The objective of this project was to prepare alkyne-functionalized polymer latexes using surfactant-free emulsion polymerization, and then functionalize these polymer latexes with three quaternary ammonium azides via Cu(I)-catalyzed azide/alkyne cycloaddition (CuAAC) in order to produce antimicrobial polymer latexes. Three quaternary ammonium azides with different linear alkyl chain lengths (C4, C8 and C12) were successfully synthesised in high yield ( > 70%) using established procedures, and their purity determined by elemental analysis, Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Alkyne-functionalized polymer latexes were prepared via surfactant-free emulsion polymerization using 2,2'-azobis(2-methylpropionamidine)dihydrochloride (AIBA) as initiator, [2-(methaccryloyloxy)ethyl]trimethylammonium chloride (MATMAC) as cationic comonomer, propargyl methacrylate (PMA) to provide the alkyne groups, and for some latexes, ethylene glycol dimethacrylate (EGDMA) as crosslinking comonomer. The effects of temperature and the concentrations of AIBA, MATMAC, PMA and EGDMA on monomer conversion, the rate of polymerization, particle diameter and colloidal stability have been investigated. The studies showed that the very high rates of polymerization were due to high values of the number of radicals per particle (in the range 3-2300). The observations also determined that the reaction conditions required to produce small particles (diameter of 150-350 nm) of narrow size distribution were: 75 oC reaction temperature, AIBA at 0.2 wt% to the total mass of monomer, MATMAC level of smaller or equal to 12 mol% to total monomer (including MATMAC), and EGDMA level of < 2.0 mol% to total monomer (excluding EGDMA). Three series of alkyne-functionalized polymer latexes have been synthesised using these conditions: non-crosslinked (NCL), crosslinked (CL) and core-shell (CS). All the latex particles were functionalized with the three quaternary ammonium azides by CuAAC. Zeta potential analysis, FTIR and Raman spectroscopy analysis confirmed the success of the click reactions. The quantitative analysis of FTIR and Raman spectra showed similar values of conversion of click reaction for both NCL and CL particles, indicating NCL and CL particles have similar swellability. The data also showed that significantly higher click reaction conversions were achieved for CS particles (around 60%) than for NCL/CL particles (less than 40%), which indicates that the click reaction only occurred at the surface of particles and that a higher proportion of alkyne groups are located on the surface of CS particles than on NCL/CL particles. The antimicrobial properties of all QAAs, MATMAC, NCL, CL and CS polymer latexes against E. coli bacteria (ATCC 25922) have been investigated using a modified liquid microdilution method in M9 medium, which was shown not to affect latex colloidal stability. It was found that all the polymer latexes showed much higher antimicrobial activities (MIC 6.5-75 µg ml-1) than many antimicrobial polymers reported recently in the literature (MIC 100-2000 µg ml-1); (Ganewatta, M.S. and C.B. Tang, Controlling macromolecular structures towards effective antimicrobial polymers. Polymer, 2015. 63: p. A1-A29). Polymer latexes with clicked-on QAAs showed significantly higher antimicrobial activities than the original latexes. The magnification of the increase in antimicrobial properties of CS particles after click reaction (~3.5 times) was greater than for NCL/CL particles (~2.5 times), showing that a larger amount of QAAs have been clicked onto the surface of CS particles than NCL/CL particles and that the clicked-on QAAs enhance the antimicrobial activity significantly.

Ce travail s’inscrit dans le cadre du conditionnement de liquides organiques radioactifs sans filière de gestion. Le procédé est basé sur une émulsification de liquide organique dans un silicate alcalin permettant la synthèse d’une matrice géopolymère. La première partie de ce travail consiste à effectuer un criblage sur différents liquides organiques. Un système modèle représentatif des différentes huiles et une formulation de référence de géopolymère sont définis. La seconde partie porte sur la structuration des enrobés de liquide organique, du mélange des réactifs jusqu’à l’obtention du matériau final, et vise à déterminer les phénomènes permettant la synthèse d’un composite homogène. Les deux dernières parties visent à caractériser le matériau en étudiant respectivement sa structure (structure chimique, porosité du géopolymère et dispersion de l’huile) et ses propriétés vis-à-vis de l’application à l’immobilisation de déchets radioactifs. Contrairement aux matrices cimentaires silico-calciques, la structuration du géopolymère n’est pas impactée par la nature chimique des liquides organiques. Seules les huiles acides inhibent ou freinent la réaction de géopolymérisation. Afin d’obtenir un matériau homogène la présence de molécules tensio-actives est obligatoire. Le mécanisme de stabilisation des émulsions, à la base du procédé, repose sur une synergie entre les molécules tensio-actives et les particules d’aluminosilicates présentes dans la pâte de géopolymère. Les cinétiques (chimique et mécanique) de la géopolymérisation ne sont pas impactées par la présence d’huile ou de tensio-actifs. Seule une augmentation des modules viscoélastiques et du caractère élastique des pâtes peut être constaté. Cette différence de comportement rhéologique est en majeure partie liée à la présence de tensio-actif. La structure de la matrice est identique à celle d’un géopolymère pur de même formulation. Le liquide organique est dispersé dans des inclusions sphériques dont le rayon est compris entre 5 et 15 μm. Ces gouttelettes sont séparées les unes des autres, et de l’environnement par le réseau mésoporal du géopolymère. Les propriétés mécaniques et de lixiviation ont aussi été évaluées. / This work is included in the management of radioactive organic liquids research field. The process is based on an emulsification of organic liquid in an alkali silicate solution allowing the synthesis of a geopolymer matrix. The first part of this work consists in carrying out a screening on different organic liquids. A model system representative of the various oils and a geopolymer reference formulation are then defined. The second part deals with the structuration of the organic liquid/geopolymer structuration, from the mixture of the reactants to the final material. It aims at determining the phenomena allowing the synthesis of a homogeneous composite. The last two parts aim at characterizing the composite by studying its structure (chemical structure, porosity of the geopolymer and dispersion of the oil) and its properties with respect to the application to the immobilization of radioactive waste. Unlike calcium silicate-based cementitious matrices, the structure of the geopolymer is not affected by the chemical nature of the organic liquids. Only acid oils inhibit or slow down the geopolymerization reaction. In order to obtain a homogeneous material, the presence of surfactant molecules is necessary. The emulsion stabilization mechanism at the base of the process is relying on a synergy between the surfactant molecules and the aluminosilicate particles present in the geopolymer paste. The kinetics (chemical and mechanical) of the geopolymerization are not impacted by the presence of oil or surfactants. Only an increase in the viscoelastic moduli and the elastic character of the pastes can be observed. This difference in rheological behavior is mainly due to the presence of surfactant. The structure of the matrix is identical to that of a pure geopolymer of the same formulation. The organic liquid is dispersed in spherical inclusions whose radius is between 5 and 15 μm. These droplets are separated from each other, and from the environment by the mesoporous network of the geopolymer. Mechanical and leaching properties were also evaluated.

Introdução: A estabilidade fisica de sistemas emulsionados pode ser avaliada através de avaliação da distribuição de gotículas, propriedades reológicas, termoanálise, microscopia, entre outras técnicas. Objetivo: Avaliar a estabilidade fisica de emulsões obtidas com diferentes concentrações de emulsificantes aniônicos (A - cetil fosfato de potássio 3, 5 e 7%) e não-iônicos (N monoestearato de glicerila, 3, 5 e 7%), e a influência da transposição de escala de produção. Metodologia: Avaliação da distribuição das gotículas formadas através de difração de raio laser, análise reológica do tipo fluxo, microscopia e termogravimetria. Resultados e Conclusão: Os valores de 90% das gotículas foram menores que 92,66 &#181;m; 50,28&#181;m e 38,80&#181;m, respectivamente para 3, 5 e 7% de emulsificante N. No sistema A, 90% das gotículas foram menores que 3,85&#181;m; 4,89&#181;m e 63,57&#181;m, para 3, 5 e 7%, respectivamente. O aumento de escala de produção influenciou ambos os sistemas, com aumento de viscosidade: Sistema A: de 6,614 Pa.s para 81,55 Pa.s e Sistema N - de 3,366 Pa.s para 7,153 Pa.s no sistema N. Na análise TG, somente água livre pôde ser detectada no sistema N e, no sistema A, água interlamelar e livre puderam ser detectadas (inicial e em estabilidade) / lntroduction: The physical stability of emulsions can be evaluated through droplets distribution evaluation, rheological properties, thermal analysis, microscopy and others. Objective: Evaluate the physical stability of emulsions containg different concentrations of anionic (A - potassium cetyl phosphate 3, 5 e 7%) and non-ionic emulsifiers (N - glyceril monostearate, 3, 5 e 7%), and the influence ofthe scale-up processo Methodology: Evaluate the droplets distribution with laser diffraction, rheology analysis, microscopy and thermogravimetry (TG). Results and Conc1usion: The values of 90% of the droplets were below 92.66 &#181;m, 50.28&#181;m and 38.80&#181;m, respectively for 3, 5 and 7% ofN emulsifier. For system A, 90% ofthe droplets were below 3.85&#181;m, 4.89&#181;m and 63.57&#181;m, for 3, 5 and 7%. The scale-up process influenced both systems, with an increase in the viscosity on system A from 6.614 Pa.s to 81.55 Pa.s and from 3.366 Pa.s to 7.153 Pa.s for system N. ln the TG analysis, only bulk water could be detected in system N and, in the system A, both interlamellar and bulk water were detected (initial and stability).

Over the past couple of decades interest in particle-stabilised emulsions or Pickering emulsions has greatly increased. When using particles as stabilisers, as opposed to surfactants, the interface becomes more rigid and this can lead to interesting physical properties. In addition, the resulting emulsions are found to be longer-lived garnering commercial interest. This thesis aims to explore the mechanical properties of some specific systems containing particle-stabilised interfaces. The main system investigated was the bicontinuous interfacially jammed emulsion gel or bijel. The bijel has two continuous interpenetrating liquid phases separated by a particle-stabilised interface. Therefore, the structure has a very large interface in a fairly small volume and the pore size is under the experimentalist's control giving it promise in a variety of applications, particularly those based on catalysis. The response of bijels stabilised by either spherical particles or anisotropic rod-shaped particles to centrifugal compression has been investigated in this thesis. It was found that, in both cases, the structure was distorted to create anisotropic particle-stabilised sheets orientated perpendicular to the force. The original method for fabricating bijels involves the arrested spinodal decomposition of partially miscible liquids. This method requires partially miscible liquid pairs and particles that are equally wetted by each phase. Due to these requirements, a new method for making bijels using mixing was developed by others and the bijel made by mixing has been tested with oscillatory rheology combined with imaging and squeeze flow experiments. It was found that at low strain the bijel displayed solid-like behaviour and the structure remained intact until well past the yielding point. In addition, two further systems were investigated. The first system was rod-shaped particle-stabilised emulsion droplets that stick together by particle bridging. Bridging is where one particle can stabilise two droplet interfaces, preventing coalescence and leading to droplet clusters. Particle bridging was found to occur regardless of shear rate, particle volume fraction and to some extent aspect ratio with these anisotropic rod-shaped particles. This behaviour is hypothesised to be a consequence of the charged nature of the silica surface above pH 2. The second system was large particle-stabilised water droplets that can sprout tubes by the partitioning of solute from a bath into the droplet. By using different solutes and mixtures of different alcohols, the key requirements for sprouting behaviour have been ascertained. The most important requirement was found to be achieving the correct balance between the interfacial tension and the amount of solute partitioning into the droplet.

<p>Predmet istraživanja ove doktorske disertacije<br />je bio formiranje i proučavanje osobina i<br />pona&scaron;anja organskih aerosola nastalih<br />atomiziranjem stabilnih emulzija dominantno<br />pod dejstvom centrifugalne sile. Kori&scaron;ćene su<br />vodene emulzije komercijalnih sredstava za<br />hlađenje i podmazivanje (SHP), koja se koriste<br />pri obradi metalnih odlivaka. Cilj istraživanja je<br />bio ispitati i objasniti uticaj koncentracije SHP<br />emulzije, brzine strujanja vazduha, prirode kako<br />ulja, tako i osobina emulzija, kao &scaron;to su gustina,<br />viskoznost, povr&scaron;inski napon, kao i udaljenost<br />od mesta atomiziranja na masenu koncentraciju,<br />broj i veličinu kapi aerosola u kontrolisanim<br />laboratorijskim uslovima.<br />Uslovi eksperimenta isključili su uticaj toplote<br />nastale kao posledica trenja alata i delova koji<br />se obrađuju. Pored toga isključeno je prisustvo<br />čvrstih mikronskih čestica koje potiču od delova<br />koji se obrađuju, kao i prisutvo plivajućeg<br />hidrauličnog ulja i mikroorganizama koji uvek<br />prate realan industrijski fluid.<br />Eksperimentalni program je realizovan na tri<br />komercijalna SHP sredstva različitog porekla.<br />Proučavani su aerosoli formirani atomiziranjem<br />emulzije tri različite koncentracije uljne faze: 1,<br />6 i 10 %. Pri jednakim eksperimentalnim<br />uslovima ispitivan je i aerosol formiran, od<br />vode kori&scaron;ćene za pripremu emulzija. Određene<br />su osobine ulja i emulzija koje su od značaja za<br />atomiziranje tečnosti. Proučavan je i uticaj<br />brzine ventilacionog vazduha na osobine<br />aerosola. Eksperimenti su realizovani pri<br />brzinama vazduha od 1, 3, 6, 8 m/s.<br />Uzorkovanje aerosola je realizovano u komori,<br />na ulazu u ventilacini vod i duž ventilacione<br />cevi dužine 8m na pet mernih tačaka koje se<br />nalaze na 0,5, 1, 2, 4, 6, 8 m u odnosu na<br />komoru.<br />Značajan doprinos ove doktorske disertacije je<br />postavljanje teorije da atomiziranjem emulzije<br />kao heterogene tečnosti, nastaje heterogen<br />aerosol, pri čemu mogu nastati kapi različite<br />prirode, između ostalog i kapi čistog ulja. Na taj<br />način je obja&scaron;njen fenomen da porastom<br />koncentracije emulzije raste veličina kapi<br />nastalog aerosola. Aerosoli nastali od<br />koncentrovanijih emulzija pokazuju uređenije<br />strujanje kroz ventilacionu cev, &scaron;to je od<br />značaja za uspe&scaron;nije projektovanje ventilacionih<br />sistema i filtara za njihovu separaciju u cilju<br />za&scaron;tite zdravlja radnika i za&scaron;tite okoline.</p> / <p> This PhD Thesis presents an experimental<br /> study of organic aerosols formed from stable<br /> water emulsions, predominantly by centrifugal<br /> force under laboratory conditions. Emulsions of<br /> metalworking fluids (MWF) were used in the<br /> experiments. The aim of this investigation was<br /> to explain the influence of MWF emulsion<br /> concentration, oil and emulsion properties<br /> (density, viscosity, and surface tension), air<br /> velocity, as well as distance from atomization<br /> generator on aerosol behavior and properties as<br /> size distribution, mass and number<br /> concentration. The experimental conditions<br /> excluded the influence of the heat arising from<br /> the friction between the tool and the<br /> workpieces. In this way the mechanism of<br /> aerosol formation by the<br /> evaporation/condensation is minimized.<br /> Besides, the presence of solid micrometer sized<br /> particulates originated from the work piece is<br /> excluded, as well as the presence of tramp oil<br /> and microorganisms, always accompanying a<br /> real industrial fluid.<br /> Three different commercial MWFs were<br /> investigated at three different oil-in-water<br /> emulsion concentrations, 1, 6, and 10 %<br /> respectively. Water aerosol was investigated<br /> under same experimental conditions. Properties<br /> of MWF oils and emulsion, which are important<br /> for liquid atomization, were determined.<br /> Influence of ventilation air velocity on aerosol<br /> properties was investigated as well.<br /> Experiments were realized under four different<br /> air velocities: 1, 3, 6, and 8 m/s. Samples were<br /> taken at three different points: at the camber, at<br /> the entrance of ventilation pipe, and at five<br /> sampling points along the pipe. Ventilation pipe<br /> was 8 m long, and sampling point were at 0.5, 1,<br /> 2, 4, 6, 8 m from the aerosol camber.<br /> The main contribution of this dissertation is<br /> the new theory that atomization of emulsion as a<br /> heterogeneous fluid leads to the formation of<br /> heterogeneous aerosol, containing droplets of a<br /> different nature, including droplets of pure oil.<br /> This theory explains the phenomenon that the<br /> aerosol droplet sizes increase with the increase<br /> of the emulsion concentration. Obtained results<br /> show that aerosols formed from the emulsions<br /> of higher concentration (6 and 10 %) have less<br /> chaotic flow through the ventilation pipe. This<br /> observation is important for better design of<br /> ventilation systems and filters for mist<br /> separation in order to protect human health and<br /> the environment.&nbsp;</p>

Emulsions are commonly found both in nature and industry. Due to the complex nature of emulsion systems, their interfacial properties and stability are poorly understood, particularly the influence of droplet deformability on the colloid and interfacial behaviour. This study has highlighted the role of emulsion droplet cross-linking (deformability and penetrability) on droplet surface chemistry, droplet colloidal stability and adsorption at the droplet-water interface and provides insight into methods for enhancing the performance of emulsion formulations.

Abstract This work investigates the kinetics of the emulsion polymerization of vinyl acetate. Several aspects of this system have been clarified, including the induced decomposition of persulfate, retardation by oxygen and entry by, and analysis of, the aqueous phase oligomeric radicals. It has been shown that the retardation period observed in the emulsion polymerization of VAc can be explained by the effect of traces of oxygen (< 10-6 M) on the entry efficiency of the initiator-derived aqueous-phase oligomeric radicals. Comparison of rates of polymerization in V and persulfate -initiated polymerizations together with electrospray mass spectrometry of aqueous phase oligomers, has shown that the mechanism for the induced decomposition of persulfate by vinyl acetate is chain transfer to initiator from aqueous-phase oligomeric radicals. A value has been determined for the rate coefficient for transfer to initiator, by fitting literature data to a model based on this mechanism. The reported independence of the rate of polymerization from the monomer concentration in the emulsion polymerization of vinyl acetate has been investigated. Possible explanations for this behaviour have been proposed and tested in this work, by measuring radical-loss rates directly with y-relaxation techniques. Although the Y relaxations were found to be affected by experimental artefacts, it has been demonstrated that rapid exit is not responsible for the high radical-loss rates in this system. The major artefact identified in the y relaxations was the significant effect of relatively small exotherms on relaxation behaviour, Methodologies were developed for correcting affected data and for avoiding exotherms under certain conditions. Arrhenius parameters were determined for the rate coefficient for chain transfer to monomer using the In^M method, which utilises the whole MWD. This section of the work is incomplete, for reasons detailed in chapter 5. However, as a preliminary indication it was found that the frequency factor was 106.38 M-1 s-1 and the activation energy was 38.8 kJ mol-1.

<p>A colloid of magnesium hydroxide is used to stabilize droplets of monomers before suspension polymerisation. The characteristics of precipitated magnesium hydroxide changes significantly during the first hours. The viscosity is high and flucctuating at first but decreases and becomes low and stable after a few hours. When the colloid ages the primary particles agglomerate into larger particles which increases in size by time due to, among other things, Oswald ripening and aggregation. This can cause problems with poor reproducibility in the production. Therefore, the purpose of this study was finding a way to age the colloid without an increase in particle size and without changing any other features. Several experiments were made to optimize the precipitation procedure and to find out what parameters that are most important. The results showed that the stirring rate and colloidal concentration have big influence.</p><p>Small amounts of chemicals that modifies the surface of the colloid was added. This made the particle size near constant over time and the colloid was aged for two months without increasing in size or changing other properties. This was confirmed by making microspheres that had the same characteristics as microspheres made with a fresh colloid.</p>

Neutrino-nucleon scattering is an effective way to investigate the inner structure of the nucleon, to extract the Standard Model parameters and to explore heavy quarks production dynamics. In the last decades, several experiments have been constructed to study weak interactions of neutrinos with nucleons. One of them was CERN-WA95 experiment operated by the CHORUS collaboration. It is based on a hybrid detector with nuclear emulsion as a target followed by electronic devices. Nuclear emulsion provides three dimensional spatial information with an outstanding resolution of the order of one micron. Therefore, it is ideal to detect short-lived particles. A special technique has been developed to reconstruct events in the emulsion which allows to perform a detailed investigation of events such as charmed hadrons production by neutrinos. As a result, the backround in the selected charm sample is up to six times lower compared to similar experiments. Such a method also permits to make direct measurements of some quantities instead of model fittings. This thesis is devoted to the study of the muonic decays of charmed hadrons and their production in emulsion. Manual inspection of charm events gives a complete reconstruction of charm decay topology. The extraction of the inclusive muonic branching ratio is based on the ratios per number of charged daughters in charm decay. Such an approach allows to separetely measure the muonic branching ratios for neutral and charged charm particles. Finally, normalization of the events with a muon in the final state to the charged current events gives dimuon production rate which is found compatible with the previous experiments. On top of that, preliminary results are shown for Bjorken x distribution and for a direct measurement of the Vcd Cabbibo-Kabayashi-Maskawa matrix element.

Thesis (Ph.D. (Pharmacy))--North-West University, Potchefstroom Campus, 2008.