Дисертації з теми "Carbon nanotubes nanocomposite"
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PAMMI, SRI LAXMI. "CARBON NANOCOMPOSITE MATERIALS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1069881274.
Повний текст джерелаPenu, Christian. "Nanocomposites à matrice polyamide 6 ou polystyrène et à renforts de nanotubes de carbone : du procédé de synthèse aux phénomènes de percolation." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL087N/document.
Повний текст джерелаThe introduction of carbon nanotubes into polymers leads to nanocomposite materials with exceptional properties. These later depend, however, on the dispersion and distribution of carbon nanotubes inside the matrix. A key objective, in nanocomposite preparation, is the set up of incorporation processes allowing a good state of dispersion of the nanotubes into the matrix. An in situ polymerization process, coupled with an ultrasound processor, was chosen to best fulfill this objective. The optimization of this process implies the knowledge of the evolution of reaction kinetics and rheological properties during the polymerization. The influence of carbon nanotubes on the anionic activated polymerization of e-caprolactam was investigated by calorimetric and rheokinetic studies. Carbon nanotubes were found to slow down polymerization kinetics and highly increase the viscosity after a certain conversion degree. This inhibition phenomenon could be produced by a reaction between carbon nanotubes and the catalyst employed for the polymerization reaction. The inhibition effect depended also on the state of dispersion of the nanotubes, consequently, kinetic and rheokinetic measurements are an indirect method to estimate the state of dispersion. The electrical and rheological properties of the nanocomposites were also investigated. The influence of the state of dispersion and other parameters, such as temperature, on the electrical and rheological percolation thresholds was identified
Muñoz, Martín Jose María. "Advanced amperometric nanocomposite sensors based on carbon nanotubes and graphene: characterization, optimization, functionalization and applications." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/311424.
Повний текст джерелаEntre la amplia gama de nanocompósitos, la incorporación de materiales conductores nanoestructurados de carbono, entre los que se encuentran los nanotubos de carbono (NTCs) y el grafeno, dentro de una matriz polimérica aislante, es una forma muy atractiva de combinar las propiedades mecánicas y eléctricas únicas del material de relleno con los atributos de los plásticos. Concretamente, los materiales nanocompósitos basados en carbono han jugado un gran liderazgo en el campo de la electroquímica analítica, sobre todo en el desarrollo de dispositivos (bio)sensores, debido a sus interesantes ventajas con respecto a un material conductor puro. Dichas ventajas les proporcionan un alto valor añadido, como versatilidad, durabilidad, fácil regeneración de la superficie e integración, simple incorporación de (bio)modificadores o baja corriente de fondo, entre otras. En este sentido, esta tesis aborda el desarrollo de sensores nanocompósitos avanzados de tipo amperométrico que, habiendo sido optimizada su relación carbono/polímero, pueden ser modificados con un amplio abanico de nanopartículas (NPs) para mejorar su eficiencia electroanalítica. Las propiedades eléctricas de estos nanocompósitos y, por lo tanto, su aplicabilidad analítica, están directamente influenciadas tanto por la naturaleza de las partículas conductoras como por la cantidad y distribución espacial de éstas a través de la matriz polimérica aislante. Una de las propiedades electroquímicas más importantes que envuelven a estos materiales es la similitud de su comportamiento electroquímico con respecto a un array de microelectrodos. Por lo tanto, una optimización de la relación carbono/polímero con respecto a la naturaleza del material conductor de partida permitirá lograr una mayor dispersión de las áreas conductoras a través de las zonas no conductoras, presentando beneficios similares a los de un array de microelectrodos. Además, es conocido que algunos parámetros, tales como la resistividad del material compuesto, la transferencia electrónica, la robustez del material y la corriente capacitiva están fuertemente influenciadas por la naturaleza física de la muestra de nanotubos de partida, como son su relación longitud/diámetro o su pureza, hecho que pueden influir fuertemente en la respuesta electroanalítica final del material transductor. Bajo este contexto, la primera etapa de esta tesis consistió en la implementación de un conjunto de técnicas instrumentales que, aplicadas de manera sistemática, han perimitido, la caracterización y optimización de la composición de materiales nanocompósitos basados en nanotubos de carbono y resina epoxi (Epotek H77) con respecto a la naturaleza de los NTCs de partida para la fabricación de sensores electroquímicos más eficientes. El protocolo de caracterización llevado a cabo incluye herramientas eléctricas, electroquímicas, morfológicas, microscópicas, espectroscópicas y electroanalíticas. Una vez optimizada las proporciones de NTC/epoxi, el siguiente paso consistió en mejorar el rendimiento analítico de estos sensores electroquímicos nanocompósitos incorporándoles diferentes NPs con la finalidad de introducir algún tipo de efecto electrocatalítico. Para alcanzar este objetivo, se desarrolló una metodología simple para la síntesis de una amplia gama de NPs. La Síntesis Intermatricial (IMS) fue utilizada como técnica verde para el diseño de tres rutas diferentes que permitan una incorporación personalizada de estas NPs en el material transductor, obteniendo así sensores amperométricos más sensibles a diferentes analitos. Finalmente, los estudios de caracterización y funcionalización implementados en los sensores nanocompósitos basados en NTCs han sido extendidos para materiales nanocompósitos basados en otra forma alotrópica del carbono: el grafeno, el cual es el último descubrimiento en términos de material de carbono nanoestructurado.
Among the wide range of nanocomposites, the incorporation of conducting nanostructured carbon materials, such as carbon nanotubes (CNTs) and graphene, into an insulating polymeric matrix is a very attractive way to combine the unique mechanical and electrical properties of individual filler with the advantages of plastics. Concretely, carbon–based nanocomposite materials have played a leading role in the analytical electrochemistry field, particularly in (bio)sensor devices, due to their interesting advantages regarding to a pure conductive material, such as versatility, durability, easy surface regeneration and integration, facile incorporation of a variety of (bio)modifiers or low background current, among others. Accordingly, this thesis tackles the development of advanced amperometric nanocomposite sensors that having been optimized regarding to carbon/polymer composition ratios, can be tunable with different types of nanoparticles (NPs) for improving their electroanalytical efficiency. The electrical properties of these nanocomposites and, therefore, their analytical applicability, are directly influenced by the conducting particles nature and the amount and spatial distribution of them through the insulating polymeric matrix. One of the most important electrochemical properties of these materials is the similarity of their electrochemical behavior with a microelectrode array. Thus, an optimization of the carbon/polymer ratio with respect to the nature of the conducting material will allow to achieve a greater dispersion of the conducting areas through the non-conducting areas, presenting similar benefits to the microelectrode array. In addition, it is known that some parameters, such as composite resistivity, heterogeneous electron transfer rate, material robustness and background capacitance current are strongly influenced by the physical nature of the raw CNT sample, such as their diameter/length ratio and purity, fact that may strongly influences the final electroanalytical response of the transducer material. Under this context, the first step of this thesis consisted of implementing a group of instrumental techniques that, systematically applied, have allowed the characterization and optimization of nanocomposite materials composition based on CNTs and epoxy resin (Epotek H77) in relation to the nature of the raw CNT sample for the fabrication of more efficient electrochemical sensors. The developed characterization protocol includes electrical, electrochemical, morphological, microscopic, spectroscopic and electroanalytical tools. Having been optimized the MWCNT/epoxy composition ratios, the next step consisted of enhancing the analytical performance of these electrochemical nanocomposite sensors introducing some electrocatalytical effect by the incorporation of different NPs. For this goal, a simple methodology for synthesizing a wide range of different NPs has been developed. Intermatrix Synthesis (IMS) has been used as a green technique to design three different routes for CNT/epoxy nanocomposite electrodes modification, which offer a customized way for the preparation of sensitive amperometric sensors. Finally, the characterization and functionalization studies applied for CNT–based electrochemical nanocomposite sensors have been extended for nanocomposite materials based on another allotropic form of carbon: the graphene, which is the last discovery in terms of nanostructured carbon material.
