<p> A recently developed surface grafting technique, surface-initiated atom transfer radical polymerization (ATRP), has the ability to directly graft polymer chains with controllable chain lengths, densities and functionalities from various kinds of surfaces. This thesis has two main focuses. First is to study the use of this technique in grafting monomers with special structures and functionalities. The other is to apply this technique to the modification of reactive metal surfaces. </p> <p> Both of fluorinated polymers and polyhedral oligomeric silsesquioxane (POSS)-containing polymers have very interesting properties. In this thesis, for the first time, a highly fluorinated monomer, 2,2,2-trifluoroethyl methacrylate (TFEMA) and a POSS-containing monomer, POSS-MA were successfully polymerized from silicon wafers by surface-initiated ATRP. This is also the first work to use this technique to graft polymers with bulky, rigid side groups. </p> <p> To achieve very high grafting density is a big challenge for surface-initiated ATRP. We designed a novel surface-attachable difunctional initiator, 11-(2,2-bis(2bromo-2-methylpropionyloxy methyl)propionyloxy) undecyltrichlorosilane. With its help, the grafting density of PTFEMA was almost doubled, from 0.48 to 0.86chains/nm2. This is so far the most effective method to increase the grafting density. </p> <p> Unlike other kinds of materials, the surfaces of metals are active in electrochemical and acid/base reactions and this reactivity complicates A TRP reactions. With the help of triethoxysilane-based initiator and mild Fe(II)/Fe(III) catalyst system, various acrylic polymers were successfully grafted from flat nickel and copper surfaces by surface-initiated ATRP. This work provided a convenient method to prepare functional polymer coatings with very stable adhesions to the metal surfaces. The same strategy can be extended to the surface modification of a shape-memory-alloy, nitinol. </p> <p> Metal nanoparticles were also modified by this technique. Polymer shells were grafted from nickel nanoparticles surfaces. After the polymer grafting, both of the dispersibility and dispersion stability of nickel nanoparticles in appropriate solvents were greatly improved. </p> / Thesis / Doctor of Philosophy (PhD)

Ph. D. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Investment casting process is the most suitable technique for producing high quality castings which are dimensionally accurate with excellent surface finish and complex in nature. Recently with the ever-changing manufacturing landscape, the process has been increasingly used to produce components for the medical, aerospace and sports industry. The present study looked at three investigative scenarios in the development of a pattern material for investment casting process: (i) the development of wax/ethyl vinyl acetate (EVA) and wax/linear low-density polyethylene (LLDPE) blends as the carrier vehicle materials for the development of pattern material for investment casting; (ii) the development of wax/EVA/polymethyl methacrylate (PMMA) based investment casting pattern and lastly (iii) the development of wax/LLDPE/PMMA based investment casting pattern material. The first part of the studies elucidates the effects in terms of the thermal, mechanical, surface and rheological properties when paraffin wax in blended with poly EVA and LLDPE. The developments involved the extrusion of seven formulations for EVA and also LLDPE using a twin-screw extrusion compounder. The paraffin wax weight percent investigated ranged from 33% to 87% thus encompassing both low and high wax loading ratios. The thermal properties of the developed binary blends were characterized via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The mechanical properties were characterized using three-point bending test. The thermo-mechanical and rheological properties were determined using thermomechanical analysis (TMA) and a rheometer respectively. A scanning electron microscope (SEM) was used to study the surface texture of the extruded blends. The thermal properties indicated that the thermal stability of paraffin wax is improved when it is blended with both EVA and LLDPE. DSC curves showed two endothermic melting peaks and two exothermic crystallisation peaks. In the case of wax/EVA blends, there was no distinct peak showing the independent melting of neat wax and EVA. The peak at a temperature of 50 – 72 °C corresponds to the melting of the wax/EVA blend. In the case of wax/LLDPE blends, the peak at 50 -66 °C corresponds to the melting of wax whereas the large peak at 112 - 125°C corresponds to the melting of the LLDPE. Wax/EVA and wax/LLDPE had improved mechanical