Dissertations / Theses on the topic 'Inorganic polymers'

The aims of this project were to synthesise and characterise a range of inorganic/organic hybrid polymers containing pendant vinyl groups and to study their uses as possible fire retardants. The work consisted of several parallel strands: the synthesis of organically modified silicas; the preparation of vinyl containing silsesquioxanes based on the hydrolysis of cyclohexyltrichlorosilane or propylmethacrylatepolysiloxane; the synthesis of latexes by co-polymerisation of either N-Isopropylacrylamide (NIPAM) or styrene with vinyltrimethoxysilane and the intercalation of styrene or NIPAM into montmorillonite. All samples were characterised using a range of instrumental techniques including infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD), elemental analysis, thermal analysis, surface area analysis and electrokinetic analysis. Vinyl modified silicas having large surface areas (about 400m2g-1) were successfully obtained. On calcining at 540°C silicas having surface area in excess of 1000m2g-1 were formed. Both the original organically modified silica and a sample after calcining were incorporated into poly(methylmethacrylate) and these samples were compared with pure poly(methymethacrylate) in a cone calorimeter to study their thermal properties. No significant enhancement to the thermal stability of the polymers was observed when the silica was incorporated. Analysis of the co-polymer latexes were inconclusive, in the case of the products obtained from NIPAM but particles having a narrow size distribution were obtained using styrene. There was no apparent trend in the value of the zeta potential with composition. Analysis of the intercalation of monomers into clays and the synthesis of silsesquioxanes were inconclusive.

This is partly because the requirements for such an ultimate material change with people’s perception about its properties as well as its environmental impact. Thus, the once-believed ultimate Portland cement binder is now becoming unacceptable for a number of reasons including poor durability as well as severe environmental impact during production. Thus, an improved mineral binder is required by modern society to serve the same purposes as the existing Portland cement binder, as well as to reduce the current environmental impact caused by Portland cement production.
Geopolymerisation is such a ‘green’ technology capable of turning both natural ‘virginal’ aluminosilicates and industrial aluminosilicate wastes, such as fly ash and blast furnace slag, into mechanically strong and chemically durable construction materials. However, the source materials for geopolymer synthesis are less reactive than Portland cement clinkers and the chemical compositions of these source materials can vary significantly. Consequently, product quality control is a major engineering challenge for the commercialisation of geopolymers.
This thesis is therefore devoted to the mechanistic understanding of the interfacial chemical interactions between a number of natural and industrial aluminosilicates and the various activating solutions, which govern the reactivity of the aluminosilicate source materials. The effects of activating solution alkalinity, soluble silicate dosage and anionic contamination on the reactivity of the aluminosilicate source materials to produce geopolymeric binders, as well as their bonding properties to natural siliceous aggregates for concrete making, are examined. In particular, a new set of novel ‘realistic’ reaction models has been developed for such purposes. These reaction models have been further utilised to develop a novel analytical procedure, which is capable of studying geopolymerisation on ‘real’ geopolymers in situ and in real time. This novel procedure is invaluable for the total understanding of geopolymerisation, which is in turn vital for effective geopolymer mix designs.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007.
Additional advisors: Houston Boyd, Tracy Hamilton, Christopher Lawson, Charles Watkins. Description based on contents viewed Feb. 8, 2008; title from title screen. Includes bibliographical references.

The prepaparation of amorphous, homogeneous blends of zwitterionic polymers and transition metal salts was investigated. Homogeneous miscibility was achieved in many cases up to equimolar amounts of salt, depending on the anion and cation chosen. Various analytical techniques point to a solid state solution of the inorganic ions in the polymer matrix.

Interest in producing hybrid organic-inorganic (HOI) materials has increased rapidly due to the unique combination of properties from the organic and inorganic components. The goal of the research described is to develop various HOI materials and explore their applications in corrosion protection over aerospace aluminum alloys, impact resistant materials, and surface protection over thermoplastic substrates. As a replacement to toxic chromate inhibitors, enrivonmentally friendly magnesium-rich primers (Mg-rich primers) have been investigated to provide corrosion protection over aerospace aluminum alloys. HOI binders were produced from an alkoxy silane and silica via sol-gel chemistry, where the combined organic and inorganic components provide flexibility, adhesion, and barrier properties. The derived topcoated Mg-rich primers showed promising corrosion protection in a salt spray exposure test and are competitive with chromate-containing primers. The condensation catalyst, tetrabutyl ammonium fluoride (TBAF), played an important role in the performance of the HOI binders and the derived Mg-rich primers. It enabled higher crosslink density and better barrier properties, however, reacted with Mg particles during salt spray exposure and caused the formation of blisters. A non-ionic condensation catalyst, dibutyltin dilaurate (DBTDL), had lower catalyst strength, but was expected to eliminate the blister formation of topcoated Mg-rich primers. Perfectly alternating polycarbonate-polydimethylsiloxane (PC-PDMS) multiblock copolymers were produced to create transparent impact resistant materials by confining the size of the rubber domains. The PC-PDMS block copolymers maintained high transparency at up to 62 wt% PDMS and shorter block length gave rise to larger partial miscibility. By incorporating the PDMS blocks to dissipate energy, the PC-PDMS block copolymers had much better impact strength than pure PC oligomers. Thermoset polycarbonate-polyhedral oligomeric silsesquioxane (PC-POSS) coatings were investigated to serve as surface coatings on PC substrate to provide abrasion resistance. The covalent bonding allowed high POSS loading at up to 18 wt% without sacrificing the transparency. The solvent composition and curing conditions largely determined the surface and bulk properties of the coatings. The incorporation of POSS molecules significantly increased the char yield and mechanical strength of the thermoset coatings, making them promising in surface protection applications.

