The introduction of a nanoscopic reinforcing phase to a polymer matrix offers great possibilities of obtaining improved properties, enabling applications outside the boundaries of traditional composites. The majority of the work in this thesis has been devoted to polymer/clay nanocomposites in coating applications, using the hydroxyl-functional hyperbranched polyester Boltorn® as matrix and montmorillonite clay as nanofiller. Nanocomposites with a high degree of exfoliation were readily prepared using the straightforward solution-intercalation method with water as solvent. Hard and scratch-resistant coatings with preserved flexibility and transparency were obtained, and acrylate functionalization of Boltorn® rendered a UV-curable system with similar property improvements. In order to elucidate the effect of the dendritic architecture on the exfoliation process, a comparative study on the hyperbranched polyester Boltorn® and a linear analogue of this polymer was performed. X-ray diffraction and transmission electron microscopy confirmed the superior efficiency of the hyperbranched polymer in the preparation of this type of nanocomposites. Additionally, an objective of this thesis was to investigate how cellulose nanofibers can be utilized in high performance polymer nanocomposites. A reactive cellulose “nanopaper” template was combined with a hydrophilic hyperbranched thermoset matrix, resulting in a unique nanocomposite with significantly enhanced properties. Moreover, in order to fully utilize the great potential of cellulose nanofibers as reinforcement in hydrophobic polymer matrices, the hydrophilic surface of cellulose needs to be modified in order to improve the compatibility. For this, a grafting-from approach was explored, using ring-opening polymerization of ε-caprolactone (CL) from microfibrillated cellulose (MFC), resulting in PCL-modified MFC. It was found that the hydrophobicity of the cellulose surfaces increased with longer graft lengths, and that polymer grafting rendered a smoother surface morphology. Subsequently, PCL-grafted MFC film/PCL film bilayer laminates were prepared in order to investigate the interfacial adhesion. Peel tests demonstrated a gradual increase in the interfacial adhesion with increasing graft lengths. / QC20100621

Bei der Herstellung und Lagerung von Milch und Milchprodukten kommt es in unterschiedlichem Ausmaß zur Bildung von reversiblen und irreversiblen Proteinquervernetzungen. Dabei verändern sich neben technologischen auch ernährungsphysiologische Eigenschaften des Produktes. Die für die Oligomerisation verantwortlichen Strukturen sind bisher nur zum Teil bekannt. Daher soll in dieser Arbeit zunächst das Ausmaß der Quervernetzung in einer größeren Anzahl an handelsüblichen Milchprodukten ermittelt und mit den für diese Proben gemessenen Gehalten der für irreversible Quervernetzungsreaktionen in Lebensmitteln wichtigen Aminosäurederivate Lysinoalanin (LAL) und Histidinoalanin (HAL) verglichen werden. Der Beitrag dieser beiden Dehydroalanin-Derivate für Oligomerisationen ist jedoch stark von der Art ihres Bildungsweges abhängig. Da es in der Literatur keine abschließenden Untersuchungen über eine intra- oder intermolekularen Bildung von LAL und HAL gibt, ist dies eine grundlegende Aufgabe, um in der Folge den Anteil von unbekannten Crosslinks für die analysierten Lebensmittel bestimmen zu können. Die Identifizierung dieser vorhandenen, jedoch strukturell unbekannten Crosslinks ist ein weiteres Ziel der vorliegenden Untersuchungen. Hierbei richtet sich das Interesse vor allem auf Quervernetzungsprodukte, die im Zusammenhang mit der nicht-enzymatischen Bräunung oder Maillard-Reaktion gebildet werden. Aus der Literatur ist eine Vielzahl von Verbindungen, die an der Oligomerisation und den damit verbundenen Eigenschaftsänderungen von Proteinen beteiligt sind, aus Modellansätzen oder in vivo-Studien bekannt. Untersuchungen zum Vorkommen dieser Strukturen in handelsüblichen Lebensmitteln fehlen jedoch in den überwiegenden Fällen. Dazu ist neben der Synthese einzelner Verbindungen als Standardmaterial die Entwicklung bzw. Optimierung der Analytik für Lebensmittelmatrices durchzuführen. Einige der bekannten, aber noch nicht in Lebensmitteln nachgewiesenen Crosslinkaminosäuren zeichnen sich durch eine charakteristische Fluoreszenz aus. Die Zunahme der Fluoreszenz in technologisch hergestellten Milchprodukten ist aus der Literatur bekannt, eine Identifizierung der dafür verantwortlichen Verbindungen fehlt hingegen. Daher ist ein weiteres Ziel dieser Arbeit, individuelle, fluoreszierende Crosslinks in Milchprodukten zu charakterisieren und zu quantifizieren.

Protein therapeutics offer numerous advantages over small molecule drugs and are rapidly becoming one of the most prominent classes of therapeutics. Unfortunately, they are delivered almost exclusively by injection due to biological obstacles preventing high bioavailability via the oral route. In this work, numerous approaches to overcoming these barriers are explored. PH-Responsive poly(itaconic acid-co-N-vinylpyrrolidone) (P(IA-co-NVP)) hydrogels were synthesized, and the effects of monomer ratios, crosslinking density, microparticle size, protein size, and loading conditions were systematically evaluated using in vitro tests. P(IA-co-NVP) hydrogels demonstrated up to 69% greater equilibrium swelling at neutral conditions than previously-studied poly(methacrylic acid-co-N-vinylpyrrolidone) hydrogels and a 10-fold improvement in time-sensitive swelling experiments. Furthermore, P(IA-co-NVP) hydrogel microparticles demonstrated up to a 2.7-fold improvement in delivery of salmon calcitonin (sCT) compared to methacrylic acid-based systems, with a formulation comprised of a 1:2 ratio of itaconic acid to N-vinylpyrrolidone demonstrating the greatest delivery capability. Vast improvement in delivery capability was achieved using reduced ionic strength conditions during drug loading. Use of a 1.50 mM PBS buffer during loading yielded an 83-fold improvement in delivery of sCT compared to a standard 150 mM buffer. With this improvement, a daily dose of sCT could be provided using P(IA-co-NVP) microparticles in one standard-sized gel capsule. P(IA-co-NVP) was also tested with larger proteins urokinase and Rituxan. Crosslinking density provided a facile method for tuning hydrogels to accommodate a wide range of protein sizes. The effects of protein PEGylation were also explored. PEGylated sCT displayed lower release from P(IA-co-NVP) microparticles, but displayed increased apparent permeability across a Caco-2 monolayer by two orders of magnitude. Therefore, PEG-containing systems could yield high bioavailability of orally delivered proteins. Finally, a modified SELEX protocol for cellular selection of transcellular transport-initiating aptamers was developed and used to identify aptamer sequences showing enhanced intestinal perfusion. Over three selection cycles, the selected aptamer library showed significant increases in absorption, and from an initial library of 1.1 trillion sequences, 5-10 sequences were selected that demonstrated up to 10-fold amplification compared to the naïve library. These sequences could provide a means of overcoming the significant final barrier of intestinal absorption. / text

No description available.