Johnson, Rolfe Bradley. "Crystallization effects of carbon nanotubes in polyamide 12." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34795.
Повний текст джерелаAbu-Zahra, Esam. "High Strength E-Glass/CNF Fibers Nanocomposite." Cleveland State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=csu1198878550.
Повний текст джерелаGuo, Yan. "Surface functionalization of carbon nanotubes for nanocomposite and biomedical in vivoImaging." Cincinnati, Ohio : University of Cincinnati, 2007. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1180118173.
Повний текст джерелаAdvisor: Dr. Donglu Shi. Title from electronic thesis title page (viewed July 17, 2009). Includes abstract. Keywords: Carbon nanotubes; plasma functionalization; alumina; nanocomposite; quantum dots; in vivo imaging. Includes bibliographical references.
Zhao, Qi. "Characterization and Thermal Decomposition Behavior of Carbon Nanotubes and Nanocomposites." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378113311.
Повний текст джерелаCampaigne, Earl Andrew III. "Fabrication and Characterization of Carbon Nanocomposite Photopolymers via Projection Stereolithography." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/50270.
Повний текст джерелаMaster of Science
Semaan, Chantal. "Polymères nanostructurés à base de nanotubes de carbone." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14187/document.
Повний текст джерелаThis work is concerned with the study of carbon nanotubes (CNT) dispersions in a polymer matrix in order to obtain nanocomposite with unique properties. In the first part, we investigated the CNT wrapping by amphiphilic block copolymers to facilitate their suspension in aqueous solution. Based on the results, we could assess the effect on CNT dispersion quality of the molar mass of copolymers, the nature of the hydrophobic block and the length of hydrophilic block. In the second part, the incorporation of CNTs in polymer matrix was developed. Water or melt processing were chosen to control the distribution of CNTs in various polymer matrices (Polyethylene oxide, polyethylene and polymethyl methacrylate) through a prior wrapping of CNT. The studies of physical properties, including rheological and electrical properties, of nanocomposites were undertaken. Relationships between the state of dispersion, the nature of the coating and the method of preparation of composites were established
He, Peng. "Surface Modification and Mechanics of Interfaces in Polystyrene Nanocomposite Reinforced by Carbon Nanotubes." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1140462871.
Повний текст джерелаAl, Mafarage Ali M. "Processing and Properties of Multifunctional Two-Dimensional Nanocomposite Based on Single Wall Carbon Nanotubes." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1556310855748631.
Повний текст джерелаSarr, Mouhamadou Moustapha. "Étude, synthèse et élaboration de nanocharges biphasées, nanotubes de carbone/diatomées pour l’amélioration des propriétés physiques de nanocomposites à matrice polymère." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0326/document.
Повний текст джерелаThis thesis is part of the GREENANONANO project ensuing from a partnership between the Luxembourg Institute of Science and Technology (LIST), Goodyear Company and Université de Lorraine, in order to address a technological challenge for increasing tires performances. The latter are directly related to the viscoelastic properties of the rubber used in tires. This gum is a composite material made by mixing an elastomeric matrix (natural rubber) and fillers (silica and carbon black). Nowadays, the filler dispersion is not optimal, which degrades the mechanical and electrostatic properties and therefore performances of tires. All these industrial limitations require the use of other types of reinforcing agents such as carbon nanotubes. Since carbon nanotubes tend to be organized into bundles, the dispersion problem still exists. We therefore propose in this thesis the synthesis of a biphased material composed by diatomite particles (natural mesoporous silica) on which are grown carbon nanotubes (CNTs). The high surface area of diatomite offers the possibility of growing a high density of CNTs, increasing the contact area with the polymer matrix. This multidisciplinary thesis started with the synthesis of metal nanoparticles by Atomic Layer Deposition (ALD) to catalyse the growth of CNTs and then a process was developed to grow CNTs on diatomite particles. The successful integration of the resulting biphased particles in polymer matrices (elastomer, thermoplastic) allowed to measure the mechanical, thermal and electrical properties of the nanocomposites thus produced
Seifert, David Ryan. "Topology Optimization of Multifunctional Nanocomposite Structures." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/86195.
Повний текст джерелаPh. D.
This dissertation presents a method that allows for the best placement of a limited amount of filler material within a base matrix material to form an optimal composite structure. Adding filler material, in this case Carbon Nanotubes, can change the effective behavior of the composite structure, enhancing the capabilities of the base matrix material by adding structural stiffness, electrical conductivity, and even the ability for the structure to measure its own strains. The degree to which these changes occur is dependent on the amount of filler material present in any given subsection of the structure. The method then is focused on determining how much of the filler to place in different subsections of the structure to maximize several measures of performance. These measures pertain to structural performance, electrical conductivity, and the structure’s ability to sense strains. Steps are taken within the method to remove non-physical designs and also to find the overall best design, called the global minima. The method is applied to several test structures of varying complexity, and it is shown that the optimization method can heavily influence performance by tailoring the filler material distribution. Further electrical and sensing performance gains can be obtained by properly selecting where the electrodes are located on the structure. This is demonstrated by including electrode placement in the design method along with the filler distribution.
Rafiee, Mohammad. "Modeling, Processing, Fabrication and Characterization of Carbon Nanomaterials-Reinforced Polymer Composites." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38126.
Повний текст джерелаGuo, Yan. "Surface Functionalization of Carbon Nanotubes for Nanocomposite and Biomedical In Vivo Imaging." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1180118173.
Повний текст джерелаUnnikrishnan, Vinu Unnithan. "Multiscale analysis of nanocomposite and nanofibrous structures." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1469.
Повний текст джерелаEzat, Gulstan S. "The influence of multi-walled carbon nanotubes on the properties of polypropylene nanocomposite : the enhancement of dispersion and alignment of multiwalled carbon nanotube in polypropylene nanocomposite and its effect on the mechanical, thermal, rheological and electrical properties." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5703.
Повний текст джерелаStubbs, Ian. "Poly(styrene)-b-Poly(dimethylsiloxane)-b- Poly(styrene)/Single Walled Carbon Nanotube Nanocomposites. Synthesis of Triblock Copolymer and Nanocomposite Preparation." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2016. http://digitalcommons.auctr.edu/cauetds/49.
Повний текст джерелаTurco, Antonio. "Use of carbon nanotubes for novel approaches towards spinal network repairing." Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8663.