L'objectiu del treball inclòs en aquesta Tesi Doctoral és el desenvolupament de noves estratègies per a la fabricació senzilla i de baix cost de components fotònics polimèrics i la seva integració en dispositius lab‐on‐chip fotònics (PhLoC). Per a això, es van desenvolupar materials polimèrics híbrids orgànics‐inorgànics amb un esquelet d'òxid de silici, mitjançant la tecnologia sol‐gel, i es van fabricar microestructures d'aquests materials usant tècniques de microfabricació senzilles i de baix cost. Diferents monòmers van ser triats seleccionats i inclosos en diverses formulacions sol‐gel. Aquestes molècules modulen no només les propietats físic‐químiques dels materials resultants, tals com la seva flexibilitat, porositat o hidrofobicitat, sinó també les seves propietats òptiques tals com la transparència o l'índex de refracció. Així mateix, els materials desenvolupats van ser dopats amb molècules colorants i fluorescents amb la finalitat de controlar les seves propietats espectrals. El microestructurat del material híbrid resultant es va dur a terme usant tècniques no fotolitogràfiques incloses en les trucades tècniques de litografia tova (de l'anglès soft lithography). Treballant amb aquests materials i aplicant senzills processos de fabricació, es van desenvolupar components fotònics polimèrics, els quals poden integrar‐se en dispositius lab‐on‐chip amb la finalitat de desenvolupar eines d'anàlisis compactes amb el potencial de ser aplicades en estudis descentralitzats per al control mediambiental o diagnòstic precoç de malalties. El manuscrit es divideix en set capítols. En el capítol I, es realitza una introducció general als conceptes principals necessaris per a una millor comprensió de la tecnologia sol‐gel, la síntesi de materials híbrids orgànics‐inorgànics i la seva aplicació en òptica i la fotònica. Igualment, es descriuen les diferents tècniques aplicades pel microestructurat d'aquests materials i, per finalitzar, s'introdueixen els dispositius labon‐ chip (LoC) i el concepte de PhLoC, que inclou components diferents, relacionats amb la micro‐òptica i l'òptica integrada. Aquest capítol va seguit de cinc capítols més que mostren el treball experimental dut a terme i descriuen els resultats experimentals obtinguts. Com a últim capítol, en el capítol VII es destaquen les principals conclusions extretes d'aquest treball. El capítol III se centra en el disseny i la síntesi de dos materials híbrids dopats amb fluoròfors i el seu microestructurat mitjançant una tècnica de litografia tova denominada micromodelat en capil∙lars. Es va realitzar una caracterització fisicoquímica exhaustiva dels materials resultants i de la seva resposta espectral. Es va realitzar el processament en un sol pas de microestructures d'aquests materials, amb diferents geometries i relacions d'aspecte i, al seu torn es van demostrar les seves excel∙lents propietats òptiques. A més, aquest capítol mostra que aquests materials són robusts i molt adequats per a la fabricació d'emissors de llum d'estat sòlid d'un sol ús, i d'altres components fotònics per a òptica integrada. En els capítols experimentals següents, es recull l'avaluació òptica de components polimèrics fotònics, i la seva posterior integració en dos dispositius PhLoC diferents. El capítol III mostra la fabricació, caracterització i implementació en un PhLoC basat en estructures *PDMS vidre, de diferents microfiltres fabricats amb els materials híbrids dopats amb colorants que absorbeixen en diferents zones de l'espectre visible. El capítol V presenta el disseny, la fabricació i el funcionament d'un emissor de llum blava fabricat emprat un material híbrid sol‐gel dopat amb un fluoròfor i seguint els procediments experimentals descrits en els capítols anteriors. El capítol VI descriu el treball realitzat en la integració d'aquest emissor en un altre dispositiu PhLoC fabricat en PDMS i vidre, el qual es va aplicar posteriorment en la fabricació d'un biosensor per a la detecció d'un analit modelo. El capítol VII explora altres materials híbrids basats en matrius de xerogel dopats amb punts quàntics, així com una tècnica de *micro‐/nanofabricació alternativa, la litografia per nanoimpresión tèrmica, per a l'estructurat dels polímers híbrids presentats en els capítols anteriors.
El objetivo del trabajo incluido en esta Tesis Doctoral es el desarrollo de nuevas estrategias para la fabricación sencilla y de bajo costo de componentes fotónicos poliméricos y su integración en dispositivos fotónicos lab‐on‐chip (PhLoC). Para ello, se desarrollaron materiales poliméricos híbridos orgánicos‐inorgánicos con un esqueleto de óxido de silicio, mediante la tecnología sol‐gel, y se fabricaron microestructuras de estos materiales usando técnicas de microfabricación sencillas y de bajo coste. Diferentes monómeros fueron elegidos seleccionados e incluidos en varias formulaciones sol‐gel. Estas moléculas modulan no sólo las propiedades físicoquímicas de los materiales resultantes, tales como su flexibilidad, porosidad o hidrofobicidad, sino también sus propiedades ópticas tales como la transparencia o el índice de refracción. Asimismo, los materiales desarrollados fueron dopados con moléculas colorantes y fluorescentes con el fin de controlar sus propiedades espectrales. El microestructurado del material híbrido resultante se llevó a cabo usando técnicas no fotolitográficas incluidas en las llamadas técnicas de litografía blanda (del inglés soft lithography). Trabajando con estos materiales y aplicando sencillos procesos de fabricación, se desarrollaron componentes fotónicos poliméricos, los cuales pueden integrarse en dispositivos lab‐on‐chip con el fin de desarrollar herramientas de análisis compactas con el potencial de ser aplicadas en estudios descentralizados para el control medioambiental o diagnóstico precoz de enfermedades. El manuscrito se divide en siete capítulos. En el capítulo I, se realiza una introducción general a los conceptos principales necesarios para una mejor comprensión de la tecnología sol‐gel, la síntesis de materiales híbridos orgánicos‐inorgánicos y su aplicación en óptica y la fotónica. Igualmente, se describen las diferentes técnicas aplicadas para el microestructurado de estos materiales y, para finalizar, se introducen los dispositivos lab‐on‐chip (LOC) y el concepto de PhLoC, que incluye componentes diferentes, relacionados con la microóptica y la óptica integrada. Este capítulo va seguido de la definición de los objetivos más otros cinco capítulos que muestran el trabajo experimental llevado a cabo y describen los resultados experimentales obtenidos. Como último capítulo, en el capítulo VIII se destacan las principales conclusiones extraídas de este trabajo. El capítulo III se centra en el diseño y la síntesis de dos materiales híbridos dopados con fluoróforos y su microestructurado mediante una técnica de litografía blanda denominada micromodelado en capilares. Se realizó una caracterización fisicoquímica exhaustiva de los materiales resultantes y de su respuesta espectral. Se realizó el procesado en un solo paso de microestructuras de estos materiales, con diferentes geometrías y relaciones de aspecto y, a su vez se demostraron sus excelentes propiedades ópticas. Además, este capítulo muestra que estos materiales son robustos y muy adecuados para la fabricación de emisores de luz de estado sólido desechables, y de otros componentes fotónicos para óptica integrada. En los capítulos experimentales siguientes, se recoge la evaluación óptica de componentes poliméricos fotónicos, y su posterior integración en dos dispositivos PhLoC diferentes. El capítulo IV muestra la fabricación, caracterización e implementación en un PhLoC basado en estructuras PDMS vidrio, de diferentes microfiltros fabricados con los materiales híbridos dopados con colorantes que absorben en diferentes zonas del espectro visible. El capítulo IV presenta el diseño, la fabricación y el funcionamiento de un emisor de luz azul fabricado empleado un material híbrido sol‐gel dopado con un fluoróforo y siguiendo los procedimientos experimentales descritos en los capítulos anteriores. El capítulo VI describe el trabajo realizado en la integración de este emisor en otro dispositivo PhLoC fabricado en PDMS y vidrio, el cual se aplicó posteriormente en la fabricación de un biosensor para la detección de un analito modelo. El capítulo VII explora otros materiales híbridos basados en matrices de xerogel dopados con puntos cuánticos, así como una técnica de micro‐/nanofabricación alternativa, la litografía por nanoimpresión térmica, para el estructurado de los polímeros híbridos presentados en los capítulos anteriores.
The aim of the work included in this PhD Thesis was the development of new strategies for the simple and low‐cost fabrication of polymeric photonic components and their integration in photonic lab‐on‐chip (PhLoC) devices. For that, tailor‐made silicon based hybrid organic‐inorganic polymeric materials were developed by the solgel technology and patterned using simple and cost‐effective microfabrication techniques. Different monomers were carefully chosen and included in several sol‐gel polymer formulations. These molecules influenced not only the physicochemical properties of the resulting materials such as their flexibility, porosity or hydrophobicity but also tuned their optical properties such as transparency or refractive index. Also, the developed materials were easily doped with colored and fluorescent dyes in order to modulate their spectral properties. Patterning of the resulting hybrid polymer was carried out using simple and cost‐effective non‐photolithographic approaches included in the so‐called soft lithography techniques. Working with these materials and applying simple patterning processes enabled the fabrication of photonic components, which could be integrated in lab‐on‐chip systems in order to develop compact analytical tools with the potential to be applied in decentralized studies for environmental monitoring or point‐of‐care diagnostics. The manuscript is divided into seven chapters. In Chapter I, a general introduction to the main concepts for better understanding the sol‐gel technology, the synthesis of organic‐inorganic hybrid materials and their application in optics and photonics. A description of the different techniques applied for the patterning of these materials is also given to end up with the introduction of the lab‐on‐chip (LoC) concept and the PhLoC approach, which includes different components, related to micro‐optics and integrated optics. This chapter is followed by the definition of the objectives and five more chapters that extensively explain the experimental work carried out and thoroughly describe the experimental results achieved. As a final chapter, Chapter VIII highlights the main conclusions drawn from this work. Chapter III is focused on the design and synthesis of two different fluorophore doped hybrid materials and their patterning by micromolding in capillaries soft lithographic technique. An exhaustive physicochemical characterization of materials, and their spectral response was carried out. The one‐step processing of these materials, showing different geometries and aspect ratios was successfully carried out, and in turn their excellent optical performance demonstrated. Additionally, this chapter demonstrates that this type of materials is robust and highly suitable for the fabrication of disposable solid‐state light emitting devices, and by extension, other photonic components for integrated optics. In the following experimental chapters, the fabrication and optical assessment of specific polymeric photonic components, which were then integrated in two different PhLoCs is presented. Chapter IV shows the fabrication, characterization and implementation in a glass‐PDMS PhLoC, of different colored dye‐doped hybrid polymeric micro‐filters whose absorbance behavior covers different wavelength ranges of the visible spectrum. Chapter V shows the design, fabrication and performance of a fluorophore‐doped polymeric blue‐light emitter fabricated following the experimental procedures described in previous chapters. Chapter VI describes the work carried out on the integration of this emitter in another glass/ PDMS PhLoC device, which was further applied as a biosensor approach for the detection of a model target analyte. Chapter VII explores other hybrid materials based on quantum dot doped xerogel matrices, as well as an alternative micro‐ /nanofabrication technique, the thermal nanoimprint lithography, for the patterning of the hybrid polymers presented in the previous chapters.