Vascular tissue engineering (VTE) with the use of polymeric scaffolds offers the potential to generate small-diameter (<6 mm) arteries. In this thesis, a degradable polar hydrophobic ionic (D-PHI) polyurethane porous scaffold was synthesized with the objective of demonstrating its potential application for VTE. D-PHI scaffold synthesis was optimized, maximizing isocyanate and methacrylate monomer conversion. Through the incorporation of a lysine-based crosslinker, scaffold mechanical properties and swelling were manipulated. Furthermore, D-PHI scaffolds demonstrated the ability to support the growth and adhesion of A10 vascular smooth muscle cells (VSMCs) during two weeks of culture. This study also investigated the effect of a double porogen approach on D-PHI scaffold properties, demonstrating an increase in the total scaffold porosity and pore interconnectivity. Specifically, it was found that the use of 10 wt% polyethylene glycol and 65 wt% sodium bicarbonate porogens resulted in a porous (79±3%) D-PHI scaffold with the mechanical properties (elastic modulus=0.16±0.03 MPa, elongation-at-yield=31±5%, and tensile strength=0.04±0.01 MPa) required to withstand the physiologically-relevant cyclic mechanical strain (CMS) that is experienced by VSMCs in vivo. Furthermore, the effects of uniaxial CMS (10% strain, 1 Hz, 4 weeks) on human coronary artery smooth muscle cells (hCASMCs), which were cultured in a porous D-PHI scaffold, were studied using a customized bioreactor. Four weeks of CMS was shown to yield greater DNA mass, more cell area coverage, a better distribution of cells within the scaffold, the maintenance of contractile protein expression and the improvement of tensile mechanical properties. The in vitro and in vivo degradation as well as the in vivo biocompatibility of D-PHI scaffolds were also investigated. Following their subcutaneous implantation in rats (100 days), porous D-PHI scaffolds demonstrated more cell/tissue infiltration within their pores and degraded in a controlled manner and at a faster rate when compared to in vitro studies (120 days), retaining the mechanical integrity required during neo-tissue formation. This thesis provides significant insight into the role of the D-PHI scaffold in combination with physiologically-relevant CMS in modulating VSMC proliferation and phenotype. The findings of this work can be used to tailor vascular tissue regeneration by regulating VSMC function in a directed manner.

Vascular tissue engineering (VTE) with the use of polymeric scaffolds offers the potential to generate small-diameter (<6 mm) arteries. In this thesis, a degradable polar hydrophobic ionic (D-PHI) polyurethane porous scaffold was synthesized with the objective of demonstrating its potential application for VTE. D-PHI scaffold synthesis was optimized, maximizing isocyanate and methacrylate monomer conversion. Through the incorporation of a lysine-based crosslinker, scaffold mechanical properties and swelling were manipulated. Furthermore, D-PHI scaffolds demonstrated the ability to support the growth and adhesion of A10 vascular smooth muscle cells (VSMCs) during two weeks of culture. This study also investigated the effect of a double porogen approach on D-PHI scaffold properties, demonstrating an increase in the total scaffold porosity and pore interconnectivity. Specifically, it was found that the use of 10 wt% polyethylene glycol and 65 wt% sodium bicarbonate porogens resulted in a porous (79±3%) D-PHI scaffold with the mechanical properties (elastic modulus=0.16±0.03 MPa, elongation-at-yield=31±5%, and tensile strength=0.04±0.01 MPa) required to withstand the physiologically-relevant cyclic mechanical strain (CMS) that is experienced by VSMCs in vivo. Furthermore, the effects of uniaxial CMS (10% strain, 1 Hz, 4 weeks) on human coronary artery smooth muscle cells (hCASMCs), which were cultured in a porous D-PHI scaffold, were studied using a customized bioreactor. Four weeks of CMS was shown to yield greater DNA mass, more cell area coverage, a better distribution of cells within the scaffold, the maintenance of contractile protein expression and the improvement of tensile mechanical properties. The in vitro and in vivo degradation as well as the in vivo biocompatibility of D-PHI scaffolds were also investigated. Following their subcutaneous implantation in rats (100 days), porous D-PHI scaffolds demonstrated more cell/tissue infiltration within their pores and degraded in a controlled manner and at a faster rate when compared to in vitro studies (120 days), retaining the mechanical integrity required during neo-tissue formation. This thesis provides significant insight into the role of the D-PHI scaffold in combination with physiologically-relevant CMS in modulating VSMC proliferation and phenotype. The findings of this work can be used to tailor vascular tissue regeneration by regulating VSMC function in a directed manner.

