Orientador: Rosiane Lopes da Cunha / Texto em inglês e português / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-22T16:01:09Z (GMT). No. of bitstreams: 1 Fasolin_LuizHenrique_D.pdf: 4514107 bytes, checksum: cbdb7bfe81fe688fefd10aac2e7238ac (MD5) Previous issue date: 2013 / Resumo: Os sistemas auto-organizáveis como meio para obtenção de produtos com diferentes características têm sido estudados como uma alternativa aos métodos tradicionais de produção de emulsões e gelificação. Todavia, a formação de produtos com ingredientes biocompatíveis ainda é pouco explorada, devido à complexidade e a toxicidade de alguns dos ingredientes geralmente utilizados. Nesse contexto, o objetivo geral desse trabalho foi produzir sistemas com diferentes características a partir do estudo do diagrama de fases de sistemas compostos por água, óleo vegetal, surfactante e co-surfactante biocompatíveis, além de um biopolímero gelificante. Na primeira parte deste estudo, a influência da concentração do co-surfactante (etanol) e da insaturação do óleo (óleo de girassol comum ou óleo de girassol alto oléico, HOSO) foi investigada. Os resultados mostraram que, dependendo da composição do meio, foram obtidas diferentes estruturas (microemulsões ou líquidos cristalinos) com distintos comportamentos reológicos. A formação dessas estruturas foi influenciada pela insaturação do óleo e pela concentração de etanol. Na segunda etapa, a substituição do etanol por ácidos orgânicos (acético e propiônico) foi estudada, bem como sua influência no comportamento reológico-estrutural dos sistemas. Nesse caso, a estruturação dos sistemas foi dependente da combinação entre os ingredientes. O óleo de girassol solubilizou maior quantidade de ácido propiônico devido sua maior hidrofobicidade, enquanto o HOSO apresentou mais afinidade com o ácido acético. Essa diferença de afinidades levou a mudanças no mecanismo de difusão do co-surfactante, bem como sua susceptibilidade à partição. A fim de estudar a viabilidade da adição da goma gelana nas microemulsões para obtenção de sistemas gelificados, uma terceira etapa foi realizada com o intuito de avaliar a interação desse polissacarídeo com o surfactante. Foram observados dois comportamentos predominantes, dependendo da concentração dos componentes. Em baixas concentrações de surfactante, a rede de gelana prevaleceu formando géis fortes com claro ponto de ruptura. Com o aumento da concentração, o surfactante começou a se auto-organizar em estruturas mais complexas até que em altas concentrações sua estrutura se tornou predominante com formação de géis fracos. Na última etapa do trabalho, a goma gelana foi adicionada em alguns sistemas do diagrama de fases formulados com HOSO com ou sem ácido acético. Os géis formulados sem ácido acético foram homogêneos e dependentes da razão água/surfactante. A maior quantidade de água levou a géis mais resistentes devido à formação de uma rede de gelana mais densa. Por outro lado, maiores concentrações de surfactante levaram a géis mais fracos e ao aparecimento de uma temperatura de transição relacionada à estruturação do surfactante. A adição de ácido levou à desestabilização da estrutura cristalina, impedindo a estruturação do surfactante. Além disso, ao invés de géis homogêneos, foram formados géis particulados ou microgéis, que foram auto-sustentáveis apenas em altas concentrações de água. Por fim, este trabalho mostrou que sistemas auto-organizados são de particular utilidade na obtenção de produtos com diferentes características tecnológicas, cujas propriedades podem ser moduladas de acordo com a aplicação / Abstract: Self-assembly systems as a way to obtaining products with different characteristics have been studied as an alternative to traditional emulsification and gelation methods. However, the use of biocompatible ingredients in these systems was scarcely explored due to the complexity or toxicity of the most common ingredients. Thus, the aim of this work was to produce systems with different technological characteristics from the study of phase diagrams composed by water, edible oil, surfactant and biocompatible cosurfactants, as well as a gelling biopolymer. In the first part of this work, the influence of the cosurfactant (ethanol) concentration and oil unsaturation (sunflower oil or high oleic sunflower oil, HOSO) was investigated from the phase-diagrams construction. Results showed that depending on the systems composition different structures could be obtained (microemulsion or liquid crystalline) with different rheological behavior. Moreover, the formation of these structures was influenced by the oil unsaturation and ethanol concentration. In the second step, the replacement of ethanol by organic acids (acetic and propionic) was evaluated, as well as their influence on the rheological-structural behavior. In this case, the systems self-assemble was dependent on the ingredients combination. Sunflower oil solubilized a great amount of propionic acid due to its higher hydrophobicity, whereas HOSO presented more affinity with acetic acid. These affinity differences between oil and cosurfactant changed the diffusion mechanism of the acid through the surfactant and oil tails as well as its susceptibility to the partition phenomenon. In order to study the feasibility of gellan gum addition in the microemulsion to obtain gelled