properties as compared to that of neat wax. The rheological properties of both the EVA based and LLDPE based blends indicated that the viscosity of the blends increased as compared to that of neat wax. SEM confirmed that EVA alters the wax crystal habit at higher concentrations. In the case of wax/LLDPE blends, at 20-30 % wax content, a heterogeneous surface was observed, indicating the immiscibility of the paraffin wax within the LLDPE matrix. At a high wax content, there was agglomeration of wax. LLDPE allows amorphous structure of wax to disperse easily between the chains. The second part of the studies focussed on the wax/EVA filled with poly (methyl methacrylate) (PMMA) microbeads. TGA behaviour on the pyrolysis of wax/EVA/PMMA showed that the compounds volatilise readily with virtually no residue remaining above 500 °C. The DSC curves indicated that, the incorporation of PMMA reduced the crystallinity of wax/EVA blend. A distinct endothermic peak and another small peak was observed in all the formulations. The mechanical properties of wax/EVA/PMMA improved significantly. The methylene group present in both wax and EVA combined to form a blend with enhanced mechanical properties whereas the PMMA microbeads improved the needle penetration hardness. The melt viscosity of wax/EVA/PMMA increased as the EVA and/or the PMMA content is increased. The rheological experimental data fitted with the data predicted using the modified Krieger and Dougherty expression. The maximum attainable volume fraction of suspended PMMA particles was at max = 0.81. The SEM micrograph of wax/EVA/PMMA revealed a near perfect spherical nature for the filler particles in the wax/EVA polymer matrix. It further shows that the PMMA microbeads were weakly bonded and well distributed in the wax/EVA matrix. The third part of the studies focussed on the wax/LLDPE filled with Poly (methyl methacrylate) (PMMA) microbeads. The incorporation of LLDPE and PMMA into paraffin wax had a strong influence on the thermal properties, tensile properties, flow properties and its morphology. The TGA analysis showed that there was a slight observable decrease in the melting onset temperatures when the wax content was increased. From the DSC curves, the corresponding values of onset temperatures observed are between melting and crystallization temperature of neat paraffin wax and neat LLDPE. The short chains of the paraffin wax and the fragments formed by scission of wax chain have sufficient energy to escape from the matrix at lower temperatures. The slight decrease in peak temperatures associated with melting and crystallization could be attributed to the decrease in the average lamellar thickness of the blends. The tensile properties by three-point bending tests indicated an increase in the stress with an increase in the LLDPE content. This can be attributed to the formation of paraffin wax crystals in the amorphous phase of the blend which may influence the chain mobility. Since the paraffin wax used for this study had a low viscosity as compared to LLDPE, both LLDPE or PMMA had an influence on the viscosities of the blends. The data obtained from the experiments fitted with the data predicted obtained from the modified Krieger and Dougherty expression. The maximum attainable volume fraction of suspended PMMA particles was at max = 0.74. Similar observation with that of wax/EVA/PMMA was made in terms of the morphology of the wax/LLDPE/PMMA blends. The excellent thermal stabilities, the superior mechanical strength of wax/EVA/PMMA and wax/LLDPE/PMMA and the flow properties with relatively high EVA and also with high PMMA loadings, open new opportunities for EVA and LLDPE based pattern material for in investment casting process. It is worth pursuing further comprehensive studies since it offers a strong potential for realizing further technological improvement in the field of investment casting and rapid prototyping technologies.

Les maladies cardiovasculaires sont une des causes de mortalités les plus élevées mondialement. Parmi celles-ci, on retrouve l’infarctus du myocarde, qui n’a pour traitement que la transplantation cardiaque. Or, dû à la faible quantité de donneur, une solution alternative est recherchée. De ce fait, l’ingénierie tissulaire permet le développement de tissus et d’implants thérapeutiques tels les patchs cardiaques, qui peuvent être bioimprimés. Or, une des limitations actuelles de l’utilisation d’une telle stratégie est la vascularisation de tissu bioimprimés. Dans cette étude, la bioimpression 3D a été utilisée afin de bioimprimer des patchs perfusables de gélatine méthacrylate (GelMA) à utiliser potentiellement pour le tissu cardiaque. Il a été possible de