Τα κελιά καυσίμου είναι ηλεκτροχημικές διατάξεις που μετατρέπουν με συνεχή τρόπο τη χημική ενέργεια ενός καυσίμου και ενός οξειδωτικού σε ηλεκτρική με ταυτόχρονη παραγωγή νερού. Μια πολύ σημαντική κατηγορία κελιών είναι είναι τα κελιά καυσίμου πολυμερικής μεβράνης.Λειτουργία σε θερμοκρασίες πάνω από 100ºC έχει διάφορα πλεονεκτήματα.Ένας ιδανικός πολυμερικός ηλεκτρολύτης θα πρέπει να είναι ανθεκτικός, να έχει καλές μηχανικές ιδιότητες, υψηλή θερμική και οξειδωτική σταθερότητα και υψηλή ιοντική αγωγιμότητα, η οποία εξαρτάται από την ικανότητά του να εμποτίζεται με κάποιο μέσο όπως ένα ισχυρό οξύ, π.χ. το φωσφορικό οξύ. Το πρώτο μέρος της παρούσας διατριβής αφορά τη σύνθεση αρωματικών πολυαιθέρων που φέρουν πολικές ομάδες πυριδίνης στη κύρια αλυσίδα, μαζί με πλευρικές σουλφονομάδες με στόχο τη δημιουργία μιας μεμβράνης που θα είναι ικανή να απορροφά φωσφορικό οξύ αλλά και νερό.Το οξύ θα διασφαλίσει υψηλές τιμές ιοντικής αγωγιμότητας ενώ η παρουσία νερού θα αυξήσει την ιοντική αγωγιμότητα.Επιπλέον παρασκευάστηκαν σύνθετες μεμβράνες, με την εισαγωγή ανόργανων εγκλεισμάτων(τροποποιημένος με όξινες σουλφονικές ομάδες μοντμοριλλονίτης (SO3-MMT) στην υδρόφοβη πολυμερική μήτρα του TPS®. Στο δεύτερο μέρος της παρούσας διατριβής αναπτύχθηκαν θερμικά διασυνδεδεμένοι πολυμερικοί ηλεκτρολύτες. Συντέθηκαν 3 νέα μονομερή και συμπολυμερή με πλευρικές ομάδες στυρολίου στη κύρια αλυσίδα.Η θερμική κατεργασία των συμπολυμερών σε υψηλή θερμοκρασία οδήγησε σε διασύνδεση της δομής χωρίς τη χρήση θερμικών εκκινητών. Ακολούθησε πλήρης χαρακτηρισμός των ιδιοτήτων όλων των νέων δομών. Τέλος, έλαβε χώρα εφαρμογή και μελέτη της απόδοσης σε μοναδιαία κυψελίδα καυσίμου. / Fuel cells are devices that convert the chemical energy of a fuel and an oxidant to electrical with simultaneous production of water. Polymer Exchange Membrane Fuel Cell (PEMFC) represents an important class of fuel cells.Operating above 150ºC has many advantages. The ideal polymer electrolyte should exhibit long term durability, good mechanical properties, high thermal/chemical and oxidative stability and high ionic conductivity which depends on the ability to be doped with a strong acid. In the first part of this thesis aromatic copolymers bearing in the main chain basic pyridine groups combined with side chain acidic sulfonate groups were synthesized, making them capable of absorbing phosphoric acid and water. The phosphoric acid will ensure high proton conductivities while presence of water will further improve the performance of the cell. Furthermore composite membranes were prepared by adding inorganic fillers( functionalized montmorrilonite with sulfonic groups, SO3-MMT)in TPS® polymer matrix. In the second part of this thesis thermal cross- linked polymer electrolytes were developed for their use in high temperature PEMFC.Three new monomers and a series of copolymers in high temperature led to crosslinking without using thermal initiators.These properties of all the new structures were fully characterized with conventional techniques. thermal cross-linked copolymers were .chosen for the membrane electrode assembly (MEA) preparation for a preliminary study of the performance of the cell in high temperatures.