systems, a third step was carried out to evaluate the interactions between this polysaccharide and the surfactant. It was observed two prevailing behavior depending on the components concentration. At low surfactant concentration the gellan network prevailed and formed hard gels were formed with clear rupture point. With the surfactant content increase, its moieties started to self-assembly in highly organized structures until that, at high concentration, these structures became predominant with the formation of weak or soft gels. In the last part of this work gellan gum was added to some systems of the phase diagram formulated with HOSO with or without acetic acid. The gels formulated without acetic acid were homogeneous gels and dependent on the water/surfactant ratio. The higher water content led to harder gels due to the formation of a denser gellan network. On the other hand, higher surfactant concentration led to weaker gels and a transition temperature related to the surfactant structuration was observed. The acid acetic addition led to the liquid crystalline destabilization, hindering the surfactant structuration. Moreover, instead of bulky gels, particulate gels or microgels were formed, which were self-supporting only at high water concentration. Finally, this work showed that self-assembly systems are particularly useful to obtain products with different technological characteristics, whose properties can be modulated according to the application / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

La première partie de ce mémoire concerne l’étude en solution de systèmes à base de POMset de cations organiques de polarité/taille variables. Ainsi, l’étude des interactions entre unanion Keplerate noté {Mo132} et une large série de cations organiques (composée d’ions alkylammonium AA) a nécessité la mise en place d’une méthodologie spécifique utilisant la RMNDOSY de 1H. La méthode s’est révélée particulièrement efficace et a permis non seulement demettre clairement en évidence l’existence d’interactions anion-cation fortes mais aussil’extraction des constantes d’association à partir d’un traitement quantitatif des données. Cetteétude révèle que le facteur qui domine le processus d’association anion-cation résulte d’un« effet hydrophobe » directement lié au caractère apolaire du cation organique et polaire dusolvant. Les constantes de stabilité sont en accord avec des interactions plutôt fortes. ParParailleurs, une expérience spécifique a permis de titrer les 20 pores présents à la surface de l’ionKeplérate, montrant ainsi la spécificité du processus d’association.La seconde partie de ce mémoire concerne la conception de matériaux à base de Képlerate enjouant sur la nature des cations imidazolium qui lui sont associés. Les phases solides ont étécaractérisées par spectrométrie infrarouge, analyse élémentaire, EDX et analysethermogravimétrique. Ces études montrent que dans certaines conditions, ces systèmes seaffichent un comportement type cristal liquide.La troisième partie s’intéresse spécifiquement aux interactions ionique et/ou van der Waals àl’origine de phénomènes de structuration. L’anion cyclique[Na2K2{Mo4O4S4(H2O)3(OH)2}2(P8W48O184)]32- ( noted 1) a été isolé à l’état solide sous laforme de sels de DODA (dioctadécyl-diméthyl-ammonium) ou d’imidazolium. L’analysestructurale de ces phases par RMN MAS de 1H, 13C et 31P montre sans ambigüitél’organisation des chaines alkyles. Ces résultats croisés avec la microscopie optique polarisée,l’analyse thermique différentielle et la diffraction des rayons X aux petits angles montrentclairement la formation de phases mésomorphes lamellaires dont l’espacement estdirectement lié à la longueur des chaines alkyles. / Herein, we report the use of 1H DOSY NMR methodology to track the interaction between aninorganic multireceptor capsule, referring to the well-defined spherical Keplerate-type{Mo132} ion and a series of organic cation (including tetraalklylammonium). The obtainedresults reveal a strong dependence of the self-diffusion coefficient of the cationic guestsbalancing from the solvated to the plugging situations. Quantitative analysis of the data basedon two-site exchange regime, involving the 20 independent {Mo9O9} receptors of the capsule,allowed determining the stability constants associated to the plugging process of the pores.Surprisingly, the affinity of the capsule for a series of cationic guests increases continuouslywith its apolar character. Such observations evidence that the major factor dictating selectivityin the trapping process is mainly the so-called “hydrophobic effect”.Further investigation focused on the design of Keplerate-based materials where theammonium cations was replaced by imidazolium cations. The obtained materials werecharacterized in the solid state by FT-IR, TGA and elemental analysis. These materials exhibitliquid crystalline phase as evidenced by polarized optical microscopy and DSC, however,folding of the alkyl chain prohibit the formation of well organized mesophase. Finally, thisstrategy was extended to cyclic [Na2K2{Mo4O4S4(H2O)3(OH)2}2(P8W48O184)]32- which wasisolated as DODA or imidazolium salt. Solid state NMR evidence the well organization of thesolid. The obtained materials exhibit smectic A liquid crystalline phase and packed ashexagonal lamellar arrangement in the solid state.

Molecular reinforcement through in-situ polymerization of liquid crystalline epoxies (LCEs) and a non-liquid crystalline epoxy has been investigated. Three LCEs: diglycidyl ether of 4,4'-dihydroxybiphenol (DGE-DHBP) and digylcidyl ether of 4-hydroxyphenyl-4"-hydroxybiphenyl-4'-carboxylate (DGE-HHC), were synthesized and blended with diglycidyl ether of bisphenol F (DGEBP-F) and subsequently cured with anhydride and amine curing agents. Curing kinetics were determined using differential scanning calorimetry (DSC). Parameters for autocatalytic curing kinetics of both pure monomers and blended systems were determined. The extent of cure for both monomers was monitored by using Fourier transform infrared spectroscopy (FT-IR). The glass transitions were evaluated as a function of composition using DSC and dynamic mechanical analysis (DMA). The results show that the LC constituent affects the curing kinetics of the epoxy resin and that the systems are highly miscible. The effects of molecular reinforcement of DGEBP-F by DGE-DHBP and DGE-HHC were investigated. The concentration of the liquid crystalline moiety affects mechanical properties. Tensile, impact and fracture toughness tests results are evaluated. Scanning electron microscopy of the fracture surfaces shows changes in failure mechanisms compared to the pure components. Results indicate that mechanical properties of the blended samples are improved already at low concentration by weight of the LCE added into epoxy resin. The improvement in mechanical properties was found to occur irrespective of the absence of liquid crystallinity in the blended networks. The mechanism of crack study indicates that crack deflection and crack bridging are the mechanisms in case of LC epoxy. In case of LC modified epoxy, the crack deflection is the main mechanism. Moreover, the effect of coreacting an epoxy with a reactive monomer liquid crystalline epoxy as a matrix for glass fiber composites was investigated. Mechanical properties of the modified matrix were determined by tensile, flexural and impact testing. The improvement in toughness of the bulk matrix by the addition of a LCEs is seen also in the composites. The improvement is related to the enhancement of adhesion between the glass fibers and the matrix.

One portion of this work was concerned with injection molding pregenerated microcomposites composed primarily of poly(ethylene terephthalate) (PET) as the matrix and HX1000 as the thermotropic liquid crystalline polymer (TLCP). Several factors were examined to maximize the mechanical properties of these composites, including injection molding temperature, matrix viscosity, and nozzle tip exit diameter. In addition, concentrated strands of HX1000/PET (50/50 wt%) were diluted using both an injection molding grade of PET and an injection molding grade of PBT. From this work, it was determined that the best mechanical properties were produced when the microcomposites were processed at the lowest injection molding temperatures, diluted with PBT, and injection molded using a large nozzle tip exit diameter. The pregenerated microcomposite properties were compared against theoretical predictions as well as glass-filled PET. It was found that the pregenerated microcomposites had tensile moduli of approximately 70% of theoretical expectations in the machine direction. Additionally, the comparisons against glass-filled PET revealed that at the same weight fraction of reinforcement, the pregenerated microcomposites had lower properties. Still, the composites were found to have smoother surfaces than glass-filled PET and at temperatures up to 150° C the storage and loss moduli of the pregenerated microcomposites were similar to those of glass filled PET. It was concluded that if the theoretically expected levels of reinforcement could be attained, the pregenerated microcomposites processing scheme would be a viable method of producing light weight, wholly thermoplastic composites with smoother surfaces than are obtained with glass reinforcement. An additional focus of this research was to evaluate the ability to modify the crystallization behavior of a high melting TLCP (HX6000, Tm = 332° C) with a lower melting TLCP (HX8000, Tm = 272°C). It was found that it was possible to tailor the crystallization behavior of these TLCP/TLCP blends by varying the weight fraction of each component, as determined by rheological cooling scans and differential scanning calorimetric cooling tests. Based on the analysis of these TLCPs at the maximum injection molding temperature of 360° C, it was speculated that they had reacted with one another. / Ph. D.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19011号 / 工博第4053号 / 新制||工||1624(附属図書館) / 31962 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 赤木 和夫, 教授 秋吉 一成, 教授 金谷 利治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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Yes / The association of the arene ruthenium metallacycle [Ru4(p-cymene)4(bpe)2(donq)2][DOS]4 (bpe = 1,2-bis(4-pyridyl)ethylene, donq = 5,8-dioxydo-1,4-naphtoquinonato, DOS = dodecyl sulfate) with pyrenyl-functionalized poly(arylester) dendrimers bearing cyanobiphenyl end-groups is reported. The supramolecular dendritic systems display mesomorphic properties as revealed by polarized optical microscopy, differential scanning calorimetry and small-angle X-ray scattering measurements. The multicomponent nature of the dendrimers and of the corresponding host–guest supramolecules (i.e., end-group mesogens, dendritic core, pyrene unit, aliphatic spacers, and metallacycle) leads to the formation of highly segregated mesophases with a complex multilayered structure due to the tendency of the various constitutive building-blocks to separate in different organized zones. The pyrenyl dendrimers exhibit a multilayered smectic A-like phase, thereafter referred to as LamSmA phase to emphasize this unaccustomed morphology. As for the corresponding Ru4–metallacycle adducts, they self-organize into a multicontinuous thermotropic cubic phase with the Im3̅m space group symmetry. This represents a unique example of liquid-crystalline behavior observed for such large and complex supramolecular host–guest assemblies. Models of their supramolecular organizations within both mesophases are proposed. / R.D. thanks the Swiss National Science Foundation (Grant No 200020-140298) for financial support.

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