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.

This diploma thesis deals with the concept of use of nanotechnology for cement composites and UHPC. In the theoretical part of this diploma thesis there are theoretical principles described for successful design of high performance concrete and characteristics of main feedstock and its production. Furthermore, there is a focus on nanoparticles, especially the ones with carbon base in the form of carbon nanotubes CNT, in addition to that, graphenes GN that are new on the market, moreover, graphene oxide GO and its application in cement composites to mechanical characteristics and its durability. The first part of the practical part devotes in trying to find out an optimal parameter for ultrasonic mix with a suitable surface active substance of three graphenes. The other two parts of the practical part are about influence of graphenes on mechanical characteristics, cement paste microstructure, and application in the mix of concrete C 35/45 and UHPC

[ES] Para abordar los desafíos ambientales, la química y los procesos químicos deben ser más sostenibles. Para ello, el desarrollo de nuevos catalizadores especialmente activos es de suma importancia. En catálisis heterogénea, el grafeno ha surgido recientemente como un excelente candidato desde que fue posible aislarlo a partir del grafito. Sus propiedades únicas han despertado un gran interés para aplicarlo en varios campos, desde el refuerzo de matrices poliméricas hasta el desarrollo de materiales para catálisis. En catálisis, su uso como soporte catalítico o como carbocatalizador es todavía objeto de varios estudios. Con el objetivo de preparar catalizadores extremadamente activos en varias reacciones de química fina o de producción de hidrógeno, nuestro trabajo de investigación se ha centrado en el uso de materiales a base de grafeno como soportes catalíticos. Se consideraron diferentes aspectos: La funcionalización del grafeno; al ser un material de baja dimensionalidad, las propiedades del grafeno están estrechamente relacionadas con la química de su superficie. Mediante la fosforilación del óxido de grafeno, hemos demostrado que la estabilidad térmica y la estabilización de las nanopartículas metálicas mejoran significativamente. La combinación de grafeno con otros materiales; Pequeñas nanopartículas de paladio estabilizadas sobre materiales porosos a base de óxido de grafeno y quitosano han demostrado una excelente actividad para la deshidrogenación del formiato de amonio. La estrategia de síntesis adoptada para preparar el grafeno; La pirólisis de películas de alginato de amonio y un precursor de rutenio (Ru) en diferentes atmósferas permitió la preparación de nanopartículas de Ru soportadas en grafeno cuya orientación depende de la atmósfera de pirólisis. Por lo tanto, fue posible una comparación de la actividad catalítica de diferentes facetas cristalográficas. Dopaje de grafeno; la presencia de diferentes heteroátomos en su estructura ha permitido una mejor estabilización de nanopartículas y clusters metálicos. Los materiales basados en nanopartículas de óxido de cobre y grafenos dopados han demostrado poseer una excelente actividad catalítica en la síntesis de nuevas moléculas de interés farmacéutico. / [CA] Per a abordar els desafiaments ambientals, la química i els processos químics han de ser més sostenibles. Per a això, el desenvolupament de nous catalitzadors especialment actius és de summa importància. En catàlisi heterogènia, el grafé ha sorgit recentment com un excel·lent candidat des que va ser possible aïllar-lo a partir del grafit. Les seues propietats úniques han despertat un gran interés per a aplicar-lo en diversos camps,des del reforç de matrius polimèriques fins al desenvolupament de materials per a catàlisis. En catàlisi, el seu ús com a suport catalític o com carbocatalitzador és encara objecte de diversos estudis. Amb l'objectiu de preparar catalitzadors extremadament actius en diverses reaccions de química fina o de producció d'hidrogen, el nostre treball de recerca s'ha centrat en l'ús de materials a base de grafé com a suports catalítics. Es van considerar diferents aspectes: La funcionalització del grafé; a l'ésser un material de baixa dimensionalitat, les propietats del grafé estan estretament relacionades amb la química de la seua superfície. Mitjançant la fosforilació de l'òxid de grafé, hem demostrat que l'estabilitat tèrmica i l'estabilització de les nanopartícules metàl·liques milloren significativament. La