Повний текст джерелаNanotechnology underwent a very rapid development in the last decades, thanks to the invention of different techniques that allow reaching the nanoscale. The great interest in this area arises from the variety of possible applications in different fields, such as electronics, where the miniaturization of components is a key factor, but also medicine. The creation of smart systems able to carry out a specific task in the body in a controlled way, either in diagnosis or therapy or tissue engineering, is the ultimate goal of a newborn area of research, called nanomedicine. In fact, to reach such an outstanding objective, a nanometer‐sized material is needed and carbon nanotubes (CNTs) are among the most promising candidates. The aim of this thesis was to study this opportunity and, in particular, the possible application of carbon nanotubes for spinal network repairing. After a review of the main features of neuronal network systems and the most common techniques to study their functionality, possible applications of nanotechnology for nanomedicine purposes are considered, focusing the attention on CNTs as neuronal interface in nerve tissue engineering. The work can be divided into two big parts. In the first part the impact of carbon nanotubes on various neuronal systems was studied. Different form of carbonaceous materials (carbon nanotubes, nanohorns and graphene) were deposited in a homogeneous way on a glass surface playing with organic functionalization and different deposition techniques. Hippocampal neuronal cells were grown on their surface to better understand how morphology and conductivity of the material could influence the activity of the neuronal network evidencing how both these characteristics could affect the electrophysiological properties of neurons. Then, also spinal neurons were grown on carbon nanotubes network deposited on a glass substrate to evaluate, for the first time, the impact of carbon nanotubes on this kind of cells. The tight interaction between these two materials appeared to cause a faster maturation of the spinal neurons with respect II to the control grown on a glass substrate. The long-term impact on a complex tissue (spinal cord slice) grown on carbon nanotubes carpet was also studied. The intimate interaction between the two materials observed by TEM and SEM analysis caused an increase in dimensions and number of neuronal fibers that comes out from the body of a spinal cord slice. An increase in electrophysiological activity of all neuronal network of the slice was also reported. In the second part of the work different conductive biocompatible nanocomposite materials based on carbon nanotubes and “artificial” polymers (such as Nafion, PVA, PET, PEI, PDMS and PANI) were investigated. The idea is to test these materials as neuronal prosthesis to repair spinal cord damage. All the prepared scaffolds showed CNTs on the surface favoring CNTs-neurons interaction. To address this aim different techniques and different organic functionalizations of CNTs were utilized to control supramolecular interactions between the nanomaterial and polymers orienting the deposition of the CNTs and preventing their aggregation. After that, an innovative method to study the possible ability of this nanocomposite materials to transmit a neuronal signal between two portions of spinal cord was designed. Functionalization of gold surfaces with thiolated carbon nanotubes have been conducted in order to develop suitable devices for neuronal stimulation and consequent spinal cord lesions repairing. In particular thiol groups were introduced on the graphitic surface of carbon nanotubes by means of covalent functionalization. First of all, the interaction of CNTs with gold nanoparticles has been evaluated, then a gold surface has been coated by means of contact printing technique with a homogeneous film of CNTs. This hybrid material could be useful to produce innovative electrodes for neuronal stimulation
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Jomaa, Mohamed Hedi. "Elaboration, characterization and modeling of electroactive materials based on polyurethanes and grafted carbon nanotubes." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0053/document.
Повний текст джерелаHarvesting systems capable of transforming dusty environmental energy into electrical energy have attracted considerable interest throughout the last decade. Several research efforts have focused on the transformation of the mechanical vibration into electrical energy. Most of these research activities deal with classical piezoelectric ceramic materials, but more recently, a promising new type of materials is represented by electroactive polymers (EAPs). Among the various EAPs, polyurethane (PU) elastomers are of great interest due to the significant electrical-field strains, and due to their attractive and useful properties such as flexibility, light weight, high chemical and abrasion resistance, high mechanical strength and easy processing to large area films as well as their ability to be molded into various shapes and biocompatibility with blood and tissues. In addition, it has recently been shown that the incorporation into a PU matrix of nanofillers, such as carbon nanotubes (CNTs), can greatly enhance the expected strain, or the harvested energy. However, it is well known that CNTs are hardly dispersed in a polymeric matrix, and that the interfacial adhesion strength is generally poor. An effective method to improves both dispersion and adhesion may consist in functionalizing CNTs by grafting polymer chains onto their surfaces. The main objective of this thesis was to develop high-efficiency polymers nanocomposites for harvesting energy and actuation. The key motivation was to use polymer-grafted CNTs to improve dispersion, interfacial adhesion in PU, and understand how this can change the electroactive properties of the PU/CNT nanocomposites. In other words, it was a pluridisciplinary project including an optimization of the elaboration process, physical characterizations ˗ including microstructural, electrical and mechanical behaviors in a wide range of frequencies and temperatures ˗ and the determination of the electroactive properties. A comprehensive study was then carried out first on pure PU to understand how their electroactive properties depend on their microstructure, and then on the nanocomposites to understand how the incorporation of functionalized CNT can improve the electromechanical properties
WEGRZYN, MARCIN. "Nanocomposites of Multiphase Polymer Blend Reinforced with Carbon Nanotubes: Processing and Characterization." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/36869.
Повний текст джерелаWegrzyn, M. (2014). Nanocomposites of Multiphase Polymer Blend Reinforced with Carbon Nanotubes: Processing and Characterization [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/36869
TESIS
Twomey, John Ryan. "Characterization of nanocomposite scaffolds composed of collagen and functionalized carbon nanotubes for tissue engineering applications." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1447691.
Повний текст джерелаBaddour, Carole. "Direct growth of carbon nanotubes on metal surfaces without an external catalyst and nanocomposite production." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103671.
Повний текст джерелаLa croissance des nanotubes de carbone (NTC) sur des surfaces métalliques est étudiée dans cette thèse. En général, les NTC sont synthétisés par la décomposition d'un gaz riche en carbone en présence d'un catalyseur métallique à des températures élevées. Les propriétés exceptionnelles des NTC génèrent un immense intérêt autant au niveau de la recherche que sur le plan industriel. Par contre, le développement d'applications commerciales des NTC reste limité par les contraintes de production à grande échelle et leur prix élevé. Une autre contrainte est la résistance d'interface générée par les nanoparticules de catalyseur utilisé par les méthodes de croissance traditionnelles. Afin d'éliminer la résistance d'interface et simultanément produire une croissance des NTC sur des grandes surfaces et géométries variable, une méthode de synthèse simple et directe est développée. Cette méthode est établie pour permettre l'extraction de la structure du NTC directement à partir de la surface du métal. Le nouveau procédé de synthèse des NTC développé dans cette thèse est utilisé avec des surfaces d'acier inoxydable 304 planes et des particules sphériques. La méthode développée consiste à créer des structures nanométriques à la surface du métal qui agissent comme des particules catalytiques, tout en faisant partie intégrales de cette surface. Le procédé utilise d'abord une gravure de la surface, puis un traitement thermique réalisé soit dans un réacteur de dépôt chimique en phase vapeur traditionnel (standard-CVD), ou en lit fluidisé (FBCVD). Le gaz carboné est l'acétylène (C2H2) et le catalyseur/support combiné est l'acier inoxydable 304. Cette méthode de croissance directe des NTC avec un substrat à double fonction élimine la nécessité de déposer des nanoparticules de catalyseur sur la surface du support, les sites actifs requis pour la croissance des NTC étant produits directement sur la surface de l'acier inoxydable. La méthode optimisée produit des nanotubes multi-parois avec diamètres de 20-70 nm. Les NTC sont caractérisés par spectroscopie Raman, analyse thermogravimétrique, microscopie électronique en transmission et par une étude d'adhérence. La pureté des NTC produits atteint 84%. Des mesures de diffraction électronique sur les régions catalytiques indiquent une zone riche en fer correspondant à la structure cubique face centrée de l'austénite (γ Fe). Dans le cas du réacteur FBCVD, 30 mg de NTC sont générés pour chaque gramme de produit brut (NTC + particules d'acier inoxydable). De plus, la récupération et réutilisation des particules d'acier inoxydable pour un deuxième cycle de croissance dans le réacteur FBCVD est démontrée. La surface de l'acier inoxydable est caractérisée par plusieurs méthodes. En résumé, les analyses XPS indiquent que la couche d'oxyde de chrome (Cr2O3) est partiellement enlevé par la gravure à l'acide, et de l'oxyde de fer (Fe2O3) se forme sur la surface de l'acier inoxydable. Du carbure de fer (Fe3C) est observé sur la surface de l'acier sous les zones de croissance des NTC. Ce carbure, de la cémentite, est en fait produit durant la croissance des NTC. Le traitement thermique produit une recristallisation de la surface suivit par une croissance des grains. L'étude par AFM démontre que la gravure à l'acide génère des ondulations topographiques à une échelle de 10-30 nm sur la surface de l'acier inoxydable. Les structures de NTC sur substrat métalliques sont utilisés pour produire un nano-composite formant une structure 3-D ouverte de NTC recouverts et retenues par une couche de carbone adamantin (DLC) ou de nitrure de titane (TiN). Ces couches sont faites par dépôt physique en phase vapeur (arc-PVD). Un nombre limité d'échantillons de DLC/NTC est étudié, et une étude détaillée est effectuée pour les nano-composites TiN/NTC. Cette dernière structure est caractérisée par nano-indentation et par mesure d'angle de contact.
Pallikonda, Mahesh Kumar Pallikonda. "FORMING A METAL MATRIX NANOCOMPOSITE (MMNC) WITH FULLY DISPERSED AND DEAGGLOMERATED MULTIWALLED CARBON NANOTUBES (MWCNTs)." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1503937490966191.
Повний текст джерелаSullivan, Erin M. "Understanding the process-structure-property relationship in biodegradable polymer nanocomposite films." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54428.
Повний текст джерелаAbdelsayed, Ihab Maher. "CHARACTERIZATION OF ELECTROSPRAYED POLY(VINYLIDENE FLUORIDE)/CNT NANOCOMPOSITE." VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd/1443.
Повний текст джерелаJain, Rahul. "Carbon nanotube reinforced polyacrylonitrile and poly(etherketone) fibers." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28257.
Повний текст джерелаCommittee Chair: Kumar, Satish; Committee Member: Bucknall, David; Committee Member: Griffin, Anselm; Committee Member: Shofner, Meisha; Committee Member: Yushin, Gleb
Mokashi, Vineet V. "Study of Mechanical Properties of Carbon Nanotubes and Nanocomposites by Molecular Simulations." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109358015.
Повний текст джерелаTunckol, Meltem. "Fonctionnalisation de Nanotubes de Carbone Multi-Parois par des Polymères." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0066/document.
Повний текст джерелаThis thesis deals with the surface modification of multi-walled carbon nanotubes with polymers with the aim to achieve a high level of dispersion in polymer matrices. Chapter I gives a comprehensive review of the state of the art of hybrids of ionic liquids with carbon nanomaterials, particularly, nanotubes and more recently, graphene. Chapter II starts with a general overview of the non-covalent adsorption of polymers onto the CNT surfaces followed by a detailed description of the study carried out on the non-covalent functionalization of CNTs with various imidazolium based polymerized ionic liquids (PIL). For this purpose, we further compare the two experimental methods: in situ polymerization and solution mixing. One of the most important applications of CNT is in polymer/CNT composites. Chapter III describes the formation of polyetherimide/CNT composites starting from PIL-CNT hybrids obtained in Chapter II. The preparation and characterization of composites using solvent casting methods have been detailed. Pristine, acid oxidized and PIL functionalized CNTs have been compared. Mechanical, thermal and electrical property measurements on these composites have also been described. The last chapter – Chapter IV, divided into two sections, discusses the covalent functionalization of CNTs with a variety of polymers using two main approaches: “grafting from” and “grafting to”. Using the first approach we have grown polyamide (PA) chains from the surface of caprolactam grafted CNTs by anionic ring opening polymerization. The tensile properties of the PA based composites prepared therefrom containing pristine, amine- and PA-functionalized CNTs have been investigated. The radical polymerization of vinyl imidazolium based IL monomers attached to the activated CNT surface is also given in this section. In the second part of Chapter IV, we have reported several “grafting to” functionalization strategies including radical addition and “defect site” grafting used for the preparation of CNTs covalently attached with polymers intended to blend well with epoxy matrices
Lutz, Vincent. "Carbon nanotubes as nanofillers or fibers for multifunctional epoxy-based composites." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0039.
Повний текст джерелаNowadays, polymer-matrix composites reinforced with carbon fibers are increasingly used in the whole transport sector (aerospace, automotive and railway industries). However, the obtained parts still suffer from low impact resistance and low damage tolerance. To improve these properties, the matrix precursors have to be combined with organic or inorganic compounds to lead to multi-phased matrices. Among them, carbon nanotubes (CNT) are especially promising for targeting multi-scale reinforcement. Since high quality of the parts are required, continuous-fibers-reinforced composites can be produced by resin transfer molding (RTM) which also offers a reduced cost if compared with high temperature- and high pressure-based processes. However, RTM requires a very low viscosity of the polymer precursors and CNT-filled precursors are far too viscous to be injected on dry performs. In addition, this strategy does not allow for a control of the CNT location and orientation in the final part. In this study, innovative ways have been developed to insert CNT in the preform with local positioning and defined orientation. Deliveries of CNT in the matrix, from a neat carbon multi-nanotubes fiber produced by direct spinning, or from a CNT grown on carbon fiber were investigated in two types of epoxy matrices (with very different TG). Different polymer matrix/fiber interfaces have been generated using neat carbon multi-nanotubes fiber, CNT grown on carbon fiber and conventional carbon fiber, with or without sizing. A fine mechanical characterization of various fibers and particularly the measurement of single fiber interfacial properties have been performed in order to determine mechanical performance of continuous fiber reinforced composites. In addition, the nature of adhesion and quality of matrix/fiber interface have been fully evaluated by different multi-scale analyses and suitable microstructural observations
Murphy, Kyle Robert. "Nanosilver and CNT-Nanocomposite Toxicology in an In Vivo Model, D. Melanogaster." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1429977804.
Повний текст джерелаPereira, André. "Preparação e caracterização por espectroscopia de impedância de compósitos de policarbonato com nanotubos de carbono." reponame:Repositório Institucional da UFABC, 2015.
Знайти повний текст джерелаDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2015.
O trabalho realizado mostra a influência do aumento da concentração de nanotubos de carbono sobre a propriedade de impedância, em um nanocompósito a base de policarbonato e nanotubos de paredes múltiplas. Neste trabalho, o polímero policarbonato (PC) foi misturado em diversas concentrações com nanotubos de carbono de paredes múltiplas (MWCNT) do tipo "não purificado" formando nanocompósitos. As amostras foram preparadas por dissolução do PC em clorofórmio, seguido pela adição de MWCNT e surfactante. As misturas foram dispersas em banho de ultrassom, o solvente foi extraído por evaporação, as amostras foram moídas, desumidificadas, extrudadas em plastômetro e preparadas para a caracterização. Foi realizada análise por meio de microscópia eletrônica de varredura, ensaios de tração e termogravimetria. Uma amostra foi exposta ao contato com álcool para verificar a possível sensibilidade a esta substância. Foi realizada medição da condutividade e da espectroscopia de impedância na faixa de frequência entre 1 MHz a 1 Hz, variando-se as tensões alternadas entre 10 mV e 500 mV. Entre os principais resultados observaram-se dois comportamentos possíveis que modelam os resultados de impedância. Em menores concentrações de MWCNT, as amostras podem ser representadas por um circuito composto por dois resistores (R1, R2) e um capacitor (CP), sendo que o conjunto R2 e CP (ligados entre si em paralelo) está ligado em série com R1. Para amostras com maiores concentrações de MWCNT, o circuito equivalente pode ser representado por apenas um resistor simples. Observa-se que com o incremento da concentração de MWCNT a resistência elétrica dos nanocompósitos é reduzida. Uma das amostras, após ser exposta ao etanol, apresentou um aumento no valor da impedância elétrica, o que se caracteriza como uma "resposta" elétrica à exposição química.
