L’usage des élastomères en tant que matériau ne peut se concevoir sans l’utilisation de certaines charges dites renforçantes. Bien qu’une variété plutôt large de minéraux en poudre puisse être associée aux élastomères, deux charges sont très majoritairement utilisées de par leur haute capacité renforçante, les noirs de carbone et les silices actives et hautement structurées. L’utilisation de la silice n’a été envisagée, à partir des années 1980, que grâce à un contrôle fin de sa chimie de surface, de ses silanols hydrophiles et de son traitement par silanes spécifiquement dessinés pour satisfaire une application précise. La preuve expérimentale quantifiant les interactions charge – polymère est grandement souhaitée. C’est précisément le premier but que cette thèse tente d’approcher. Pour tenter d’atteindre cet objectif, nous proposons d’étudier dans ce travail l’évaluation de l’adsorption d'un polymère, une série de HNBR, sur des charges, noir de carbone et silice traitée ou non par des silanes spécifiquement désignés, d’un point de vue énergétique et moléculaire au moyen de la microcalorimétrie à écoulement (FMC). L'application de cet outil, relativement connu dans le cadre des interactions petite molécule – charge est plutôt original dans l’étude des couples polymère – charge. Notre deuxième but est donc, et grâce à une connaissance fine de la chimie des surface d'une silice, de ses traitements par des silanes, et de l'adsorption du polymère sur sa surface, d'explorer la corrélation entre le traitement et les propriétés macroscopiques dans le but d'établir une relation de cause à effet. / Most actual uses of elastomers are not even conceivable without the assistance of reinforcing filler. In this field, "silane-technology" brought into evidence the necessity of monitoring the competition that routinely rises between two determinant factors: polymer-filler interactions and filler-filler interactions. As a result, an important database founded essentially on the characterization of the surfaces chemistry and surface energy of the two antagonist elements had to be gathered. However, the determination of the consequence of such characters on the factual polymer-filler interactions remains rudimentary, such as bound rubber gravimetric measurements. Experimental prove which is able to quantify such interactions is badly needed. This is, actually, the first objective that we tried to achieve. In order to do so, we propose in this work to study, from the energy point of view using flow micro calorimeter (FMC), the evolution of the adsorption of a series of HNBR on the surface of carbon black (CB) and silicas unmodified and modified by selected silanes. If the goal of the silane technology is to design coupling agents that are able to satisfy a specific application, especially those related to the energy dissipation, the mechanism through which such a process is achieved is not fully understood. Thus, and based on a fine knowledge of surface chemistry, surface treatments and polymer adsorption, our second objective is to explore the cause-to-effect links that ought to exist between filler surface treatments and blends macroscopic properties.

No description available.

L'objectif de cette thèse est de proposer un procédé de recyclage de mélanges ABS-PC issus des Déchets d'Equipements Electriques et Electroniques (DEEE) réels capable de s'affranchir des contraintes liées au recyclage des polymères.Ces contraintes sont liées, entre autre, à la présence d'impuretés (autres polymères) après l'étape de tri et au procédé de remise en forme. L'influence de la présence d'impureté dans un alliage ABS-PC sur ces propriétés mécaniques (résistance au choc et traction) a donc été étudiée en s'appuyant sur des observations morphologiques. Il s'est avéré que la présence d'impureté non miscible conduit à la dégradation des propriétés mécaniques de l'ABS-PC. L'ajout de compatibilisants a été étudié afin de masquer l'effet de l'impureté. Il a ainsi été montré que l'amélioration de la résilience du mélange (ABS-PC/impureté) est intimement liée à la modification de la morphologie et à la nature de l'adhésion aux interfaces. Il a ensuite été constaté que l'optimisation des paramètres de mise en oeuvre engendre une modification de la morphologie. Cette modification peut entrainer une augmentation de la résistance au choc.Ces deux méthodes ont ensuite été appliquées à un mélange d'ABS-PC ignifugé issu des DEEE contenant une impureté. L'ajout de compatibilisant et de la modification des paramètres de mise en oeuvre améliore la résilience. En revanche, cela a un effet néfaste sur le comportement au feu de l'alliage ABS-PC ignifugé.

A novel hetero Diels-Alder reaction has been developed to facilitate the synthesis of annelated pyridines as models for pyridoacridine alkaloids. The key reaction is based on an intramolecular Diels-Alder reaction of an aza-1,3-butadiene with an appropriate dienophile, to yield the desired annelated pyridine. An extension of this methodology is to exploit the Eglinton copper (IT) dimerisation of terminal acetylenes. This allows for a unique double intramolecular hetero Diels-Alder reaction, where four new rings are formed in one step. This allows for a facile route to annelated bipyridines. Ultimately this methodology has led to an approach to the total synthesis of the natural product eilatin, a member of the class of compounds known as pyridoacridines.

