This research presents a critical evaluation of chitin- and chitosan-based materials as innovative treatment alternatives for water contaminated with insensitive munitions (IMs) compounds. Specifically, chitin, chitosan, amineunctionalized chitin (AFC) were evaluated for adsorptive removal of these compounds. Cellulose and cellulose triacetate were evaluated for adsorptive performance for comparison. Chitosan-graphene oxide (CSGO) composite membranes were evaluated for removal via adsorption and filtration and compared against nanofiltration and reverse osmosis membranes in the current market. Insensitive munitions evaluated include nitrotriazolone (NTO), nitroguanidine (NQ), and 2,4-dinitroanisole (DNAN); 2,4,6-trinitrotoluene (TNT) was also studied as a traditional munition for comparison. AFC is an effective adsorbent for NTO, DNAN, and TNT. Cellulose triacetate was the only commercially available biopolymer adsorbent effective at removing munitions compounds from solution; only DNAN and TNT were removed. CSGO membranes effectively removed NTO, DNAN, and TNT, but removal performance degraded with time. Overall, this research shows that the materials studied are viable options for removing IM and traditional munitions from water.

In this study, surface plasmon resonance (SPR) and quartz crystal microbalance with dissipation monitoring (QCM-D) were combined to investigate the adsorption behavior of two platelet adhesion-related blood proteins, human serum albumin (HSA) and human serum fibrinogen (HSF), on two polysaccharide materials used for hemodialysis membrane applications: regenerated cellulose and cellulose acetate. The study aims to provide insight into the design of novel hemocompatible polysaccharide materials. Information such as real-time adsorption curves, adsorbed amounts, and water contents of the protein layers were obtained and analyzed. The results suggested 1) monolayer adsorption of HSA on both cellulose and cellulose acetate, possibly with different HSA conformations; 2) a multilayer of HSF or some degree of end-on adsorption on both surfaces. The study of HSA adsorption onto cellulose acetate surfaces with different degrees of substitution indicated that the change in content of acetyl groups may not be the main factor governing the adsorbed HSA amount but may affect the conformation of adsorbed HSA molecules. / Master of Science

The objective of this thesis was to further develop the polymer composite system consisting of cellulose acetate butyrate (CAB) and high modulus, continuous, regenerated cellulose fiber (lyocell). Of particular concern were both the interfacial adhesion between the fiber and matrix and the consolidation process in the manufacture of these composite materials. Interfacial adhesion was found to be substantial due to the relative lack of the fiber pull-out phenomenon observed after tensile failure in the unmodified fiber composites. This result was then supported in the second study in which similar unmodified fiber composites experienced very little fiber pull out with evidence of a large amount of cohesive failure of the matrix accompanied by matrix particles adhering to the fiber surfaces. Void volume formation was mitigated to a small extent by the use of optimal consolidation conditions. Composites formed at moderate temperature (200 °C), low consolidation pressure (11.8 p.s.i.) and high consolidation time (13 min.) were found to have the lowest void volume formation of ca. 2.8 %. These composites were generally found to have the highest interfacial shear strength, ca. 16 MPa. A tensile modulus of 22 GPa and an ultimate strength of 246 MPa was obtained for this composite having a fiber volume content of ca. 62 %. / Master of Science