développer une bioencre pouvant être utilisée pour une application dans le tissu cardiaque, d’évaluer l’imprimabilité de l’encre et de bioimprimer de patchs standards et perfusables. Pour ce faire, GelMA a été synthétisé et les propriétés mécaniques ont été évaluées pour finalement sélectionner une encre de 10 % GelMA, ayant un module de Young approprié pour le tissu cardiaque, de 23,7±5,1 kPa. Par la suite, les processus d’impression, standard et coaxial, de patchs standards et perfusables ont pu être optimisés. Finalement, des patchs perfusables de GelMA 10% et gélatine 2% ont pu être imprimés avec une viabilité cellulaire élevée, jusqu’à 79,7±8,7 % et 83,5±5,7 % obtenue aux jours 1 et 7 de culture respectivement, avec des fibroblastes 3T3. La présence de canaux vides et la perfusabilité des patchs démontrent le potentiel de cette méthode pour éventuellement bioimprimer des patchs cardiaques vascularisés épais. / Cardiovascular diseases are a leading cause of death worldwide. Myocardial infarction captures a significant segment of this population, and the end-stage myocardial infarction can only be treated by heart transplantation. However, due to the scarcity donors, tissue engineering has been considered as an alternative solution. Tissue engineering allows the development of tissues and therapeutic implants such as cardiac patches. However, one of the main hurdles in the use of such a strategy is the vascularization of bioprinted tissue. In this study, 3D bioprinting was used to bioprint perfusable gelatin methacrylate (GelMA) patches for a potential use in cardiac tissue. This work consists in the development of a bioink that can be used for the cardiac tissue, the evaluation of the printability of the ink, and the final bioprinting of standard and perfusable patches. For this purpose, GelMA was synthesized and a final concentration of 10 % was selected as it showed an appropriate Young's modulus for cardiac tissue, of 23.7±5.1 kPa, while maintaining high biocompatibility. Subsequently, the printing process of standard and perfusable patches could be optimized with the use of GelMA and gelatin inks. Finally, 10% GelMA and 2% gelatin vascularized patches could be printed with high cell viability, of up to 79,7±8,7 % and 83,5±5,7 % on days 1 and 7 of culture respectively for 3T3 fibroblasts. Additionally, the presence of hollow channels of the perfusable patches demonstrates the potential of this method to be eventually applied to the bioprinting of thick vascularized cardiac patches.

Ph. D. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Driven by the need of sustainably sourced catalysts and the use of reaction systems that generate environmentally benign by-products, the present study aimed to deposit stable, dispersed palladium (Pd) nanoparticles on the modified surfaces of granular macadamia nutshell (MNS) biomass for catalytic reduction of hexavalent chromium [Cr(VI)] to trivalent chromium [Cr(III)]. Through wet impregnation with Pd(II) ions and subsequent hydrazine-mediated reduction to Pd(0), Pd nanoparticles were embedded in a scaffold of polyethyleneimine grafted on bleached MNS previously coated with a chemically bound layer of polyglycidyl methacrylate. Visualization and imagery from scanning electron microscopy showed the formation of different layers of the polymeric coating and dispersed palladium resulting from surface modification and palladium nanoparticle synthesis, respectively. X-ray diffraction, energy-dispersive X-ray spectroscopic analysis confirmed the formation of Pd on the modified MNS surface. An estimate of 5.0 nm for crystallite size was calculated by application of the Scherrer equation. The composite material, denoted Pd@PEI-MNS, exhibited catalytic activity in formic acid-mediated Cr(VI) reduction. Through a one-factor-at-a-time experimental design, the activity of the Pd@PEI-MNS was illustrated to be dependent on solution pH; initial Cr(VI) concentration, initial formic acid concentration, and presence of competing anions; Pd@PEI-MNS dose; and temperature. Subsequent modeling of the Cr(VI) removal process by response surface methodology revealed that the most influential factor was Pd@PEI-MNS dose followed by temperature and formic acid concentration. The influence of initial Cr(VI) concentration, was surpassed by the dose-temperature and dose-formic acid concentration interactive effects. Elucidation of the Cr(VI) removal mechanism by XPS and FTIR demonstrated the active participation of surface -CH2OH functional groups, the bulk of which originated from the reduction of esters of the grafted ligands. Replacement of formic acid to carbon dioxide, the -CH2OH groups were converted to -COO- groups.