The work shows the influence of the concentration of carbon nanotubes on the impedance property in a nanocomposite based polycarbonate and multi-walled nanotubes. In this work, polycarbonate polymer (PC) was mixed at various concentrations with multi-walled carbon nanotubes (MWCNT) type "as grown" forming a nanocomposite. The samples were prepared by dissolving the PC in chloroform, followed by addition of MWCNT and surfactant. The mixtures were dispersed in an ultrasound bath, the solvent was removed by evaporation, the samples were ground, dried, extruded in plastometer and prepared for characterization. Analysis was performed using scanning electron microscopy, tensile and thermogravimetry tests. A sample was exposed to contact with alcohol to verify the possible sensitivity to this substance. Conductivity and Impedance spectroscopy measurements were conducted in the frequency range from 1 MHz to 1 Hz by varying alternating voltages between 10 mV and 500 mV. The main results were observed two possible behaviors that model the impedance results. At lower concentrations of MWCNT samples may be represented by a circuit composed of two resistors (R1, R2) and a capacitor (CP). The group R2 and CP, connected in parallel, is connected in series with R1. For samples with higher concentrations of MWCNT the equivalent circuit can be represented by just a single resistor. It is observed that with increasing concentration MWCNT the electrical resistance of the nanocomposite is reduced. One of the samples after being exposed to ethanol, showed an increase in the value of electrical impedance, which is characterized as an electrical "response" to the chemical exposure.
Pras, Maxime. "Influence de l’état de dispersion de nanotubes de carbone sur leur relargage et aérosolisation lors de la sollicitation tribologique de nanocomposites MWNT/polymère." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0020/document.
Повний текст джерелаCarbon nanotubes (CNT) reinforced polymer-based composites represent a significant opportunity in terms of mechanical reinforcement and electrical and thermal conductivity improvements. However specific issues for nanotubes and related composites on human health are still under studied. It is strongly expected that standards and regulations on carbon nanotubes and on carbon nanotubes composites should appear soon. Due to their high aspect ratio they could migrate into breathing apparatus (because of their small diameter) and remain stuck to the walls (due to their length) causing damages like pulmonary fibrosis or cancer. Exposition of human people to carbon nanotubes must be controlled and an occupational exposure limit must be defined. That is why suppliers of carbon nanotubes have large interest to predict rules in controlling carbon nanotube release during the use of materials prepared from nanotubes, especially under abrasion or other cyclic mechanical solicitations. A key point is to check if a good dispersion state is a required condition to decrease isolated carbon nanotubes release. As the dispersion state of carbon nanotubes in polymer-based nanocomposites was known and controlled, standardized abrasion tests were performed in a glove box in order to simulate the wear use of a nanocomposite during its lifecycle, i.e. to generate particles. Released particles were collected on TEM grids and by particle sizing devices and these ones were analyzed in term of number, size and nature thanks to different characterization methods. Granulometric data, TEM micrographs and EDX measurements were all performed and founded to be influenced by several parameters amongst which the carbon nanotubes dispersion state. Carbon nanotubes were found in the abraded particles but never isolated from other polymer particles but could be linked to released polymer particles via Van der Waals interactions and physical entanglement. It clearly appears that the dispersion state of CNT has an influence on the shape and the aspect of released particles
Golosova, Anastasia [Verfasser], Christine M. [Akademischer Betreuer] Papadakis, and Rainer [Akademischer Betreuer] Jordan. "Chemical modification of carbon nanotubes for nanocomposite applications / Anastasia Golosova. Gutachter: Christine M. Papadakis ; Rainer Jordan. Betreuer: Christine M. Papadakis." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1014330661/34.
Повний текст джерелаAxel, Salinier. "Préparation d’un composite hybride par co-malaxeur : influence des paramètres de mise en oeuvre sur les propriétés." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3047/document.
Повний текст джерелаThis PhD work deals with the relationship between the processing parameters at the melt state and the polymer matrix hybrid composite material’s properties. The fillers studied are short glass fibres (micrometric scale) and carbon nanotubes (CNT) (nanometric scale) dispersed in a high temperature polymer matrix, the poly(etherimide) (PEI). We showed that glass fibres strongly participate in the CNT network structuration and that electrical conductivity of multiscale composite materials is higher than the one of nanocomposite materials. The combination of the two fillers allows obtaining a synergy effect for the mechanical properties especially for the elongation at break which is due to a preferential localization of CNT at the PEI/glass fibres interfaces. The study of the influence of processing parameters on the properties of nanocomposite materials and hybrid composite materials showed that Specific Mechanical Energy (SME) has a strong influence on the hybrid composite material properties and especially on the electrical conductivity. These variations are the consequences of CNT network modifications. Glass fibres concentration has also a strong influence on the electrical conductivity of the hybrid composite materials. It is possible to adjust the electrical conductivity with modifying the concentration of glass fibres especially for the CNT amount closed to the electrical percolation threshold
Bardash, Liubov. "Synthesis and investigation of nanostructured polymer composites based on heterocyclic esters and carbon nanotubes." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10174/document.
Повний текст джерелаThe thesis relates to synthesis and investigation of nanostructured polymer composites based on oligomers of cyanate esters of bisphenol a (DCBA) or cyclic butylene terephthalate (CBT) and multiwalled carbon nanotubes (MWCNTS). Catalytic effect of mwcnts in process of DCBA polycyclotrimerization as well as in cbt polymerization has been observed. Significant increase in crystallization temperature of nanocomposites based on polybutylene terephthalate (cPBT) with adding of MWCNTS is observed. The effect of processing method of cpbt/mwcnts nanocomposites on its electrical properties has been found. It has been established that the additional heating of the samples (annealing) at temperatures above melting of cPBT leads to reagglomeration of MWCNTS in the system. It is established that reagglomeration of MWCNTS results in increase of conductivity values of nanocomposites due to formation of percolation pathways of MWCNTS through polymer matrix. In the case of polycyanurate matrix (PCN), it is found that addition of small mwcnts contents (0.03-0.06 weight percents) provides increasing tensile strength by 62-94 percents. It has been found that addition of even 0.01 weight percents of MWCNTS provides significant increase in storage modulus of cPBT matrix. This is explained by effective dispersing of small amount of the nanofiller during in situ synthesis of pcn or cpbt matrix that is confirmed by microscopy techniques. It has been established that the properties of the nanocomposites based on heterocyclic esters and MWCNTS can be varied from isolator to conductor and has low percolation thresholds (0.22 and 0.38 weight percents for cPBT and PCN nanocomposites respectively). The conductivity of samples is particularly stable on a very large range of temperature from 300 to 10 degrees Kelvin that make these materials perspective for practical applications in microelectronics, as parts of aircraft and space constructions
Bardash, Liubov, and Liubov Bardash. "Synthesis and investigation of nanostructured polymer composites based on heterocyclic esters and carbon nanotubes." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00821160.
Повний текст джерелаEscobar, Teran Freddy David. "A new approach towards understanding the ion transfer dynamics in nanostructured carbon-based thin films for energy storage applications." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066363/document.
Повний текст джерелаCarbon nanotubes (CNTs) and Electrochemically Reduced Graphene Oxide films were prepared on gold electrodes of microbalance and tested in different electrolytes such as LiCl, NaCl and KCl. The capacitive charge storage of carbon-based film electrodes were investigated by ac-electrogravimetry which couples fast quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). The chemical nature and the role of each species, anion, cation, solvated cation, free solvent, involved in the charge storage mechanism, have been clearly identified during the cathodic and anodic polarization through ac-electrogravimetry measurements for the very first time. The ac-electrogravimetric results confirm that the cations are predominantly electroadsorbed when the surface is negatively charged while the anions are electroadsorbed when the surface is positively charged. Nanocomposite films, namely SWCNT/Prussian Blue and SWCNT/Polypyrrole were electrochemically examined. The main idea was to emphasize the capacitive and faradic behavior of these different films by combining two materials. The chemical nature and the role of each species involved in the pseudo-capacitive and capacitive processes were highlighted by the ac-electrogravimetry. The methodology adapted to characterize carbon based electrodes can be suggested as a baseline diagnostic tool to study the pore/ion size relationship, the concentration and the solvent effects, the dynamics of the ions interactions at the interfaces (electroadsorption and/or faradaic process) of the electrode materials which may pave the way towards more performant electrode/electrolyte systems in energy storage devices
Al-Kawaz, Ammar. "Development and rheological analysis of a surface polymer nanocomposite anti-friction." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE025/document.