Made available in DSpace on 2016-06-02T19:19:54Z (GMT). No. of bitstreams: 1 DANTAS_Patricia_2011.pdf: 2256820 bytes, checksum: e36b1fbb6b7a53c4ba196910208d1dd3 (MD5) Previous issue date: 2011-12-16 / Financiadora de Estudos e Projetos / Hydrogels derived from cellulose acetate propionate (CAP) and cellulose acetate (CA) were synthesized with the cross-linking agents PMDA (Pyromellitic Dianhydride) and BTDA (Dianhydride 3, 3 ', 4, 4' Benzophenone Tetracarboxylated) with 3:1 stoichiometry in relation to the mass of the crosslinker agent x mass of available hydroxyls in the polymer chain. The gels were obtained in the form of films and particles, the raw materials were characterized with Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Spectroscopy in Region of Fourier Transform Infrared (FTIR) and in relation to the degree of substitution (GS). The gels synthesized were characterized using FTIR techniques in order to show the esterification, TGA and DSC to perform comparative analysis and study of thermal properties between the CAP and CA reagents and gels, and Scanning Electron Microscopy (SEM) were used for observation of the gels synthesized and the geometry of the particles obtained, the porosity of observation and observation of surface changes, was performed to determine the crosslinking density of the second theory of Flory Rehner, study the density of the gels, and degree of swelling of the study best solvent for swelling of the gels. Gels derived from CAP were tested in the adsorption studies and controlled release of the herbicide paraquat. For the phenomenon of controlled release, we studied the phenomena of transport and release curves. The release profiles were studied by using the mathematical model published by Korsmeyer-Peppas and the mainly results has showed that model was appropriated for process data analysis of controlled release in long periods. / Hidrogéis derivados de Propionato Acetato de Celulose (CAP) e Acetato de Celulose (CA) foram sintetizados com os agentes reticuladores PMDA (Dianidrido Piromelítico) e BTDA (Dianidrido 3, 3´, 4, 4´ Benzofenona Tetracarboxílico), com estequiometrias 3:1 em relação à massa do agente reticulador x massa de hidroxilas disponíveis na cadeia polimérica, com obtenção de géis em formato de filmes e particulados; as matérias-primas foram caracterizadas com Análise Termogravimétrica (TGA), Calorimetria Diferencial de Varredura (DSC), Espectroscopia na Região do Infravermelho com Transformada de Fourier (FTIR) e em relação ao Grau de Substituição (GS). Os géis sintetizados foram caracterizados utilizando as técnicas de FTIR, para evidenciação da esterificação; TGA e DSC para realização de análise comparativa e estudo das propriedades térmicas entre os reagentes CAP e CA e os géis obtidos; e Microscopia Eletrônica de Varredura (MEV), utilizada para observação dos géis sintetizados em relação à geometria das partículas obtidas, observação da porosidade e observação de alterações superficiais; foi realizada a determinação da densidade de ligações cruzadas segundo a Teoria de Flory Rehner; estudo da densidade dos géis, que variaram de 0,4 a 1,51 g/cm3; grau de inchamento que obteve variações entre os diferentes géis de 6,53 à 11,8; e o estudo do melhor solvente para intumescimento dos géis. Nos géis derivados de CAP, foram realizados ensaios de adsorção e liberação controlada do herbicida Paraquat. Para o fenômeno de liberação controlada, foram estudados os fenômenos de transporte e as curvas de liberação; os perfis de liberação foram estudados pelo modelo matemático de Korsmeyer-Peppas; e apresentaram como o gel com maior porcentagem de adsorção e melhor potencial para liberação controlada por longos períodos o gel CAP 3B1.

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2009. / The study concerns the use of the electrospinning technique for the formation of cellulose acetate hollow nanofibers. These hollow fibers are used to manufacture hollow fiber membranes. Important properties that should be inherent to these hollow-nanofibers include excellent permeability and separation characteristics, and long useful life. They have potential applications in filtration, reverse osmosis, and the separation of liquids and gases. It is apparent from the available literature on electrospinning and co-electrospinning that the diameter and the morphology of the resulting fibers are significantly influenced by variations in the system and process parameters, which include the solution concentration, solvent volatility, solution viscosity, surface tension and the conductivity of the spinning solution. The materials used include cellulose acetate (CA) (concentration = 11~14 wt %), (feed rate = 1~3 ml/h), acetone:dioxane (2:1) and mineral oil (feed rate = 0.5~1 ml/h) with core and shell linear velocity of 2 and 0.7 mm/min respectively. These materials were used as received without further purification. The co-electrospinning setup used comprised a compound spinneret, consisting of two concentric small-diameter capillary tubes/needles, one located inside another (core-shell/co-axial design). The internal and external diameters of the inside and outside needles were 0.3 and 1.2 mm respectively (0.3 mm shell/core gap space). The liquids CA (shell) and mineral oil (core) are pumped to the coaxial needle by a syringe pump, forming a compound droplet at the tip of the needle. A high voltage source is used to apply a potential of several kilovolts over the electrospinning distance. One electrode is placed into the spinning solution and the other oppositely charged (or neutral) electrode attached to a conductive collector. If the charge build up reaches approximately 15 kV the charged compound droplet, (poorly conductive polymer solution) deforms into a conical structure called a Taylor cone. On further increasing, the charge at the Taylor cone to some critical value (unique to each polymer system) the surface tension of the compound Taylor cone is broken and a core-shell jet of polymer solution ejects from the apex of the Taylor cone. This jet is linear over a small distance, and then deviates in a course of violent whipping from bending instabilities brought about by repulsive charges existing along the jet length. The core-shell jet is stretched and solvent is evaporated and expelled, resulting in the thinning and alignment of the fiber. Ultimately dry (most solvent having been removed) submicron fibers are collected in alignment form in a simple collector design (water bath). The shell to core solution flow rate ratio was chosen according to the parameter response of shell-core diameter of the resulting fibers in order to achieve an optimal hollow structure after removal of the mineral oil core. The mineral oil of the dry collected core-shell fibers is removed by immersion in octane. The aforementioned response is determined by measurement of core-shell diameters using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained results showed that the ability of the spinning solution to be electrospun was directly dependent on its concentration and the feed rate of the spinning solution and also parameters such as the spinning distance and type of solvents used. The preferable polymer solution concentration is 14 wt %, shell feed rate of 3 ml/hr, core feed rate of 0.5 ml/hr (2 and 0.7 mm/s core and shell linear velocity respectively), applied voltage of 15 KV, spinning distance of 8 cm and coaxial spinnerets having internal diameters of 0.3 mm and 1.2 mm core and shell needles respectively (0.3 mm shell/core gap space) have been found to make uniform cellulose acetate hollow fibers with an average inside and outside diameter of approximately 495 and 1266 nm, respectively.

The mechanisms of the deterioration of cellulose acetate compounded with triphenyl phosphate were investigated. A key peak shift of 726cm⁻¹ to 718cm⁻¹ in the Raman spectrum of triphenyl phosphate (726cm-1 uncompounded) when compounded in cellulose acetate (718cm⁻¹) was tied to the action of C-O bonds in triphenyl phosphate. The molecular bonds responsible for the 726cm⁻¹ peak were identified by collecting and examining spectra of chemicals with functional groups similar to triphenyl phosphate. Initially it was hypothesized that triphenyl phosphate acts as nucleophilic catalyst of deacetylation. This mechanism was evaluated by dissolving triphenyl phosphate in solvents that served as functional group analogues of cellulose acetate. These liquid-solution systems have a faster rate of reaction and complete mixing with triphenyl phosphate compared with what is seen in cellulose acetate solid-solution systems. The results of the cellulose acetate analogue experiments did not support the hypothesis of triphenyl phosphate acting as a nucleophilic catalyst of deacetylation. The results instead support a new theory of deterioration induced by the recrystallization of triphenyl phosphate. Additionally, the prevailing theory of triphenyl phosphate induced deterioration as proposed by Shinagawa et al. in 1992 was reviewed. The experiments conducted here do not support Shinagawa's theory.

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No. of bitstreams: 1 PDF - João Paulo Tavares Malheiro.pdf: 2553515 bytes, checksum: 47c2d0425241d35a5f696b608aae504e (MD5) Previous issue date: 2014-06-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The application of polymers in modified release of drugs is already a reality in the pharmaceutical field. The polymers obtained from plants, especially cellulosic derivatives, are among the most used in the production of new release systems groups and the origin of the raw material, a critical factor in the quality and the final properties of polymer and systems. This work aimed to produce and characterize cellulose acetate extracted from cactus pear and apply it to modified release of drugs. The botanical collection and identification of Opuntia ficus-indica L. Miller was held at National Institute for the Semiarid. The plant was dried, pulverized and subjected to successive chemical treatments for obtain/pulp and purification production of acetylated derivative. The extraction yield of cellulose by the method adopted was 8,41%. The polymer and the acetylated derivative were characterized by Spectroscopies of Nuclear Magnetic Resonance (NMR) and Forrier Infrared (FTIR), Scanning Electron Microscopy with energy dispersive (SEM-XRD), and analytical techniques, analyses which confirmed their identities and quality. The microparticles were produced by emulsification / solvent evaporation, presenting itself as spherical structures, in micrometer range (2-7μm), with roughness on the surface and the presence of small pores. The method of quantification by spectrophotometry of sodium diclofenac (drug model) has been validated, being considered: linear, selective, exact and precise, according to requirement of RE. 899/2003. obtained approximately 57% of sodium diclofenac encapsulated in the system, with release maintained constant the concentration percentage average of 57-62% in the range of 8-64hs. it is therefore concluded that the cellulose acetate obtained from forage palm presented excellent technological properties for application in the production of micro-particles with good results on the drug release kinetics model and favourable prospects for future applications of other drugs in this system, adding even greater value to cactus pear culture. / A aplicação de polímeros na liberação modificada de fármacos já é uma realidade no campo farmacêutico. Os polímeros obtidos a partir de plantas, com destaque para os derivados celulósicos, estão entre os grupos mais utilizados na produção dos novos sistemas de liberação, sendo a origem da matéria prima, um fator crítico na qualidade e nas propriedades finais do polímero e do sistema. Este trabalho teve como objetivo produzir e caracterizar acetato de celulose a partir da celulose extraída da palma forrageira, e aplicá-lo para liberação modificada de fármacos . A coleta e identificação botânica da Opuntia ficus-indica L. Miller foi realizada no INSA. A planta foi seca, pulverizada e submetida a tratamentos químicos sucessivos para obtenção/ purificação da celulose e produção do derivado acetilado. O rendimento da extração da celulose pelo método adotado foi de 8,41%. O polímero e o derivado acetilado foram caracterizados por Espectroscopias de Ressonância Magnética Nuclear (RMN) e de Infravermelho com Transformada de Fourrier (FTIR), Microscopia Eletrônica de Varredura com sonda de Energia Dispersiva de Rios-X (MEV-EDS), Difração de Raios-X (DRX) e técnicas analíticas, análises que confirmaram suas identidades e qualidade. As micropartículas foram produzidas por emulsificação/evaporação de solvente, apresentando-se como estruturas esféricas, em escala micrométrica (2-7μm), com rugosidades na superfície e presença de pequenos poros. O método de quantificação por espectrofotometria do diclofenaco de sódio (fármaco modelo) foi validado, sendo considerado: linear, seletivo, exato e preciso, segundo as exigências da RE. 899 / 2003. Obteve-se cerca de 57% de diclofenaco de sódio encapsulado no sistema, com liberação mantida relativamente constante na concentração percentual média de 57-62% no intervalo de 8-64hs. Conclui-se, portanto, que o acetato de celulose obtido da palma forrageira apresentou excelentes propriedades tecnológicas para aplicação na produção de micropartículas, com bons resultados na cinética de liberação do fármaco modelo e com perspectivas favoráveis à aplicações futuras de outros fármacos neste sistema, agregando ainda maior valor a cultura da palma forrageira.

