Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work aims the synthesis and study of ZSM-5 catalysts for the conversion of ethanol to light olefins, especially, using an alternative and inexpensive route. The ethanol emerges as a renewable source for the production of olefins and the ZSM-5 catalyst has important characteristics for this type of reaction such as acidity, surface area and particle size. The synthesis was carried out in hydrothermal treatment at 170 °C. Were performed two conventional synthesis with templates, using n-Butylamine and tetrapropylammonium hydroxide (TPAOH), and an third and alternative route using a nucleating gel. The catalyst characterization was performed using several techniques (XRD, BET, XRF, SEM and TGA) and was observed the formation of the ZSM-5 structure in all the synthesis methods. The catalysts were evaluated in the ethanol to olefins (ETO) reaction, and was evaluated the influence of the reaction temperature (250 to 450 °C) and SAR (SiO2/Al2O2 ratio) in the selectivity for olefins. The products analyses were made with a gas chromatograph with a FID-type detector. The ethylene yield was above to 80 % for all catalysts, and some above 90 %. Lower SAR values provided higher yields for propylene, around to 9 %. The temperature, SAR and template used in the synthesis influenced in the selectivity. In addition, was evaluated the influence of the catalyst mass, dilution and also its modification with different metals. When the mass was increase, the yield for propylene increased. The catalyst dilution with common sand provided, in some concentrations, greater propylene formation. The nucleating gel method showed to be a viable alternative for ZSM-5 synthesis and its use in the ETO reaction. / Este trabalho relata o estudo da síntese e caracterização de catalisadores ZSM-5 para seu posterior uso na reação de conversão de etanol para olefinas, especialmente utilizando uma rota alternativa mais econômica. O etanol surge como uma fonte renovável para a produção de olefinas e o catalisador ZSM-5 possui importantes características para esse tipo de reação, tais como acidez, área superficial e tamanho de partícula. A síntese foi conduzida de maneira hidrotérmica a 170 °C. Foram realizadas duas sínteses convencionais com direcionadores de estrutura, utilizando n-butilamina e hidróxido de tetrapropilamônio (TPAOH), e uma terceira rota alternativa utilizando um gel nucleante. A caracterização dos compostos sintetizados foi realizada com diversas técnicas (DRX, BET, FRX, MEV e TGA) sendo observada a formação da estrutura de ZSM-5 em todas as técnicas de síntese utilizadas. Os catalisadores foram avaliados na reação de conversão de etanol à olefinas (ETO) e foi avaliada a influência da temperatura de reação (250 a 450 °C) e SAR (SiO2/Al2O3 ratio) na seletividade das olefinas. A análise dos produtos formados foi realizada em um cromatógrafo a gás com detector tipo FID. O rendimento para eteno foi superior a 80 % em todos os catalisadores, sendo para alguns acima de 90 %. Baixos valores de SAR proporcionaram maiores rendimentos para propeno, em torno de 9 %. A temperatura, o valor de SAR e os direcionadores empregados na síntese influenciaram na seletividade. Também, foi avaliada a influência da quantidade de massa do catalisador, a diluição e também a modificação com diferentes metais (Ga, La, In) e um não metal (P). Quando a massa foi aumentada, o rendimento para propeno aumentou consideravelmente. A diluição com areia comum, em algumas concentrações, proporcionou maior formação de propeno. O método de síntese via gel nucleante mostrou ser uma alternativa viável para a síntese de ZSM-5 e seu uso como catalisador na reação ETO.

This diploma thesis deals with study of crystalline structure of polyhydroxybutyrate (PHB), which contains different types of additives for studying of their nucleation activity and which were prepared by mixing. It is about boronitrid (BN), sacharin, hydroxapatit, plasticizer Tegmer a tree types of talc. Crystal structure was analysed by differential scanning calorimetry and x-ray diffraction, supramolecular structure was observed by optical microscopy (polarized and confocal laser scanning). Nucleating activity was evaluated by isothermal and non-isothermal crystallization made on calorimeter and heated table of optical microscope. There is not influence of additives on crystallographic structure, but additives affects number and size of spherulites including crystal domains defects, which can have impact on final mechanical properties. BN and talcs react as nucleating agents, other additives during low and high cooling speeds (vc) inhibit nucleation and in middle cooling speeds are without effect. Nucleating activity is not evaluated by numerically, because decrease of crystallization temperature together with vc is not linear. Results of direct methods are based on picture analysis, which is great benefit for understanding of crystal behaviour of PHB.

Diploma thesis is summarizing sources and technology of PHB and its physical and chemical properties compared to other polymers. Thesis mentions usage and function of certain additives in PHB matrix and their impact on the final product. Practical part of the thesis is concerned with technological parameters and degradation of the PHB during extrusion. The thesis also observes behaviour of nucleating agents on crystallinity and crystallization properties of prepared compounds. Degradation was analyzed by MFI and colour difference against standard material, FTIR was not successfully used for the purpose of degradation. Crystallinity and crystallization behaviour was analysed by DSC and optical microscopy with heated operating table. Graphs were created from results of analysis and suitable usage of each nucleating agent was considered. Boron nitride was selected as the most suitable nucleating agent due to creating higher amount of smaller spherulites.