Повний текст джерелаThe goal of this thesis is the identification of couplings (nanoparticles / matrix poly (methyl methacrylate) PMMA) which ensure PMMA surface rigidity while maintaining maximum transparency. The choice fell on three types of carbonaceous nanoparticles: Few layer graphene (FLG), graphene oxide (GO) and carbon nanotubes (MWCNT). A first part describes the preparation and functionalization of these three types of nanoparticles to provide a better dispersion in the matrix. Two methods were used to prepare nanocomposite materials: bulk polymerization and solution blending. A second part presents the characterization of the mechanical properties of these coatings in three stages: volume, surface and thin layer coating (15-20μm). The main results show that nanocomposites made delay the onset of plasticity compared with pure PMMA, even at a low percentage, and help to limit the effects of surface scratches. The small percentage of reinforcement keeps the transparency and the more the thickness decreases the more the rate of reinforcement can increase without degrading the mechanical properties of the coating. Moreover, nanoparticles chosen as the polymer matrix of reinforcing agents prove to be very good candidates for reduction in friction compared to a plasticizer such Erucamide
Dinh, Nghia Trong, and Olfa Kanoun. "Temperature-Compensated Force/Pressure Sensor Based on Multi-Walled Carbon Nanotube Epoxy Composites." Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-175255.
Повний текст джерелаHuang, Hui. "Electrochemical Application and AFM Characterization of Nanocomposites : Focus on Interphase Properties." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203239.
Повний текст джерелаQC 20170315
Changyong, Lu. "Synthesis and characterization of magnetic nanocomposites and their applications study." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/457572.
Повний текст джерелаNanomaterials especially nanoparticles become one of the most attractive area not only in scientific research but also in industrial applications. In this thesis, the preparation of magnetite nanoparticles, their related nanocomposites and the application of those obtained nanomaterials have been studied. The Fe3O4@SiO2 core-shell nanoparticles were synthesized via normal and microwave assistance reverse microemulsion methods. The obtained nanoparticles were fully characterized with different laboratory techniques and the effect of reaction parameters on final products was also studied. These nanoparticles were used as a support of Ag catalysts nanoparticles and the as synthesized nanocomposites shown nice catalytic property and high recyclability. A novel Fe3O4@GNF@SiO2 nanocapsulates were also prepared via in situ formation of magnetite nanoparticles and silica coverage process. The obtained nanocapsulates have nice stabilities even in the acid environments. The potential application of these nanocapsulates in magnetic resonance imaging research was also studied. On the other hand, the cytotoxity and interaction with cell of Fe3O4@SiO2 core-shell nanoparticles were studied which indicate the possibility of using them in biomedical research. Then, the Fe3O4@SiO2 core-shell nanoparticles were further decorated with biomolecules such as MC540 and L-thyroxine. The Fe3O4@SiO2 core-shell nanoparticles with the surface functionalized with molecule imprinted polymers also suggested the potential application in biosensor research.
Benchirouf, Abderrahmane. "Carbonaceous Nanofillers and Poly(3,4-ethylenedioxythiophene) Poly(styrenesulfonate) Nanocomposites for Wireless Sensing Applications." Universitätsverlag der Technischen Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A31903.
Повний текст джерелаLemes, Ana Paula. "Nanocompositos de poli(3-hidroxibutirato-co-3-hidroxivalerato) e nanotubos de carbono." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248933.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Esse trabalho avaliou o efeito da adição de nanotubos de carbono de paredes múltiplas (NTC) nas propriedades térmicas e mecânica, morfologia e hidrofobicidade do poli(3-hidroxibutirato-co-3-hidroxivalerato), o PHBV. A adição de nanotubos de carbono poderia implicar em melhora das propriedades do PHBV, um poliéster natural que devido à sua biodegradabilidade e biocompatibilidade possui um grande potencial de aplicação. Assim, nanocompósitos de PHBV/NTC foram produzidos por mistura em solução, seguida de evaporação do solvente. Na produção dos PHBV/NTC, avaliou-se a utilização de banho de ultrassom, processador ultrassônico e a funcionalização dos NTC por reações de oxidação. Primeiramente, foi realizada a caracterização e a funcionalização dos NTC por dois métodos: oxidação com ácido nítrico (HNO3) e oxidação com peróxido de hidrogênio (H2O2), variando-se o tempo de reação. Após oxidação, os NTC foram abreviados como NTCOOH e caracterizados quanto à presença de grupos funcionais em sua superfície e danos causados em sua estrutura. Os NTCOOH obtidos na oxidação com HNO3 mostraram uma maior estabilidade térmica em comparação àqueles obtidos na oxidação com H2O2. A produção de carbono amorfo variou em função do tempo de oxidação para HNO3 e permaneceu constante para H2O2. Não foi verificada diferença significativa na quantificação de hidroxilas, carbonilas e carboxilas na superfície dos NTCOOH. A oxidação com HNO3 3 mol L por 12 horas mostrou-se mais apropriada para a produção dos nanocompósitos de PHBV/NTCOOH. Posteriormente, nanocompósitos de PHBV/NTC e PHBV/NTCOOH com 0,05 % (m/m) de NTC e de NTCOOH, respectivamente, foram produzidos utilizando banho de ultrassom. As análises de DSC mostraram que os NTC e NTCOOH agem como agentes nucleantes no processo de cristalização do PHBV e que o PHBV/NTC e PHBV/NTCOOH possuem o mesmo comportamento térmico. As micrografias de SEM mostraram uma boa adesão interfacial dos NTC e NTCOOH com a matriz de PHBV, e a formação de aglomerados menores no caso dos PHBV/NTCOOH, indicando que a oxidação dos NTC melhorou sua dispersão na matriz de PHBV. Finalmente, nanocompósitos de PHBV/NTC contendo 0,05, 0,50, 1,00, 1,50 e 2,00 % (m/m) de NTC e PHBV/NTCOOH 2,00 % (m/m) foram produzidos, utilizando processador ultrassônico para a dispersão dos NTC. Verificou-se que o efeito nucleante do NTC foi proporcional ao aumento de sua concentração nos PHBV/NTC e que o pequeno aumento de estabilidade térmica (~7 ºC) verificada não variou com a concentração de NTC. A utilização do processador ultrassônico melhorou acentuadamente a dispersão dos NTC nos nanocompósitos e a hidrofobicidade das superfícies dos PHBV/NTC aumentou em função da concentração de NTC. O nanocompósito de PHBV/NTC 1,50 % (m/m) apresentou os melhores resultados nos ensaios mecânicos de tração, com aumento de 48 % no módulo de elasticidade, 49 % na tensão na força máxima e menor perda de alongamento (37 %) em comparação ao PHBV puro. Essas melhorias não foram verificadas para o PHBV/NTC 2,00 % (m/m), mas foram verificadas para PHBV/NTCOOH 2,00 % (m/m), indicando que a oxidação dos NTC permitiu a obtenção de boas propriedades mecânicas para maiores concentrações de NTC. Um resultado muito importante desse trabalho foi a sua baixa adesão a coágulos sanguíneos (baixa Trombogenicidade) verificada para o PHBV/NTC, o que amplia a possibilidade de aplicação desses nanocompósitos na área médica
