Orientadores: Liliane Maria Ferrareso Lona, Paula Forte de Magalhães Pinheiro Bonassi Machado / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-22T16:56:26Z (GMT). No. of bitstreams: 1 Moraes_SamaraBoaventurade_M.pdf: 2271450 bytes, checksum: 53f3a25eef4f92dd7e80b68fe8945abd (MD5) Previous issue date: 2013 / Resumo: O interesse pelos nanocompósitos de matriz polimérica tem crescido acentuadamente nos últimos anos, pois estes materiais apresentam melhores propriedades mecânicas, térmicas, entre outras, quando comparados aos materiais convencionais. Entre os diferentes tipos de nanocompósitos de matriz polimérica, aqueles reforçados com compostos lamelares têm sido amplamente estudados. Os hidroxissais lamelares (HSLs) são exemplos de compostos lamelares e o estudo sobre estes materiais é um assunto novo. Trabalhos na literatura que envolvem os HSLs são relativamente escassos e a maioria está relacionada à sua síntese e caracterização estrutural. Neste trabalho foram sintetizados nanocompósitos de poliestireno utilizando hidroxissais lamelares como agente de reforço. Os nanocompósitos foram produzidos via polimerização in situ utilizando a polimerização em massa e diferentes frações mássicas de HSL. Foram produzidos HSLs intercalados com o ânion dodecilsulfato e o ânion laurato. O polímero puro foi caracterizado pelas análises de cromatografia de permeação em gel, análise gravimétrica, difração de raios-x, espectroscopia no infravermelho por transformada de Fourier, calorimetria exploratória diferencial, termogravimetria e teste de inflamabilidade. Os hidroxissais lamelares foram caracterizados pelas técnicas de inchamento de Foster, difração de raios-x e espectroscopia no infravermelho por transformada de Fourier. Os nanocompósitos poliméricos sintetizados foram caracterizados pelas técnicas de difração de raios-x, espectroscopia no infravermelho por transformada de Fourier, calorimetria exploratória diferencial, termogravimetria e teste de inflamabilidade. Foi escolhido um dos nanocompósitos sintetizados e foi realizada análise gravimétrica para avaliar a influência do HSL na conversão do polímero. Dentre as propriedades do material, os resultados obtidos mostram que os nanocompósitos sintetizados tendem a apresentar melhoras na inflamabilidade quando comparados ao polímero puro e, também apresentam temperatura final de degradação superior ao do poliestireno, além de não influenciarem significativamente na temperatura de transição vítrea do polímero / Abstract: Interest in the nanocomposite polymeric matrix has grown dramatically in recent years because these materials exhibit better mechanical and thermal properties, among others, when compared to conventional materials. Among the different types of nanocomposite polymeric matrix, those reinforced with layered compounds has been widely studied. The layered hydroxides salts (LHSs) are examples of layered compounds and the study of layered hydroxides salts is a new subject. Studies in the literature involving the LHSs are relatively scarce and most of them are related to their synthesis and structural characterization. In this work nanocomposites of polystyrene using layered hydroxides salts as a reinforcing agent were synthesized. The nanocomposites were produced via in situ bulk polymerization. Polymer nanocomposites were synthesized with different mass fractions of LHS. LHSs intercalated with dodecyl sulfate anion and laurate anion was produced. The pure polymer was characterized by analysis of gel permeation chromatography, gravimetric analysis, x-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric and flammability test. The layered hydroxides salts were characterized by swelling of Foster techniques, x-ray diffraction and Fourier transform infrared spectroscopy. The synthesized polymer nanocomposites were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric and flammability test. One of the synthesized nanocomposites was chosen and gravimetric analysis was performed to assess the influence of LHS on the conversion of the polymer. Among the material properties, the results obtained show that the nanocompósito synthesized tend to have improved flammability compared to the pure polymer, and also present final temperature higher than the degradation of polystyrene, and do not significantly influence the glass transition temperature of the polymer / Mestrado / Desenvolvimento de Processos Químicos / Mestra em Engenharia Química

