The work herein covers the complete process for development, production and testing of a melt processable pyrotechnic composition, with the goal of using the composition as a printing material in a fused deposition modelling (FDM) type 3D printer. 3D printing is fast becoming an area of interest for energetic materials research. This is due to the role that geometry can play in combustion performance of a composition and 3D printing’s ability to produce a variety of complex designs. Melt processable fluoropolymers were selected as oxidisers. The polymers selected for the study were FK-800® and Dyneon 31508®. Both are co-polymers of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE). Aluminium was the choice fuel in this instance as it had better energetic performance than the alternatives investigated. It was also deemed to be a safer fuel when considering the combustion products. Hazardous combustion products like hydrofluoric and hydrochloric acid could be suppressed by increasing the fuel loading to 30 wt.%, thereby reducing the risks associated with burning the composition. Preliminary differential thermal analysis (DTA) analysis indicated that the compositions would only ignite above 400 °C which was well above the suggested processing temperature of 230 °C as determined from thermogravimetric (TGA) analysis. These thermal analysis techniques indicated that the reactions were most likely a gas-solid reactions due to ignition temperatures being significantly lower than those associated with phase changes occurring in the fuels tested, yet above the decomposition temperatures for the oxidisers. ii Extrusion of the compositions proceeded with addition of LFC-1® liquid fluoroelastomer. This addition was made in order to order to lower the melt viscosity, thereby improving the quality of the filament produced. Compositions were extruded with an aluminium loading of 30 wt.%. Oxidiser and LFC-1® made up the rest of the mass with the LFC-1® contributions being either 7 wt.% or 14 wt.%. Burn rates, temperatures and ignition delays were all influenced by the addition of LFC-1® to the system. FK-800® was found to be a better oxidiser in this instance since its burn rates were consistent especially when compared to erratic nature of the Dyneon 31508® burns. Linear burn rates for the FK-800® increased from 15.9 mm·s−1 to 18.9 mm·s−1 with the increase in LFC-1® loading. Combustion temperature also increased by approximately 180 °C from 794 °C. Printing with the material was achieved only after significant alterations were made to the hot end used. Printing proceeded in a staged, start-stop manner. After each new layer of material was deposited the printer was cleared of material and the hot end was allowed to cool. If this procedure was not followed it led to significant preheating of the material within the feeding section of the extruder. This premature heating caused feeding problems due to softening and swelling of the material within the cold side of the hot end which led to blockages, leading to the conclusion that the composition was not compatible with the off-the-shelf hot end used in this study. Low quality printing could be achieved with both FK-800® and Dyneon 31508® compositions. This would suggest that slight compositional changes paired with the alterations made to the hot end could improve the quality of the prints to an extent that would be comparable to that of more commonplace printing materials. / Dissertation (MEng)--University of Pretoria, 2017. / Chemical Engineering / MEng / Unrestricted

This work was concerned with evaluating the behavior of thermoplastics reinforced with melt processable phosphate glasses processed by techniques including injection molding, compression molding, and thermoforming. Thermoplastic resins consisting of polyphenylene sulfide (PPS), polyetherimide (PEI) and polyetheretherketone (PEEK) were combined with phosphate glasses having glass transition temperatures (Tg) that ranged from 230-290°C to form composite systems where both the matrix and reinforcing phase were deformable during processing. For the process of injection molding, several factors were examined to maximize the mechanical properties obtained with the addition of the phosphate glasses. The influence of variables such as the glass and matrix viscosity, glass loading, melt temperature, and mold fill rate were examined for a variety of composite blends consisting of the PPS, PEI, and PEEK reinforced with a lower Tg (234°C) phosphate glass and PEEK blended with a higher Tg (282°C) glass. From this work, it was determined that the best mechanical properties were generally produced by using processing temperatures and material combinations that minimized the viscosity differences between the thermoplastic resin and phosphate glass. Variations in the material combinations and processing conditions utilized were also found to result in the formation of a variety of glass phase morphologies that consisted of droplets, ribbons, and an interpenetrating network structure. The addition of the phosphate glass to the neat thermoplastics resins was found to be an effective way to produce injection moldable composite blends. The stiffness of the composite blends increased with glass loading with composites containing up to 45 vol% phosphate glass exhibiting machine direction tensile and flexural moduli in the range of 3-5 times greater than that those of the neat thermoplastics. Additionally, these composites were found to offer moduli and strengths that ranged from 25-50% lower than conventional E-glass fiber reinforced materials of the same loading. The lower mechanical properties of the neat phosphate glasses coupled with a lack of adhesion between the matrices and the glasses helped contribute to the lower mechanical properties exhibited by the phosphate glass reinforced composites. Still, the phosphate glass reinforced blends offered certain advantages including lower mechanical anisotropy, smoother surfaces, and lower viscosities. The processing behavior of phosphate glass reinforced thermoplastics was also examined at temperatures commonly used in forming and shaping operations such as compression molding and thermoforming. It was determined that it was possible to deform the phosphate glass reinforcing phase along with the matrix resin at temperatures only 30-50°C above the Tg of the glass. The deformable phosphate glass reinforcing phase resulted in composite blends that exhibited greater extensibility than a solid E-glass fiber reinforced material. The elongation of the phosphate glass into a higher aspect ratio reinforcing morphology was found to result in an almost 25% increase in the tensile modulus for a polyphenylene sulfide based composite. / Ph. D.