Made available in DSpace on 2016-12-08T17:19:35Z (GMT). No. of bitstreams: 1 Tatiana da Cunha Gomes Leitzke.pdf: 2438825 bytes, checksum: 8c0dbce0f01fadf8eb99d5b68ba3e534 (MD5) Previous issue date: 2003-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Aiming the development of polymer materials with high toughness, poly(butadiene-coacrylonitrile) rubbers (NBRs), with acrylonitrile (AN) contents varying from 32,9 to 45,7%, were added to poly(styrene-co-acrylonitrile) (SAN) by casting, mini-extrusion and monoscrew extrusion followed by injection molding. Addition of NBR resulted in significant improvements in the impact strength and the elongation at break, that were strongly influenced by the blend composition, the AN contents and the NBR melt viscosities, but the tensile strength is slightly decreased. The best impact strength results (157,1 ± 3.7 J/m) were obtained with a 70/30 (w/w) SAN/NBR blend using NBR with 33,1% of AN and 51 ML 1+4 (100°C), being ca. 700% higher than the values for pure SAN (22,4 ± 1.1 J/m). Differential scanning calorimetry (DSC) measurements indicated a partial miscibility between the copolymers, showing a shifting of the SAN glass transition temperature from 108,1 to 101,7oC for the 70/30 blend with NBR containing 45,7% of AN. This is in agreement with infrared spectroscopy (FTIR) analysis that displayed a significant shift of the dienic band from 967 cm-1 to ca. 1060 cm-1 for all 70/30 blends, suggesting segmental interactions between NBR and SAN. Scanning electron micrographs (SEM) from fracture surfaces revealed homogeneously dispersed spherical elastomeric domains, and the appearance of yielding and/or crazing processes for all blends. The size of NBR domains decreased as the AN content increased, while the number of NBR domains decreased as the melt viscosity increased. From these results it can be concluded that SAN thoughening by the addition of NBR is directly related to the AN content and the melt viscosity of the elastomer, depending on the morphology of the dispersed rubber phase. Higher NBR domain sizes cause better impact strengths, as large rubber particles are more effective in initiating crazing processes. / Com o objetivo de desenvolver materiais poliméricos com elevada tenacidade, borrachas de poli(butadieno-co-acrilonitrila) (NBR), com teores de acrilonitrila variando de 32,9 a 45,7%, foram incorporadas ao poli(estireno-co-acrilonitrila) (SAN), por evaporação desolventes, mini-extrusão e extrusão seguida de injeção. A adição do NBR resultou em um aumento significativo na resistência ao impacto e na deformação na ruptura, que foram fortemente influenciadas pela composição da blenda, pelo teor de acrilonitrila e pela viscosidade dos NBRs, porém, houve a diminuição da resistência à tração. O melhor resultado de resistência ao impacto (157,1 ± 3.7 J/m) foi obtido para a blenda 70/30 (m/m) utilizando NBR com 33,1% de acrilonitrila e 51 ML 1+4 (100°C), um valor cerca de 700% maior que o verificado para o SAN puro (22,4 ± 1.1 J/m). A técnica de calorimetria diferencial de varredura (DSC) indicou uma miscibilidade parcial entre os copolímeros, mostrando o deslocamento da temperatura de transição vítrea do SAN de 108,1 a 101,7ºC para a blenda 70/30 utilizando o NBR com 45,7% de acrilonitrila. Este resultado concorda com a análise de espectroscopia de infravermelho (FTIR), que mostrou um deslocamento significativo da banda da parte butadiênica de 967 cm-1 para 1060 cm-1, para todas as blendas 70/30, sugerindo assim interações segmentais entre o NBR e SAN. A análise da superfície de fratura por microscopia eletrônica de varredura (MEV), revelou homogeneidade dos domínios elastoméricos dispersos na matriz, bem como o aparecimento de microtrincas e/ou deformação plástica para todas as blendas. O tamanho dos domínios de NBR diminui com o aumento do teor de acrilonitrila presente no NBR, enquanto a quantidade de domínios diminui com o aumento da viscosidade. A partir destes resultados conclui-se que a tenacificação do SAN com a adição de NBR está diretamente relacionada com o teor de acrilonitrila e viscosidade do elastômero e depende da morfologia da fase elastomérica dispersa na matriz. Os domínios maiores de NBR proporcionaram melhor resistência ao impacto, sendo que partículas de borracha maioresfavorecem o aparecimento de microtrincas.