As linhas flexíveis, estruturas compostas por um determinado número de camadas plásticas e de aço, possibilitam o escoamento de fluidos em operações de exploração e produção de hidrocarbonetos entre plataformas marítimas de petróleo e o leito marinho e/ou a costa. E, atualmente, têm sido utilizadas na exploração de hidrocarbonetos em lâminas dágua cada vez maiores. O presente estudo visa modificar quimicamente o LLDPE através de processos de extrusão reativa envolvendo a graftização de VTMS na presença de peróxidos orgânicos, e posterior formação de ligações cruzadas promovida pela água. Visa analisar também o efeito da introdução de ligações cruzadas nas propriedades térmicas e mecânicas do LLDPE. De forma a atingir os objetivos propostos, um planejamento experimental foi realizado para analisar o efeito de variáveis como velocidade de rotação do parafuso da extrusora, tipo e teor de peróxido nos índices de fluidez dos produtos da reação do LLDPE com peróxido de dicumila (DCP) e 2,5-dimetil-peróxi-hexano (Trigonox 101). Essa metodologia também foi utilizada para avaliar o efeito da concentração de silano, da velocidade de rotação do parafuso da extrusora e do procedimento de imersão nos índices de fluidez dos produtos da reação do LLDPE com 0,02% p/p de DCP e concentrações variáveis de silano. As amostras foram caracterizadas através dos ensaios para determinação de índice de fluidez (MFI) e teor de gel, ensaios convencionais de tração e técnicas de análise térmica, TGA e DSC. A técnica de FTIR foi utilizada para verificar a ocorrência das reações de graftização e formação de ligações cruzadas no LLDPE. As amostras reagidas com teores de 0,07% de DCP e 1,0 e 1,5% de silano, respectivamente, apresentaram valores significativos para os teores de gel em ambas as velocidades de rotação (10 e 50rpm). A amostra reagida com 0,07% de DCP e 1,5% de silano, a 10rpm, apresentou um teor de gel de 74,77%. A análise termogravimétrica (TGA) realizada evidenciou que houve um aumento da estabilidade térmica do polímero devido à formação de ligações cruzadas. Não se observou um aumento significativo para o limite de resistência para o LLDPE modificado devido à heterogeneidade dos corpos de prova. As análises de FTIR mostraram que houve a graftização e a formação de ligações cruzadas no LLDPE. / The flexible lines are flexible structures manufactured through plastic and steel layers that allows its use in order to permit fluid flow in exploration and production of hydrocarbon between offshore oil units and sea bed and/or coast. Nowadays these pipes are one of the main ways to permit the exploration of hydrocarbon in deepwater. The present study aims to analyze the LLDPE (Low Density Polyethylene) chemical changing through a reactive extrusion process involving VTMS grafting in presence of organic peroxides. After a crosslinking due to water, an analysis will be carried out in order to assess the PEX (crosslinked polyethylene) application in flexible pipe structures. The crosslinking effect at thermal and mechanical properties will also be studied. An experimental planning was carried out in order to evaluate the effect of variable variations such as the rotational velocity of the single-screw extruder, type and concentration of peroxides at melt flow index of the products originated from the LLDPE-peroxides (DCP and Trigonox 101) reaction, and in order to analyze the silane concentration effect, rotational velocity and immersion procedure at melt flow index in products with LLDPE and contents with DCP variable concentrations of silane. The samples were characterized through tests such as MFI (Melt Flow Index), gel content determination, tensile testing and thermal analyses, DSC (Differential Scanning Calorimetry) and TGA (Thermal Gravimetric Analysis). The Fourier Transformed Infrared Spectroscopy (FTIR) was also used to characterize the samples. The samples content 0,07% of DCP and 1,0 and 1,5% of silane, respectively, showed considerable value for gel contents in both rotational velocities (10 and 50rpm). The sample with 0,07% of DCP and 1,5% of silane, at 10rpm, a value of 74,77% of gel content could be noticed. The thermal analyses carried out showed that an increase of thermal stability for the polymer due to crosslinking generation happened. After tensile testing, a considerable changing in mechanical proprieties of the changed LLDPE was not seen due to the specimens heterogeneity. However through FTIR, silane linking was noticed demonstrating the LLDPE reticulation.

