Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T17:38:38Z No. of bitstreams: 0 / Made available in DSpace on 2016-11-11T17:38:38Z (GMT). No. of bitstreams: 0 / O polímero de policaprolactona (PCL) dopado com [Eu (TTA) 3 (H2O) 2] no complexo 1, 2, 5, 10 e 15% de concentrações foram preparadas e as suas propriedades térmicas e de luminescência discutidas. As bandas de absorção de infravermelho no intervalo de 1800-1550 cm-1 correspondente ao ν sensível (C = O) foram seleccionados para a técnica de ajuste de curva de desconvolução e confirmou-se que os picos de componentes são deslocados gradualmente com o aumento da concentração de dopagem. O deslocamento do ν (C = O) banda para os β-dicetonato complexos para novas posições nos sistemas dopados (pCLE) proporcionam boa evidência de que o ião de metal está coordenado aos átomos de oxigénio dos grupos carbonilo PCL. Calorimetria exploratória diferencial (DSC) não mostraram alterações significativas na segunda temperatura de fusão (Tm2) para as amostras de cinema. No entanto, a cristalinidade é afectada pelo complexo dopante em materiais de polímero em maior concentração. A análise termogravimétrica (TGA) não mostra nenhuma perda de peso na gama de 50-200 ° C para os sistemas poliméricos dopados, corroborando a interacção da matriz de polímero com Eu3 + complexo n por substituição das moléculas de água no complexo precursor. A observação das bandas de emissão característicos resultantes das transições 5D0 → 7FJ (J = 0-4) dominadas pela hipersensibilidade transição 5D0 → 7F2 em torno de 614 nm, de íon Eu3 +, indicando que a incorporação de Eu3 + complexo no sistema de polímero. O valor da eficiência quântica de emissão de nível 5D0 para os materiais poliméricos dopados (η = 40-62%) são mais elevados do que para o complexo [Eu (TTA) 3 (H2O) 2] complexo (η = 29%), sugerindo que o matriz de polímero actua como co-sensibilizador do processo de luminescência. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-12-21T18:14:50Z No. of bitstreams: 0 / Made available in DSpace on 2016-12-21T18:14:50Z (GMT). No. of bitstreams: 0 / Com a alta taxa de desertificação dos solos e a necessidade de irrigação constante dos plantios, existe a necessidade da criação de um polímero superabsorvente (SAP) com a característica de ser biodegradável. Observando o estágio tecnológico relacionado às atividades de pesquisa e desenvolvimento de SAPs no Brasil, foi utilizado o poli (álcool vinílico)/PVA e o amido de mandioca para a formação de hidrogéis a partir de blendas poliméricas. Assim, soluções aquosas desses polímeros foram reticuladas quimicamente, usando o glutaraldeído como agente reticulante e comparadas com amostras reticuladas por radiação gama, irradiadas a uma dose de 25 kgy. Os hidrogéis resultantes foram caracterizados por diversas técnicas analíticas como a fração gel, o intumescimento em água destilada, a espectroscopia de infravermelho com refletância total atenuada ATR (FT-IR), a termogravimetria (TG/DTG), a calorimetria exploratória diferencial (DSC) e a microscopia eletrônica de varredura (MEV). Observou-se uma maior reticulação nos hidrogéis reticulados com o glutaraldeído e em consequência um menor grau de intumescimento quando comparadas com as amostras que foram irradiadas. Com vias a produzir hidrogéis em uma escala industrial, misturas de PVA e amido foram processadas por extrusão reativa, mudando assim o processo de preparação de solução aquosa para misturas secas. Foram extrudadas amostras de PVA com diferentes pesos moleculares tais como o PVA 26-88, o PVA 40-88, o PVA 110-99 e o poli (ácido glioxílico vinílico)/PVGA, este último sintetizado a partir da modificação do PVA 110-99. Foi adicionado na mistura o ácido glioxílico no desenvolvimento do SAP por reticulação química nas amostras do PVA, por ter grupos carboxílicos que podem aumentar o intumescimento e também servir como agente reticulante. Também foram feitas formulações de extrusão sem o ácido glioxílico para serem usados como brancos. Adicionou-se nas misturas diversos agentes plastificantes como a glicerina e o polietilenoglicol (PEG 400) e as propriedades mecânicas foram estudadas. Foram desenvolvidas duas análises fatoriais de 23 para analisar as mudanças na reticulação das formulações. Os pellets foram caracterizados com as mesmas técnicas analíticas que os hidrogéis feitos em solução, adicionando-se análises de intumescimento e reversibilidade de intumescimento em diversos solventes como a água pura, a água da chuva, as soluções tampão de pH 3, pH 7 e pH 10, além de soro fisiológico, visando a aplicação em diferentes solos com diferentes pH e salinidades. Os testes de intumescimento em diferentes sais demonstraram a ter menor retenção de água quando comparada com água pura. Os testes de reversibilidade de intumescimento dos pellets mostraram que a maioria das formulações perde a sua capacidade de intumescimento máximo aos seis primeiros ciclos. Foi feita a compressão dos pellets para observar a flexibilidade dos mesmos, visando aplicações debaixo do solo. Realizou-se um estudo de biodegradação em terra ao longo de 120 dias, e estudou-se a relação direta com os valores da fração gel. Os resultados mostraram que os pellets menos reticulados intumesceram mais, enquanto as microscopias mostraram que essas amostras tinham uma morfologia mais porosa, o que contribuiu na melhora na retenção do líquido. Além disso, eram mais flexíveis e biodegradaram mais rápido, sendo extremamente viáveis para a aplicação na agricultura. Foi verificado que o PVA 40-88 apresentou os melhores valores de intumescimento em diferentes sais. Com o SAP obtido, foi constatado que a extrusão reativa é um método viável para a produção dos SAPs. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