Se sintetizaron nanocompuestos híbridos en bloque de poli(etil metacrilato-co-hidroxietil acrilato) 70/30 wt%/sílice, P(EMA-co-HEA)/SiO2, con distintas proporciones de sílice hasta el 30 wt%. El procedimiento de síntesis consistió en la copolimerización de los monómeros orgánicos durante la polimerización sol-gel simultánea de tetraetoxisilano, TEOS como precursor de sílice. El TEOS se hidroliza eficientemente y condensa dando lugar a sílice, y presenta una distribución homogénea en forma de agregados inconexos de nanopartículas de sílice elementales en los híbridos con bajos contenidos de sílice (<10 wt%) o redes continuas interpenetradas con la red orgánica tras la coalescencia de los agregados de sílice (>10 wt%). La red polimérica orgánica se forma en los poros producidos en el interior de las nanopartículas elementales de sílice, y también en los poros formados entre los agregados de nanopartículas. Los nanohíbridos con contenidos de sílice intermedios (10-20 wt%) exhibieron las propiedades más equilibradas e interesantes: i) refuerzo mecánico de la matriz orgánica conseguida gracias a redes de sílice continuas e interpenetradas, ii) buena capacidad de hinchado debida a la expansión de la red orgánica no impedida todavía por un esqueleto de sílice rígido, y a un número alto de grupos silanol terminales hidrófilos (concentraciones inorgánicas en los alrededores de la coalescencia), y iii) mayor reactividad superficial debido a un contenido relativo bastante elevado de grupos polares silanol terminales disponibles en las superficies. La 'bioactividad' o capacidad de los materiales en bloque de formar hidroxiapatita (HAp) sobre sus superficies fue estudiada in vitro sumergiéndolos en fluido biológico simulado (simulated body fluid, SBF). La formación de la capa de HAp viene controlada por el mecanismo y el tiempo de inducción a la nucleación de la misma, que dependen a su vez de la estructura de la sílice. / Vallés Lluch, A. (2008). P(EMA-co-HEA)/SiO2 hybrid nanocomposites for guided dentin tissue regeneration: structure, characterization and bioactivity [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/3795

The polymerization of methyl methacrylate (MMA) was investigated in this dissertation. Selected kinetic models from the literature were reviewed, and two new, generalized models of diffusion-limited effects (gel- and glass effects), derived from the current models were proposed and tested for bulk and solution polymerization of MMA in batch and semi-batch reactors, under isothermal and non-isothermal conditions. The newly proposed models include the capability of modeling termination by combination, radical transfer to monomer and depropagation reaction. The new and previous models were compared with experimental data of bulk and solution polymerizations of MMA, under a selection of non-steady state processes conditions (initiator and monomer feed, step changes in temperature) and compositions (initiator and chain transfer agents, regarding both type and dosages). The particular case of a non-isothermal bulk polymerization was also investigated. A simulation program (Reactormodel) was developed in Matlab, and its algorithm is provided. / Sem resumo.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / PURPOSE: To assess the influence of simulated oral erosive/abrasive challenges on the bond strength of an etch-and-rinse two-step bonding system to enamel using an in situ/ex vivo protocol. METHODS: Bovine enamel blocks were prepared and randomly assigned to four groups: CONT - control (no challenge), ABR - 3x/day-1 minute toothbrushing; ERO - 3x/day - 5 minutes extraoral immersion into regular Coca Cola; and ERO+ABR - erosive protocol followed by a 1-minute toothbrushing. Eight blocks were placed into an acrylic palatal appliance for each volunteer (n = 13), who wore the appliance for 5 days. Two blocks were subjected to each of the four challenges. Subsequently, all the blocks were washed with tap water and Adper Single Bond 2/Filtek Z350 were placed. After 24 hours, 1 mm2 beams were obtained from each block to be tested with the microtensile bond strength test (50 N load at 0.5 mm/minute). The data were statistically analyzed by one-way RM-ANOVA and Tukey's tests (alpha = 0.05). RESULTS: No difference was detected among the ABR, ERO, and CONT groups (P > 0.05). ERO+ABR group yielded lower bond strengths than either the ABR and ERO groups (P < 0.0113). / Revisión por pares

Esta tese envolveu o estudo da dinâmica molecular em copolímeros em bloco compostos de poli(metacrilato de metila) (PMMA), poli(ácido acrílico) (PAA) e Poli(acrilato de chumbo) (PAPb) por técnicas de Ressonância Magnética Nuclear e de análise térmica (DSC e DMTA). Estes copolímeros em bloco foram sintetizados visando a obtenção de compostos para serem utilizados, tanto como lentes oftálmicas com maiores índices de refração, como materiais dedicados à proteção radiológica, sendo estas duas propriedades de emprego individual ou integrado. Para o estudo destes materiais, as amostras foram confeccionadas com várias composições, incluindo aquelas nas formas puras contendo apenas um bloco, resultantes da combinação de dois blocos, e as triblocos, com diferentes quantidades relativas de PAPb, variando de 1 a 40%. Para o caso do PMMA, a dinâmica molecular é bem conhecida, sendo caracterizada por uma relaxação &beta;, que envolve mais especificamente movimentos de seus ramos laterais e que ocorre dentro de um amplo intervalo de temperatura centrado em torno da ambiente, e pela transição vítrea, que envolve, predominantemente, movimentos da cadeia principal que ocorrem para temperaturas em torno de 100oC. Devido à extensão destes dois eventos em grandes intervalos de temperatura, eles acabam se superpondo já em temperaturas abaixo de 100oC. O fato da