Increased understanding of plasma-polymer interactions is required to further the technological use of such processes, and elucidates heterogeneous physico-chemical reactions which occur under bombardment by complex combinations of energetic species. This thesis presents a systematic investigation into the effect of exposing organic and inorganic polymeric surfaces to controlled non-isothermal plasmas. Concurrently, a novel process is presented by which metal oxide gas barrier coatings are synthesized on polymer substrates by non- isothermal plasma treatment. Organic polymers exhibiting a range of structures were modified using non-isothermal plasmas at atmospheric and low pressure. The extent of atmospheric discharge oxygenation, measured by X-ray photoelectron spectroscopy (XPS), correlated with the polymers' ozonolysis rate constants. Surface physical disruption, studied using atomic force microscopy (AFM), after atmospheric discharge treatment was more pronounced than after low pressure plasma treatment. During low pressure oxygen plasma treatment, polymers containing phenyl groups were oxygenated to an extent which varied with the strength of π-π* valence band excitation in XPS C(1s) spectra of the untreated polymers, suggesting a dominance of reaction of plasma atomic oxygen at polymer radical sites excited by plasma vacuum ultraviolet radiation. The size of globules, observed by AFM, on the plasma modified surfaces correlated with the extent of surface chemical modification, inkeeping with a mechanism of chemically driven agglomeration of plasma oxidized low molecular weight polymer material. Oxygen plasma was more effective than water plasma in chemically modifying the surface of films of zirconium-normal-butoxide spin coated on polyester substrates, and the resulting optimized treatment produced a significant reduction in gas permeation of the substrate. XPS studies showed that oxygen plasma treatment of a polyphenylsilsesquioxane film on polyester film created a SiO(_2) layer less than 8 nm thin, which reduced O(_2) and Ar permeation of the coated film by 37.5 % and 31.6% respectively.