The uniform dispersion of the nano fillers without agglomeration in a polymeric matrix is widely adapted for the purpose of mechanical properties enhancement. In the context to biomedical applications, the type and amount of nanoparticles can potentially influence the biocompatibility. In order to address these issues, High Density Polyethylene (HDPE) based composites reinforced with graphene oxide (GO) were prepared by melt mixing followed by compression moulding. In an attempt to tailor the dispersion and to improve the interfacial adhesion, polyethylene (PE) was immobilized onto GO sheets by nucleophilic addition-elimination reaction. A good combination of yield strength (ca. 20 MPa), elastic modulus (ca. 600 MPa) and an outstanding elongation at failure (ca. 70 %) were recorded with 3 wt % polyethylene grafted graphene oxide (PE-g-GO) reinforced HDPE composites. Considering the relevance of protein adsorption as a biophysical precursor to cell adhesion, the protein adsorption isotherms of bovine serum albumin (BSA) were determined to realize three times higher equilibrium constant (Keq) for PE-g-GO reinforced HDPE composites as compared to GO reinforced composites. In order to assess the cytocompatibility, osteoblast cells (MC3T3) were grown on HDPE/GO and HDPE/PE-g-GO composites, in vitro. The statistically significant increase in metabolically active cell was observed, irrespective of the substrate composition. Such observation indicated that HDPE with GO or PE-g-GO addition (upto 3 wt %) can be used as cell growth substrate. The extensive proliferation of cells with oriented growth pattern also supported the fact that tailored GO addition can support cellular functionality, in vitro. Taken together, the experimental results suggest that the PE-g-GO in HDPE can effectively be utilized to enhance both mechanical and cytocompatibility properties and can further be explored for potential biomedical applications.