Nanoparticles are used more and more extensively in today's society, especially in the industry sector. Humans get exposed to nanoparticles daily but the effect is a topic that has not been fully explored yet and its effect on humans is still unknown.The purpose of this project was to investigate whether the size of nanoparticles is a factor that influences their effect on humans, mainly the effect on blood activation. In order to study this, nanopaticles of polystyrene with three different sizes (75, 120 and 260 nm) were selected and incubated in a human whole blood model, the Chandler loop. The samples from the Chandler loop experiments were analysed with three different ELISA's: C3a, terminal complement complex (TCC, sC5b-9) and thrombin-antithrombincomplexes (TAT).The results in this study indicate that the smallest nanoparticle has a higher potential for activating the coagulation system than the larger ones. The complement system did not seem to be significantly activated from the nanoparticles. More experiments needs to be done in order to get a better statistic value but just as it is the results look promising and there is a tendency for a higher activation of the coagulation system with the 75 nm nanoparticles.

Water is the essential part of every organism and it is also a vital constituent of healthy living and diet. Unfortunately water contamination over the past decade has increased dramatically leading to various diseases. As technology advances, we are detecting many pollutants at smaller levels of concentrations. Arsenic (As) is one of those major pollutants, and Arsenic poisoning is a condition caused due to excess levels of arsenic in the body. The main basis for Arsenic poisoning is from ground water which naturally contains high concentrations of arsenic. A case study from 2007 states that over 137 million people in 70 countries were affected by arsenic poisoning from drinking water [1]. This thesis work is motivated by this study and investigates the fabrication, characterization, and testing of Opuntia ficus-indica mucilage nanofiber membranes formed using a mucilage, polystyrene (PS) and iron oxide (Fe2O3) solution by an electrospinning process. Cactus mucilage is a jelly-like substance, which is extracted from the cactus pad, and is an inexpensive, biodegradable and biocompatible material. It is also an abundant material available in nature. Polystyrene is a synthetic aromatic polymer prepared from monomer styrene. Polystyrene is further dissolved using D-Limonene as a solvent. D-Limonene is a non-toxic solvent and is a citrus extract of orange peelings. In an effort to enhance adsorption capacity for the mucilage nanofiber membranes, iron oxide nanopowder is incorporated into the polymeric solution. A mucilage and polystyrene-iron oxide solution is mixed in different ratios and electrospun to obtain nanofibers. The fibers will be characterized by certain techniques such as Scanning electron microscopy (SEM), contact angle measurements, viscosity and Fourier transform infrared spectroscopy (FTIR). The fibers obtained from mucilage and PS-Fe2O3 will be further tested under Atomic fluorescence spectrometry (AFS) for testing the removal of arsenic from water. Also, a life cycle analysis (LCA) is conducted to evaluate the environmental impacts of the fabrication of the membranes by using SimaPro® software.

This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.