Alkali activation has been emerging as a sustainable technology to produce innovative construction materials. Alkali-activated materials have been extensively investigated, but different levels of scientific understanding and industrial implementation can be found among several subgroups of such materials. The most widely examined alkali-activated materials are commonly known as geopolymers. The scientific knowledge of their reaction mechanisms and structures is mature, and their market implementation fairly consolidated. Conversely, inorganic polymers (IP) is a different subgroup of alkali-activated materials since their chemistry does not exactly correspond to the definition of geopolymers. These systems are challenging but unlikely geopolymers can admit a wide range of precursors offering an opportunity to valorize low-value raw materials that include several wastes and industrial by-products. The diversity of precursors that can be used in IP production hinders the definition of production guideposts, and dedicated research is needed to define ad hoc mix designs according to the precursors’ characteristics and envisioned applications. This doctoral research was focused on the multiscale development of inorganic polymers and the conceptual design of sustainable and multifunctional materials for near-zero energy consume buildings. Vitrified residues produced during the thermochemical conversion of refused derived fuel were taken as a representative case study of a broad group of currently underutilized industrial by-products, namely calcium-iron-rich slags. The aim of this work was to understand the fundamental processing parameters affecting the reaction mechanism involved in the formation of calcium-iron-rich IPs and their correlation with the chemical and physico-mechanical properties of the developed materials. The major technological constraints related to the use of such slags as IP precursors were examined, and the most suitable production conditions to obtain IP products with enhanced properties identified. A broad range of IP materials with engineered properties was developed and optimized. The efforts made in developing predictive models, in optimizing mixture proportions and in minimizing the shrinkage of IP binders and mortars are described. Optimized products characterized by a high dosage of residues in their composition, increased volumetric stability, excellent mechanical properties, and good residual characteristics after exposure to high temperatures were developed. The functionalization of IP mortars was addressed, and the effects of incorporating phase change materials in the mix design investigated. Lightweight IPs were developed using different processing routes, and their mechanical and thermal properties examined. Different IP products were used to develop multi-layer sandwich panels that were both thermal insulating and reactive to temperature fluctuations. The problematics related to their upscaling were analyzed, and the production processes optimized. Semi-industrial sandwich panels were produced to demonstrate the feasibility of the solutions proposed. The topic analyzed in this doctoral research and the insights provided are a significant contribution to the implementation of alkali-activation technology as a viable upcycling solution for industrial by-products, and particularly interesting to the construction sector in which current efforts to achieve lower environmental impacts are considerable. The use of calcium-iron-rich slags, like the ones produced in thermochemical conversion processes, in such production schemes is a plausible large-scale upcycling route that can absorb significant volumes of those residues and, by doing so, contribute to increasing the sustainability of industrial sectors in which such residues are produced.
I leganti ad attivazione alcalina (nella formulazione originale inglese “alkali-activated materials”) stanno sempre più affermandosi come soluzione tecnologica sostenibile ed innovativa nella produzione di materiali da costruzione. Molti lavori esistono al riguardo, ma il livello di comprensione scientifica e di implementazione industriale di questi materiali, varia a seconda dei diversi tipi di leganti ad attivazione alcalina a cui si fa riferimento. I materiali ad attivazione alcalina più studiati sono i geopolimeri. I meccanismi e le reazioni coinvolte nella formazione di questi materiali sono ormai noti e consolidati da tempo nella comunità scientifica, così come la loro implementazione sul mercato. Un diverso sottogruppo dei materiali ad attivazione alcalina sono i polimeri inorganici (“inorganic polymers”). La loro chimica differisce dai geopolimeri in quanto non ottenuti dall’esclusiva attivazione alcalina di materiali allumino-silicatici. Gli polimeri inorganici derivano da sistemi chimicamente complessi ma sono allo stesso tempo versatili. Contrariamente ai geopolimeri infatti, i polimeri inorganici possono essere prodotti utilizzando una vasta gamma di precursori, offrendo quindi l’opportunità di valorizzare materie prime di basso costo che includono anche numerosi rifiuti e sottoprodotti industriali. Tuttavia, l’ampia varietà di questi materiali fa sì che studi ad hoc siano necessari per ogni potenziale precursore in funzione della sua composizione chimica e dell’applicazione finale prevista. La presente tesi di dottorato è finalizzata allo sviluppo di materiali da costruzione funzionalizzati e sostenibili, utili alla realizzazione di edifici ad un consumo di energia quasi zero (“near Zero Energy Building, nZEB”) e messi a punto attraverso lo studio di polimeri inorganici prodotti da rifiuti non altrimenti valorizzabili: le scorie vetrose ottenute dalla conversione termochimica di combustibili derivato da rifiuti (CDR). Caratterizzati da alti contenuti di Ca e Fe, questi residui possono essere considerati rappresentativi di un più ampio gruppo di rifiuti e sottoprodotti attualmente scarsamente utilizzabili e spesso destinati al conferimento in discarica. Obiettivo principale del presente lavoro era quello di comprendere i meccanismi delle reazione coinvolte nella formazione di polimeri inorganici ottenuti dall’attivazione alcalina di queste scorie, e di determinarne le correlazioni con le proprietà chimiche e fisico-meccaniche del prodotto finale. Attraverso l’uso di modelli statistici predittivi, sono stati sviluppati, ottimizzati ed ingegnerizzati un’ampia gamma di polimeri inorganici. I risultati sperimentali riportati nel presente lavoro riguardano innanzitutto lo sviluppo e l’ottimizzazione di mix design, in grado di massimizzare il contenuto di scoria come precursore. Altro aspetto molto importante di studio ha riguardato la riduzione dei ritiri per una migliore stabilità volumetrica di leganti e malte prodotti a partire dagli polimeri inorganici ottimizzati. Eccellenti proprietà meccaniche e buone prestazioni residue dopo l’esposizione alle alte temperature, sono fra le principali proprietà analizzate che caratterizzano le formulazioni sviluppate. Con lo scopo di ottenere un prodotto in grado di incrementare l’efficienza energetica degli edifici, un importante parte del lavoro ha riguardato la funzionalizzate del materiale sviluppato. L’ingegnerizzazione della microstruttura, per ottenere un materiale leggero e termicamente isolante, e l’aggiunta di materiali a cambiamento di fase (“Phase Change Materials, PCMs”), capaci di ridurre le fluttuazioni termiche, sono le due principali tematiche tecnologiche investigate. Tale studio ha portato alla realizzazione di panelli multistrato in grado di offrire entrambe le proprietà termiche desiderate. Attraverso l’ottimizzazione dei parametri di produzione, compatibili con i requisiti di scalaggio industriale, sono stati realizzati in laboratorio prototipi in scala naturale, che dimostrando la piena fattibilità tecnica delle soluzioni proposte. Il tema proposto e gli approfondimenti forniti in questa tesi di dottorato sono di particolare interesse per il settore delle costruzioni, sempre più attento a soluzioni innovative capaci di ridurre l’impatto sull’ambiente. La valorizzazione di scorie ricche in calcio e ferro, così come proposta nel presente lavoro, rappresenta una plausibile via di riciclo su larga scala in grado di assorbire significativi volumi di scarti. Valorizzare questi rifiuti convertendoli in materiali da costruzione che, nella loro vita utile, consentono di ridurre l’impatto energetico degli edifici, ha quindi un elevato beneficio che è sia economico che ambientale.