combinació de grafé amb altres materials; Xicotetes nanopartícules de pal·ladi estabilitzades sobre materials porosos a base d'òxid de grafé i quitosà han demostrat una excel·lent activitat per a la deshidrogenació del formiat d'amoni. L'estratègia de síntesi adoptada per a preparar el grafé; La piròlisi de pel·lícules de alginat d'amoni i un precursor de ruteni (Ru) en diferents atmosferes va permetre la preparació de nanopartícules de Ru suportades en grafé, l'orientació del qual depén de l'atmosfera de piròlisi. Per tant, va ser possible una comparació de l'activitat catalítica de diferents facetes cristal¿logràfiques. Dopatge de grafé; la presència de diferents heteroàtoms en la seua estructura ha permés una millor estabilització de nanopartícules i clústers metàl·lics. Els materials basats en nanopartícules d'òxid de coure i grafens dopats han demostrat posseir una excel·lent activitat catalítica en la síntesi de noves molècules d'interés farmacèutic. / [EN] To address environmental challenges, chemistry and chemical processes need to be more sustainable. For this, developing new particularly active catalysts is of paramount importance. In heterogeneous catalysis, graphene has emerged as an excellent candidate since it was possible to isolate it from graphite. Its properties have aroused substantial interest, earning it applications in various fields spanning from the reinforcement of polymer matrices to the development of materials for catalysis. In catalysis, its use both as a catalytic support or as a carbocatalyst is still the subject of several studies. Aiming to prepare extremely active catalysts in various fine chemical reactions or hydrogen production, our research work has focused on the use of graphene-based materials as catalytic supports. Different aspects were considered: The functionalization of graphene; being a material of low dimensionality, the properties of graphene are intimately related to the chemistry of its surface. Through phosphorylation of graphene oxide, we have shown that the thermal stability and stabilization of metal nanoparticles are significantly improved. Combination of graphene with other materials; small palladium nanoparticles stabilized on porous materials based on graphene oxide and chitosan have demonstrated excellent activity for the dehydrogenation of ammonium formate. The synthetic strategy adopted to prepare graphene; pyrolysis of films of ammonium alginate and ruthenium precursor (Ru) in different atmospheres enabled the preparation of Ru nanoparticles supported on graphene whose orientation depends on the atmosphere of pyrolysis. Thus, a comparison of the catalytic activity of different crystallographic facets was possible. Doping of graphene; the presence of different heteroatoms in its structure has allowed a better stabilization of metal nanoparticles and clusters. Materials based on copper oxide nanoparticles and tridoped graphene have demonstrated an excellent catalytic activity in the synthesis of new molecules of pharmaceutical interest. / Anouar, A. (2021). Préparation de matériaux à base de graphène et leur application en catalyse [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/164030 / TESIS

This master´s thesis is focused on measurement of optical properties of thin layer of materials used in organic solar cells (OSC). The usage of graphene oxides and its reduced forms as parts of hole transport layer (HLT) in OSC were studied. At the beginning of the thesis, there is described basic theory necessary to understand the optical properties of thin layers. The thin layer deposition and reduction of GO are discussed too. The experimental part is aimed to the optical characterization of prepared thin films. The results from optical microscopy, UV-VIS spectroscopy, FT-IR spectroscopy and spectroscopic ellipsometry were obtained. At the end of the thesis, the results are concluded and compared with already published literature.

The objective of my work was to develop HDPE clay nanocomposites for packaging with superior barrier (gas and water) properties by economical processing technique. This work also represents a comparative study of thermoplastic nanocomposites for packaging based on linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and Nylon12. In this study properties and processing of a series of linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and Nylon 12 nanocomposites based on Na-MMT clay and two different aspect ratio grades of kaolinite clay are discussed.