionanocompósitos de quitosana com NCCs foram utilizadas três diferentes estratégias. Primeiro, os bionanocompósitos de quitosana com NCCs foram preparados utilizando o método de evaporação do solvente. O efeito da incorporação dos NCCs nas propriedades mecânicas, térmicas e de capacidade de absorção de água dos filmes dos nanocompósitos com diferentes concentrações de NCCs foram avaliados. Foi verificado que os NCCs encontram-se uniformemente dispersos na matriz interagindo fortemente com as cadeias poliméricas da quitosana. Essas interações fortes resultaram em melhorias de até 160% no módulo de elasticidade, 115% na resistência a tração e numa diminuição significativa da capacidade de absorção de água do biopolímero. Nos bionanocompósitos obtidos através da ligação química entre os NCCs e a quitosana foram observadas propriedades mecânicas semelhantes às observadas para os materiais preparados com NCCs não funcionalizados. No entanto, neste compósito, a diminuição da capacidade de absorção de água foi consideravelmente maior que a observada no material obtido pela simples incorporação de NCCs no biopolímero. A técnica de deposição camada por camada foi também utilizada para preparação de filmes finos de bionanocompósitos QT/NCCs. Verificou-se, com a espectroscopia UV-Vis, um crescimento linear dos filmes com os ciclos de imersão, e, em cada ciclo mediu-se uma deposição de 14,7 mg.m-2 de quitosana. Essa massa de quitosana depositada, mais a camada de NCC formaram uma bicamada (QT+NCC) de 7 nm de espessura. Além disso, imagens obtidas com MEV mostraram que a superfície dos filmes apresentam uma morfologia porosa tipo ¿espaguete¿ sendo caracterizada, por microscopia de força atômica (MFA), como relativamente suave com um valor de rugosidade médio menor que 11 nm para um filme de 20 bicamadas. Os NCCs foram também utilizados na preparação de nanoestruturas de carbono por meio de pirólise em diferentes temperaturas. Foi verificado que as diferentes temperaturas de pirólise modificam profundamente as características do carbono obtido. Com a pirólise a 300ºC tem-se uma carbonização incompleta, entretanto foi possível identificar através da MET-AR a presença de estruturas tubulares com ordenamento grafítico. Com o aumento da temperatura de pirólise para 600 e 900ºC, as estruturas tubulares desaparecem e outras, constituídas de carbono amorfo e carbono grafítico, com morfologia esférica e oval predominam. Além disso, há um significativo aumento na área específica e volume de micro e mesoporos com a elevação da temperatura de pirólise. Os materiais obtidos foram então utilizados na adsorção de bisfenol A. A amostra de NCC pirolisada a 900°C (CANCC900) apresentou uma significativa afinidade pela molécula do bisfenol A, apresentando uma capacidade de adsorção rápida e alta. A capacidade máxima de adsorção, obtida com o ajuste dos dados pela isoterma de Langmuir, foi de 1029 mgg-1. Essa alta capacidade de adsorção foi atribuída à maior área superficial e também a maior acessibilidade à superfície, proporcionada pelo significativo montante de mesoporos. Finalmente, os NCCs foram dispersos e depositados sobre a superfície de vermiculitas expandidas através do simples controle dos ciclos de imersão. A deposição de NCCs sobre a superfície da vermiculita foi confirmada por FTIR e TG. Posteriormente, as vermiculitas recobertas com NCC foram pirolisados a 900ºC para a formação de uma camada superficial de carbono nanoestruturado amorfo e grafítico. A presença desta camada de carbono modificou significativamente a morfologia da superfície, assim como o seu caráter hidrofóbico/hidrofílico aumentado a capacidade de absorção de óleo vegetal e de motor em 250 e 100%, respectivamente, em relação à VE In this work, cellulose nanocrystals (CNCs) were prepared from eucalyptus cellulose pulp and were used as reinforcement material for chitosan biopolymer (CH). In addition, the CNCs were used to form carbon nanostructures through controlled pyrolysis and the carbon nanostructures obtained were use to modify the surface of expanded vermiculite clay (EV). The CNCs were obtained by hydrolysis of eucalyptus cellulose pulp using H2SO4 and characterized with different techniques including TEM, XRD, FT-IR and potentiometric titration. The length and diameter of the CNWs were characterized as being 145 25 nm and 6 1.5 nm, respectively. Potentiometric titration gave 141 mmol.kg-1 of sulfates groups on the whiskers surface. In order to prepare the chitosan/CNCs bionanocomposites, three different strategies were used. Firstly, chitosan/CNCs were prepared using the simple casting method. The effect of different concentrations of CNCs on the mechanical and thermal properties and water absorption capacity of the films were evaluated. It was found that the CNCs were uniformly dispersed throughout the matrix, interacting strongly with the polymer chains of chitosan. These interactions resulted in a strong improvement in the tensile modulus (up to 160%) and in the tensile strength (up to 115%). Also, a significant decrease in water absorption capacity of the biopolymer was measured. The second approach was the preparation of bio-based nanocomposite through covalent linkage between CH and CNCs. These nanocomposites showed similar mechanical properties compared to those observed for materials prepared from the simple casting method. On the other hand, the water resistance properties were considerably enhanced for the CH-graft-CNCs relative to those systems obtained from the casting method. Finally the layer-by-layer (LBL) technique was also used to prepare thin films of chitosan/NCCs. The film growth was followed by UV-vis spectroscopy and showed the deposition of 14.7 mgm-2 of chitosan polymer in each cycle. Scanning electron microscopy showed high density and homogeneous distribution of CNCs adsorbed on each chitosan layer. Cross section characterization of the assembled films indicates an average of ~ 7 nm of thickness per bilayer. The surface of the film also shows a morphology made by laterally aggregated nanowhiskers generating a morphology which looks like a bundle of spaghetti-like fibers. The film surface was also characterized by AFM and showed a relatively smooth surface having the roughness values lower than 11 nm for a film of 140nm. The NCCs were also used in the preparation of carbon nanostructures by pyrolysis at different temperatures. It was found that different pyrolysis temperatures deeply modify the characteristics of the carbon obtained. With the pyrolysis at 300 °C, the CNCs presented an incomplete carbonization, but this sample showed (using HR-TEM) the presence of tubular structures with graphitic order.With increasing pyrolysis temperature to 600 and 900 °C, the tubular structures disappear, and other carbon nanostructures take place, mainly spherical nanoparticles, consisting of amorphous and graphitic carbon. In addition, it was observed a significant increase in specific surface area and volume of micro-and mesopores with increasing temperature of pyrolysis. The materials were then used in the adsorption of bisphenol A. The sample obtained at 900°C (CANCC900) showed a significant affinity for bisphenol A moieties, showing a rapid and high adsorption capacity. The maximum adsorption capacity obtained from the fitting data of the Langmuir isotherm was 1029 mgg-1. This high adsorption capacity was attributed to large surface area and also due to the great accessibility to the surface by the significant amount of mesopores. Finally, the NCCs were dispersed on the expanded vermiculite surface (EV) through the simple control of dipping cycles. The deposition of the NCCs on the surface of the vermiculite was confirmed by FTIR and TG. Subsequently, the composites CNCs/EV were pyrolyzed at 900 °C to form a surface layer of amorphous and nanostructured graphitic carbon. The presence of these carbon nanostructures on the EV surface produced a hydrophobic character on the vermiculite surface and strongly increased the oil absorption capacity for soy bean and engine oil