The incorporation of phosphine or amine structural units into dendritic polymers offer significant potential in building macromolecular species with desired properties for heterogenizing homogeneous catalysis. To this end, synthetic methodologies based on the chemistry of acid-base hydrolysis of aminosilanes with molecules possessing hydroxyl end groups, and that of phosphorus halides/amides with alkynyl/alcohol monomers were explored as approaches to construct phosphorus(III)- and nitrogen-containing dendritic polymers. Attempted implementation of a three-step, divergent synthetic methodology led to the discovery of two new phosphorus(III)-based compounds, P[O(CH2) 2C≡CH]3 and P[O(CH2)2C≡CSn(CH 3)3]3. Efforts to execute a two-step, divergent synthetic route to nitrogen-containing dendrimers afforded first- and second-generation dendrimers, N4 and N10. Attempts to adapt this methodology to one-pot procedures for hyperbranched polyamines show promise. Finally, single-step and pseudo-single-step procedures for synthesizing hyperbranched polyphosphines were employed in the preparation of several phosphorus(III)-containing macromolecules. These materials were successfully functionalized with Rh(I) organometallic complexes.

During the last 30 years a new research and technology field of organic electronic materials has grown thanks to a groundbreaking discovery made during the late 70’s. This new field is today a worldwide research effort focusing on exploring a new class of materials that also enable many new areas of electronics applications. The reason behind the success of organic electronics is the flexibility to develop materials with new functionalities via clever chemical design and the possibility to use low‐cost production techniques to manufacture devices. This thesis reports different aspects of electrochemical applications of organic electronics. We have shown that the color contrast in reflective and transmissive electrochromic displays can be almost doubled by adding an extra electrochromic polymer. The choice of electrochromic material was found to be limited by its electrochemical over‐oxidation (ECO) properties, which is one of the main degradation mechanisms found in displays. The irreversible and non‐conducting nature of over‐oxidized films encouraged us to use it in a novel patterning process in which polythiophene films can be patterned through local and controlled deactivation of the conductivity. ECO can be combined with various patterning tools such as screen printing for low‐cost roll‐to‐roll manufacturing or photolithography, which enables patterning of small features. Studies have shown that electronic conductivity contrasts beyond 107 can be achieved, which is enough for various simple electronic systems. To generate better understanding of the ECO phenomenon, the effect of pH on the over‐oxidation characteristics was studied. The results suggest that a part of the mechanism for over‐oxidation depends on the OH– concentration of the electrolyte used. Over‐oxidation has also been used in electrochemical loggers, where the temperature and time dependence of the propagation of an over‐oxidation front is used to monitor and record the temperature of a package.
Dagligen kommer vi i kontakt med olika plastmaterial. Dessa har vanligtvis mycket dålig elektrisk ledningsförmåga och används oftast som isolerande material. Det finns dock en klass av plaster som är halvledande eller ledande. Sedan upptäckten av dessa material för mer än 30 år sedan har nya material och användningsområden utvecklats och nu börjar de första produkterna baserad på organisk elektronik komma ut på marknaden. En stor fördel med de ledande plasterna är att egenskaperna kan anpassas genom att ändra den kemiska strukturen. Man kan dessutom lösa upp dem och skapa ledande bläck, som sedan kan användas i vanliga tryckmaskiner. Detta gör det möjligt att på ett enkelt och billigt sätt tillverka elektronik på liknande sätt som till exempel tidningar trycks idag. Den här avhandlingen behandlar en del av det nya området som berör elektrokemiska komponenter och några av dess tillämpningar. Fokus ligger främst på billig, tryckt elektronik. Bland annat presenteras ett sätt att fördubbla kontrasten för tryckta pappersdisplayer, ett nytt sätt att mönstra ledande plaster och elektrokemisk temperaturloggningsetikett som kan övervaka temperaturen för förpackningar under transport. Den mekanism som förstör ledningsförmågan vid höga spänningar har varit ett återkommande inslag i de studier som har genomförts här. Denna mekanism förstör komponenterna under drift men kan också användas för att ta bort ledningsförmågan som mönstringsmetod eller för att lagra information, permanent, i temperaturloggningsetiketten.

This thesis presents a study on the integration of polymer organic materials, onto GaN-based micron-scale light-emitting diodes, or 'micro-LEDs'. Several pertinent micro-patterning techniques are investigated along with their used in the realisation of such hybrid devices. Polymers are an attractive family of materials whose properties can be tailored to the requirements of specific applications. The interest of this thesis focuses on an 'in-house' synthesised transparent polymer ('HTP2') designed for encapsulation of micro-LEDs emitting in the UV-blue region of the spectrum and on conjugated light-emitting materials whose semiconducting properties are used in this work for colour conversion.

