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1
Duigou, Stéphane. "Caractérisation génétique et fonctionnelle de PolY1 et PolY2 chez B. Subtilis." Paris 6, 2004. http://www.theses.fr/2004PA066451.
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Neumaier, Sebastian, and Axel Polleres. "Geo-Semantic Labelling of Open Data. SEMANTiCS 2018-14th International Conference on Semantic Systems." Elsevier, 2018. http://epub.wu.ac.at/6452/1/neum%2Dpoll%2D2018SEMANTiCS.pdf.
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In the past years Open Data has become a trend among governments to increase transparency and public engagement by opening up
national, regional, and local datasets. However, while many of these datasets come in semi-structured file formats, they use di
ff
erent
schemata and lack geo-references or semantically meaningful links and descriptions of the corresponding geo-entities. We aim to
address this by detecting and establishing links to geo-entities in the datasets found in Open Data catalogs and their respective
metadata descriptions and link them to a knowledge graph of geo-entities. This knowledge graph does not yet readily exist, though,
or at least, not a single one: so, we integrate and interlink several datasets to construct our (extensible) base geo-entities knowledge
graph: (i) the openly available geospatial data repository GeoNames, (ii) the map service OpenStreetMap, (iii) country-specific sets
of postal codes, and (iv) the European Union's classification system NUTS. As a second step, this base knowledge graph is used
to add semantic labels to the open datasets, i.e., we heuristically disambiguate the geo-entities in CSV columns using the context
of the labels and the hierarchical graph structure of our base knowledge graph. Finally, in order to interact with and retrieve the
content, we index the datasets and provide a demo user interface. Currently we indexed resources from four Open Data portals, and
allow search queries for geo-entities as well as full-text matches at
http://data.wu.ac.at/odgraph/
.
3
Bloomer, Melissa. "Polly." Digital Commons at Loyola Marymount University and Loyola Law School, 2019. https://digitalcommons.lmu.edu/etd/787.
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Le, Van-Ly. "Polly two - a public key cryptosystem based on Polly cracker." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967582806.
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Trafton, Robin C. Connelly Frances S. "Polly Apfelbaum redefined /." Diss., UMK access, 2007.
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Thesis (M.A.)--Dept. of Art and Art History. University of Missouri--Kansas City, 2007."A thesis in art history." Typescript. Advisor: Frances Connelly. Vita. Title from "catalog record" of the print edition Description based on contents viewed Dec. 18, 2007. Includes bibliographical references (leaves 89-95). Online version of the print edition.
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Sunde, Jadranka. "Polya-type inequalities /." Title page, contents and introduction only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phs9578.pdf.
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Toh, Chee-Seng. "Alcohol dehydrogenase biosensor based on poly(aniline)-poly(vinylsulfonate) modified electrode and : enhancement effect of CA'2'+ions on the electrocatalytic oxidation of NADH at poly(aniline)-poly(vinylsulfonate) and poly(aniline)-poly(styrenesulfonate)." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393941.
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Flugel, Michael. "Synthese und Charakterisierung von Poly(epoxynorbornan) und Poly(epoxycyclohexan)." [S.l. : s.n.], 1999. http://archiv.ub.uni-marburg.de/diss/z1999/0199.
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Jacobs, Jaco. "Poly(N-vinylpyrrolidone) - Poly(γ-benzyl-L-glutamate) conjugates." Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20369.
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Thesis (MSc)--Stellenbosch University, 2012.ENGLISH ABSTRACT: The combination of natural and synthetic polymers allow for the synthesis of advanced hybrid copolymers. These hybrid copolymers have applications in biomedical areas, one such area being in drug delivery systems (DDS). In this study, a modular approach was used to prepare amphiphilic block copolymers with the ability to self-assemble into three dimensional structures. Reversible addition-fragmentation chain transfer (RAFT) was the synthetic tool used to mediate the polymerization of N-vinylpyrrolidone. RAFT is a versatile method to prepare polymers with control over molecular weight and dispersity. A xanthate chain transfer agent (CTA) was used to obtain the hydrophilic poly(N-vinylpyrrolidone) (PVP) block. An aldehyde functionality could be introduced due to the lability of the xanthate moiety, the procedure of which was effectively optimized to produce quantitative conversion. A dixanthate CTA was synthesized to produce a PVP chain which after the modification reaction, resulted in a α,ω-telechelic polymer. A polypeptide was synthesized via the ring-opening polymerization of Ncarboxyanhydrides (ROP NCA). The living and controllable ROP of NCAs is a method which results in polypeptides, but without a well-defined amino acid order. Poly(γ- benzyl-L-glutamate) (PBLG) was synthesized with a narrow dispersity (Đ = 1.10 – 1.15) using conditions that promote the retention of a terminal primary amine. A protected cysteine functionality was introduced via the terminal amine PBLG chain-end, using peptide synthesis techniques. This resulted in the conjugation of the aldehyde functional PVP and the cysteine terminal PBLG using a covalent, non-reducible thiazolidine linkage. The deprotection of the cysteine, more specifically the deprotection of the thiol was a non-trivial procedure. The thiol protecting acetamidomethyl (Acm) group could not be cleaved using traditional methods, but instead a modified procedure was developed to effectively remove the Acm group while inhibiting hydrolysis of the benzyl esters. It was determined that the conjugation reaction could effectively proceed in N,Ndimethylformamide (DMF) at a slightly elevated temperature and so continued to prepare the amphiphilic hybrid block copolymers, PVP-b-PBLG. A structurally different PBLG chain, namely PBLG-b-Cys was conjugated to the ω-aldehyde PVP and the conjugation efficiency was compared to our PBLG-Cys block. In the case of PBLG-b- Cys the in situ deprotection and conjugation as well as a two-step deprotection and conjugation reaction with PVP resulted in very low conjugation efficiency. The cysteine end-functional PBLG resulted in near quantitative conjugation with PVP. The critical micelle concentration (CMC) for PVP90-b-PBLG54 was determined to be 6 μg/mL, using fluorescence spectroscopy. Particle sizes were determined with TEM and DLS and found to range from 25 nm to 120 nm depending on the polymer block lengths as well as hydrophobic/hydrophilic block length ratios. Furthermore, when the micelles were subjected to an increased acidic environment, the labile benzyl ester bonds were hydrolyzed. This was observed with TEM where the particle sizes increased 10-fold to form vesicular structures. Hydrolysis was further confirmed with ATR-FTIR and 1H-NMR spectroscopy. Cytotoxicity tests confirmed that the copolymer micelles had good cell compatibility at high concentrations such as 0.9 mg/mL. Investigation into drug loading using a pyrene probe confirmed the viability of using PVP-b-PBLG as a responsive DDS.
AFRIKAANSE OPSOMMING: Die kombinasie van natuurlike en sintetiese polimere maak dit moontlik vir die sintese van gevorderde hibried kopolimere. Hierdie kopolimere het aanwending in biomediese gebiede, een so 'n gebied is in medisinale vervoer sisteme (MVS). 'n Modulêre benadering is in hierdie studie gebruik om amfifiliese blok kopolimere te berei. Omkeerbare addisie-fragmentasie kettingoordrag (OAFO) is gebruik as die sintetiese tegniek vir die polimerisasie van N-vinielpirolidoon (NVP). OAFO is 'n veelsydige metode om polimere te berei met beheer oor molekulêre gewig en dispersiteit (Đ). 'n Xantaat kettingoordrag agent (KOA) is gebruik om die hidrofiliese poli(N-vinielpirolidoon) (PVP) blok te sintetiseer. ‘n Aldehied endgroep was deur die terminale xantaat funksionaliteit berei, ‘n proses wat geoptimiseer is tot kwantitatiewe omsetting. 'n Di-xantaat KOA is gesintetiseer om, na modifikasie, 'n α, ω-telecheliese polimeer te produseer. Die polipeptied was gesintetiseer deur middel van ’n ringopening polimerisasie van Nkarboksianhidriede (ROP NKA). Die lewende en beheerbare ROP van NKAe is 'n metode wat lei tot polipeptiede sonder ’n gedefinieerde aminosuur volgorde. Poli(γ- benzyl-L-glutamaat) met 'n lae dispersiteit (Đ = 1.10 – 1.15), is gesintetiseer deur gebruik te maak van kondisies wat die behoud van 'n terminale primêre amien bevorder. 'n Beskermde sistien-funksionaliteit is ingebou via die terminale amien met behulp van peptiedsintese tegnieke. Die tiol beskerming van die asetamidometiel (Asm) groep kon nie gekleef word deur gebruik te maak van tradisionele metodes nie, maar ‘n nuwe proses is ontwikkel om die Asm groep te kleef sowel as om die hidrolise van die bensiel esters te inhibeer. Die koppelings reaksie het effektief verloop in DMF by 'n effens verhoogde temperatuur en sodoende is die amfifiliese hibried blok-kopolimere, PVP-b-PBLG berei. Twee verskillende PBLG kettings is gekoppel aan die ω-aldehied PVP en die koppeling doeltreffendheid is vergelyk. Daar is bevind dat net die sistien end-funksionele PBLG tot kwantitatiewe konjugasie kon lei. Die kritiese misel konsentrasie is bepaal vir PVP90-b-PBLG54 as 6 μg/mL met behulp van fluoressensie spektroskopie. Die deeltjie-groottes is bepaal met TEM en DLS en wissel van 25 nm tot 120 nm, afhangende van die polimeer bloklengtes sowel as hidrofobiese / hidrofiliese blok lengte verhoudings. Die miselle is blootgestel aan 'n verhoogde suur omgewing, wat tot die hidrolise van die bensiel ester groepe gelei het. TEM het getoon dat die deeltjie-groottes met 10-voud vergroot het tot vesikulêre strukture. Hidrolise is verder bevestig met ATR-FTIR en 1H-KMR spektroskopie. Sitotoksiese toetse het bevestig dat die miselle geen of min toksisiteit toon teenoor eukariotiese selle nie, selfs teen 'n hoë konsentrasies soos 0.9 mg/ml. Die medisinale behoud vermoë is met behulp van pireen bevestig en dus ook die potensiaal van PVP-b-PBLG as ‘n moontlike MVS.
10
Hobson, Rachel Jane. "The structure of poly(vinyl chloride) and poly(acrylonitrile)." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307019.
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Richter-Egger, Dana L. "Spectroscopic investigations of poly(amidoamine) and poly(propyleneimine) dendrimers /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3025648.
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Preston, Christopher M. L. "Poly(dimethylsiloxane) : blends with poly(urethane) & radiation chemistry /." [St. Lucia, Qld.], 2000. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16169.pdf.
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Werry, Brian Scott. "Modifiable Poly(arylene ether)s and Hyperbranched Poly(esters)." Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1187277614.
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Marinetti, Loris. "The effect of poly(lactide)-poly(carbonate) based block copolymers on the morphology and crystallization of double crystalline poly(lactide)/poly(ε-caprolactone) blends." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11965/.
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Block copolymers of poly(lactide) and poly(carbonate) were synthetized in three different compositions and characterized by 1H-NMR and ATR analyses. The compatibilization effect of this copolymers on 80/20 (w/w%) PLA/PCL blend was evaluated. SEM micrographs show that all the blends exhibit the typical sea-island morphology characteristic of immiscible blends with PCL finely dispersed in droplets on a PLA matrix. Upon the addiction of the copolymers a reduction on PCL droplets size is observable. At the same time, a Tg depression of the PLA phase is detected when the copolymers are added in the blend. These results indicate that these copolymers are effective as compatibilizers. The copolymer that acts as the best compatibilizer is the one characterized by the same amount of PLA and PC as repeating units. As result, in the blend containing this copolymer PLA phase exhibits the highest spherulitic growth rate. An analyses on PLA phase crystallization behaviour from the glassy state within the blends was evaluated by DSC experiments. Isothermal cold crystallization of the PLA phase is enhanced up an order of magnitude upon the blending with PCL. Annealing experiments demonstrated that the crystallization of the PCL phase induces the formation of active nuclei in PLA when cooled above cooled below Tg. When the crystallization rate of PCL is retarded, a reduction on PLA nucleation is observed.
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Rodrigues, José Carlos. "Síntese e caracterização de macromoléculas do tipo Poli(Ácido carboxílico)-Poli(Eter-poliol) com propriedades termoplásticas e termorrígidas e avaliação de propriedades mecânicas cerâmicos à base de caulim." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-04112009-090435/.
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Este trabalho apresenta o estudo de um sistema polimérico bi-componente formado por Poli(Ácido carboxílico)-Poli(Eter-poliol), constituído primariamente de um polímero acrílico polimerizado pelo processo de polimerização em solução aquosa por mecanismo de radicais livres ao qual foi adicionado seqüencialmente, um Poli(Eter-poliol), ambos de baixo peso molecular médio. Tal sistema tem por finalidade atuar como dispersante-ligante em sistema cerâmico à base de caulim CADAM, uma vez que este sistema apresenta propriedades termoplásticas e termorrígidas a diferentes temperaturas. Foram sintetizados 03 protótipos de um sistema polimérico e o critério para escolha teve como base o pH do sistema em sentido generalizado, isto é, compreendendo as diversas fases de preparação dos polímeros e sua aplicação final. É do conhecimento comum que a reação de esterificação entre grupos COOHOH requer catálise ácida para ocorrer, o qual usualmente é realizada em pH abaixo de 4 e, neste ensaio, este pH ácido é devido à presença de ácido para-toluenosulfônico, que atua como catalisador de esterificação. Em tal intervalo de pH, em virtude do ponto isoelétrico do caulim ser comumentemente abaixo de 4, a estabilização da dispersão de caulim por repulsão eletrostática utilizando polímeros sintéticos é improvável de ocorrer, razão pela qual buscou-se mecanismos alternativos para obtenção de uma tal estabilização, entre os quais o mecanismo estérico surge como opção. O sistema polimérico do presente estudo apresenta-se na forma de uma solução aquosa sendo, de fato, uma mistura homogênea de um copolímero de ácido acrílico, N- metiloacrilamida e metacrilato de metoxipolietileno glicol e um poli(eter-poliol). O poli(eter-poliol) e N-metilolacrilamida presentes no sistema polimérico são principais fontes de grupo hidroxila para reação de poliesterificação e formação de ligações cruzadas à temperatura de 150 a 200 °C. No estado termoplástico o sistema polimérico produzido pela mistura poli(ácido carboxílico)-poli(eter-poliol) pode ser utilizado como dispersante de argilas com especial fóco sobre caulim como tratado neste trabalho. A propriedade dispersante pode ser atribuida à presença de grupos carboxílicos e metoxipolietilenoglicol aleatoriamente distribuídos ao longo da cadeia polimérica e, também, ao baixo peso molecular médio. A temperaturas entre 150 a 200 °C, o polímero é reticulado (crosslinked) por reação de poliesterificação, catalisada por ácido, entre grupos carboxila e grupos hidroxila, sendo as hidroxilas provenientes tanto de poliol como de N-metilolacrilamida (NMAM). Assim, do ponto de vista térmico comporta-se como termorrígido, sendo nesta condição insolúvel em água e adequado atuar como ligante na manufatura de materiais cerâmicos. Medidas de mobilidade eletroforética e viscosidade são aplicadas à caracterização de caulim e do sistema polimérico a fim de avaliar a potencialidade de aplicação como dispersante desta argila. Também, as transições dos estados termoplásticos para termorrigidos foram determinadas por análise termogravimétrica (TG) e análise dinâmico mecânica (DMA) nos polímeros isoladamente e depois com medidas de resistência mecânica do sistema caulim/polímero. O sistema apresentou comportamento dispersante em água e ligante após cura. Um sistema polimérico assim sintetizado foi propriamente curado por calor tornando- se, na forma termorrígida, um ligante para peças cerâmicas com propriedades mecânicas de alto desempenho, como resistência a flexão no estado cru (green strenght).This work presents the study of a polymeric bi-component system made from Poly(carboxylic acid)-Poly(ether-polyol) primarily constituted of an acrylic acid polymerized through the process of aqueous solution polymerization by free radical mechanism, to which a poly(ether-polyol) has been sequentially added, both of them of low average molecular weight. Such a system has the aim to act as dispersing-binding balance on CADAM kaolin targeting to evaluate the applicability potential or the preparation of ceramic bodies as this polymeric system presents thermoplastic and thermosetting properties at different temperatures. Were made the synthesis of 03 polymeric system prototypes which criteria for choice was based on pH of the system at whole sense, that is, regarding the several steps for polymers preparation and its final application. It is knowledge that esterification reaction between COOH-OH groups requires acid catalyst to occur, which usually is done at pH below 4 and, in this work this pH is due to p-toluene sulfonic acid that act as esterification catalyst. In this range of pH, due to the isoeletric point of kaolin to be below 4 the electrostatic stabilization of dispersion is unlikely to occur, from which reason was looked for an alternative mechanism to achieve the dispersion stabilization, among them the steric mechanism arises an option. The polymeric system of this study is the form of an aqueous solution, which actually is a homogeneous blend of a copolymer of acrylic acid, N-Methylolacrylamide Methoxypolyethyleneglycol Methacrylate (MPEGMA) and Poly(ether-polyol). The Poly(etherpolyol) and the N-Methylolacrylamide presents at the polymeric system are the main sources of hydroxyl groups to enhance the polyesterification reaction for further crosslinking at temperatures from 160 to 200 °C. At the thermoplastic state the polymeric system made by Poly(carboxilic acid)poly(ether-polyol) macromolecules may be used as clay dispersant focusing on kaolin for this work. The dispersant property may be attributed to the carboxylic and methoxypolyethyleneglycol group randomly distributed along the polymeric chain backbone and, also to the low average molecular weight. At temperatures between 150 to 200 °C, the polymer is crosslinked by polyesterification reaction catalized by acid between carboxyl groups and hydroxyl groups, in such way that hydroxyls groups comes both from the polyol base polymer and NMethylolacrylamide (NMAM) present at first polymer backbone. Thus, through a thermal standpoint it behaves as thermoset being that, under this condition, water insoluble and adequate to act as binder for manufacturing of ceramic materials. Electrophoretic mobility and viscosity measurements were applied for the characterization of kaolin and the polymeric system targeting to the evaluation its potential application as a dispersant for this clay. Also, the transitions from the thermoplastic to the thermoset state have been determined by thermo-gravimetric analysis (TG) and dynamicmechanical analysis (DMA) for the Poly(carboxylc acid)poly(ether-polyol) polymers alone and further by mechanical resistance measurements for a clay-polymer system. The system has presented both dispersant behavior on aqueous media and binder just afterward cure. A polymeric system thus synthesized was properly cured by heat turning and then, at the thermoset state, become suitable for act as a binder for ceramic bodies with high performance mechanical properties measured as flexural resistance at green strength.
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Yusuf, Said Abdi. "Miscibility study of poly(vinyl pyrrolidone)poly(vinyl butyral) blends." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60693.
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The miscibility of poly(vinyl pyrrolidone) PVP with copolymers of vinyl butyral and vinyl alcohol, containing 11% and 19% by weight of vinyl alcohol, has been investigated. To examine how the state of miscibility of these blends varies with the vinyl alcohol content of the copolymers, differential scanning calorimetry(DSC) and solid-state NMR methods were employed. PVP was found to form miscible blends with poly(vinyl butyral) PVB, containing 11wt% of vinyl alcohol, up to a weight ratio of 40/60(PVP/PVB11). At higher PVP loading, phase separated blends were obtained. In contrast, poly(vinyl butyral) containing 19wt% vinyl alcohol units was found to be miscible with PVP, over the entire composition range, with an estimated domain size of 2.5nm. Taken together, the results indicate the importance of the number of hydroxyl groups in achieving miscibility.
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Redford, K. "Block copolymers of poly(ethylene oxide) and poly(methyl methacrylate)." Thesis, Loughborough University, 1991. https://dspace.lboro.ac.uk/2134/14710.
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A series of five AB block copolymers of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) has been synthesised by the coupling of mono-functional homopolymers by an esterification reaction. In this series polymers all contain a PMMA component of number average molecular weight 908 gmo1·1, as measured by end group analysis, and the PEO components have number average molecular weights of 596, 689, 979, 2023 and 2884 gmol·1, as measured by proton nuclear magnetic resonance spectroscopy. Aqueous "solutions" of these copolymers have been prepared both by direct mixing and via methanol, a solvent for both blocks of the copolymer. Cloud points for these copolymers have been determined and range from 275K to 368K for the lowest and highest PEO blocks respectively. Small angle X-ray scattering (SAXS) of aqueous solutions has been interpreted in terms of a core - shell model and dimensions determined for both. Radii of gyration for the micellar cores have been shown to vary very little with variations in copolymer composition, concentration and temperature up to the cloud point. Fringe thicknesses show a dependence on PEO block length and relating measured fringe thicknesses to calculated chain conformations indicates that the the chain conformation is best described as an unperturbed chain. The measured fringe thickness is not altered by concentration or temperature up to the cloud point. Above the cloud point it is not possible to interpret the SAXS data in terms of a core shell micellar model. Significant differences in the SAXS data have been observed depending upon the mode of addition of copolymer to water. This can be interpreted as differences in micellar II structure With the exception of the lowest molecular weight copolymer all of the copolymers could be used as steric stabilisers for the aqueous emulsion polymerisation of methyl methacrylate. Polymerisations were only successful if the copolymer was introduced to the aqueous phase either via methanol or via the monomer. Direct addition of copolymer to water resulted in low polymerisation rates and unstable/flocculated products. Emulsions produced have been shown to be stable at pH levels where the electrophoretic mobility was zero, ie. the emulsions were sterically stabilised with no contribution from ionic I dipole interactions.
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Clarson, S. J. "Investigations of cyclic and linear poly(dimethysiloxanes) and poly(phenylemethylsiloxanes)." Thesis, University of York, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303862.
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Barouti, Ghislaine. "New poly(hydroxyalkanoate)-based copolymers : from synthesis to tunable self-assembled systems." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S064/document.
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Les copolymères à blocs amphiphiles s’auto-assemblent en solution aqueuse grâce à l’association de leurs segments hydrophobes. Les nanoparticules formées à partir de copolymères biocompatibles et biodégradables tels que les poly(hydroxyalkanoates) (PHAs) sont particulièrement attractives pour la conception de systèmes à libération prolongée de principes actifs. La relation entre la composition/structure chimique du copolymère, ses propriétés d’auto-assemblage et ses effets sur les cellules in-vitro doit être étudiée. Des copolymères à blocs poly(acide malique)-b-poly(3-hydroxybutyrate) (PMLA-b-PHB), PMLA-b-PHB-b-PMLA et poly(triméthylène carbonate)-b-poly(acide-malique) (PTMC-b-PMLA) ont été synthétisés par polymérisation par ouverture cycle (ROP) des monomères correspondants, suivie d’une hydrogénolyse. Une gamme de copolymères bien définis, caractérisés par spectroscopie RMN 1H, 13C{1H}, HSQC, HMBC, et DOSY, par analyses SEC, DSC, TGA, et mesure des angles de contact, présentant des balances hydrophile/hydrophobe modulables, a été obtenue grâce au control précis de la fraction hydrophile f (11-82%). Des auto-assemblages modulables ont été formés par nanoprécipitation des copolymères en l’absence d’agent tensio-actif. De larges agrégats ainsi que des micelles cœur-couronne (Rh = 16-335 nm) ont été obtenus en fonction du copolymère utilisé (dibloc vs. tribloc). Des micelles stables pendant 10 jours à 37 °C en solution aqueuse ont été obtenues pour les copolymères avec f allant jusqu’à 50%. Les copolymères PMLA-b-PHB et PTMC-b-PMLA n’ont pas révélé de toxicité aigüe in-vitro. De plus, l’utilisation du PHB a avantageusement permis de diminuer la captation des nano-objets par les macrophages et d’augmenter la captation par les cellules hépatiquesAmphiphilic block copolymers are able to form self-assembled systems in aqueous solution by association of their hydrophobic segments. Nanoparticles formed from biodegradable and biocompatible polymers such as poly(hydroxyalkanoate) copolymers are particularly attractive for drug delivery applications. The relationship between the chemical structure/composition of the macromolecule, its self-assembly properties and its effect on cells in-vitro has to be studied.The synthesis of poly(-malic acid)-b-poly(3-hydroxybutyrate) (PMLA-b-PHB), PMLA-b-PHB-b-PMLA, and poly(trimethylene carbonate)-b-poly(-malic acid) (PTMC-b-PMLA) was established through the ring-opening polymerization (ROP) of the corresponding monomers followed by hydrogenolysis. A range of well-defined copolymers characterized by 1H, 13C{1H}, HSQC, HMBC, DOSY NMR spectroscopy, SEC, DSC, TGA, contact angle analyses, with tunable hydrophilic/hydrophobic balance were thus obtained through the precise control of the hydrophilic weight fraction f (11-82%). Tunable self-assembled systems were obtained by nanoprecipitation of the amphiphilic PHA-based copolymers without the use of a surfactant. Large aggregates and core-shell micelles (Rh = 16-335nm) were obtained depending on the polymer topology. PHB-based copolymers with f up to 50% formed highly stable micelles at 37 °C over a period of 10 days in aqueous solution. PMLA-b-PHB as well as PTMC-b-PMLA copolymers revealed no acute in-vitro cytotoxicity. The use of PHB as hydrophobic segment enabled to minimize the non-specific scavenging by macrophages cells while the cellular uptake by hepatocytes was favored
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Barjovanu, Raluca A. "Poly(ferrocenyldimethylsilane)-b-Poly(dimethylsiloxane) micelles, morphology control through composition variation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0029/MQ63246.pdf.
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Lucke, Andrea. "Interactions of poly(a-hydroxy [poly(alpha-hydroxy] acids) with peptides /." Aachen : Shaker, 2002. http://www.gbv.de/dms/bs/toc/34212448X.pdf.
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Backson, Sofie Cecilia Ellinor. "Transesterification in mixtures of poly(ethylene terephthalate) and poly(butylene terephthalate)." Thesis, Durham University, 1994. http://etheses.dur.ac.uk/5670/.
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The morphology of poly(ethylene terephthalate)/poly(butylene terephthalate) (PET/PBT) blends before to and after heat treatment have been studied using differential scanning calorimetry (DSC), wide and small angle x-ray scattering (WAXS and SAXS), nuclear magnetic resonance spectroscopy (NMR) and small angle neutron scattering (SANS). Blends with PET/PBT compositions of 100/0, 97/3, 90/10, 60/40, 50/50, 40/60, 25/75 and 0/100%w/w were prepared by precipitation from solutions of the two polymers at the required concentrations. Blends were heat treated to induce ester interchange reactions for a) 6 hours at 476K and b) 1/2 hour at 573K.NMR data showed that the samples iieat treated for 6 hours at 476K were block copolymers and the samples heat treated for 1/2 hour at 573K were random copolymers. DSC, WAXS and SAXS experiments established the morphology of the blends, block and random copolymers. SANS experiments were carried out to study the kinetics of transesterification of PET/PBT copolyesters. Deuterated PET has been synthesised. Data was compared for different molecular weights of deuterium-PET/hydrogenous-PBT blends prior to and after heat treatment to investigate changes in molecular weight of the deuterated chain length as a result of transesterification reactions. From these data it was possible to establish the activation energy of PBT and the results indicate that transesterification reactions take place randomly along the polymer backbone, i.e. by ester-ester interchange.
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Chokalingam, Kumar. "Poly (Allylamine Hydrochloride) and Poly (Acrylic Acid) Multilayers for Gas Separation." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1187019230.
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Morris, David Jonathan. "Electrical and spectral characterisation of inkjet printed poly (3,4-ethylenedioxythiopene):poly(4-styrenesulphonate)." Thesis, Bangor University, 2004. https://research.bangor.ac.uk/portal/en/theses/electrical-and-spectral-characterisation-of-inkjet-printed-poly-34ethylenedioxythiopene-poly-4styrenesulphonate(1d71e2fa-2b2e-4fbd-a279-84152275099e).html.
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This thesis describes a pioneering investigation in which time resolved scanning Kelvin probe microscopy (SKPM) and Raman spectroscopy were combined to identify processes occurring at the interface of inkjet printed poly(3,4- ethylenedioxythiophene): poly(4- styrenesulphonate) (PEDOT: PSS) and aluminium and indium tin oxide (ITO) electrodes. In order to undertake these measurements an experimental inkjet printing system was designed and constructed capable of robustly inkjetting polymer solutions with micron resolution suitable for inkjetting typical polymer device structures. The main findings of the SKPM work showed; (i) that there was good charge transfer between ITO and polymer as indicated by the lack of a significant potential drop at the interface, however this was not the case with the aluminium electrodes where large potential drops were seen at the interface and (ii) that ionic impurities in the polymer migrated under an applied electric field to the electrodes where they were not discharged, resulting in a collapse of the potential across the bulk of the polymer. These mechanisms were likely to be those responsible for the I oc t-" behaviour seen in potential step response measurements. This behaviour was confirmed by the Raman spectroscopy which showed changes in the spectra in the range 1200 to 1600cm-1 related to the structure of the conjugated polymer backbone and its doping levels. The observed charge transfer and ionic migration results have significant implications for polymer devices including the efficiency and degradation of PLEDs and FETs and the operating mechanism of polymer memory devices.
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Rayeroux, David. "Polymérisation radicalaire contrôlée par transfert d'iode en mode inverse (RITP) : Synthèse de copolymères amphiphiles." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2012. http://www.theses.fr/2012ENCM0025/document.
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Ce travail de thèse décrit la synthèse de copolymères diblocs amphiphiles par polymérisation radicalaire contrôlée par transfert d'iode en mode inverse (RITP). Dans un premier temps, des homopolymères à base de monomères activés (styrène, acrylate de méthyle, méthacrylate de méthyle), non activés (acétate de vinyle) et fonctionnels (chlorométhylstyrène, acrylate de tert-butyle), ont été synthétisés par RITP. Des aspects tels que le contrôle des masses molaires ainsi que la fonctionnalité en iode du bout de chaîne ont été examinés. Afin de démontrer la compatibilité de la RITP avec d'autres techniques de polymérisation contrôlée/vivante (non radicalaires), le copolymère amphiphile non-ionique poly(styrène)-b-poly(2-méthyl-2-oxazoline) (PS-b-P(MOx)) a été élaboré par la voie toute iode en procédé « one-pot » en combinant de manière consécutive la RITP du styrène avec la polymérisation cationique par ouverture de cycle (CROP) de la 2-méthyl-2-oxazoline. Par ailleurs, des copolymères cationiques poly(styrène)-b-poly(chlorométhylstyrène) quaternisé avec la triéthylamine (PS-b-PCMS+) et anioniques poly(styrène)-b-poly(acide acrylique) (PS-b-PAA-) ont été synthétisés par RITP du styrène suivie de l'ITP du bloc hydrophile. Tous ces copolymères amphiphiles ont été obtenus à partir de polystyrène iodé (PS-I) de faibles masses molaires, allant de 1000 à 3000 g.mol-1, jouant le rôle de macro-amorceurs (CROP) ou de macro-agents de transfert (ITP). L'étude de l'auto-organisation en phase aqueuse de ces copolymères amphiphiles a révélé la formation de micelles pour des concentrations supérieures à la concentration d'agrégation critique (CAC) dont la valeur a été déterminée par diffusion dynamique de la lumière (DDL) et spectroscopie de fluorescence. Enfin, des résultats très prometteurs ont été obtenus dans l'utilisation d'un copolymère cationique amphiphile PS-b-PCMS+ comme agents structurants de matériaux siliciques mésoporeux nanostructurés élaborés par procédé sol-gel en milieu basique. La synthèse de ces copolymères amphiphiles ainsi que leur caractérisation physico-chimique ont mis en exergue que la RITP permet de couvrir la synthèse de différentes catégories de copolymères amphiphiles, tout en étant une technique simple à mettre en œuvre, peu couteuse et robusteThis manuscript describes the synthesis of amphiphilic diblock copolymers by reverse iodine transfer polymerization (RITP). Firstly, homopolymers derived from activated (styrene, methyl acrylate, methyl methacrylate), non-activated (vinyl acetate) and functional monomers (chloromethylstyrene, tert-butyl acrylate) synthesized by RITP, were studied. Aspects including molecular weight control as well as iodine chain-end functionality were investigated. In order to highlight the compatibility of RITP with other living/controlled (non-radical) polymerization techniques, a poly(styrene)-b-poly(2-methyl-2-oxazoline) (PS-b-P(MOx)) non-ionic copolymer was conceived through an ‘all-iodine', ‘one-pot' process by combining successively RITP of styrene with cationic ring-opening polymerization (CROP) of 2-methyl-2-oxazoline. Besides, poly(styrene)-b-poly(chloromethylstyrene) quaternized with triethylamine (PS-b-PCMS+) cationic copolymers and poly(styrene)-b-poly(acrylic acid) (PS-b-PAA-) anionic copolymers were elaborated by RITP of styrene, followed by ITP of the hydrophilic moiety. All these amphiphilic copolymers were obtained from iodine-bearing chain-end poly(styrene) (PS-I) of low molecular weights, in the range of values of 1000 to 3000 g.mol-1, playing the role of macro-initiators (CROP) or macro-transfer agents (ITP). Studies of the self-assembly of these amphiphilic copolymers in aqueous phases revealed the formation of micelles for concentrations superior to the critical aggregation concentration (CAC). The latter value was determined by dynamic light scattering (DLS) and fluorescence spectroscopy. Moreover, highly-promising results were obtained in the use of PS-b-PCMS+ cationic copolymers as structuring agents meant for the elaboration of nanostructured, mesoporous silica-based materials through the sol-gel process in basic medium. Both the synthesis of the amphiphilic copolymers and their physico-chemical characterizations have evidenced that RITP fosters the synthesis of different categories of amphiphilic copolymers, while being a simple, cheap and robust technique
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Waddon, Alan J. "The crystallisation and morphology of poly(ether-ether-ketone) (PEEK), poly(ether-ketone) (PEK) and poly(phenylene-sulphide) (PPS)." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328229.
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Oghide, Godwin O. "Miscibility studies of poly (methyl acrylate) poly (vinyl acetate) and poly (vinyl acetate)/ poly (vinylidene fluoride) blends using differential scanning calorimetry and fourier transform infra red spectroscopy." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 1985. http://digitalcommons.auctr.edu/dissertations/3294.
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The miscibility of poly (methyl acrylate)/poly (vinyl acetate) (PMA/PVAc) and poly (vinyl acetate)/poly(vinylidene fluoride) (PVAc/PVF2) blends has been studied. Films of compositions 100/0, 80/20, 60/40, 50/50, 40/60, 20/80, and 0/100 (w/w) were cast for each system. Films of PMA/PVAc were found transparent and those of the PVAc/PVf2 were slightly opaque. While all the compositions of the PMA/PVAc exhibit single sharp Tgs, as measured with the differential scanning calorimeter, almost all of those of the PVAc/PVF2 exhibit s1 ng1 e broad TgS. By the single Tg criterion, the PVA/PVAc and PVAc/PVF2 systems are miscible in all proportions. Fourier transform infra-red spectroscopy spectra indicate molecular interaction complex involvement in the two systems. Evidence for such interaction was found to be significant in the 80% PMA/20% PVAc and 20% PVAc/80% PVF2 compositions.
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Lagoutte, Sébastien. "Nanocomposites polythiophènes/nanotubes de carbone alignés : élaboration, caractérisations et applications aux supercondensateurs en milieu liquide ionique." Thesis, Cergy-Pontoise, 2010. http://www.theses.fr/2010CERG0459.
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Le présent travail a porté sur l’élaboration d’électrodes à base de polymère conducteur et d’un tapis de nanotubes de carbone alignés pour les applications de supercondensateur.Dans la première partie de ce travail, nous avons porté notre attention sur le choix de nos matériaux et nous avons pu déterminer leur comportement électrochimique en milieu liquide ionique. Les deux polymères choisis : le poly(3-méthylthiophène) et le poly(3,4-diméthylthiophène) possèdent des propriétés très différentes en terme de capacitance, de potentiel d’oxydation, de résistance ou de cyclabilité. Afin d’allier ces propriétés entre elles, nous avons réalisé la synthèse de copolymères obtenus par voie électrochimique en milieu liquide ionique aprotique. Cette électro-co-polymérisation nous a permis d’obtenir une large gamme de matériaux aux propriétés variables selon la composition du polymère.Dans la deuxième partie de ce travail, nous avons optimisé la synthèse électrochimique d’un nanocomposite poly(3-méthylthiophène)/nanotubes de carbone alignés en milieu liquide ionique. Les matériaux obtenus offrent la propriété d’être « auto-supportés » et permettent ainsi de s’affranchir de collecteur de courant. La nanostructuration grâce aux nanotubes et l’absence de collecteur de courant nous ont permis d’améliorer d’un facteur 3 la capacitance spécifique de nos électrodes. Une optimisation des conditions d’élaboration des nanocomposites permettent d’atteindre une capacitance de 180F.g-1 dans EMITFSI à 30°CThe present work concerned the elaboration of electrodes containing electronic conducting polymer and a carpet of aligned carbon nanotubes for supercapacitor applications. In the first part of this work, we put our attention on the choice of our materials and we were able to determine their electrochemical behavior in ionic liquid. Both chosen polymers : poly(3-méthylthiopène) and poly(3.4-diméthylthiophène) possess very diffrent properties in term of capacitance, oxidation potential, resistance or cyclability. In the second part of this work, we optimized the electrochemical synthesis of a nanocomposite poly(3-méthyltiophène)/aligned carbon nanotubes in ionic liquid. The obtained materials offer the property to be "self-supported" and allow using themselves without current collector. And optimization of the conditions of nanocomposites elaboration allows reaching a capacitance of 180 F.g-1 in EMITFSI in 30°C
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Stubbs, Ian. "Poly(styrene)-b-Poly(dimethylsiloxane)-b- Poly(styrene)/Single Walled Carbon Nanotube Nanocomposites. Synthesis of Triblock Copolymer and Nanocomposite Preparation." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2016. http://digitalcommons.auctr.edu/cauetds/49.
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Molecular weights of 2,000, 6,000 and 10,000 of silane functionalized atactic polystyrene (aPS) and α,ω-divinyl functionalized polydimethylsiloxane (PDMS) were prepared via living anionic polymerization and bulk anionic ring opening polymerization respectively. Functionalization of the homopolymers was confirmed by FT-IR and 1H-NMR spectroscopy and their molecular weights were determined via 1H-NMR end group analysis. A hydrosilylation reaction between the functionalized homopolymers of different molecular weights produced nine polystyrene-block-polydimethylsiloxane-block-polystyrene (aPS-b-PDMS-b-aPS) triblock copolymers. Field emission scanning electron microscopy observations revealed the copolymers self-assemble into supramolecular structures. Dynamic Light Scattering measurements show only small increase in the order of nanometers of its hydrodynamic radius as the individual molecular weights of the homopolymers were increased.