As linhas flexíveis, estruturas compostas por um determinado número de camadas plásticas e de aço, possibilitam o escoamento de fluidos em operações de exploração e produção de hidrocarbonetos entre plataformas marítimas de petróleo e o leito marinho e/ou a costa. E, atualmente, têm sido utilizadas na exploração de hidrocarbonetos em lâminas dágua cada vez maiores. O presente estudo visa modificar quimicamente o LLDPE através de processos de extrusão reativa envolvendo a graftização de VTMS na presença de peróxidos orgânicos, e posterior formação de ligações cruzadas promovida pela água. Visa analisar também o efeito da introdução de ligações cruzadas nas propriedades térmicas e mecânicas do LLDPE. De forma a atingir os objetivos propostos, um planejamento experimental foi realizado para analisar o efeito de variáveis como velocidade de rotação do parafuso da extrusora, tipo e teor de peróxido nos índices de fluidez dos produtos da reação do LLDPE com peróxido de dicumila (DCP) e 2,5-dimetil-peróxi-hexano (Trigonox 101). Essa metodologia também foi utilizada para avaliar o efeito da concentração de silano, da velocidade de rotação do parafuso da extrusora e do procedimento de imersão nos índices de fluidez dos produtos da reação do LLDPE com 0,02% p/p de DCP e concentrações variáveis de silano. As amostras foram caracterizadas através dos ensaios para determinação de índice de fluidez (MFI) e teor de gel, ensaios convencionais de tração e técnicas de análise térmica, TGA e DSC. A técnica de FTIR foi utilizada para verificar a ocorrência das reações de graftização e formação de ligações cruzadas no LLDPE. As amostras reagidas com teores de 0,07% de DCP e 1,0 e 1,5% de silano, respectivamente, apresentaram valores significativos para os teores de gel em ambas as velocidades de rotação (10 e 50rpm). A amostra reagida com 0,07% de DCP e 1,5% de silano, a 10rpm, apresentou um teor de gel de 74,77%. A análise termogravimétrica (TGA) realizada evidenciou que houve um aumento da estabilidade térmica do polímero devido à formação de ligações cruzadas. Não se observou um aumento significativo para o limite de resistência para o LLDPE modificado devido à heterogeneidade dos corpos de prova. As análises de FTIR mostraram que houve a graftização e a formação de ligações cruzadas no LLDPE. / The flexible lines are flexible structures manufactured through plastic and steel layers that allows its use in order to permit fluid flow in exploration and production of hydrocarbon between offshore oil units and sea bed and/or coast. Nowadays these pipes are one of the main ways to permit the exploration of hydrocarbon in deepwater. The present study aims to analyze the LLDPE (Low Density Polyethylene) chemical changing through a reactive extrusion process involving VTMS grafting in presence of organic peroxides. After a crosslinking due to water, an analysis will be carried out in order to assess the PEX (crosslinked polyethylene) application in flexible pipe structures. The crosslinking effect at thermal and mechanical properties will also be studied. An experimental planning was carried out in order to evaluate the effect of variable variations such as the rotational velocity of the single-screw extruder, type and concentration of peroxides at melt flow index of the products originated from the LLDPE-peroxides (DCP and Trigonox 101) reaction, and in order to analyze the silane concentration effect, rotational velocity and immersion procedure at melt flow index in products with LLDPE and contents with DCP variable concentrations of silane. The samples were characterized through tests such as MFI (Melt Flow Index), gel content determination, tensile testing and thermal analyses, DSC (Differential Scanning Calorimetry) and TGA (Thermal Gravimetric Analysis). The Fourier Transformed Infrared Spectroscopy (FTIR) was also used to characterize the samples. The samples content 0,07% of DCP and 1,0 and 1,5% of silane, respectively, showed considerable value for gel contents in both rotational velocities (10 and 50rpm). The sample with 0,07% of DCP and 1,5% of silane, at 10rpm, a value of 74,77% of gel content could be noticed. The thermal analyses carried out showed that an increase of thermal stability for the polymer due to crosslinking generation happened. After tensile testing, a considerable changing in mechanical proprieties of the changed LLDPE was not seen due to the specimens heterogeneity. However through FTIR, silane linking was noticed demonstrating the LLDPE reticulation.