O crescimento na geração de rejeitos de equipamentos elétricos e eletrônicos (REEE), legislações mais rigorosas e o valor agregado destes materiais incentivam o desenvolvimento de tecnologias de reciclagem. Contudo, a reciclagem dos componentes poliméricos dos REEE (CP-REEE) precisa superar desafios como a degradação durante o uso e reprocessamento, a presença de diferentes aditivos nos rejeitos e a depreciação de propriedades causada pela mistura não controlada de polímeros. Assim, o objetivo deste trabalho foi desenvolver um estudo sobre a reciclagem mecânica na forma de blendas poliméricas de rejeitos do copolímero acrilonitrila-butadieno-estireno (ABS) e do poliestireno de alto impacto (HIPS), empregando agentes compatibilizantes. No desenvolvimento do trabalho foram realizadas a caracterização dos CP-REEE, análise das propriedades mecânicas, químicas, térmicas e morfológicas dos polímeros e das blendas de ABS/HIPS nas proporções de 1:3, 1:1 e 3:1 com variações na composição dos polímeros reciclados e virgens e por fim, realizado um estudo do envelhecimento foto-oxidativo acelerado de uma blenda ABS/HIPS. Os resultados mostraram que os polímeros ABS e HIPS reciclados ainda apresentam boas propriedades mecânicas e que a presença de agentes compatibilizantes provoca o aumento da tenacidade nas blendas ABS/HIPS. A incorporação de polímeros virgens nos materiais reciclados não promove ganho significativo nas propriedades mecânicas das blendas. Blendas com até 50% de ABS demonstraram ter propriedades próximas às do HIPS, enquanto as blendas com altos teores de ABS não alcançaram valores de propriedades mecânicas similares aos do ABS virgem. O comportamento das propriedades das blendas virgens e recicladas frente ao envelhecimento fotoquímico foi similar, indicando que o material reciclado apresenta grande potencial para aplicações. O estudo de blendas ABS/HIPS de CP-REEE demonstra que o controle da composição das blendas definem a sua aplicação. / The growth in waste electrical and electronic equipment (WEEE) generation, directives more stringent and the aggregate value presents in these waste are encouraging the development of recycling technologies. However, recycling of polymeric components from WEEE (PC-WEEE) must overcome challenges such as degradation during use and reprocessing, the presence of various additives in the waste and the depreciation of properties caused by uncontrolled polymers mixture. The aim of this work was to develop a study of the mechanical recycling in the form blends with of polymeric waste of acrylonitrile-butadiene-styrene copolymer blends (ABS) and high impact polystyrene (HIPS) using compatibilizers. During the study was carried out the characterization of the PCWEEE and mechanical, chemical, thermal and morphological analysis of the polymers and the ABS / HIPS blends in proportions of 1:3, 1:1 and 3:1 with recycled and virgin polymers, as well as a study of the accelerated photo-oxidative aging of the ABS/HIPS blends. The results showed that ABS and HIPS recycled polymers still have good mechanical properties and the presence of compatibilization agents leads to increased toughness in ABS/HIPS blends. The incorporation of virgin polymers in recycled materials does not promote significant gain in the mechanical properties of the blends. Blends with up to 50% ABS have demonstrated to be closer to the HIPS, while blends with high content of ABS did not reach values of mechanical properties similar to the virgin ABS. The mechanical properties of virgin and recycled blends during the photochemical aging were similar, indicating that the recycled material has great potential for applications. The study of ABS/HIPS blends from PC-WEEE demonstrated that control of the blend composition establish their applications.