Le but de ce travail était d'étudier le comportement des cristaux de théophylline lors de la déshydratation statique en monocouche dans différentes conditions hygrothermiques et le comportement du même produit lors de la déshydratation séchage en lit agité dans un séchoir par contact sous vide dans des conditions hygrothermiques semblables. Tout d'abord, la forme hydratée et les formes déshydratées de la théophylline ont été identifiées par DSC, ATG et DRXP. Ensuite, des essais gravimétriques statiques à température et humidité relative constantes ont été effectués et les évolutions de teneur en eau au cours du temps ont été enregistrées à des températures de 20 à 80 °C et des humidités relatives de 4 à 50%. Les données à l'équilibre thermodynamique ont été utilisées pour tracer les isothermes de désorption et établir le diagramme de phase solide-solide de la théophylline. Enfin, les cinétiques de déshydratation ont été étudiées. Il a été constaté que la constante de vitesse de déshydratation augmente exponentiellement avec la température et diminue de façon exponentielle avec l'humidité relative. Un modèle semi-empirique permettant la prédiction de l'évolution dans le temps de la teneur en eau du produit pour différentes conditions opératoires a été développé. Dans la seconde partie du travail, il a été d'abord démontré que la SPIR couplée avec la régression PLS permet de suivre en ligne et in situ la composition exacte du mélange des différentes formes de la théophylline (et d'eau) pendant le séchage. Ensuite, l'influence des paramètres de fonctionnement (température et l'activité de l'eau) sur les cinétiques de transformation de l'état solide a été étudiée. Il a été observé que la déshydratation commence d'abord par la formation de la forme anhydre métastable puis, après un temps de latence, continue par la formation de la forme anhydre stable. Il s'est avéré aussi que la température a été le principal facteur contrôlant la vitesse globale du procédé, mais aussi la teneur finale de la forme anhydre stable et de la forme métastable, ceci étant valable pour le séchoir étudié et pour les conditions opératoires considérées. Finalement, un modèle semi-empirique permettant la simulation de l'état du produit (température, teneur en eau, teneur en forme hydratée, anhydre métastable et stable) au cours du temps pour différentes conditions opératoires du séchage (pression dans la cuve et température du fluide caloporteur) a été proposé / The aim of this work was to investigate the dehydration process of a single static layer of theophylline's crystals under different hygrothermal conditions and the dehydration-drying process of a stirred bed of theophylline in a vacuum contact dryer in nearly the same hygrothermal conditions. First of all, the hydrated and dehydrated forms of theophylline were identified using DSC, TGA and PXRD devices. Next, the static gravimetric experiments at constant temperature and relative humidity were carried out and the water content evolutions with time were recorded at temperatures from 20 to 80°C and humidities from 4 to 50%. Then, the thermodynamic equilibrium data were reported as desorption isotherms and solid-solid phase diagrams. Finally, the dehydration kinetics were analyzed. The dehydration rate constant was found to increase exponentially with temperature and to decrease exponentially with relative humidity. A simple semi-empirical model allowing for prediction of the product water content time evolution time for different processing parameters was developed. In the second part of the work, it was first proven that NIRS coupled with PLS regression enabled to monitor inline and in-situ the exact composition of the mixture of different forms of theophylline (and of water) during drying. Second, the influence of operating parameters (temperature and water activity) on the kinetics of solid state transformations was investigated. It was observed that the dehydration begun by the formation of the metastable anhydrate and, after a time delay, continued by the formation of the stable one. It was also pointed out that the temperature was the main process factor controlling not only the overall process rate but also the final contents of the stable and metastable anhydrates, this observation being valid for the considered dryer and for the considered operating conditions. Finally, a semi-empirical model allowing for simulation of the product state (temperature, hydrate content, metastable and stable anhydrate contents and water content) time evolution for different processing parameters (pressure in the vessel and temperature of the heating fluid) was proposed

Curcumin is the major phenolic diarylheptane derivative in Curcuma longa and has been reported to possess pharmacological activities. Unfortunately this compound suffers from poor bioavailability and rapid neutral-alkaline degradation. Co-crystal of curcumin is one option under exploration, motivated by the fact that a number of active pharmaceutical ingredient (API) co-crystals with improved dissolution have recently been synthesized. Hence, co-crystallization technique highlights an alternative means to improve the performance of curcumin. Within our work evidences for a co-crystal was ascertained from DSC, Kofler hot stage screening and PXRD, and all confirmed a new crystal phase could have been formed between curcumin and a co-crystallizing agent, nicotinamide. We report that re-crystallization step essentially aids the purification of commercial curcumin, a herbal based actives. Otherwise the prevalence of a new crystal phase in solvent-mediated co-crystallization will be significantly reduced. Besides, phase diagram is an effective tool for the study of solubility behaviours in co-crystal system. In order to acquire related techniques, fenbufen, a poorly water soluble drug, was selected. The result showed the huge difference in solubility between fenbufen and nicotinamide lead to difficulty in the construction of phase diagram.

No description available.