Pensando em um melhor aproveitamento para o excedente do bagaço de cana, esse trabalho tem como objetivo a obtenção de membranas de acetato de celulose composta com ligninas oxidadas, ambos isolados do bagaço da cana. Para tal, os componentes macromoleculares do bagaço foram separados, aplicando-se um pré-tratamento de explosão a vapor para retirada da parte hemicelulósica e um tratamento com hidróxido de sódio para a separação da lignina e obtenção da polpa bruta de celulose. Essa polpa foi branqueada e acetilada e, posteriormente, foram sintetizadas membranas deste acetato de celulose, incorporando-se lignina oxidada a estas membranas com o objetivo de aumentar a capacidade de retenção de metais destas membranas. Assim, pretende-se obter um produto com maior valor comercial, que tem aplicações em tratamento de água e efluentes, podendo contribuir ainda mais para a manutenção do ambiente. As membranas foram sintetizadas por inversão de fase, utilizando dois métodos distintos: I. por evaporaçãoprecipitação e, II. por imersão em banho de coagulação. O material acetilado foi analisado por IR, confirmando-se a acetilação pelo aparecimento de bandas características do acetato e analisadas quanto ao grau de substituição, caracterizando um diacetato. As membranas sintetizadas pelo método I foram analisadas por MEV, constatando-se membranas de estrutura densa para todas as composições, e mais rígidas que uma membrana preparada a partir de um triacetato comercial, de acordo com os dados da análise dinâmico-mecânica. Foram realizados ainda, testes de permeabilidade e retenção de cobre. Apesar de rígidas, resistiram a pressões de até 20 bar. A membrana aditivada com lignina oxidada por lacase foi a que apresentou melhor desempenho nesse teste, atingindo maior fluxo necessitando menor pressão. No teste de retenção de cobre, apresentaram uma capacidade média de 15%, correspondendo a 50,5 mg Cu2+/g lignina. As membranas sintetizadas pelo método II foram analisadas por MEV, constatando-se diferenças na morfologia quando a lignina é adicionada dissolvida em NaOH. As análises térmicas mostraram a Tg do material perto de 80°C, além de evidenciar uma maior estabilidade térmica do material aditivado com lignina oxidada, comparado ao material sem lignina e com lignina original. No teste de permeabilidade, realizado aqui à pressão constante de 10 bar, a membrana sintetizada apenas com o acetato de celulose de bagaço de cana não apresentou fluxo. As membranas aditivadas com lignina original e lignina oxidada apresentaram fluxo, de 3,5 e 6,1 L/h.m2 respectivamente. O fato foi atribuído à morfologia das membranas, dado que as duas últimas, que apresentaram fluxo, possuem estrutura porosa, enquanto a outra possui estrutura densa. No teste de retenção de cobre, foi possível visualizar o efeito da adição da lignina na membrana, que aumenta 3,5 vezes a capacidade de retenção de cobre e, ainda, o efeito da oxidação da lignina, que aumenta em mais 50 % essa capacidade de retenção em comparação à adição apenas da lignina original. Contudo, os resultados indicam que as membranas sintetizadas, principalmente as membranas aditivadas com lignina oxidada, são promissoras para o objetivo proposto. / Thinking of a better use for the surplus of sugarcane bagasse, this study aims to obtain membranes of cellulose acetate composite with oxidized lignins, both isolated from sugarcane bagasse. To this purpose, the macromolecular components of bagasse were separated by applying a steam explosion pre-treatment for removal of hemicellulose and a treatment with sodium hydroxide to separate the lignin and obtaining of crude cellulose pulp. This pulp was bleached and acetylated, and subsequently cellulose acetate membranes were synthesized incorporating oxidized lignin in these membranes in order to increase the metal retention capacity of them. Thus, we intend to obtain a product with higher commercial value, which has applications in water and effluent treatment, which can further contribute to the maintenance of the environment. The membranes were synthesized by phase inversion, using two different methods: I. evaporation-precipitation and II. immersion in coagulation bath. The acetylated material was analyzed by FTIR, confirming the acetylation by the appearance of bands characteristic of acetate and analyzed for degree of substitution, featuring a diacetate. The membranes synthesized by method I were analyzed by SEM, verifying dense structure for the membranes in all compositions, and more rigid than a membrane prepared from a commercial triacetate, according to the data of dynamic mechanical analysis. Tests about permeability and copper retention also were done. Although rigid, they resisted to pressures up to 20 bar. The membrane added with lignin oxidized by laccase showed the best performance in this test, reaching higher flow requiring less pressure. In the test of copper retention, they showed an average retention capacity of 15%, corresponding to 50.5 mg Cu2+/ g lignin. The membranes synthesized by method II were analyzed by SEM, noting differences in morphology when the lignin is added dissolved in NaOH. Thermal analysis showed the Tg of the material near 80 °C, besides showing a higher thermal stability of the material added with oxidized lignin compared to material without lignin and with original lignin. In the permeability test, held at constant pressure of 10 bar, the membrane synthesized with only cellulose acetate cane bagasse showed no flow. The membranes added with original lignin and oxidized lignin showed flow of 3.5 and 6.1 L/h.m2, respectively. The fact was attributed to the morphology of the membranes, since the two latter, which showed flow, have porous structure, while the other has a dense structure. In the test of copper retention, it was possible to visualize the effect of the addition of lignin in the membrane, which increases 3.5 times the cupper retention capacity and, the effect of lignin oxidation, with increases in more 50% this retention capacity in comparison to the addition of the lignin in the original form. However, the results indicate that the synthesized membranes, mainly membranes added with oxidized lignin, are promising for the proposed objective.

Submitted by Cátia Araújo (catia.araujo@unipampa.edu.br) on 2017-01-25T12:43:50Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Efeito inibidor do tungstato de sódio e da amoxicilina em solução e em filmes de acetato de celulose na corrosão da liga de aço-carbono AISI 1020 em NaCl 0,05 molL.pdf: 3082976 bytes, checksum: 0cd5a0b855088834038b5aff2432de07 (MD5) / Approved for entry into archive by Cátia Araújo (catia.araujo@unipampa.edu.br) on 2017-01-25T12:44:16Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Efeito inibidor do tungstato de sódio e da amoxicilina em solução e em filmes de acetato de celulose na corrosão da liga de aço-carbono AISI 1020 em NaCl 0,05 molL.pdf: 3082976 bytes, checksum: 0cd5a0b855088834038b5aff2432de07 (MD5) / Made available in DSpace on 2017-01-25T12:44:16Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Efeito inibidor do tungstato de sódio e da amoxicilina em solução e em filmes de acetato de celulose na corrosão da liga de aço-carbono AISI 1020 em NaCl 0,05 molL.pdf: 3082976 bytes, checksum: 0cd5a0b855088834038b5aff2432de07 (MD5) Previous issue date: 2014-02-21 / Este trabalho teve por objetivo avaliar o tungstato de sódio (Na2WO4) e a amoxicilina como inibidores de corrosão para a liga de aço-carbono AISI 1020 adicionados a um meio contendo 0,05 mol/L de Cloreto de Sódio (NaCl). Além disso, avaliar o efeito desses inibidores quando inseridos em um filme de acetato de celulose. O estudo compreendeu a exposição do metal no meio proposto, na ausência e presença de 0,005, 0,01 e 0,07 mol/L de Na2WO4, e/ou 1000, 2000 e 3000 ppm de amoxicilina inseridos ou não em filmes de 5% e 10% de acetato de celulose. Foram empregadas técnicas eletroquímicas de monitoramento do potencial de circuito aberto (PCA), espectroscopia de impedância eletroquímica (EIE) e polarização anódica. Todos os experimentos foram realizados à temperatura ambiente e em meio aerado. Quanto aos objetivos propostos pode-se concluir que: 1) As medidas de PCA para as diferentes concentrações de Na2WO4, apresentaram deslocamento dos potenciais (E) para valores mais positivos durante os 7 dias de imersão no NaCl, principalmente para 0,07 mo/L de Na2WO4, com E = - 0,407 V no 7º dia, indicando um comportamento inibidor. Para as diferentes concentrações de amoxicilina os valores de potencial não apresentaram variação tão significativa, em 1000 ppm de amoxicilina o E = - 0,560 V no 7º dia. Quando inserida a amoxicilina ao WO4-2, as concentrações melhores foram para 1000, 2000 e 3000 ppm de amoxicilina inserida em 0,07 mol/L Na2WO4, obtendo-se ao 7º dia de imersão valores respectivamente de E = - 0,380 V, E = -0,400 V e E = -,0370 V. Já para os revestimentos a base de acetato de celulose, não apresentaram valores de potencial significativos, ficando entorno de E = -0,645 V ao 7º dia. Quando inserido 2000 ppm amoxicilina e 0,07 mol/L de Na2WO4 ao filme 5 %, continuou estável ao deslocamento do potencial, 2) Por EIE demostrou-se que para 0,07 mol/L de Na2WO4 os valores de resistência aumentaram significativamente do que os demais inibidores, 3) E as curvas de polarização anódica, mostraram que para 0,07 mol/L de Na2WO4 o potencial de rompimento de filme (ERP) possuiu valores mais positivo, ERP = +0,07 V quando comparados com os demais inibidores. / This study aimed to evaluate the sodium tungstate (Na2WO4) and amoxicillin as corrosion inhibitors for carbon steel alloy AISI 1020 added to a medium containing 0.05 mol/L sodium chloride (NaCl). Moreover, to evaluate the effect of these inhibitors when inserted in a film of cellulose acetate. The study consisted of exposing the metal in the proposed environment, in the absence and presence of 0.005, 0.01 and 0.07 mol/L of Na2WO4 and/or 1000, 2000 and 3000 ppm of amoxicillin or not inserted into films 5 % and 10 % cellulose acetate. Electrochemical techniques