Abstract: This work has evaluated the effect of addition of multi walled carbon nanotubes (NTC) in the thermal and mechanical properties, morphology and hydrophobicity of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), the PHBV. The addition of carbon nanotubes could result in an improvement of PHBV properties, a natural polyester that due to its biodegradability and biocompatibility has an important application potential. Thus, nanocomposites of PHBV/NTC were produced by solution mixing, and then solvent casting. In the production of PHBV/NTC, we have evaluated the use of ultrasonic bath, ultrasonic processor and the functionalization of NTC by oxidation reactions, in the NTC dispersion in the PHBV matrix. First, we have performed the NTC characterization and functionalization by two methods: oxidation with nitric acid (HNO3) and oxidation with hydrogen peroxide (H2O2), at different reaction times. After oxidation, NTC (abbreviated as NTCOOH) were characterized for the presence of functional groups on their surface and the damage of their structure. The NTCOOH obtained from oxidation with HNO3 showed a higher thermal stability compared to those obtained in the H2O2 oxidation. The amorphous carbon production varied with the oxidation time to HNO3 and remained constant for H2O2. There was no significant difference in the quantification of hydroxyl, carbonyl and carboxyl groups on the surface of NTCOOH. The oxidation with HNO3 3 mol L for 12 hours was more suitable for the production of nanocomposites PHBV/NTCOOH. Subsequently, nanocompósitos of PHBV/NTC and PHBV/NTCOOH were produced using ultrasonic bath with 0.05 % (m/m) of NTC and NTCOOH, respectively. The DSC analysis showed that the NTC and NTCOOH act as nucleating agents and that the PHBV/NTC and PHBV/NTCOOH have the same thermal behavior. The SEM micrographs showed a good interfacial adhesion between the NTC and NTCOOH with PHBV matrix, and the formation of smaller agglomerates in the case of PHBV/NTCOOH indicated that oxidation of NTC improved their dispersion in the PHBV matrix. Finally, nanocomposites PHBV/NTC with 0.05, 0.50, 1.00, 1.50 and 2.00 % (m/m) of NTC and PHBV/NTCOOH with 2.00 % (w/w) were produced using ultrasonic processor for the NTC dispersion. It was found that the nucleating effect of NTC was proportional to increase of its concentration in the PHBV/NTC and the small increase observed in the thermal stability (~7°C) did not depended on the concentration of NTC. The use of ultrasonic processor greatly improved the dispersion of NTC in the nanocomposites and the hydrophobicity of the PHBV/NTC increases with increasing concentration of NTC. The nanocomposite of PHBV/NTC 1.50 % (w/w) showed the best results in tensile test, with 48 % increase in elastic modulus of, 49 % in maximum tensile strength and smaller decrease on elongation (37 %) compared to the pure PHBV. These improvements were not observed for PHBV/NTC 2.00 % (m/m) but were observed for PHBV/NTCOOH 2.00 % (m/m), indicating that oxidation of NTC allowed to obtain better mechanical properties for higher concentrations of NTC. A very important result in this work was the low adherence to blood clots (low thrombogenicity) verified for the PHBV/NTC 2.00 % (w/w), which extends the application of these nanocomposites in the medical field
Doutorado
Físico-Química
Doutor em Ciências
Bozlar, Mickaël. "Modification de surface des nanotubes de carbone par un polymère conducteur électrogénéré pour la réalisation de nanocomposites multifonctionnels." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2009. http://www.theses.fr/2009ECAP0043/document.
Повний текст джерелаCarbon nanotubes (CNTs) are ideal candidates to reinforce thermoset polymers due to their exceptional intrinsic properties. The resulting multifunctional nanocomposite has electrical, thermal and mechanical properties sensitively higher than pristine polymer. Therefore, this new material possesses various potential applications, and particularly in the domain of electronics and aerospace. The aim of this PhD thesis is oriented towards two directions. In the first one, we establish efficient techniques to produce composite materials with multifunctional properties. Then, the objective consists in the enhancement of these properties by proposing valuable alternatives to previous results cited in the litterature. In the first chapter, we present the state of the art research concerning the materials studied during this work. Among these, there are in particular: CNTs, hybrids constituted of CNTs and alumina microparticles, electronically conducting and thermoset polymers. Moreover, this chapter deals with the characteristics of each material, i.e. elaboration techniques, structures and properties. The second chapter of the manuscript contains first, the elaboration techniques allowing the synthesis of high quality nanocomposites according to international standards. Then, we analyze the properties of these nanomaterials, and particularly in terms of electrical and thermal transports. Further characterization procedures allow better understanding of the obtained structures in a domain ranging from macroscopic to atomic scales. This is realized using scanning/transmission electron microscopy, Raman spectroscopy, EELS, XPS, and AFM. Electrical and thermal conductivity measurements obtained on these new materials give prominence to the necessity of some improvements. Thereby, we have focused our research on the physico-chemical phenomena at the matrix/filler interface. We have proposed to modify the surface of CNTs, in order to favour the matrix/filler cohesion, but also and mainly to decrease contact resistances between the randomly distributed CNTs within the polymer matrix. Finally, the last chapter deals with the surface functionalization of CNTs using electrochemistry. First, we have implemented an accurate technique to deposit a nanometric layer of electronically conducting polymer on the surface of CNTs. This conducting polymer, namely polypyrrole (Ppy) is in the meantime biocompatible. The accuracy and efficiency of our approach are demonstrated through various characterization techniques, and particularly using transmission electron microscopy. Further studies using AFM coupled with a resiscope indicate the electrical resistance distribution performed on CNT-Ppy hybrids. In the second part of this chapter, we present our method to control precisely the thickness of the Ppy layer around the CNTs
Motaragheb, Jafarpour Saeed. "Patterned Nanocomposite of Carbon Nanotube/Polymer." Thesis, Umeå universitet, Institutionen för fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-133332.
Повний текст джерелаLeal, Claudenete Vieira 1972. "Desenvolvimento, caracterização e avaliação 'in vitro' de nanocompósitos de poli(L-ácido lático) e nanotubos de carbono de paredes múltiplas purificados." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265775.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Nanocompósitos poliméricos exibem potencial para aplicações como biomateriais, pois podem melhorar as propriedades dos polímeros por meio da associação com nanoestruturas, resultando em um material com propriedades estruturais e funcionais superiores. O objetivo desse trabalho foi o desenvolvimento e posterior caracterização de nanocompósitos de poli (L-ácido lático) (PLLA) e nanotubos de carbono (NTC). Os NTC têm sido pesquisados para aplicações biomédicas devido às suas excelentes propriedades, entretanto, os NTC possuem características estruturais que podem causar toxicidade em ambiente biológico. Nesse trabalho, primeiramente foi aplicado um método para purificar os NTC por modificação química com objetivo de melhorar a dispersibilidade e diminuir os efeitos tóxicos. Posteriormente foram preparados os nanocompósitos na forma de membranas de PLLA com NTC em diferentes concentrações, utilizando o método de evaporação de solvente. Foram realizadas caracterizações morfológicas com microscopia eletrônica de varredura e microscopia de força atômica, estudo do comportamento térmico por calorimetria exploratória diferencial e microscopia ótica com luz polarizada, e ensaios mecânicos sob módulo de tração, análise dinâmico-mecânica e nanoindentação. Na última etapa foi realizado teste in vitro de cultura de células. Resultados indicaram aumento da rugosidade das amostras após a adição de NTC, o estudo do comportamento térmico revelou que o NTC atua como agente nucleante nos nanocompósitos, promovendo a formação de maior quantidade de núcleos cristalinos na matriz polimérica. As propriedades mecânicas indicaram aumento no módulo de elasticidade, alongamento e dureza nos nanocompósitos. Na análise biológica, os resultados obtidos comprovaram que, após a adição de NTC, as células foram capazes de aderir e sustentar a proliferação celular sobre as membranas, apresentando favorável citocompatibilidade