relaxação &beta; ocorrer para o PMMA em torno da temperatura ambiente, confere-lhe uma de suas características mais importantes, não ser quebradiço. Porém, devido à presença do grupo hidroxila no PAA, que permite a ocorrência de ligações de hidrogênio entre os diferentes ramos laterais, a relaxação &beta; é suprimida neste material, tornando-o quebradiço e não adequado para as aplicações desejadas. No caso do copolímero tribloco, espera-se que o PAPb também possa interferir na característica mecânica final do material, em função de sua participação na dinâmica molecular do copolímero. Para este estudo foram preparadas várias amostras com diferentes quantidades relativas de PMMA, PAA e PAPb, de modo entendermos a dinâmica molecular destes materiais, individual e coletivamente, afim de selecionar os mais indicados para as aplicações tecnológicas almejadas. Para o estudo destas amostras, utilizamos tanto técnicas de análise térmica (DSC e DMTA), que fornecem, de forma relativamente rápida, dados importantes sobre a dinâmica macroscópica, quanto métodos básicos e avançados de RMN no estado sólido, que propiciam informações mais detalhadas sobre a dinâmica molecular. Estes estudos indicaram que a presença do PAA, obrigatória na rota de síntese utilizada para a inserção do PAPb, é um elemento indesejável no produto final, pois ele sempre atua na supressão da relaxação &beta;. Adicionalmente, os dados obtidos indicaram que o PAPb, em grandes quantidades, também age na supressão desta relaxação. Embora a proposição destes novos materiais para a área oftálmica não ser muito adequada, já que a quantidade de PAPb necessária para a obtenção de amostras com bons índices de refração deve ser grande (bem acima de 5%, quando elas tornam-se quebradiças), as amostras com pequenos conteúdos de PAPb (até 5%) permitiram uma redução de até 50% dos raios-x incidentes. Finalmente, os estudos realizados por técnicas que observam detalhes da dinâmica molecular, tanto em níveis macroscópicos (DSC e DMTA), quanto moleculares (RMN), ofereceram excelentes informações básicas tanto sobre a mobilidade dos diferentes ramos que compõem os copolímeros em bloco, quanto a interação/miscibilidade entre os diferentes blocos, que afeta também a dinâmica global do sistema. / This thesis involved the study of molecular dynamics in triblock copolymers consisting of poly (methyl methacrylate) (PMMA), poly (acrylic acid) (PAA) and Poly (lead acrylate) (PAPb) by solid-state Nuclear Magnetic Resonance (NMR) and thermal analyses (DSC and DMTA). These block copolymers were synthesized in order to obtain materials not only presenting higher refractive index but also offering good radiological protection, which are useful for individual and combined applications. For the study of these materials, the samples were prepared with various compositions, including those in pure form containing only a block, resulting from the combination of two blocks, and the triblock with different relative amounts of PAPb, ranging from 1 to 40%. In the case of PMMA, the molecular dynamics is well known, characterized by a &beta; relaxation, which involves more specifically the ester side-group dynamics occurring within a broad temperature range centered around the room temperature, and the glass transition, predominantly involving the main chain dynamics that occur for temperatures around 100oC. Due to large extension of these two dynamical events in wide temperature ranges, they merge at temperatures below 100oC. The fact that the &beta; relaxation occurs for the PMMA around the room temperature, confers to it one of its most important features, toughness. However, due to the presence of the hydroxyl group in PAA, which allows the occurrence of hydrogen links between different branches, the &beta; relaxation in this material is strongly suppressed, making it brittle and not suitable for the desired applications. In the case of the triblock copolymer, it is also expected that PAPb may also interfere with the mechanical properties of the final material due to its involvement in the full molecular dynamics of the copolymer. For this study, several samples were prepared with different relative amounts of PMMA, PAA and PAPb, in order to understand the molecular dynamics of these materials, individually and collectively, and select the most suitable ones for the desired technological applications. To characterize and study these samples, we employed thermal analyses (DSC and DMTA), which give quick and important data on the macroscopic dynamics, and basic and advanced solid-state NMR methods, which provide more detailed information about he molecular dynamics. These studies indicated that PAA, necessary along the synthesis route used for the insertion of PAPb in the triblock copolymers, is an undesirable element in the final product, because it is always acting on the suppression of &beta; relaxation. Although the proposition of these new materials for the ophthalmic area is not very appropriate, since the amount of PAPb necessary to obtain good refraction indexes would be necessarily large (over 5%, when they become brittle), the samples with small amounts of PAPb (up to 5%, when they present good mechanical properties) allowed a significant reduction of about 50% of the incident x-rays. Finally, using solid-state NMR methods, including modern Exchange experiments and thermal analyses (DSC and DMTA), it was possible to understand in detail the individual and cooperative motions of the main chain and side groups. The most import result obtained indicate that, despite being important inserting PAPB and PAA in the block copolymer for improving the desired optical and x-ray shielding properties, the presence of these blocks tend to suppress the &beta; relaxation, reducing thesample mechanical properties.