Cette étude s’inscrit dans le projet ANR Blanc COPIN qui a pour but de développer et de comprendre les nanocomposites à partir de nanoparticules inorganiques mélangées à un polymère semi-cristallin. L’innovation du partenaire du projet, Imerys, a été de synthétiser des particules de talcs à l’échelle nanométrique. Le talc étant connu pour ces effets nucléants, l’objectif est d’utiliser ces nanoparticules pour voir leur influence sur un matériau semi-cristallin et plus spécifiquement sur la cristallisation de ce dernier lorsqu’elles sont orientées. Différents talcs synthétiques ont été étudiés changeant au niveau de leur durée de synthèse ou encore de leur modification de surface. Pour cela, la première partie de cette étude a été de disperser le talc en utilisant ou non des modifications chimiques de surface ainsi que des compatibilisants afin d’obtenir le meilleur état de dispersion et de distribution des particules. Ces continuums d’interactions ainsi créés montrent une nette amélioration de l’état de dispersion mais aussi l’amélioration des propriétés telles que la tenue en température. Les parties suivantes ont concernées plus spécifiquement la cristallisation en convoitant d’expliquer comment les nanoparticules peuvent s’orienter lors de l’écoulement tel que le cisaillement, comment elles génèrent une orientation cristalline spécifique du à leur effet nucléant, quel est le mécanisme prépondérant de la cristallisation entre la nucléation par l’orientation de macromolécules ou la nucléation provenant des nanoparticules. Il a aussi été question de déterminer les morphologies cristallines des nanocomposites lors du cisaillement / This study is part of the ANR Blanc COPIN which aim is to develop and understand the nanocomposites from inorganic nanoparticles mixed with a semi-crystalline polymer. The innovation of the project partner, Imerys, was to synthesized talc particles at the nanoscale. Talc is known for his nucleating effects and the goal is to use these nanoparticles to see their influence on a semi-crystalline material. Several synthetic talcs were employed differing from the synthesis time and chemical surface modifications. For this, the first part of this study was to disperse the talc using or not chemical modifications of surfaces as well as compatibilizers to obtained the best dispersion state and particles distribution. These continuums interaction created show a real improvement in the dispersion but also of properties such as heat resistance. The following parties concerned more specifically the crystallization trying to explain how nanoparticles can be oriented during shear flow, what is the leverage of these talcs on the crystallization when it was oriented, how they generate a specific crystal orientation coming from their nucleating effect, which is the predominant mechanism of crystallization nucleation between the macromolecules orientations or the nucleation of nanoparticles. It was also a question of determining the resulting crystal morphologies

No description available.

Ce travail se focalise sur l’étude de cellules solaires organiques modèles basées sur le mélange de poly(3-hexylthiophène) (P3HT) et de l'ester méthylique de l'acide [6,6]-phényl C61 butyrique (PCBM). La corrélation entre la morphologie de la couche active, les paramètres de mises en œuvre et le rendement photovoltaïque a été soigneusement étudiée afin d’obtenir l’optimisation de l’efficacité de tels dispositifs. Une méthode originale pour contrôler la séparation de phases dans ces mélanges a été proposée et consiste à l'intégration de copolymères blocs comme additifs. Trois copolymères séquencés ont été utilisés en tant qu’agents de nanostructuration et/ou d'agents de nucléation. Il a notamment été montré que l'incorporation de P3HT-b-PI permet l'augmentation du nombre de cristallites de P3HT tout en limitant l’agglomération du PCBM. D'autre part, l'incorporation de P3HT-b-P4VP dans les mélanges de P3HT:PCBM a permis de contrôler l'orientation des cristallites de P3HT, améliorant par ce fait le transport de charge dans les dispositifs. / This work investigates organic solar cells made of a blend of polymeric materials based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as model system. The correlation between the photovoltaic active layer morphology and the performance of the organic solar cell is thoroughly investigated. The chosen method for controlling phase separation in the polymeric blends is to incorporate block copolymers as additives. Three systematically selected block copolymers were used as nanostructuring and/or nucleating agents. Indeed, the incorporation of P3HT-b-PI induces the increase in the number of P3HT crystallites as well as suppresses the growth of PCBM aggregates. On the other hand, the incorporation of P3HT-b-P4VP into P3HT:PCBM decreases the crystallization of P3HT but increases its face-on orientation, a requirement for an enhanced charge transport in organic PV devices.

No description available.

The aim of submitted diploma thesis is the study of non-isothermal crystallization kinetics of polylactide (PLA) with selected agents (1 %) and observation of the emerging crystalline structure under polarizing optical microscope. The agents were talc, a mixture of organic salts with the addition of amorphous SiO2 (HPN 68L) and zinc stearate (HPN 20E) and LAK-301 (potassium salt of 5-dimethylsulfoisophtalate), which is a nucleating agent developer for PLA. The PLA matrix served as a reference. Non-isothermal crystallization took place on a differential scanning calorimeter at cooling rates () 0,3; 0,5; 0,7; 1; 1,5; 2 °C/min After non-isothermal crystallization, the crystalline fraction (Xc) od PLA was evaluated from X-ray diffraction analysis, and the supramolecular structure was observed after chemical degradative etching using confocal laser scanning microscope. The crystallization kinetics were evaluated by the methods of Jeziorny and Mo and the activation energy of the crystallization was determined according to the Friedmann method. All prepared materials were amorphous (Xc 40 % for up to 1,5 °C/min). However, for LAK-301, Xc decreased to 30 % already at the = 2 °C/min and it can be assumed that with increasing its nucleation activity will decrease. A spherulitic structure was observed in all samples, but the number and size of spherulites decreased with increasing and the appearance varied according to the type of agent. Both kinetic models proved to be unsuitable for materials with low Xc and the highest because the rate of crystallization did not change. With the Jeziorny method, it was possible to evaluate the kinetics only for the relative crystallinity Xt = 29–50 % and with the Mo method it was not possible to evaluate the data for the highest for PLA matrix and sample with HPN 68L. The samples with LAK-301 and HPN 68L showed the lowest activation energy.