Abstract: Polymer nanocomposites exhibit potential for applications as biomaterials because they can improve the properties of polymers by combination with nanostructures, resulting in a material with superior structural and functional properties. The purpose of this work was the development and further characterization of poly (L-lactic acid) (PLLA) and carbon nanotubes (CNT) nanocomposites. CNTs have been investigated for biomedical applications due to their excellent properties, however, pristine NTC have structural characteristics that may cause toxicity in biological environment. In this work, a method to purify the NTC by chemical modification in order to improve the dispersibility and to reduce the toxic effects was firstly applied. Subsequently, PLLA/NTC nanocomposite membranes were prepared at different concentrations by solvent casting. Samples were characterized by scanning electron microscopy, atomic force microscopy, polarized optical microscopy, differential scanning calorimetry, dynamic mechanical analysis, tensile test, nanoindentation and X ray diffraction. In the last step, in vitro cell culture assay was performed. The results indicated an increase of the roughness of the samples after the addition of NTC. Thermal behavior study showed that the NTC act as a nucleation agent in nanocomposites, promoting the formation of a larger amount of crystal nucleous in the polymer matrix. Mechanical properties indicated an increase in elastic modulus, elongation and hardness in the nanocomposites. In biological testing, the results showed that, after addition of NTC, cells were able to adhere and sustain cellular proliferation on membranes and showed a favorable cytocompatibility
Doutorado
Materiais e Processos de Fabricação
Doutora em Engenharia Mecânica
Pedroni, Lucas Gomes. "Nanocompositos elastomericos baseados em MWCNTs : preparação, caracterização, e aplicações." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248452.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Nanocompósitos poliméricos baseados em nanotubos de carbono possuem um dos mais elevados potenciais tecnológicos devido à possibilidade de produção de materiais com destacadas propriedades mecânicas, alta condutividade elétrica em baixos teores (baixos limites de percolação), e boa processabilidade. São sistemas versáteis que podem apresentar propriedades excepcionais, as quais podem ser controladas pela alteração na proporção de seus componentes, permitindo que sejam moldados para atender à aplicação exigida. Nesse trabalho, nanocompósitos de nanotubos de carbono de paredes múltiplas (MWCNTs) e um elastômero comercial (Kraton-D®), que é um copolímero em bloco de estireno-butadieno-estireno (SBS), foram preparados por extrusão e pela técnica de evaporação de solvente (casting). As propriedades térmicas, mecânicas, e elétricas desses materiais foram comparadas. A caracterização foi realizada através de medidas de condutividade elétrica (método de Coleman), microscopias eletrônicas de varredura e de transmissão (caracterização morfológica), termogravimetria (determinação do teor de cargas e estabilidade térmica), ensaios de tração e análise dinâmico-mecânica (propriedades mecânicas). Além disso, o potencial de aplicação dos compósitos em células solares de TiO2/corante (DSSC) e como materiais absorvedores de radiação (MAR) foi avaliado. Os resultados evidenciaram uma forte influência da metodologia de preparo nas propriedades finais dos compósitos, a qual é creditada a mudanças de morfologia do sistema em função das condições de preparação utilizadas. As amostras preparadas por casting apresentaram condutividades elétricas mais elevadas, enquanto as propriedades mecânicas foram superiores para os filmes extrudados, e ambas tiveram melhoria da estabilidade térmica. Os compósitos se mostraram promissores quanto ao uso em DSSC e como MAR, mas muitos estudos ainda são necessários para aprimorar sua eficiência nesses campos
Abstract: Polymeric nanocomposites based on carbon nanotubes (CNTs) have one of the highest technological potential due to the possibility of produce materials with improved mechanical properties, high electrical conductivity at low loadings (low percolation threshold), and good processability. These systems are versatile, may present astonishing properties, and are allowed to control them by changing the proportion of their components, being able to tailor these materials to suit a desired application. In this work, nanocomposites of multiwalled carbon nanotubes (MWCNTs) and a commercial elastomer (Kraton-D®), which is a block copolymer of styrenebutadiene- styrene (SBS), were prepared by extrusion and by casting. The thermal, mechanical, and electrical properties presented by these materials were compared. The characterization was performed by measurement of the electrical conductivity (Coleman¿s method), scanning and transmission electron microscopy (for morphologic characterization), thermogravimetry (for thermal stability and determination of the loading of filler), stress-strain tests and dynamic mechanical analysis (for the mechanical properties). Furthermore, the potential of application of the extruded composites in dye-sensitized solar cells (DSSC) and as radiation absorbing materials (RAM) was tested. The results showed a strong influence of the methodology of preparation upon the final properties of composites, which was attributed to changes in the morphology of the system with conditions used to prepare the samples. Composites made by casting showed a higher electrical conductivity than the extruded ones, although the latter presented better mechanical properties than the former ones. Despite the requirement of further studies to improve their efficiency in DSSC and as RAM, the composites were promising for these applications
Mestrado
Quimica Inorganica
Mestre em Química
Rahmat, Meysam. "Carbon nanotube - polymer interaction in nanocomposites." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104648.
Повний текст джерелаLes nanocomposites avec des polymères renforcés de nanotubes de carbone ont été le centre d'attention de nombreuses études dans les dernières années. Les propriétés supérieures des nanotubes de carbone et la flexibilité des polymères à être utilisés dans de diverses applications ont créé de grandes attentes pour cette classe de nanocomposites. Des études de modélisation ont démontré un fort potentiel pour ces matériaux, cependant la validation expérimentale de ces propriétés prédites reste un défi. Une des principales difficultés est l'obtention d'une interaction optimale entre les nanotubes et la matrice polymère. Cette interaction influence la dispersion des nanotubes dans le polymère et affecte les propriétés globales du nanocomposite. De ce fait, l'objectif principal de ce travail de recherche a été l'étude de l'interaction entre les nanotubes de carbone et le polymère dans les nanocomposites. A partir d'une revue détaillée de la littérature, la méthode de dynamique moléculaire et la microscopie à force atomique ont été choisies comme techniques numériques et expérimentales pour étudier l'interaction. Dans la partie de modélisation, les propriétés d'interface d'un nanotube à paroi simple avec du poly(methyl methacrylate) ont été obtenues à partir d'une simulation d'un test d'arrachement en trois phases. Une énergie de liaison d'interface de 0.39 kcal/molÅ2 a été calculée par la simulation de dynamique moléculaire. Dans la section expérimentale, une méthode de discrétisation par étapes a été proposée en tant que nouvelle technique de mesure de l'interaction par microscopie à force atomique. De plus, un nouvel paramètre d'interaction, appelé contrainte d'interaction, a été introduit pour évaluer la qualité de l'interaction dans les nanocomposites. La méthode de discrétisation par étapes a été utilisée pour le nanocomposite de poly(methyl methacrylate) avec un nanotube de carbone à paroi simple, et une interaction maximale de contrainte de 7 MPa a été obtenue. Les résultats ont été ensuite utilisés pour la théorie classique de contact et une théorie de contact à l'échelle nano. Les données sur les interactions de contraintes ont été aussi utilisées comme entrées pour des simulations de dynamique moléculaire «gros grains» afin d'obtenir les propriétés d'interface des nanocomposites. Cette nouvelle approche bénéficie de la flexibilité de la méthode de dynamique moléculaire «gros grains» et de la fiabilité des données expérimentales obtenues par la microscopie à force atomique. À partir des résultats de la méthode de dynamique moléculaire «gros grains», l'énergie de liaison d'interface d'un nanocomposite de nanotube de carbone–poly(methyl methacrylate) a été estimée à 0.44 kcal/molÅ2. Cette valeur a été comparée à l'énergie de liaison d'interface obtenue par la méthode de dynamique moléculaire (i.e., 0.39 kcal/molÅ2). La bonne corrélation entre les résultats basés sur des approches numériques et expérimentales démontre la validité de cette étude ainsi que la robustesse des méthodes proposées et des paramètres développés.
Battisti, Andrea. "Conductive carbon nanotube thermosetting polyester nanocomposites." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/7621.
Повний текст джерела