for monitoring the open circuit potential (PCO), electrochemical impedance spectroscopy (EIS) and anodic polarization were employed. All experiments were performed at room temperature and aerated environment. As for the proposed objectives can be concluded that: 1) PCO measures for the different concentrations of Na2WO4 showed displacement of the potential (E) towards more positive values during the 7 days of immersion in NaCl mainly to 0.07 mol/L Na2WO4 with E = - 0.407 V on day 7, indicating an inhibitory behavior. For different concentrations of amoxicillin potential values showed no significant variation as in 1000 ppm of amoxicillin E = - 0.560 V on the 7th day. When inserted amoxicillin to WO4-2 concentrations were the best for 1000, 2000 and 3000 ppm of amoxicillin inserted in 0.07 mol/L Na2WO4 obtaining the 7th day of immersion values respectively E = - 0.380 V, E = -0.400 V and E = - 0370 V. As for the coatings based on cellulose acetate showed no significant potential values, getting around E = -0.645 V to day 7. When inserted amoxicillin 2000 ppm and 0.07 mol/L of Na2WO4 the film 5 % remained stable potential shift, 2) It is demonstrated that EIS to 0.07 mol/L of Na2WO4 resistance values increased significantly than other inhibitors, 3) and the anodic polarization curves showed that for 0.07 mol/L of the Na2WO4 potential breakup film (ERP) possessed more positive values, ERP = +0.07 V when compared with the other inhibitors.

Pensando em um melhor aproveitamento para o excedente do bagaço de cana, esse trabalho tem como objetivo a obtenção de membranas de acetato de celulose composta com ligninas oxidadas, ambos isolados do bagaço da cana. Para tal, os componentes macromoleculares do bagaço foram separados, aplicando-se um pré-tratamento de explosão a vapor para retirada da parte hemicelulósica e um tratamento com hidróxido de sódio para a separação da lignina e obtenção da polpa bruta de celulose. Essa polpa foi branqueada e acetilada e, posteriormente, foram sintetizadas membranas deste acetato de celulose, incorporando-se lignina oxidada a estas membranas com o objetivo de aumentar a capacidade de retenção de metais destas membranas. Assim, pretende-se obter um produto com maior valor comercial, que tem aplicações em tratamento de água e efluentes, podendo contribuir ainda mais para a manutenção do ambiente. As membranas foram sintetizadas por inversão de fase, utilizando dois métodos distintos: I. por evaporaçãoprecipitação e, II. por imersão em banho de coagulação. O material acetilado foi analisado por IR, confirmando-se a acetilação pelo aparecimento de bandas características do acetato e analisadas quanto ao grau de substituição, caracterizando um diacetato. As membranas sintetizadas pelo método I foram analisadas por MEV, constatando-se membranas de estrutura densa para todas as composições, e mais rígidas que uma membrana preparada a partir de um triacetato comercial, de acordo com os dados da análise dinâmico-mecânica. Foram realizados ainda, testes de permeabilidade e retenção de cobre. Apesar de rígidas, resistiram a pressões de até 20 bar. A membrana aditivada com lignina oxidada por lacase foi a que apresentou melhor desempenho nesse teste, atingindo maior fluxo necessitando menor pressão. No teste de retenção de cobre, apresentaram uma capacidade média de 15%, correspondendo a 50,5 mg Cu2+/g lignina. As membranas sintetizadas pelo método II foram analisadas por MEV, constatando-se diferenças na morfologia quando a lignina é adicionada dissolvida em NaOH. As análises térmicas mostraram a Tg do material perto de 80°C, além de evidenciar uma maior estabilidade térmica do material aditivado com lignina oxidada, comparado ao material sem lignina e com lignina original. No teste de permeabilidade, realizado aqui à pressão constante de 10 bar, a membrana sintetizada apenas