L’objectif de cette thèse est de proposer un procédé de recyclage de mélanges ABS-PC issus des Déchets d’Equipements Electriques et Electroniques (DEEE) réels capable de s’affranchir des contraintes liées au recyclage des polymères.Ces contraintes sont liées, entre autre, à la présence d’impuretés (autres polymères) après l'étape de tri et au procédé de remise en forme. L’influence de la présence d’impureté dans un alliage ABS-PC sur ces propriétés mécaniques (résistance au choc et traction) a donc été étudiée en s’appuyant sur des observations morphologiques. Il s’est avéré que la présence d’impureté non miscible conduit à la dégradation des propriétés mécaniques de l’ABS-PC. L’ajout de compatibilisants a été étudié afin de masquer l’effet de l’impureté. Il a ainsi été montré que l’amélioration de la résilience du mélange (ABS-PC/impureté) est intimement liée à la modification de la morphologie et à la nature de l’adhésion aux interfaces. Il a ensuite été constaté que l’optimisation des paramètres de mise en oeuvre engendre une modification de la morphologie. Cette modification peut entrainer une augmentation de la résistance au choc.Ces deux méthodes ont ensuite été appliquées à un mélange d’ABS-PC ignifugé issu des DEEE contenant une impureté. L’ajout de compatibilisant et de la modification des paramètres de mise en oeuvre améliore la résilience. En revanche, cela a un effet néfaste sur le comportement au feu de l’alliage ABS-PC ignifugé. / The aim of this PhD work was to propose a recycling process method of PC-ABS blend from real Waste Electrical and Electronic Equipment deposit (WEEE) deposits. This recycling process has to be able to overcome the problematic related to polymer recycling.The main constraints about recycling process are the presence of polymeric impurities after sorting step as well as mechanical reprocessing (extrusion and injection molded). Firstly, the effect of impurities on the mechanical properties (tensile and impact strength) and morphology (SEM, TEM) of PC-ABS blends have been studied. The presence of immiscible impurity deteriorates the mechanical properties of PC-ABS. The addition of an appropriate compatibilizer enhances the interface between PC-ABS and the impurity. The compatibilizer improves the impact strength and changes the morphology of this blend. Secondly, the optimization of injection molding parameters generates a change in morphology. This change leads to an increase of the impact strength.Both methods were applied to a flame retardant PC-ABS from WEEE with an impurity. The addition of a compatibilizer and the modification of injection molding parameters improve the impact strength. The presences of an impurity and a compatibilizer have a negative effect on the flame retardant properties of the PC-ABS blend

Polyethylene (PE) resins being non-polar in nature and having a high degree of crystallinity have limited miscibility and compatibility when blended with polar polymers. The miscibility and compatibility of these blends are generally worsened when they are prepared by direct injection moulding without a precompounding process. Such situations are commonly encountered in particular by polymer converters when blending colour and/or additive concentrates, commonly known as masterbatches. Typically, masterbatches are mixtures containing high loading of pigments and/or additives predispersed in a suitable solid vehicle (commonly known as carrier) such as a polyethylene resin. These masterbatches are usually used for the colouration of a wide range of polymers and the carrier used must therefore be compatible with these matrix (host) polymers. The preliminary stage of this study involved the investigation of the properties of blends based on high density polyethylene (HDPE) and a range of engineering thermoplastics (ABS, PC, PBT, PA6), prepared by injection moulding. Five different types of compatibilisers namely, ethylene-vinyl acetate (EVA) copolymer, ethylene-methyl acrylate (EMA) copolymer, ethylene-glycidyl methacrylate (E-GMA) copolymer, ethylene-methyl acrylateglycidyl methacrylate (E-MA-GMA) terpolymer and maleic anhydride grafted HDPE (HDPE-g-MAH) copolymer were evaluated with respect to their efficiencies in compatibilising HDPE with the four engineering polymers. The pre-compounded HDPE/compatibiliser binary blends at 2 different blend ratios (1:1 and 3:1) were added at 15 wt% concentration to each engineering thermoplastics and test samples were produced directly by injection moulding. Results of mechanical testing and characterisation of the blends showed that glycidyl methacrylate compatibilisers, E-MA-GMA, in particular have the most universal compatibilising effectiveness for a range of engineering thermoplastics including ABS, PC, PBT, and PA6. Blends compatibilised with E-MA-GMA compatibiliser had the best notched impact performance irrespective of matrix polymer type. The presence of an acrylic ester (methyl acrylate) comonomer in E-MA-GMA resulted in increased polarity of the ii compatibiliser leading to improved miscibility with the polar matrix polymers demonstrated by fine blend morphologies, melting point depression and reduction in crystallinity of the HDPE dispersed phase. The second stage of this study involved the reactive modification of HDPE using a low molecular weight di-functional solid diglycidyl ether of bisphenol A (DGEBA) type epoxy resin compatibilised with HDPE-g-MAH in an attempt to improve its compatibility with ABS, PBT and PA6. The maleic anhydride moieties in HDPE-g-MAH served as reactive sites for anchoring the epoxy moieties while the HDPE backbone was miscible with the HDPE resin. An excessive amount of reactive groups resulted in the formation of crosslinked gels while the addition of EVA co-compatibiliser helped in the reduction of gel content and further improved the dispersion of the epoxy. The effectiveness of epoxy grafted HDPE (with and without EVA co-compatibiliser) in compatibilising ABS/HDPE, PBT/HDPE, and PA6/HDPE was investigated by injection moulding of 5 wt% functionalised HDPE with these matrix polymers into test bars for mechanical testing, and characterisation by differential scanning calorimtery (DSC) and optical microscopy. The reactively functionalised HDPE blends, improved the mechanical properties of ABS and PA6 blends especially with EVA as co-compatibiliser. However, the mechanical properties of PBT blends were unmodified by the functionalised HDPE which was believed to be due to end-capping of the PBT chain-ends by ungrafted epoxy resins.