Gegenstand dieser Arbeit ist die Herstellung nicht hierarchischer und hierarchischer, poröser Polymermembranen mittels eines Templatverfahrens. Bei der Herstellung der hierarchischen Membranen wird eine Stützschicht mit mikrometergroßen Mulden und eine aktive Membranschicht mit submikrometergroßen Poren in einem Arbeitsschritt und aus einem Material erzeugt. Als Template für die Poren der nicht hierarchischen Membranen bzw. Mulden der hierarchischen Membran in der Stützschicht dienen Flüssigkeitstropfen. Diese werden auf Substraten mit Bereichen unterschiedlicher Benetzbarkeit erzeugt. Die Substrate werden anschließend mit einer Polymerlösung überschichtet, welche im Falle der hierarchischen Membranen sphärische, monodisperse Siliziumdioxidpartikel enthält. Die Siliziumdioxidpartikel ordnen sich bevorzugt in der Grenzfläche zwischen den Templattropfen und der Polymerlösung an. Nach Verdunsten des Lösungsmittels, Entfernen des Substrats und ggf. der Siliziumdioxidpartikel werden poröse Polymermembranen erhalten. Die nicht hierarchischen weisen Poren in der Größe der Templattropfen aus. Die hierarchischen Membranen zeigen dagegen eine Stützstruktur mit mikrometergroßen Mulden, entstanden durch die Templattropfen und eine Schicht auf der Oberseite der Membran mit submikrometergroßen Poren, die durch die Siliziumdioxidpartikel gebildet wurden. Außerdem wird gezeigt, wie das dargelegte Verfahren auf die Herstellung von Membranen aus dem Monomer VISIOMER HEMA-TMDI übertragen werden konnte

In der vorliegenden Arbeit wird die Synthese neuartiger, polynuklearer Bismutoxido-Cluster sowie deren Potential zur Verwendung als Bausteine zum Aufbau organisch-anorganischer Hybridmaterialien beschrieben. Die molekularen Verbindungen werden nach partieller Hydrolyse eines basischen Bismutnitrats in DMSO erhalten. Durch Zugabe von Additiven wie Carbon- und Sulfonsäuren können funktionalisierte Bismutoxido-Cluster erzeugt werden, die eine gute Löslichkeit in organischen polaren Lösungsmitteln besitzen. Die Charakterisierung der Produkte erfolgte mittels Einkristallröntgenstrukturanalyse, NMR- und IR-Spektroskopie sowie ESI-Massenspektrometrie. Erste Untersuchungen zur Synthese röntgenopaker organisch-anorganischer Hybridmaterialien auf der Basis von Bismutoxido-Clustern und Methylmethacrylat wurden durchgeführt. Hierzu wurde der nanoskalige Bismutoxido-Cluster [Bi38O45(OMc)24] als anorganischer Baustein gewählt. Die Oberfläche des Bismut-Sauerstoff-Gerüsts dieser Verbindung ist mit Methacrylat-Liganden bedeckt, welche eine gute Löslichkeit vermitteln und durch ihre polymerisierbaren Funktionalitäten eine kovalente Anbindung z. B. an Vinylmonomere ermöglichen. Die radikalische Copolymerisation von [Bi38O45(OMc)24] mit Methylmethacrylat liefert transparente Komposite, die anhand von Festkörper-NMR-Spektroskopie, IR-Spektroskopie sowie TG- und DSC-Analyse charakterisiert wurden.