Este trabalho teve como objetivo estudar o processo de plasticização do amido via mistura física e por reação química para a produção de novos materiais. A plasticização via mistura física foi realizada empregando-se como agentes plasticização diferentes compostos hidroxilados. Os amidos termoplásticos (TPS) foram processadas em misturador intensivo a 150°C, a partir de misturas contendo de 15 a 40% de agente plasticizante. A plasticização via reação química foi realizada com isocianatos monofuncionais e difuncionais, os quais levaram a obtenção de produtos de enxertia e entrecruzamento, respectivamente. Os produtos obtidos foram caracterizados por difração de Raios X, Calorimetria Exploratória Diferencial (DSC), Termogravimetria (TG), Análise Dinâmico-Mecânica (DMA), Microscopia Eletrônica de Varredura (SEM) e Cromatografia de Permeação em Gel (HPSEC). O estudo dos diferentes plasticizantes propiciou a determinação das características que estas substâncias devem possuir para a preparação de amidos termoplásticos. O cisalhamento desenvolvido durante o processamento em misturador intensivo levou à perda da estrutura cristalina e à desestruturação dos grânulos de amido. O processamento do TPS em misturador intensivo não provoca mudanças significativas na massa molar do amido termoplasticizado. Os amidos termoplasticizados com sorbitol foram aqueles que apresentaram menores valores de absorção de água. Os valores de módulo de Young das amostras plasticizadas com propilenoglicol aumentaram com o aumento do conteúdo de plasticizante. Para as amostras plasticizadas com etilenoglicol o módulo aumenta até 30% de conteúdo de plasticizante, quando ocorre uma diminuição do valor do módulo. Os TPS plasticizados com propilenoglicol, 1, 4-butanodiol, sorbitol e dietilenoglicol apresentaram um aumento da temperatura de transição vítrea com o aumento do tero de plasticizante. Os diferentes TPS obtidos via mistura física apresentaram estabilidade térmica similares à exibida pelo amido in natura. As propriedades mecânicas destes materiais variaram de acordo com o tipo e a quantidade de plasticizante empregado. A análise dos produtos obtidos via reação química (amidos enxertados e entrecruzados) revelou que estas reações promoveram a desestruturação dos grânulos de amido e, independentemente do regente empregado, a modificação produziu derivados mais hidrofóbicos que o amido in natura. A reação do amido com o oligômero de poli-óxido de propileno tolueno di-isocianato permitiu a obtenção de um derivado com propriedades de material elastomérico e elevada capacidade de intumescimento. Os derivados enxertados ou entrecruzados apresentaram perda de cristalinidade, redução do caráter hidrofílico e estabilidades térmicas semelhantes à apresentada pelo amido in natura. / This main of this work was to study of the cornstarch granules plasticization by means of physical or chemical treatments in order to prepare new materials. The plasticization by physical processing was performed in an intensive mixer at 150°C using ditferent hydroxylated compounds as plasticizers. The production of thermoplastic starch (TPS) by chemical reaction was carried out using mono and di-isocyanates to obtain grafted and cross linked derivatives, respectively. All the products were characterized by X Ray Diffraction, Ditferential Scanning Calorimetry (DSC), Thermogravimetry (TG), Dynamical Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), High Pressure Size Exclusion Chromatography (HPSEC). The utilization of ditferent plasticizer permitted determining which characteristics the substances must present to be used in the TPS preparation. The shear developed in the processing step lead to the loss of crystalline pattern and disruption of the starch granules. The utilization of intensive mixer does not produce significant changes in the molar mass of the thermoplastic starch. TPS produced using sorbitol as plasticizer presented the lowest level of water uptake. The valous of Young modulus for TPS produced with propylene glycol increased with the content of plasticizer. To samples produced with ethylene glycol the values of Young modulus increased until 30% and after the modulus decrease. TPS prepared with propylene glycol, 1, 4-butanediol, sorbitol and diethyleneglycol showed an increase in the glass transition temperature with the increase in the plasticizer content. The ditferent TPS produced by physical mixture shoed thermal stabilities similar to the one exhibited by in natura starch. The mechanical properties of these materials were dependent of the type and amount of plasticizer. The analysis of the derivatives obtained by chemical reaction (grafted and cross linked) revealed the occurrence of disruption of the starch granules and, independent1y of isocyanate, the products presented higher hydrophobic character than that one presented by in natura starch. By reaction starch with propylene toluene polyoxide oligomer, it was obtained a derivative with elastomeric properties and high swelling capability. The grafted or cross linked derivatives showed loss of crystallinity, decrease in hydrophilic character, and thermal stability similar to the one exhibited by in natura starch.