Cette thèse a pour objet de développer une nouvelle méthodologie pour valoriser les poudrettes de pneus usagés (PPU). Celles-ci résultent du broyage de la partie caoutchoutique des pneus usagés qui conserve l’excellente élasticité. L’idée est de profiter de leur élasticité pour renforcer la résistance au choc des polymères fragiles tels que le polystyrène (PS) en y incorporant les PPU. Cependant, la réalisation de cette idée a besoin de relever deux défis majeurs : (1) les PPU commerciales ont typiquement des diamètres de l’ordre de plusieurs centaines de micromètres. Or elles doivent être deux ordres de grandeur plus petits en taille pour pouvoir améliorer la résistance au choc des polymères fragiles. (2) L’adhésion interfaciale entre les polymères et les PPU est mauvaise et constitue donc des défauts mécaniques du matériau. Ces deux défis sont liés à la nature même des PPU qui sont intrinsèquement des réseaux réticulés chimiquement. Cette thèse choisit le PS pour représenter les polymères fragiles. La méthodologie visant à renforcer sa résistance au choc est de polymériser le styrène par voie radicalaire au sein des PPU. Cette polymérisation forme à la fois des chaines en PS libres et des greffons en PS liés chimiquement aux mailles du réseau des PPU. Les inclusions des chaines en PS libres facilitent la dispersion des PPU en taille plus petite lorsqu’une action mécanique leur est appliquée lors de l’extrusion par exemple. La formation des greffons en PS sur les mailles du réseau des PPU renforce l’adhésion interfaciale entre le PS et les PPU. Cette thèse a développé un modèle complet permettant de décrire la cinétique de polymérisation radicalaire du PS libre et celle des greffons en PS liés aux mailles du réseau des PPU. Elle l’a validé par un plan d’expériences judicieux / This thesis aims to develop a novel approach to value ground tire rubber (GTR). The latter results from grounding of the rubber part of used tires which retains excellent elasticity. The idea is to take the advantage of its elasticity to toughen brittle polymers such as polystyrene (PS) upon incorporating GTR into them. However, two challenges have to be overcome to realize this idea. (1) Commercial GTR is typically in the form of particles of a few hundreds of micrometers in diameter. However, it has to be at least one to two orders of magnitude smaller when incorporated in a brittle polymer so as to be able to improve its impact resistance. (2) The interfacial adhesion between the polymer and GTR is weak. These two challenges are related to the intrinsic nature of the GTR which is chemically cross-linked. This thesis chooses PS to represent brittle polymers. The approach aiming at toughening it is to polymerize styrene in a free radical manner inside cross-linked GTR particles. This leads to the formation of both free PS and PS that is grafted onto the GTR, denoted as grafted PS. The inclusions of the free PS inside the GTR particles help break them down by mechanical shear in a screw extruder for example and the formation of grafted PS improves the interfacial adhesion between the PS and the GTR. This thesis has developed a comprehensive kinetic model for the polymerization of free PS and that of grafted PS. This model is validated by experimental designs

The diagnostic methods implemented at the Canadian Food Inspection Agency for the detection of Shiga toxin producing E. coli (STEC) are time consuming and tedious, taking up to 5 days before a positive sample can be confirmed. The goal of this project was to streamline the detection procedure for serogroup O157 and 6 important non-O157 serogroups of STEC. Following a short enrichment step (4-6 hrs), two approaches were considered: (1) the filtration of enrichment culture through a gradient of filtration membranes (decreasing pore sizes), followed by capture using specific monoclonal antibody (mAb)-coated Dynabeads, and detection via fluorescence microscopy, (2) the addition of enrichment culture into a flow through system consisting of a column packed with large polystyrene beads (≥ 100 μm) coated with specific mAbs for capture. The results indicate that the filtration approach can only be applied to simpler food matrices. However, at least 100 CFU of the target STEC could be recovered using the filtration system following 4 hrs of enrichment of these matrices spiked with ≤ 15CFU of the target STEC. Similar capture results were obtained in the second approach using specific mAbs immobilized on covalently coupled protein G polystyrene beads and diluted enrichment media. A combination of these strategies together with immunofluorescence microscopy (IMS) and polymerase chain reaction (PCR) could provide diagnostic laboratories with a means to confirm a positive sample within 2 days of testing.

Le travail présenté dans ce mémoire de thèse porte sur la préparation de nouveaux nanocomposites polystyrène-argile en utilisant des argiles modifiées par divers tensioactifs cationiques polymérisables fluorés. Des systèmes de référence ont aussi été envisagés en utilisant des tensioactifs classiques de structure proche de celles des surfmers (surfmers et tensioactifs hydrocarbonés) et ce, afin de mettre en évidence le rôle joué par le groupement polymérisable et l’atome de fluor sur la structure et les propriétés des nanocomposites obtenus. Les propriétés de surface des tensioactifs ont été étudiées en termes de CMC, tensions de surface et enthalpies de micellisation de Gibbs afin d’évaluer le comportement en solution de ces tensioactifs. Ces tensioactifs ont été par la suite utilisés pour modifier une montmorillonite sodée via un processus d’échange cationique. Les organoargiles ainsi obtenues ont été caractérisées par IR, ATG et DRX. Les données DRX obtenues sont en faveur d’un alignement de la majorité des surfmers fluorés en bicouche La préparation des nanocomposites polystyrène-argile contenant diverses quantités d’organoargiles variant de 1 à 15% en utilisant la technique de polymérisation radicalaire en masse ou en solution, a montré l’effet positif de l’introduction d’une chaîne fluorée et d’une fonction polymérisable sur la stabilité thermique des nanocomposites. Des morphologies exfoliées ont été obtenues pour la majorité des nanocomposites fluorés préparés. Une relation structure-propriétés de surface et propriétés thermique a été établie sur la base des analyses ATG, DRX et TEM/MEB. / The work presented in this thesis focuses on the preparation of new polystyrene-clay nanocomposites using fluorinated polymerizable cationic surfactants as modifiers. Reference systems have also been proposed using conventional surfactants of similar structure than surfmers. The main objective is to highlight the role of the polymerizable group and the fluorine atoms on the structure and the properties of the obtained nanocomposites. The surface properties of surfactants were studied in terms of CMC, surface tensions and Gibbs enthalpies of micellization to evaluate the solution behavior of these surfactants. These surfactants were subsequently used to modify a sodium montmorillonite via cation exchange process. The resultant organoclays were characterized by IR, TGA and XRD analysis. XRD data are in favor of an alignment of the majority of fluorinated surfmers to form a bilayer structure while conventional surfactants tend to form a pseudotrimolecular layer. Determination of surfmer reactivity ratios by NMR was used to predict the behavior of these derivatives in radical copolymerization with styrene. Preparation of polystyrene-clay nanocomposite containing various amounts of organoclays from 1 to 15 wt% by radical polymerization process in bulk or solution, showed the positive effect of the introduction of fluorinated chain and polymerizable functional group on thermal stability of nanocomposites. Exfoliated morphologies were obtained for the majority of the fluorinated nanocomposite. A structure-surface and thermal properties relationship was established on the basis of TGA, XRD and TEM / SEM analysis.

Orientador: Liliane Maria Ferrareso Lona / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-24T08:44:00Z (GMT). No. of bitstreams: 1 Botan_Rodrigo_D.pdf: 8541673 bytes, checksum: fc88cab0852acd3cb9bf0b6052e4458d (MD5) Previous issue date: 2014 / Resumo: Ao longo da última década, nanocompósitos poliméricos vêm atraindo grande atenção da comunidade científica e industrial. Este fato se deve à notável melhora em inúmeras propriedades destes novos materiais, proporcionado pelo uso de uma pequena quantidade de nanoreforços. Entre as propriedades melhoradas é possível citar com maior destaque as propriedades mecânicas e térmicas. Buscando alcançar melhores propriedades para o poli(estireno) (PS), o objetivo deste trabalho foi o de sintetizar nanocompósitos in situ de PS com hidróxidos duplos lamelares (HDLs) e hidroxissal lamelar (HSL). Para isto, foram sintetizados dois tipos de HDLs e um tipo de HSL, os HDLs foram modificados com ácido láurico, ácido palmítico e uma mistura destes dois ácidos e o HSL foi modificado com ácido palmítico. Os HDLs e HSL sintetizados foram caracterizados por difração de raios x (DRX), microscopia eletrônica de varredura (MEV), espectroscopia no infravermelho por transformada de Fourier (FTIR) e análise termogravimétrica (TGA). Os nanocompósitos foram sintetizados in situ por polimerização em massa e foram caracterizados por DRX, FTIR, TGA, calorimetria exploratória diferencial (DSC), microscopia eletrônica de transmissão (MET), ensaio de flexão, análise da fratura e teste de flamabilidade. Os resultados obtidos demostram que estes novos nanocompósitos foram sintetizados, apresentando, de uma forma geral, uma boa interação polímero ¿ reforço com morfologia variando da intercalada/esfoliada a esfoliada. A estabilidade térmica e, principalmente, a propriedade mecânica apresentaram ganhos significativos em todos os materiais estudados quando comparadas com o polímero puro, fato que possibilita uma vasta gama de aplicação destes novos materiais em diversos campos da pesquisa e engenharia / Abstract: Over the past decade, polymer nanocomposites have attracted interest, both in the industry and in the academia. They often exhibit remarkable improvement in their properties when compared with neat polymer or conventional micro and macrocomposites using low levels of reinforcements, usually maximum 5% by weight. The improvements mainly include mechanical, thermal, and physical properties. Seeking to achieve better properties for poly(styrene) (PS), the purpose of this work was to in situ synthesize PS with layered double hydroxides (LDHs) and layered hydroxide salt (LHS) nanocomposites. Thus, two types of LDH and a type of LHS was synthesized, the LDHs were modified with lauric acid, palmitic acid and a mixture of both, and LHS was modified with palmitic acid. The LDHs and LHS synthesized were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The nanocomposites were synthesized by in situ bulk polymerization and were characterized by XRD, FTIR, TGA, differential scanning calorimetry (DSC), transmission electron microscopy (TEM), bend test, fracture analysis and flammability test. The obtained results show that indeed these new nanocomposites were synthesized. These nanocomposites have in general good interaction polymer ¿ reinforcement with morphology varying from intercalated/exfoliated to exfoliated. The thermal stability and mechanical property mainly, showed significant improvement in all materials studied, when compared with the neat polymer, a fact that enables a wide range of application of these new materials in various fields of research and engineering / Doutorado / Engenharia Química / Doutor em Engenharia Química

Polystyrene (PS) is one of the most important polymers in the plastic sector due to its inexpensive cost as well as many preferred properties. Its international market is expected to achieve $28.2 billion by 2019. Although PS has a high calorific value of 87 GJ tonne-1, there is no a practical method to manage its waste but landfill. As a result, the PS debris in the oceans has reached 70% of the total plastic debris. This issue is considered as the main economical and environmental drivers of converting polystyrene waste into renewable chemical feedstocks. The aim of this work is to develop a catalyst for converting PS into renewable chemicals under mild conditions. We introduce FeCu/Alumina with excellent catalytic activity to fully degrade polystyrene with 66% liquid yield at 250 °C. The GC/MS confirmed that the primary products are in the gasoline range. Next, we present the bimetallic FeCo/Alumina and successfully we have obtained 100% PS conversion and 90% liquid yield with maintaining the products selectivity. Later, the tri-metallic FeCuCo/Alumina was synthesized and showed 100% PS conversion and 91% liquid yield. Surprisingly, ethylbenzene was the major product in which 80 wt. % was achieved with excellent reproducibility. Furthermore, the real waste Styrofoam was thermally and catalytically degraded at 250 °C. Interestingly, a high styrene content of 78 wt. % was recovered after 30 minutes of the reaction under mild conditions. Keeping in mind that a good balance between acidity and basicity is required to convert PS into aromatic under mild reaction conditions catalytically. Finally, the performance of the catalysts was compared to literature reports and showed novel liquid yields. In conclusion, we have synthesized cheap, easy to scale up, and efficient catalysts to fully degrade PS into high liquid yields of aromatics with excellent selectivity.

Photocatalysis is a robust synthetic tool capable of breaking and assembling chemical bonds using single electron chemistry. This is achieved through the catalytic conversion of light energy to chemical energy in situ, such that the photons being delivered are themselves reagents. Herein, an inexpensive and environmentally-benign platform for scaling up photocatalytic reaction is disclosed, harnessing blue light naturally emitted by deep-sea bioluminescent bacteria. Photobacterium angustum GB-1 was demonstrated to photoexcite both polypyridyl organometallic chromophores and organic dyes at short molecular distances, enabling photocatalysis without any external energy-consuming lamps.While improving the eco-friendliness of photocatalysis itself, we also present a method to use photocatalysis for environmental remediation. Using visible light, a nontoxic organic photosensitizer, and oxygen, we demonstrate the controlled oxidative depolymerization of polystyrene—including polystyrene retrieved from waste receptacles in Havemeyer—to acetophenone. This method is based on results obtained in the controlled aerobic deannulation of cycloalkanes, which is also discussed herein. Lastly, a means by which catalysis itself can be made more cost, resource, and time effective is presented. An innovative computational platform in development predicts new catalysts for reactions currently energetically inaccessible. In collaboration with the developers, we present experimental validation of their theoretical predictions, as well as perform the synthesis of a de novo fluorinated thiazolium precatalyst calculated to significantly lower the energetic barrier of an otherwise energetically prohibitive Stetter reaction.