Dan Beaty (1937-2002) was a prolific composer, pianist, researcher, educator, and writer. His large compositional output included chamber works, choral works, songs, orchestral pieces, electronic music, and keyboard works. Beaty was well versed in traditional Western music as well as the more avant-garde and perplexing idioms of the twentieth century. Beaty's compositions reflect the many fascinating, if not always popular, musical trends of his time. His music encompasses styles from serial to jazz, shows compositional influences from Arnold Schoenberg to Indonesian music, and demonstrates thought-provoking and highly intellectual craftsmanship. This document explores several of Beaty's songs through a discussion of the composer's life and compositional process. Songs included in this document are Three Weeks Songs, October, November, A Sappho Lyric, Love Song, That Night When Joy Began, and War Lyrics. This document was written to accompany the author's DMA Lecture-Recital at the University of North Texas. Unfortunately, Beaty's vocal music was never published and is mostly unknown. One goal of the project was to initiate interest in Beaty's songs. Through this document, Lecture-Recital, and additional performances, considerable strides have been made to bring Beaty's songs to new audiences throughout the United States. In addition, the author has received permission from the Beaty family to publish Dan Beaty's songs.

Ce travail concerne l'étude des modifications de nanocharges lamellaires synthétiques (α-ZrP) et de leur influence sur les propriétés mécaniques et barrière aux gaz de nanocomposites à matrice élastomère (SBR). Cette étude s'inscrit dans le cadre de l'amélioration de l'étanchéité des pneumatiques. L'une des originalités de ce travail a résidé dans l'introduction des nanocharges hydrophiles par le biais d'une dispersion aqueuse (slurry), dans la matrice SBR hydrophobe. La première phase de ce travail a consisté à entreprendre plusieurs types de modification des nanocharges afin d'étudier les mécanismes d'intercalation et/ou d'exfoliation des ces dernières dans le slurry. Ces différentes familles de charges modifiées ont été utilisées pour réaliser des nanocomposites selon différentes voies de mise en oeuvre : principalement solvant et latex. Nous avons ensuite étudié l'influence, (i) de la nature des intercalants, (ii) des distances interfoliaires initiales des nanocharges et (iii) des procédés de mise en oeuvre des nanocomposites, sur la morphologie et les propriétés finales des matériaux. Cette étude a montré la synergie de ces trois paramètres et mis en évidence l'importance du contrôle des interactions charges modifiées/matrice sur les propriétés de transport de gaz. Parmi l'ensemble des matériaux synthétisés, nous avons pu mettre en avant une formulation, permettant d'atteindre des propriétés mécaniques et barrière intéressantes. Cette formulation, en voie latex, est basée sur l'utilisation de la charge modifiée aminosilane et de l'agent de couplage Si69 / This work concerns the study of the modification of synthetic lamellar nanofillers (α-ZrP) and their influence on mechanical and gas barrier properties of elastomeric nanocomposites (SBR). This study is part of improving the tire tightness. One of the originalities of this work is the introduction of hydrophilic nanofillers through an aqueous dispersion (slurry) in the hydrophobic SBR matrix. The first step of this work was to undertake several types of nanofiller modifications state in order to study their intercalation/exfoliation mechanisms in a slurry. These different families of modified fillers were then used to make nanocomposites with different ways of implementations: mainly solvent and latex ones. The influence of, (i) the nature of the intercalating agent, (ii) the initial nanofiller interlayer distance and (iii) the nanocomposite implementation processes, on the morphology and final properties of materials were studied. The synergy of these three parameters was demonstrated and the importance of controlling the modified filler/matrix interactions on the gas transport and mechanical properties was also proved. Among all the synthesized materials, a formulation was put forward which allowed to achieve interesting mechanical and barrier properties. This formulation, processed by the latex route, is based on the use of aminosilane modified nanofillers and the Si69 coupling agent