Formaldehyde-based adhesives have been reported to be detrimental to health. Petrochemical-based adhesives are non-renewable, limited and costly. Therefore, the improvement of environmental-friendly adhesive from natural agricultural products has awakened noteworthy attention. A novel adhesive for wood application was successfully prepared with enhanced shear strength and water resistance. The Fourier transmform infrared spectra showed the surface functionalities of the functionalized carbon nanotubes (FCNTs) and soy protein isolate nanocomposite adhesive. The attachment of carboxylic functional group on the surface of the carbon nanotubes (CNTs) after purification contributed to the effective dispersion of the CNTs in the nanocomposite adhesive. Hence, enhanced properties of FCNTs were successfully transferred into the SPI/CNTs nanocomposite adhesive. These unique functionalities on FCNTs however, improved the mechanical properties of the adhesive. The shear strength and water resistance of SPI/FCNTs was higher than that of the SPI/CNTs. SEM images showed the homogenous dispersion of CNTs in the SPI/CNTs nanocomposite adhesive. The carbon nanotubes were distributed uniformly in the soy protein adhesive with no noticeable clusters at relatively reduced fractions of CNTs as shown in the SEM images, which resulted into better adhesion on wood surface. Mechanical (shear) mixing and ultrasonication with 30 minutes of shear mixing both showed an improved dispersion of CNTs in the soy protein matrix. However, ultrasonication method of dispersion showed higher tensile shear strength and water resistance than in mechanical (shear) mixing method. Thermogravimetric analysis of the samples also showed that the CNTs incorporated increases the thermal stability of the nanocomposite adhesive at higher loading fraction. Incorporation of CNTs into soy protein isolate adhesive improved both the shear strength and water resistance of the adhesive prepared at a relatively reduced concentration of 0.3%.The result showed that tensile shear strength of SPI/FCNTs adhesive was 0.8 MPa and 7.25MPa at dry and wet state respectively, while SPI/CNTs adhesive had 6.91 MPa and 5.48MPa at dry and wet state respectively. There was over 100% increase in shear strength both at dry and wet state compared to the pure SPI adhesive. The 19% decrease in value of the new adhesive developed compared to the minimum value of ≥10MPa of European standard for interior wood application may be attributed to the presence of metallic particles remaining after purification of CNTs. The presence of metallic particles will prevent the proper penetration of the adhesive into the wood substrate. The type of wood used in this study as well as the processing parameters could also result into lower value compared to the value of European standard. Therefore, optimization of the processing parameter as well as the conversion of carboxylic acid group on the surface of the CNTs into acyl chloride group may be employed in future investigation. However, the preparation of new nanocomposite adhesive from soy protein isolate will replace the formaldehyde and petrochemical adhesive in the market and be of useful application in the wood industry. / Civil and Chemical Engineering / M. Tech. (Chemical Engineering)

Formaldehyde-based adhesives have been reported to be detrimental to health. Petrochemical-based adhesives are non-renewable, limited and costly. Therefore, the improvement of environmental-friendly adhesive from natural agricultural products has awakened noteworthy attention. A novel adhesive for wood application was successfully prepared with enhanced shear strength and water resistance. The Fourier transmform infrared spectra showed the surface functionalities of the functionalized carbon nanotubes (FCNTs) and soy protein isolate nanocomposite adhesive. The attachment of carboxylic functional group on the surface of the carbon nanotubes (CNTs) after purification contributed to the effective dispersion of the CNTs in the nanocomposite adhesive. Hence, enhanced properties of FCNTs were successfully transferred into the SPI/CNTs nanocomposite adhesive. These unique functionalities on FCNTs however, improved the mechanical properties of the adhesive. The shear strength and water resistance of SPI/FCNTs was higher than that of the SPI/CNTs. SEM images showed the homogenous dispersion of CNTs in the SPI/CNTs nanocomposite adhesive. The carbon nanotubes were distributed uniformly in the soy protein adhesive with no noticeable clusters at relatively reduced fractions of CNTs as shown in the SEM images, which resulted into better adhesion on wood surface. Mechanical (shear) mixing and ultrasonication with 30 minutes of shear mixing both showed an improved dispersion of CNTs in the soy protein matrix. However, ultrasonication method of dispersion showed higher tensile shear strength and water resistance than in mechanical (shear) mixing method. Thermogravimetric analysis of the samples also showed that the CNTs incorporated increases the thermal stability of the nanocomposite adhesive at higher loading fraction. Incorporation of CNTs into soy protein isolate adhesive improved both the shear strength and water resistance of the adhesive prepared at a relatively reduced concentration of 0.3%.The result showed that tensile shear strength of SPI/FCNTs adhesive was 0.8 MPa and 7.25MPa at dry and wet state respectively, while SPI/CNTs adhesive had 6.91 MPa and 5.48MPa at dry and wet state respectively. There was over 100% increase in shear strength both at dry and wet state compared to the pure SPI adhesive. The 19% decrease in value of the new adhesive developed compared to the minimum value of ≥10MPa of European standard for interior wood application may be attributed to the presence of metallic particles remaining after purification of CNTs. The presence of metallic particles will prevent the proper penetration of the adhesive into the wood substrate. The type of wood used in this study as well as the processing parameters could also result into lower value compared to the value of European standard. Therefore, optimization of the processing parameter as well as the conversion of carboxylic acid group on the surface of the CNTs into acyl chloride group may be employed in future investigation. However, the preparation of new nanocomposite adhesive from soy protein isolate will replace the formaldehyde and petrochemical adhesive in the market and be of useful application in the wood industry. / Civil and Chemical Engineering / M. Tech. (Chemical Engineering)

Made available in DSpace on 2014-10-09T12:35:42Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:56Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:42:04Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:42Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP