No description available.

Ionomers are valued for their exceptional physical properties, antimicrobial activity and superior adhesion to high surface energy solids and polymer blend components. Carboxylate, or sulfonate derivatives, of ethylene-rich thermoplastics are the most commercially available ionomers. Elastomeric ionomers bearing quaternary ammonium and phosphonium halide functionality have a literary standing in both scientific and patent-based publications. Currently cationic ionomers have shown great prominence in their inactivity to a wide range of bacteria and fungi. The specific focus of this research is in the derivatives of isobutylene-rich elastomers due to their exceptional impermeability, oxidative stability and vibration dampening characteristics. Imidazole-derived ionomers support a wider range of ionomer chemistry compared to ammonium and phosphonium analogues. N alkylation of nucleophiles including butyl imidazole, vinyl imidazole and 1,1’(1,4-butanediyl)bis(imidazole) by brominated poly(isobutylene-co-isoprene) yield thermally stable imidazolium bromide salts capable of supporting free radical cures and/or siliceous filler dispersions through further chemical modifications. The versatility of imidazole chemistry extends to the synthesis of isobutylene rich thermoset ionomers. This derives material properties from both a network of covalent crosslinks and a network of ion pair aggregates. Un-crosslinked elastomers are prone to creep and stress relaxation, hence a need for thermoset ionomer chemistry. Ion pairs are poorly solvated by the low dielectric constant of the polymer backbone and favoured thermodynamically by way of self assembly of the ionic functionality. The aggregation of ion pairs establishes a non covalent network of polymer chains whose dynamic mechanical properties approach those of conventional covalent thermosets comprised of carbon-carbon and/or sulfide crosslinks. However, the lability of this ionic network leads to a poor response to static loads leaving the thermoformable ionomers unqualified for engineering applications. A direct route is a more desirable method in preparing thermoset ionomers comprised of covalent crosslink networks and ionic functionality. In all, these reactive imidazolium ionomers look promising in supporting new value added applications for isobutylene rich derivatives, which include yet are not limited to elastomer thermosets, emulsions, filler composites and clay nanocomposites. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2013-12-11 15:34:32.691

Halogenation of poly(isobutylene-co-isoprene) (IIR) increases its reactivity towards sulphur and other nucleophiles. Currently brominated (BIIR) and chlorinated (CIIR) derivatives are commercially available; however, an iodinated derivative has been briefly investigated. The effects of leaving group ability and microstructure on the reactivity of halogenated poly(isobutylene-co-isoprene) were studied to put iodobutyl rubber reactivity into context and to compare existing commercial products to their isomeric derivatives. Polymers containing halomethyl (r-CIIR, r-BIIR, r-IIIR) isomers of butyl rubber were prepared from as-received BIIR to compare the effect of leaving group on thermal stability and reactivity towards nucleophilic substitution. The polymer containing (E,Z)-endo-iodomethyl isomers (r-IIIR) readily underwent nucleophilic substitution at low temperatures; however, it was sensitive towards dehydrohalogenation at temperatures above 65⁰C. At temperatures between 100⁰C and 135⁰C, the bromomethyl derivative (r-BIIR) demonstrated the best balance between reactivity toward nucleophilic substitution and dehydrohalogenation. Exceptional thermal stability at temperatures up to 190⁰C was displayed by the chloromethyl derivative (r-CIIR); however, it was unreactive at low temperatures towards certain nucleophiles. This lack of reactivity shown by r-CIIR was not consistent with all nucleophiles, as reaction dynamics with TBAAc display its variable reactivity towards nucleophilic substitution with results parallel to those of r-BIIR. Exo-methylene allylic halides (Exo-Br, Exo-Cl) and (E,Z)-endo-halomethyl (r-BIIR, r-CIIR) isomers were vulcanized with sulphur to determine the effect of microstructure on reactivity. Results showed a clear effect of microstructure on the ability to cure with sulphur. While the Exo-Cl isomer has no ability to cure, when rearranged to its (E,Z)-endo-chloromethyl isomer curing occurs readily. Both the Exo-Cl and (E,Z)-endo-bromomethyl isomers readily vulcanize in the presence of sulphur, however Exo-Br cures to a greater extent. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-09-30 12:55:25.665

Abstract: Isobutylene is a high demand chemical that contributes to the production of fuel, plastic, and rubbers. It is produced industrially by different processes, as a byproduct of steam cracking of naphtha or a fluidized catalytic cracking or by isobutane dehydrogenation. Catalytic dehydrogenation of isobutane is in increasing importance because of the growing demand for isobutylene and the better economic advantage compared to other isobutylene production processes. Isobutane dehydrogenation is an endothermic reaction and to achieve good yields; it is preferred to work at higher temperatures. At these temperatures, carbon deposition leads to catalyst deactivation, which requires the catalyst to be regenerated on a frequent basis. Most of the current processes to produce isobutylene use either expensive platinum-based metal or toxic chromium-based catalysis. Hence, there is a demand to search for alternative catalysts that are a relatively cheap and non-toxic. To achieve this goal, Zirconia-supported Iron catalysts were prepared. To study the effect of active phase distribution, different iron loadings were tested for impregnation (3% to 10%) and co-precipitation (10%-20%). The catalysts show promising results that can achieve an isobutylene selectivity and yield of 91% and 31%, respectively, with isobutane conversion of 35%.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24642号 / 工博第5148号 / 新制||工||1983(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 大嶋 正裕, 教授 竹中 幹人, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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Ces travaux ont porté sur l’intérêt de l’utilisation d’une membrane composite zéolite (CHA SSZ-13) accessible à l’échelle commerciale au travers de la technologie membranaire de perméation de gaz et de vapeurs. L’applicabilité de cette technologie séparative s’est principalement focalisée sur la récupération du méthane, propane et d’isobutène issus de flux produits à des échelles industrielles par des procédés durables. La mise au point d’un banc expérimental pour la mesure de données de perméation de gaz et de vapeur a été réalisé. En se basant sur des mesures expérimentales de perméation menées avec la membrane zéolite de l’étude, un premier cas d’application pratique a été de simuler les performances séparatives d’un procédé hybride associant un module membranaire zéolite avec une condensation cryogénique à partir d’un cahier des charges industriel pour la récupération d’isobutène. Le procédé hybride étudié est toujours plus performant que le procédé de condensation cryogénique seul de référence en termes de pureté du produit condensé obtenu et de consommation énergétique. Des cartographies ont été dressées afin de situer les performances de séparation simulées en fonction de l’objectif de récupération d’isobutène souhaité. Un second cas théorique de récupération du propane à partir d’évents de purge à l’azote avec un procédé hybride de séparation cryogénique couplée à une membrane permsélective a été étudié. Une cartographie des performances de séparation membranaire relative au couple propane/diazote selon les données de la littérature ouverte actuelles a été présentée. La membrane la plus permsélective au diazote et au propane (respectivement CHA SSZ-13 et PEBAX 2533) a été sélectionné afin de simuler des procédés hybrides dont les performances séparatives ont été comparées à celles de la condensation cryogénique seule de référence. Pour de faibles teneurs en propane, il a été constaté que le procédé le plus performant (besoin énergétique et qualité du produit condensé) impliquait un module membranaire polymère de type PEBAX 2533 avec un système de mise sous vide du perméat. / This work focused on the interest of using a zeolite composite membrane (CHA SSZ-13) accessible on a commercial scale through the membrane technology of gas and vapor permeation. The applicability of this separation technology has mainly focused on the recovery of methane, propane and isobutene from fluxes produced at industrial scales by sustainable processes. The development of an experimental lab scale pilot for gas and vapor permeation data measurements is detailed. Based on experimental permeation measurements carried out with the zeolite membrane of the study, a first case of practical application was to simulate the separation performance of a hybrid process associating a zeolite membrane module with a cryogenic condensation from an industrial specification for the recovery of isobutene. The hybrid process studied is always more efficient than the only cryogenic condensation process taken as reference in terms of purity of the condensed product obtained and energy consumption. A chart was generated to locate the simulated separation performance based on the desired isobutene recovery objective. A second theoretical case of propane recovery from nitrogen purging vents with hybrid membrane cryogenic separation process was studied. This study presented a chart of the membrane separation performance of propane over nitrogen according to data from the open literature. The most nitrogen- and propane-selective membrane (CHA SSZ-13 and PEBAX 2533 respectively) was then selected and used in order to simulate hybrid processes where separation performances were compared to a baseline cryogenic standalone process. For low propane contents in the nitrogen feed mixture, it was found that the most efficient process (energy need and quality of the condensed product) involved a PEBAX 2533 polymer membrane module with a vacuum system for the permeate.

L´objectif du travail présenté dans ce manuscrit consiste à conserver les bonnes propriétés mécaniques du poly(butadiène) dihydroxytéléchélique (PBHT) tout en améliorant sa stabilité. Un des principaux verrous techniques de cette approche réside dans le fait que les doubles liaisons responsables la flexibilité du matériau sont également la cause de son vieillissement par oxydation. Les solutions proposées reposent sur l´utilisation de la métathèse comme outils de synthèse de polymères insaturés. Deux grandes voix de synthèse ont été étudiées : la polymérisation par ouverture de cycle via métathèse (ROMP) ainsi que la dépolymerisation fonctionnalisante (ADMET). Ces deux approches bien que prometteuses n’ont pas permis de sortir de la relation ciseau existante entre flexibilité et stabilité. Finalement, une solution basée sur le mélange entre deux polymères dihydroxytéléchéliques de basse température de transition vitreuse – poly(butadiene) et poly(isobutylene) a permis de répondre dans une certaine mesure aux cahier des charges. En parallèle a ces parties synthèses, une étude physique des relations structure-propriétés visant à améliorer la stabilité des oligomères a été apporté par mesure rhéologique du temps critique de réticulation. / The work reported in the following document is aiming at maintaining the good mechanical properties of diHydroxyTelechelic PolyButadiene HTPB while improving its stability. The major challenge of this approach is that the unsaturations responsible for the outstanding flexibility of the material are also rather sensitive to oxidation. The solutions presented in this study are based on the use of metathesis reactions as a tool for the design of new difunctional unsaturated oligomers. Two functionalization techniques have been investigated, on the one hand, the Ring Opening Methathesis Polymerisation (ROMP) and, on the other hand, the depolymerisation via Acyclic Diene METathesis (ADMET). Although promising, the latters proved to fall into the vicious circle consisting in simultaneously increasing the stability while losing the flexibility. Finally, a blending concept based on the mixture of two dihydroxytelechelic polymers, namely, poly(isobutylene) and poly(butadiene), could enable us to achieve our initial goal. In addition to the chapters focusing on polymer chemistry and synthesis, a physical study of the parameters influencing the aging of unsaturated oligomers have been set-up and the properties relationship using measurements of the critical time.

We introduce new oxygen- and moisture-proof polymer matrixes based on polyisobutylene (PIB) and its block copolymer with styrene [poly(styrene-block-isobutylene-blockstyrene), PSt-b-PIB-b-PSt] for the encapsulation of colloidal semiconductor nanocrystals. In order to prepare transparent and processable composites, we developed a special procedure of nanocrystal surface engineering including ligand exchange of parental organic ligands to inorganic species followed by the attachment of specially designed short-chain PIB functionalized with an amino group. The latter provides excellent compatibility of the particles with the polymer matrixes. As colloidal nanocrystals, we chose CdSe nanoplatelets (NPLs) because they possess a large surface and thus are very sensitive to the environment, in particular in terms of their limited photostability. The encapsulation strategy is quite general and can be applied to a wide variety of semiconductor nanocrystals, as demonstrated on the example of PbS quantum dots. All obtained composites exhibited excellent photostability, being tested in a focus of a powerful white-light source, as well as exceptional chemical stability in a strongly acidic media. We compared these properties of the new composites with those of widely used polyacrylate-based materials, demonstrating the superiority of the former. The developed composites are of particular interest for application in optoelectronic devices, such as color-conversion light-emitting diodes, laser diodes, luminescent solar concentrators, etc.