Nanocomposites of the copolymers were prepared by incorporating 1% of oxidized single walled carbon nanotubes (SWNTs) within the aPS-PDMS-aPS matrices via coagulation precipitation. Differential scanning calorimetry (DSC) thermal analysis shows the SWNT interacting with both aPS and PDMS constituting blocks. SWNTs interaction with aPS block either increases the polymer glass transition temperature (Tg) by restricting its segmental motion or decreases the Tg by a plasticization effect. Within the PDMS block the SWNTs act as nucleating sites accelerating the crystallization rate of the polymer. This is evident by the appearance of single and double melting endotherms in the DSC thermograms.
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Voigt, Ina. "Synthese und Oberflächencharakterisierung von Poly(vinylamin)-co-Poly(vinylformamid)-Kieselgel-Hybrid-Materialien." Doctoral thesis, Universitätsbibliothek Chemnitz, 2001. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200101082.
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In der vorliegenden Arbeit wird der Einfluß der Ladungsdichte des Polyelektrolyts sowie der Molmasse und der Ionenkonzentration der Lösung bei der Adsorption von Poly(vinylformamid) und Poly(vinylamin) an Kieselgel 60 und an Titandioxid unter-sucht. Die Charakterisierung der Polyelektrolyteigenschaften der modifizierten anorganischen Partikel erfolgt mit elektrokinetischen und potentiometrischen Mes-sungen. Es konnte gezeigt werden, daß Poly(vinylamine) mit geringen Ladungs-dichte ein Screening-enhanced-Verhalten zeigen, während bei hoher Ladungsdichte am Polyelektrolyt ein Screening-reduced-Verhalten vorliegt. Der Einfluß der Polymerfunktionalisierung auf die Oberflächenpolarität der Hybridpartikel wurde durch UV-VIS-spektroskopische Bestimmung der ET(30)-Werte nach Reichardt nachgewiesen.
Ausgehend von den Ergebnissen der Adsorption von Poly(vinylaminen) wird die Synthese von geladenen Netzwerken auf der Oberfläche der anorganischen Partikel vorgestellt. Die aus wässriger Lösung adsorbierte Polyelektrolytschicht wird dabei in einem zweiten Schritt in einem organischen Lösungsmittel mit bifunktionellen Vernetzermolekülen (4,4´-Diisocyanato)diphenylmethan, Fulleren C60] umgesetzt. Der erfolgreiche Ablauf der Reaktion konnte im Fall des Isocyanats mit Festkörper-NMR-, ESCA- und ATR-FTIR-Messungen nachgewiesen werden. Um die Umsetzung mit Fullerenen nachzuweisen, wurde die EPR-Spektroskopie eingesetzt.
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O'Neil, Conlin. "Novel applications of poly(ethylene glycol)-bl-poly(propylene sulfide) block copolymers /." [S.l.] : [s.n.], 2008. http://library.epfl.ch/theses/?nr=4200.
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D, Aguiar Donna-Leigh. "Surface modified cross-linked poly(vinyl alcohol)/poly(vinyl pivalate) suspension particles." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5475.
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Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: In papermaking, fillers and additives are used to enhance paper properties. In this study spherical modified poly(vinyl alcohol) (PVA) particles were prepared for use as fillers. In order to determine the mechanism of adhesion of additives to cellulose (paper) fibres, these particles were modified to have surface functionality, with cationic and anionic surface charges, similar to charged polyelectrolyte additives. Typically, retention aids used to improve the fibre–fibre and fibre–filler bonding are able to conform to the surface of the fibres and fillers. Oppositely charged components show strong affinity for each other, e.g. cationic polyelectrolyte groups adhere to anionic surface charges on the fibres. The spherical PVA particles were prepared by the saponification of spherical poly(vinyl pivalate) (PVPi) precursor particles. These PVPi particles, prepared via suspension polymerisation, were cross-linked with a divinyl ether comonomer. The vinyl pivalate (VPi) suspension polymerisation was successfully carried out and afforded relatively uniformly distributed PVPi particles, with diameters of 0.5–10 mm. The cross-linked PVPi particles were then saponified in tetrahydrofuran (THF) as swelling solvent, to afford PVA with various degrees of saponification (DS). The spherical shape was lost and fibrous material was obtained when uncross-linked PVPi particles were saponified. Cross-linking the spherical PVPi particles (PVA precursor) proved innovative, and essential in maintaining the spherical form during saponification to PVA/PVPi. By varying the saponification time periods, various DS were obtained, as characterised by solid state NMR spectroscopy. Surface modification of the PVA/PVPi particles was carried out with cationic and anionic groups via the Williamson ether synthesis. Ionic modification of these rigid spherical PVA/PVPi particles was carried out in order to study their adherence to cellulose fibres, compared to the adherence of similarly modified starches with cellulose fibres. Fluorescent labelling of the different modified particles was carried out using two complimentary coloured fluorescent markers. Fluorescence imaging and scanning electron microscopy (SEM) enabled the observation of particle– fibre and particle–particle interaction. Results indicated that the negative groups are sparse on the cellulose fibres, and therefore particles with low functionality but which are able change shape and conform and adhere to the surface of the cellulose fibres are required for effective adhesion. These modified spherical PVA/PVPi particles are unique as they mirror the chemistry of functionalised starch and cellulose particles, yet maintain their shape and have a fixed size, measurable by SEM and transmission electron microscopy (TEM). Field-flow fractionation was also used to characterise and measure these relatively large cross-linked and fixed diameter particles.