Commercially important superabsorbent polymers are crosslinked polymers of partially neutralised acrylic acid which can typically absorb and retain up to a hundred times their own weight in water. Superabsorbent polymers are most widely used in the personal hygiene industry where they are found in the core of disposable nappies, external feminine sanitary products and adult incontinence pads as absorbents for bodily fluids. Many other applications have been found through their amazing absorptive properties including artificial snow, artificial muscles and the prevention of water leakage into underground transmission cables. Superabsorbent polymers have many important industrial uses although little investigation into their structure and mechanisms has been done to date. As a result of superabsorbent polymers being totally insoluble in all NMR solvents solid state 13C CP/MAS NMR was used to investigate various structural aspects of the polymer in both dry and hydrated states. The NMR work carried out on the structure of the superabsorbent polymers suggests differences in structure between polymers neutralised before and after polymerisation takes place. It also suggests different tacticity within the polymer, seen as the polymer becomes more hydrated. 23Na relaxational studies have given an insight into the change in the sodium ion environment as the polymer becomes more hydrated. The effect of increasing neutralisation of the polymer was also investigated. Nuclear Magnetic resonance imaging was also used to try and investigate the mechanism of absorption of liquid by the polymer. From the images produced it was seen that the liquid is not absorbed homogeneously throughout the polymer sample and a more intense region is seen at the front of the image suggesting a solvent front. Commercial superabsorbent polymers are usually coated to enhance their absorptive properties. Experiments were carried out using a sodium ion-selective electrode to try and determine whether or not this coating provided the polymer with an osmotic ion-exclusion membrane. The sodium ion-selective electrode allowed differences in [Na+] before and after the addition of polymer to a solution of NaCl to be detected, and consequently allowed the presence of an osmotic ion-exclusion membrane to be determined.

This study is concerned with the synthesis of conjugated polyheterocycles with potential metal binding sites for applications in sensors, catalysis and electronics. The first synthetic approach to polyheterocycles was based on the interfacial polycondensation of a dihydrazide derivative of pyridine with a diacid chloride to produce a precursor polymer. It was shown, however, the starting materials could not be easily prepared in high yield. Model studies confirmed the feasibility of the route but these studies also suggested that the precursor polymers were unlikely to be very soluble. The second precursor route explored began with the preparation of 2,6-diethynylpyridine. The intermolecular Glaser coupling of the ethyne groups afforded the precursor polymer, poly((2,6'-pyridyl)but-l,3-diyne), as a black powder which was insufficiently soluble to allow conversion to the poly heterocycles. A series of dimers and trimers containing various combinations of 2-furyl, 2-thienyl and 2-pyridyl moieties were prepared using two different coupling procedures that yielded compounds with the required 2,2'-heteroatom arrangement as required for metal binding. Some of these monomers were electropolymerised and the metal binding properties of these polymers was investigated by cychc voltammetry. In particular, the two trimers: 2,5-di-(2-thienyl) pyridine; and 2,6-di-(2-thienyl) pyridine showed potential metal coordination despite their hydrophobic nature and impermeability towards metal complexes. Evidence was presented to suggest that these polymers are protonated during the electropolymerisation reaction. X-ray analysis of the 2,5-di-(2-thienyl) pyridine showed that only the 2,2'-linked thiophene was coplanar with the pyridine due to a charge transfer interaction. This interaction insures that S and N atoms have a planar syn arrangement conducive to metal binding. Several oligothiophenes were prepared to investigate methods for enhancing the solubility of polyheterocycles. The knowledge gained from these investigations was used to prepare a series of regiochemically well-defined poly((3-alkyl)thiophenes). The regularity of these polymers was confirmed by NMR analysis. Related monomers were prepared containing the necessary solubilising alkyl groups as well as phenyl groups designed to act as acceptor ligands for the low-valent transition metals such as ruthenium(II). The electrochemistry of these novel thiophene monomers is reported.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.
Includes bibliographical references (p. [189]).
Many structural polymers exhibit brittle behavior at low temperatures and/or high strain rates. It has been shown that the incorporation of rubber and inorganic particles can have significant toughening effects. Previous studies have shown that the particles can alter the matrix morphology at the particle-polymer interface to provide the material with a low shear yield strength tangential to the particle interface thus promoting extensive plastic flow. Through finite element analysis, this thesis examines the micromechanisms of deformation for the toughened polymer blends. Particularly, how the nature of the particles and its bonding with the matrix affect the development of plastic deformation in the matrix material. Micromechanical models are constructed for the both the isotropic and anisotropic polymer matrix modified by rubber and inorganic particles. For the case of the inorganic particle, the two limiting bonding cases examined are the incoherent and the perfectly bonded particle.
by Thao D. Nguyen.
S.B.

The aim of the work carried out for this thesis was to explore way to synthesise and characterise π-conjugated ferrocene containing polymers by using a condensation polymerization technique. Three types of such compounds were investigated: namely polyquinoxalines (pox)s, polyimines (PJ)s and polyketones (PK)s. The work was started by carrying out the same reactions on small molecules, in order to understand the reaction pathway and to establish the reaction conditions and to obtain the benchmark characterisation data. Initially monofunctional ferrocene derivatives were prepared and condensed with mono- and bi-functional organic molecules, and bifunctional ferrocene derivatives were synthesised and condensed with mono functional organic molecules, to yield the small molecular condensation products. When the reaction conditions had been optimised the same reactions were extended to bifunctional ferrocene derivatives and bifunctional organic entities to obtain the co-polymers. After citing the relevant references in chapter one, the synthesis of mono- and bi-functional ferrocene containing diketones (FcCOCOK) by the oxidation of the synthesised mono-ketones is described in chapter 2 and their condensation with unsubstituted and substituted organic di- and tetra-amines to produce ferrocene containing mono-, bis - and poly-quinoxalines is described in chapter 3. The crystal structures of some of the compounds are also determined as definitive proof of characterisation. The attempted oxidation of ferrocenyl monoketones (FcCH2COR) to diketones by using selenium dioxide produced the coupled, dimeric, products (FcCHCOR)2. Electrochemical studies of the synthesised quinoxalines were also carried out. In chapter 4 are described the condensation of ferrocene aldehyde (FcCHO) and dialdehyde [(Fcd(CH0)2] with aromatic amines to yield ferrocene containing mono-, bis-and poly-imines. Chapter 5 deals with the synthesis and characterisation of ferrocene containing mono-, bis- and poly ketones synthesised by Friedel Crafts acytation reactions. The molecular weights of the synthesised ferrocene-containing polymers are also estimated with the help of hi NMR spectra.