<p>There are still technique hurdles that needed to be overcome in the commercialization of electrochromic devices (ECDs) for energy-saving smart windows. Among them, the long-term stability of ECDs and the high fabrication cost are <a>the critical issues</a>. The pricey ECDs can only be paid off through saving the energy for years, and their price will be dramatically lower if they can be solution-processed. Here, we studied the ions behaviors in the open-circuit state of electrochromic conjugated polymers (ECPs) which is important to the stability of ECDs during the operation. Moreover, we investigated the solution-processable ion storage layers and paired them with p-type ECPs and demonstrated the possibility of using them in the highly efficient roll-to-roll fabrication of ECD.</p> <p>The crosslinkable non-color changing nitroxy radical-based polymer was investigated as the ion storage layer. With the applied of crosslinking strategy, the dissolution problems of radical polymers-based counter electrode in the electrolyte was suppressed, resulting in the enhancement of both performance and cycling stability of ECDs. Although p-type ion storage materials are widely studied as the ion storage layers for ECPs, they need to go through complicated pretreatment processes, including pre-oxidation, washing, and drying, before they can be paired with ECPs in an ECD. This complicated process greatly increases the fabrication cost. </p> <p>In our last work, we applied the UV ozone (UVO) pretreatment to the solution-processed n-type niobium oxide and evaluated its potentials to be used as the ion storage layer for p-type ECPs. The UVO pretreatment generates strong oxidants like ozone or atomic oxygen which induce the photolysis of organic residues of ligands and organic solvent trapped in the solution-processed metal oxide layer led to the formation of free radical species. These highly reactive species promoted the formation of the amorphous metal−oxygen network. Following by low-temperature annealing (< 150 ^oC), the ion-storage properties of niobium oxide is comparable with the high temperature annealed (300 ^oC) niobium oxide. The method is successfully applied to fabricate niobium oxide on a flexible conductive substrate and demonstrate the capability to pair with p-type ECPs and fabricate high-performance ECDs without the need of any pretreatments. The low-temperature solution processing of both layers will significantly reduce the fabrication cost of ECDs. </p>

Tailored fluoropolymers remain the leading choice for a wide variety of advanced high-performance applications, including electronic/optical and energy conversion, owing to their unique blend of complementary high-performance properties. Amorphous semi-fluorinated polymers exhibit improved solubility and melt processability when compared to traditional perfluoropolymers. A leading class of semi-fluorinated aryl ether polymers includes perfluorocyclobutyl (PFCB), perfluorocycloalkenyl (PFCA), and fluoroarylene vinylene ether (FAVE) polymers. Monomers containing aromatic trifluorovinyl ethers (TFVE) are used to synthesize PFCB polymers via radical-mediated [2+2] cyclodimerization. On the other hand, FAVE and PFCA polymers are polymerized via base-mediated nucleophilic addition/elimination of bisphenols with TFVE monomers and decafluorocyclohexene respectively. The use of different monomer cores (aromatic, aliphatic, contorted, and renewable) should help to develop general structure/property relationships for this versatile and expanding approach to semi-fluorinated aryl ether polymers. The enchainment of polycyclic aromatic hydrocarbon (PAH) cores with functional fluorocarbon groups (or segments) recently afforded a new class of semi- fluorinated polymers in the continuing quest for novel organic materials for potential applications in optoelectronic, gas-separation, and advanced composites. Chapter 2 details the incorporation of commercially available acenaphthenequinone was achieved to afford PFCB aryl ether polymers with excellent solubility, high thermal stability, and film-forming capability. Chapter 3 represents base-promoted nucleophilic addition/elimination of commercial bisphenols with TFVE-triphenylene monomers affording FAVE aryl ether polymers possessing excellent solution processability, high thermal stability and photostability. In addition, triphenylene-enchained FAVE polymers exhibit extreme thermal-oxidative photostability and emit blue light after heating in air at 250 °C for 24 h. Further, time-dependent density functional theory (TD-DFT) computations were performed to understand electronic polymer structures. In one case, post-polymerization Scholl coupling converted the central triphenylene core to afford a hexabenzocoronene containing semi-fluorinated polymer with new optoelectronic properties. Chapter 4 demonstrates synthesis and characterization of renewable semi-fluorinated polymers obtained using aliphatic diol isosorbide. This renewable diol readily polymerizes with bis-TFVE derivatives of bisphenol A and 6F to provide high molecular weight thermoplastics exhibiting excellent solubility and tough, transparent film-forming capability. Finally, Chapter 5 presents synthesis of TFVE enchained corannulene which gave blue-light emission and outstanding processability. Synthesis and characterization, including the new materials' optical, thermal, and electronic properties, is presented.

A long-term goal within the field of organic electronics has been to developflexible and functional devices, which can be processed and patterned withlow-cost and energy-efficient solution-based methods. This thesis presents anumber of functional paths towards the attainment of this goal via thedevelopment and demonstration of novel fabrication and patterningmethods involving the important organic-semiconductor family termedfullerenes.Fullerenes are soccer-shaped small molecules, with two often-employedexamples being the symmetric C60 molecule and its more soluble derivative[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We show that PCBM canbe photochemically transformed into a dimeric state in a bi-excited reactionprocess, and that the exposed material features a significantly reducedsolubility in common solvents as well as an effectively retained electronmobility. This attractive combination of material properties allows for adirect and resist-free lithographic patterning of electronic PCBM films downto a smallest feature size of 1 µm, using a simple and scalable two-stepprocess constituting light exposure and solution development. In a furtherdevelopment, it was shown that the two-step method was useful also in thearea-selective transformation of fullerene/conjugated-polymer blend films,as demonstrated through the realization of a functional complementary logiccircuit comprising a 5-stage ring oscillator.In another project, we have synthesized highly flexible, single-crystal C60nanorods with a solution-based self-assembly process termed liquid-liquidinterfacial precipitation. The 1-dimensional nanorods can be deposited fromtheir synthesis solution and employed as the active material in field-effecttransistor devices. Here, it was revealed that the as-fabricated nanorods canfeature an impressive electron mobility of 1.0 cm2 V-1 s-1, which is on par withthe performance of a work horse in the transistor field, viz. vacuumdeposited amorphous Si. We further demonstrated that the processability ofthe nanorods can be improved by a tuned light-exposure treatment, duringwhich the nanorod shell is polymerized while the high-mobility interior bulkis left intact. This has the desired consequence that stabile nanoroddispersions can be prepared in a wide range of solvents, and we anticipatethat functional electronic devices based on solution-processable nanorodscan be realized in a near future.

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Die enormen Fortschritte im Bereich der organischen Elektronik in den letzten Jahrzehnten haben zur Entwicklung effizienter optoelektronischer Bauelemente geführt wie z. B. organische Leuchtdioden (OLEDs), organische Feldeffekttransistoren (OFETs) und organische Photovoltaikzellen (OPV). Darüber hinaus ermöglichen halbleitende Polymere die Herstellung kostengünstiger, großflächiger elektronischer Bauelemente mit Hilfe von Niedertemperatur Lösungsverfahren auf flexiblen Substraten. Der erste Teil dieser Arbeit befasste sich mit der Entwicklung von Host-Materialien für die emittierende Schicht (EML) von OLEDs. Effiziente Host-Materialien sollten bestimmte Eigenschaften aufweisen, z. B. eine hohe Triplett-Energie, einen hohen und ausgeglichenen Ladungsträgertransport, geeignete Grenzorbitalniveaus, die mit denen der Nachbarschichten übereinstimmen, und morphologische Stabilität. Zu diesem Zweck wurden Polymere auf Carbazolbasis mit einer elektronenziehenden Gruppe (EWG) an verschiedenen Stellen der Kette entworfen und durch Suzuki Kupplung synthetisiert. Die Polymere wurden chemisch und optisch charakterisiert, bevor sie nach Dotierung mit Tris(2-phenylpyridin)iridium(III) (Ir(ppy)3) in eine funktionierende grüne OLED eingebaut wurden. Zusätzlich wurden die Ladungstransporteigenschaften durch die Herstellung von Einzelträgergeräte untersucht. Der zweite Teil widmete sich der Herstellung von Halbleitermaterialien für OFET Anwendungen. Nach einem neuartigen Moleküldesign wurde eine Reihe von Verbindungen auf der Basis von Diketopyrrolopyrrol (DPP) und Thiophen durch Stille-Kupplung und phosphinfreie direkte Heteroarylierung synthetisiert. Dieses molekulare Design erwies sich als flexibel für die Synthese neuartiger Derivate durch Modifikation der Endgruppen. Die Korrelation zwischen Struktur und Morphologie wurde ebenfalls untersucht. Die Mobilität der Ladungsträger, welche von der chemischen Struktur und Morphologie des Halbleiters beeinflusst wird, ist einer der wichtigsten Parameter eines OFET. Daher wurden die erhaltenen Materialien mit niedriger Bandlücke in Transistoren verschiedener Architekturen integriert, die durch Lösungsverfahren wie Spin-Coating und Scherbeschichtung hergestellt wurden. Die Mobilität sowie andere OFET-Parameter wurden im p- und n-Typ-Betrieb gemessen.:1 Theoretical background 1.1 Introduction 1.2 Organic semiconductors 1.3 Organic Light Emitting Diodes 1.3.1 Physics of OLEDs 1.3.2 Solution processable OLEDs 1.3.3 Polymer Light-Emitting Diodes 1.4 Organic Field-Effect Transistors 1.4.1 Device operation 1.4.2 Ambipolar transistors 1.5 Synthesis of π-conjugated polymers 1.6 Characterisation methods 1.6.1 Chemical structure characterisation 1.6.2 Optical characterisation 1.6.3 Morphology and microstructure 2 Motivation and aim 3 Results and discussion 3.1 Polymers for ambipolar semiconductors 3.1.1 Molecular design 3.1.2 (N-carbazole)triphenylphosphine oxide polymers 3.1.3 Bis(carbazol-3-yl)triphenylphosphine oxide polymers 3.1.4 ((Carbazol-3-yl)phenoxy)hexyl diphenylphosphinate polymers 3.1.5 ((Phenothiazin-10-yl)phenyl)diphenylphosphine oxide polymers 3.1.6 Device integration 3.1.7 Summary 3.2 DPP based molecules for OFETs 3.2.1 Molecular design 3.2.2 DBT-I series 3.2.3 DBT-II 3.2.4 Device integration 3.2.5 Summary 4 Conclusions and outlook 5 Experimental part 6 Supporting Information 7 Bibliography / Staggering progress in the field of organic electronics over the past decades has led to the development of efficient optoelectronic devices, such as organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs)and organic photovoltaic cells (OPV). Moreover, semiconducting polymers enable the fabrication of low-cost, large-area electronic devices using low-temperature solution-processing methodologies on flexible substrates. The first part of this thesis focused on the development of host materials for the emitting layer (EML) of an OLED. Efficient hosts should possess a number of properties, such as high triplet energy, good and balanced charge-carrier transport, suitable frontier orbital levels that match those of the neighbouring layers, and morphological stability. To this end, carbazole-based polymers featuring an electron-withdrawing group (EWG) at different positions of the chain were designed and synthesised by Suzuki coupling. Chemical and optical characterisations of the polymers were performed prior to their incorporation into a functioning green OLED upon doping with tris(2-phenylpyridine)iridium(III) (Ir(ppy)3). Additionally, the charge-transport properties were studied through the fabrication of single-carrier devices. The second part was dedicated to the production of semiconductor materials for OFET applications. Following a novel molecular design, a series of compounds based on diketopyrrolopyrrole (DPP) and thiophene were synthesised by Stille coupling and phosphine-free direct heteroarylation. This molecular design was proven to be flexible for the synthesis of novel derivatives by modification of the end-groups. The correlation between structure and morphology was also studied. Mobility, influenced by the chemical structure and morphology of the semiconductor, is one of the most important parameters of an OFET. Thus, the obtained low bandgap materials were integrated into devices of different architectures, fabricated by solution processing methodologies, such as spin coating and shear coating, and the mobility, as well as other OFET parameters, were measured in p- and n-type operation.:1 Theoretical background 1.1 Introduction 1.2 Organic semiconductors 1.3 Organic Light Emitting Diodes 1.3.1 Physics of OLEDs 1.3.2 Solution processable OLEDs 1.3.3 Polymer Light-Emitting Diodes 1.4 Organic Field-Effect Transistors 1.4.1 Device operation 1.4.2 Ambipolar transistors 1.5 Synthesis of π-conjugated polymers 1.6 Characterisation methods 1.6.1 Chemical structure characterisation 1.6.2 Optical characterisation 1.6.3 Morphology and microstructure 2 Motivation and aim 3 Results and discussion 3.1 Polymers for ambipolar semiconductors 3.1.1 Molecular design 3.1.2 (N-carbazole)triphenylphosphine oxide polymers 3.1.3 Bis(carbazol-3-yl)triphenylphosphine oxide polymers 3.1.4 ((Carbazol-3-yl)phenoxy)hexyl diphenylphosphinate polymers 3.1.5 ((Phenothiazin-10-yl)phenyl)diphenylphosphine oxide polymers 3.1.6 Device integration 3.1.7 Summary 3.2 DPP based molecules for OFETs 3.2.1 Molecular design 3.2.2 DBT-I series 3.2.3 DBT-II 3.2.4 Device integration 3.2.5 Summary 4 Conclusions and outlook 5 Experimental part 6 Supporting Information 7 Bibliography

Este trabalho apresenta uma proposta de publicação de dados de execução do orçamento público em acordo com a legislação brasileira. A partir das leis e da revisão da literatura foram levantados requisitos que devem ser considerados numa publicação de dados que seja processável por máquina. São apresentadas dimensões de dados como qualidade de dados, metadados e taxonomia, além das abordagens Dados Governamentais Abertos e Linked Data. A proposta de publicação resultante além de alinhada com os requisitos estudados prevê processamento por máquina em três níveis: tratamento de dados, validação de dados e colecionamento de conjuntos de dados. Com as tecnologias selecionadas, como XBRL e XSLT, alcançou-se um modelo que atendeu cartorze requisitos levantados, abrindo caminho para estudos como a de uma rede de conjuntos de dados baseada nesta proposta. / This paper presents a proposal for publishing public budget data in accordance with Brazilian law. From the laws have raised requirements that must be considered in the publication data format that is machine-processable. From the literature review were also raised requirements that are part of the proposed publication of this work, such as controlled vocabularies, metadata and taxonomy. Two approaches of open data were also considered in the preparation of the publication format: Open Government Data and Linked Data. The proposed publication resulting from this work, that use technologies like XBRL and XSLT, is aligned with the raised requirements provides three levels of machine-processing: data processing, data validation and collecting datasets.

Este trabalho apresenta uma proposta de publicação de dados de execução do orçamento público em acordo com a legislação brasileira. A partir das leis e da revisão da literatura foram levantados requisitos que devem ser considerados numa publicação de dados que seja processável por máquina. São apresentadas dimensões de dados como qualidade de dados, metadados e taxonomia, além das abordagens Dados Governamentais Abertos e Linked Data. A proposta de publicação resultante além de alinhada com os requisitos estudados prevê processamento por máquina em três níveis: tratamento de dados, validação de dados e colecionamento de conjuntos de dados. Com as tecnologias selecionadas, como XBRL e XSLT, alcançou-se um modelo que atendeu cartorze requisitos levantados, abrindo caminho para estudos como a de uma rede de conjuntos de dados baseada nesta proposta. / This paper presents a proposal for publishing public budget data in accordance with Brazilian law. From the laws have raised requirements that must be considered in the publication data format that is machine-processable. From the literature review were also raised requirements that are part of the proposed publication of this work, such as controlled vocabularies, metadata and taxonomy. Two approaches of open data were also considered in the preparation of the publication format: Open Government Data and Linked Data. The proposed publication resulting from this work, that use technologies like XBRL and XSLT, is aligned with the raised requirements provides three levels of machine-processing: data processing, data validation and collecting datasets.

The growing demand in portable and compact consumer devices and appliances has resulted in the need for the miniaturisation of electronic components. These miniaturised electronic components are sensitive and susceptible to damage by voltages as low as 20V. Electrically conductive styrenic thermoplastics are widely used in electronic packaging applications to protect these sensitive electronic components against electro-static discharge (ESD) during manufacturing, assembly, storage and shipping. Such ESD applications often require the optimal volume resistance range of ≥ 1.0x105 to < 1.0x108 Ω. The best known method to render styrenic thermoplastics conductive is by the incorporation of conductive fillers, such as carbon black but the main limitation is the difficulty in controlling the conductivity level due to the steep percolation curve. Thus the aim of this research is to develop electrically conductive styrenic thermoplastics by blending several styrenic resins with polymeric conductive additives to achieve optimal volume resistance range for ESD applications with the ease in controlling the conductivity level.