com o acetato de celulose de bagaço de cana não apresentou fluxo. As membranas aditivadas com lignina original e lignina oxidada apresentaram fluxo, de 3,5 e 6,1 L/h.m2 respectivamente. O fato foi atribuído à morfologia das membranas, dado que as duas últimas, que apresentaram fluxo, possuem estrutura porosa, enquanto a outra possui estrutura densa. No teste de retenção de cobre, foi possível visualizar o efeito da adição da lignina na membrana, que aumenta 3,5 vezes a capacidade de retenção de cobre e, ainda, o efeito da oxidação da lignina, que aumenta em mais 50 % essa capacidade de retenção em comparação à adição apenas da lignina original. Contudo, os resultados indicam que as membranas sintetizadas, principalmente as membranas aditivadas com lignina oxidada, são promissoras para o objetivo proposto. / Thinking of a better use for the surplus of sugarcane bagasse, this study aims to obtain membranes of cellulose acetate composite with oxidized lignins, both isolated from sugarcane bagasse. To this purpose, the macromolecular components of bagasse were separated by applying a steam explosion pre-treatment for removal of hemicellulose and a treatment with sodium hydroxide to separate the lignin and obtaining of crude cellulose pulp. This pulp was bleached and acetylated, and subsequently cellulose acetate membranes were synthesized incorporating oxidized lignin in these membranes in order to increase the metal retention capacity of them. Thus, we intend to obtain a product with higher commercial value, which has applications in water and effluent treatment, which can further contribute to the maintenance of the environment. The membranes were synthesized by phase inversion, using two different methods: I. evaporation-precipitation and II. immersion in coagulation bath. The acetylated material was analyzed by FTIR, confirming the acetylation by the appearance of bands characteristic of acetate and analyzed for degree of substitution, featuring a diacetate. The membranes synthesized by method I were analyzed by SEM, verifying dense structure for the membranes in all compositions, and more rigid than a membrane prepared from a commercial triacetate, according to the data of dynamic mechanical analysis. Tests about permeability and copper retention also were done. Although rigid, they resisted to pressures up to 20 bar. The membrane added with lignin oxidized by laccase showed the best performance in this test, reaching higher flow requiring less pressure. In the test of copper retention, they showed an average retention capacity of 15%, corresponding to 50.5 mg Cu2+/ g lignin. The membranes synthesized by method II were analyzed by SEM, noting differences in morphology when the lignin is added dissolved in NaOH. Thermal analysis showed the Tg of the material near 80 °C, besides showing a higher thermal stability of the material added with oxidized lignin compared to material without lignin and with original lignin. In the permeability test, held at constant pressure of 10 bar, the membrane synthesized with only cellulose acetate cane bagasse showed no flow. The membranes added with original lignin and oxidized lignin showed flow of 3.5 and 6.1 L/h.m2, respectively. The fact was attributed to the morphology of the membranes, since the two latter, which showed flow, have porous structure, while the other has a dense structure. In the test of copper retention, it was possible to visualize the effect of the addition of lignin in the membrane, which increases 3.5 times the cupper retention capacity and, the effect of lignin oxidation, with increases in more 50% this retention capacity in comparison to the addition of the lignin in the original form. However, the results indicate that the synthesized membranes, mainly membranes added with oxidized lignin, are promising for the proposed objective.