A new divergent methodology to prepare a variety of dendritic polymers containing dimethylsilyl-linked-3,5-dihydroxybenzyl alcohol units in the backbone is reported. This simple and versatile synthetic route is based on the acid-base hydrolytic chemistry of 3,5-dihydroxybenzyl alcohol (DHBA) and dimethyldiaminosilane Me2Si(NMe2)2. Controlled sequential addition of reactants was used to prepare dendrimer generations 1--5. The dendritic growth was found to be dictated by a preferential attack of the benzylic hydroxyl group of DHBA on the aminosilane, as no traces of residual benzylic OH groups were observed using 1H NMR spectroscopy. By a continuation of this divergent route, these dendrimers were functionalized with a variety of terminal units, including trimethylsilyl, n-octanoate, organic dye disperse red 1, and hydroxypropyldiphenylphosphine. Uncontrolled reaction protocols using the same reacting partners were also investigated to prepare the corresponding hyperbranched polymers. Resulting macromolecules showed structural fragments ranging from that of dendrimer generation 1 to that of dendrimer generation 2 in their MALDI-TOF mass spectra. Addition of more reactants did not seem to increase the size of these hyperbranched polymers.
Determination of some of the structure-property relationships in these dendrimers was carried out to obtain a better understanding of their potential applications. Hydrolytic stability of the dendrimers was examined using dendrimer generations 1--3 solvated in wet DMSO. Their resistance towards hydrolysis was found to increase with an increase in generation number. Intrinsic viscosities were determined for dendrimer generations 1--5. A non-linear relationship was found between the generation number and the intrinsic viscosity, as it reached a maximum for dendrimer generation 4, followed by a decrease. 3,5-dihydroxybenzyl alcohol based dendrimers were found to self-assemble via hydrogen bonding between terminally situated hydroxyl groups. This phenomenon was found to be dependent on their concentration in solution, and a critical aggregation concentration was determined at 3.7 mg mL-1 for dendrimer generations 1--3. Higher generation dendrimers showed aggregate formation at low concentrations as the number of peripheral OH groups was significantly increased.
By functionalizing dendrimers and hyperbranched polymers with hydroxypropyldiphenylphosphine ligands, followed by coordination with [Rh(COD)Cl], we were able to synthesize metallodendrimers and organometallic hyperbranched polymers, in which active organometallic fragments are present at the periphery. Their catalytic activity was assessed in hydrogenation of 1-decene. Conversion rates of decene into decane for metallodendrimers were found to be dependent on the time of reaction and the generation number. Maximum conversion rates were found after 5 h reaction time in each case.

Dielectric spectroscopy is employed to analyze the molecular dynamics and the charge transport in mixtures of zwitterionic polymers of the type poly{3 [N(-methacryloyloxyalkyl)] N, [N-dimethylammonio propanesulfonate] with sodium iodide in the frequency range of 10²Hz-10(up)7 Hz and in the temperature range of 110 K-400 K. The amount of inorganic salt added varies from 0-200 mol-% relative to the number of zwitterionic groups present in the polymer, contributing strongly to the conductivity. One relaxation process is observed whose relaxation rate depends strongly on the length of the aliphatic spacer between the polymethacrylate main chain and the zwitterionic group. Exhibiting an Arrhenius-like temperature depence with activation energy EA = 47 KJ/mol, this relaxation process is assigned to fluctuation of the quaternary ammonium groups in the side chains. At higher temperatures, the dielectric properties and the conductivity are primarily dominated by the mobile inorganic ions: conductivity strongly depends on the salt concentration, showing a pronounced electrode polarization effect. The frequency and salt concentration, dependences of the conductivity can be quantitatively described as hopping of charge carriers being subject to spatially randomly varying energy barriers. For the low-frequency regime and for the critical frequency marking the onset of the conductivity's dispersion, the Barton-Nakajima-Namikawa (BNN) relationship is fulfilled.

Aluminosilicate inorganic polymers (AIPs) are network heteropolymers consisting of Si04 and AlO4 tetrahedra linked by a shared oxygen. The use of these materials as a cementing agent, toxic waste storage and fibre reinforced material, amongst a multitude of prospective applications, has grown in recent years. The utilisation of AIPs is hampered by a lack of knowledge about their formation and structure. In order to allow the materials to achieve their full potential, the way in which the material behaves and forms under different conditions must be elucidated. The basic questions that this study aimed to answer were: 1) How does the structure of these AIPs change with composition? and 2) Can this change in structure explain the material properties of the AIP? The AIPs investigated in the study covered the molar composition ranges Si:Al ratio = 1 - 3 and Na:Al ratio = 0.5 - 2. They were made by the sodium hydroxide activation of metakaolinite, derived from the dehydroxylation of kaolinite. The Si content of the AIP was altered by the addition of amorphous silica fume via the activation solution. The study considered the structural nature of the AIPs at the macro, micro and nanoscales, and found that the structure changed at all scales and with all compositions. The nature of the AIP structure was studied at the macroscale utilising compressive strength testing. The results from this work showed that the compressive strength of the AIPs varied systematically with the chemical composition. The strengths recorded ranged from 0.4 ± 0.2 MPa for a sample with Si:Al:Na molar ratios = 1.08:1:0.5, to 64 ± 3 MPa for a sample with Si:Al:Na molar ratios = 2.5:1:1.3. The higher strengths measured exceed those exhibited by Portland cement pastes. The microstructure of the AIPs was investigated by scanning electron microscopy and energy dispersive spectroscopy.Microscopy showed that the microstructure variations correlated with the compressive strength. In general, AIPs with low compressive strengths exhibited an inhomogeneous two-phase microstructure; grain and matrix. The grain phase consisted of undissolved metakaolinite, whilst the matrix was the fully formed inorganic polymer. AIPs with high compressive strengths exhibited a microstructure that was more homogeneous than the samples with low compressive strength. The compressive strength of the AIPs depended on both the chemical composition and the level of residual MK present in the microstructure. EDS microanalysis showed that the composition of the two phases was significantly different, and that the differences depended on the overall composition of the AIP. EDS results also demonstrated that the impurity elements present in the metakaolinite were affected by the polymerisation process. Soluble elements such as Ca and Mg were found primarily in the matrix, indicating that they had leached out of the metakaolinite grains, whereas insoluble elements such as Fe and Ti were found primarily in the grains. The nanoscale structure of the AIPs was examined by solid-state nuclear magnetic resonance (NMR) and x-ray scattering (XRS). The NMR measurements revealed that the average coordination of Si varied according to the composition of the AIP, whereas the coordination of Al was constant. Na is present in the network in both hydrated and non-hydrated forms. It is postulated that the variation in the Si coordination can be explained by the formation of Si-O-Na bonds with Na forming an ionic bond with 0 in the polymer network. Radial distribution function (RDF) analysis of the XRS patterns revealed little difference in the structure of the different AIPs beyond ~2.5 Å.Unfortunately, the data were of insufficient resolution to allow for a full evaluation of the differences in the Si-O and Al-O bonds between different AIPs. However, the trends present in the shape and position of the RDF peak corresponding to the Si-O and Al-O bonds do follow the composition of the AIP. It has been shown that a variety of experimental techniques can be used in concert to obtain information on the structural nature of AIPs. To this end, it has been found that the compressive strength of AIPs can be optimised, and that the microstructure of the AIPs changes systematically with variations in the compressive strength. An improved model for the structure of AIPs has also been proposed.

Aluminosilicate inorganic polymers (AIPs) are network heteropolymers consisting of Si04 and AlO4 tetrahedra linked by a shared oxygen. The use of these materials as a cementing agent, toxic waste storage and fibre reinforced material, amongst a multitude of prospective applications, has grown in recent years. The utilisation of AIPs is hampered by a lack of knowledge about their formation and structure. In order to allow the materials to achieve their full potential, the way in which the material behaves and forms under different conditions must be elucidated. The basic questions that this study aimed to answer were: 1) How does the structure of these AIPs change with composition? and 2) Can this change in structure explain the material properties of the AIP? The AIPs investigated in the study covered the molar composition ranges Si:Al ratio = 1 - 3 and Na:Al ratio = 0.5 - 2. They were made by the sodium hydroxide activation of metakaolinite, derived from the dehydroxylation of kaolinite. The Si content of the AIP was altered by the addition of amorphous silica fume via the activation solution. The study considered the structural nature of the AIPs at the macro, micro and nanoscales, and found that the structure changed at all scales and with all compositions. The nature of the AIP structure was studied at the macroscale utilising compressive strength testing. The results from this work showed that the compressive strength of the AIPs varied systematically with the chemical composition. The strengths recorded ranged from 0.4 ± 0.2 MPa for a sample with Si:Al:Na molar ratios = 1.08:1:0.5, to 64 ± 3 MPa for a sample with Si:Al:Na molar ratios = 2.5:1:1.3. The higher strengths measured exceed those exhibited by Portland cement pastes. The microstructure of the AIPs was investigated by scanning electron microscopy and energy dispersive spectroscopy.
Microscopy showed that the microstructure variations correlated with the compressive strength. In general, AIPs with low compressive strengths exhibited an inhomogeneous two-phase microstructure; grain and matrix. The grain phase consisted of undissolved metakaolinite, whilst the matrix was the fully formed inorganic polymer. AIPs with high compressive strengths exhibited a microstructure that was more homogeneous than the samples with low compressive strength. The compressive strength of the AIPs depended on both the chemical composition and the level of residual MK present in the microstructure. EDS microanalysis showed that the composition of the two phases was significantly different, and that the differences depended on the overall composition of the AIP. EDS results also demonstrated that the impurity elements present in the metakaolinite were affected by the polymerisation process. Soluble elements such as Ca and Mg were found primarily in the matrix, indicating that they had leached out of the metakaolinite grains, whereas insoluble elements such as Fe and Ti were found primarily in the grains. The nanoscale structure of the AIPs was examined by solid-state nuclear magnetic resonance (NMR) and x-ray scattering (XRS). The NMR measurements revealed that the average coordination of Si varied according to the composition of the AIP, whereas the coordination of Al was constant. Na is present in the network in both hydrated and non-hydrated forms. It is postulated that the variation in the Si coordination can be explained by the formation of Si-O-Na bonds with Na forming an ionic bond with 0 in the polymer network. Radial distribution function (RDF) analysis of the XRS patterns revealed little difference in the structure of the different AIPs beyond ~2.5 Å.
Unfortunately, the data were of insufficient resolution to allow for a full evaluation of the differences in the Si-O and Al-O bonds between different AIPs. However, the trends present in the shape and position of the RDF peak corresponding to the Si-O and Al-O bonds do follow the composition of the AIP. It has been shown that a variety of experimental techniques can be used in concert to obtain information on the structural nature of AIPs. To this end, it has been found that the compressive strength of AIPs can be optimised, and that the microstructure of the AIPs changes systematically with variations in the compressive strength. An improved model for the structure of AIPs has also been proposed.

A study was carried out on formulations of organic-inorganic hybrids and their subsequent use as matrices for unidirectional carbon fibre-reinforced composites. The hybrids consist of low molecular weight polyimide precursors and silica which is generated in-situ via the sol-gel route. A special feature of these systems is the use of organofunctional trialkoxysilanes as coupling agents for the two phases and for controlling the resultant morphology. Enhancements are obtained in physicochemical, thermal and mechanical properties of hybrids through morphological modifications achieved in the parent polyimide and silicate materials. Small variations to the composition of the precursors display a substantial effect both on the kinetics of the associated reactions and the final properties of hybrids, often as a result of a change in miscibility of the organic and the inorganic components of the system. The processability of the matrix was evaluated with respect to the fabrication of composites, which in this case is strongly influenced by the gelation behaviour of both the organic pre-polymer and also the inorganic sol-gel component. The kinetics of gelation reactions were examined by dynamic viscometry and by practical tests based on visual observation of the cessation of flow. Differential scanning calorimetry, infrared spectroscopy, thermogravimetric analysis and electron microscopy formed part of the evaluation of the matrix materials. Composites were produced by application of the matrix solution from a variety of formulations on pre-tensioned fibres, followed by vacuum drying and curing under pressure at high temperatures. The properties of these composites were determined by such methods as dynamic mechanical thermal analysis, flexural testing and thermomechanical analysis. From the results obtained in this study, it is concluded that the inclusion of silicate phase in a polyimide matrix in the form of fine co-continuous networks improves the thermal and mechanical properties of the base material, although these are dependent on the overall silicate content and the amount of the coupling agent. High loadings of the coupling agent can cause degradation by chain scission and a reduction of the crosslinking density of the organic pre-polymer.