AFRIKAANSE OPSOMMING: In papierproduksie word vulstowwe en bymiddels gebruik om die eienskappe van papier te verbeter. In hierdie studie is sferiese poli(vinielalkohol) (PVA) partikels berei vir gebruik as vulstowwe. Om ten einde die meganisme van die bymiddelklewing aan die sellulose vesels (papier) te bepaal, is die oppervlakke van hierdie partikels gewysig met kationiese of anioniese groepe, om 'n oppervlak soortgelyk aan dié van funksionele poliëlektrolietbymiddels te verskaf. Die retensiemiddels wat gebruik word om die vesel–vesel en vesel–vulstof binding te verbeter is tipies in staat om te konformeer aan die oppervlak van die vesels en vulstowwe. Teenoorgesteldgelaaide komponente toon 'n sterk affiniteit vir mekaar, bv. kationiese poliëlektrolietgroepe is vasklewend aan die anioniesgelaaide oppervlakke van die vesel. Die sferiese PVA partikels is berei deur die verseping van sferiese poli(vinielpivalaat) (PVPi) partikels. Hierdie voorloper PVPi partikels, berei deur suspensiepolimerisasie, is gekruisbind met 'n divinieleter ko-monomeer. Die vinielpivalaat (VPi) suspensiepolimerisasie is suksesvol uitgevoer en relatief eenvormig verspreide sferiese PVPi partikels is berei, met deursnitte tussen 0.5–10 mm. Die gekruisbinde PVPi partikels is daarna gesaponifiseer in tetrahidrofuraan (THF) as oplosmiddel, om PVA met verskillende grade van verseping (DS) te berei. Die sferiese vorm raak verlore en veselagtige materiaal is verkry wanneer PVPi partikels met geen kruisbinding verseep is. Kruisbinding van die sferiese PVPi partikels (PVA voorloper) is voordelig en noodsaaklik om die sferiese vorm tydens die verseping tot PVA/PVPi te behou. Deur die tydsduur van verseping te verander, is verskeie grade van verseping verkry en bevestig deur vaste toestand KMR spektroskopie. Oppervlakwysiging van die PVA/PVPi partikels, om kationiese en anioniese groepe aan te heg, is uitgevoer via die Williamson etersintese. Ioniese wysiging van hierdie stram, sferiese PVA/PVPi partikels is uitgevoer om ten einde hul klewing met sellulose vesels te bestudeer en te vergelyk met die klewing van soortgelyk gewysigde stysels. Fluoressensie merking van die verskillende gewysigde partikels is uitgevoer met behulp van twee komplimentêre gekleurde fluoressensie merkers. Fluoressensie beeldvorming en SEM verskaf die waarneming van partikel–vesel en partikel–partikel interaksie. Die resultate dui daarop dat die negatiewe groepe van die sellulose vesels skaars is, en daarom is partikels met ‘n lae funksionaliteit, maar wat in staat is om van vorm te verander, aan te pas en te konformeer aan die oppervlak van die sellulose vesels, nodig vir effektiewe adhesie. Hierdie gewysigde sferiese PVA/PVPi partikels is uniek aangesien hulle die chemie van gewysigde stysel en sellulose partikels naboots, maar steeds hul vorm behou met 'n vaste grootte; meetbaar deur SEM en TEM. Veld-vloei-fraksionering is ook gebruik vir die karakterisering van hierdie relatief groot, stram, gekruisbinde partikels met bepaalde deursneë.
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McDonald, Lynn. "Synthesis and characterisation of novel poly(estersulphonate)s and poly(esteramide)s." Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/712.
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Fontaine, Adam. "Degradation of poly(ε-caprolactone)-based 'green' plasticizers for poly(vinyl chloride)." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117014.
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Poly(vinyl chloride) (PVC) requires the addition of large quantities of plasticizers in order to improve the flexibility and processability of the polymer. Since the plasticizer is not bound to the PVC polymer matrix, there is a tendency of the plasticizer to migrate into the surroundings. The most commonly used PVC plasticizer, di-2-ethylhexyl phthalate (DEHP), has become a ubiquitous environmental contaminant. As with other plasticizers, it may either accumulate or lead to the formation of metabolites, which resist further degradation and can themselves be toxic. Accordingly, there is incentive for the development of a 'green' plasticizer as a replacement to DEHP in order to minimize the environmental impact of PVC production and use. In this study, a method was developed to quantify the degradation of plasticizers used in PVC formulation or proposed as alternatives. The method is based on derivatization in order to lower the boiling points of the compounds and allow for analysis by gas chromatography (GC). Using this developed method, the biodegradation of two different families of potential 'green' plasticizers was considered. The biodegradation was assessed using Rhodococcus rhodochrous and evaluated based on the rate and completeness as well as the toxicity and stability of any observed metabolites. It was found that the poly([ε]-caprolactone)-based plasticizers containing octanoate-terminal groups degraded much more rapidly and completely than the benzoate-terminated ones. Furthermore, no metabolites were observed during the degradation of octanoate-terminated plasticizers while the benzoate-terminated plasticizers gave rise to metabolites which contributed substantial toxicity to the culture media. Under ideal conditions, these metabolites were shown to be biodegraded themselves. The methodology and data presented in this thesis can be used as a tool in selecting a 'green' plasticizer based on the degradation criteria, and aid in the selection of alternative plasticizers to DEHP.Le polychlorure de vinyle (PVC) requiert l'ajout important de plastifiant afin d'obtenir un polymère flexible et plus facile à mettre en forme. Comme ces plastifiants ne sont pas chimiquement liés à la matrice, ils ont toutefois tendance à migrer dans le milieu environnant. Le phtalate de diéthylhéxyle (DEHP) est le plastifiant le plus couramment utilisé et est maintenant un contaminant omniprésent. Tout comme d'autres plastifiants, il peut s'accumuler dans l'environnement ou se biodégrader et former des métabolites qui peuvent résister à la biodégradation et être potentiellement toxiques. Cette situation inquiétante a susciter l'intérêt envers le développement de plastifiants verts offrant une alternative au DEHP et permettant de minimiser l'impact environnemental de la production et de l'utilisation du PVC.Dans le cadre de l'étude présentée dans cette thèse, une méthodologie a été développée afin de permettre la quantification et le suivi de la biodégradation de plastifiants utilisé pour le PVC ou proposés comme alternatives. Cette méthode basée sur le dérivatisation permet la diminution du point d'ébullition des composés et l'analyse par chromatographie en phase gazeuse (GC). Cette méthode a été utilisée ici afin d'étudier la biodégradation de deux familles de composés proposés comme plastifiants verts. La biodégradation a été étudiée à l'aide de la bactérie Rhodococcus rhodochrous et évaluée en fonction de la cinétique et l'étendue de la dégradation ainsi que selon la formation de métabolites et la toxicité résiduelle. Les résultats ont démontré que les plastifiants à base de poly([ε]-caprolactone ayant des groupes terminaux octanoïque se biodégradent plus rapidement et que ceux ayant des groupes terminaux benzoïque. De plus, aucun métabolite n'a été détecté lors de la dégradation des plastifiants octanoïque alors que les plastifiants benzoïques ont formés des métabolites et engendré une toxicité résiduelle du milieu de culture. Dans des conditions idéales de biodégradation, les métabolites se sont dégradés. La méthodologie développée et les résultats présentés dans cette thèse seront utiles à la sélection de plastifiants verts offrant une alternative au DEHP.
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Ciemniecki, Scott Lawrence. "The blending of bydroxypropyl lignin with poly(methylmethacrylate) and poly(vinyl alcohol)." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/104310.
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Nakatsuji, Masayuki. "Dilute Solution Properties of Poly( n-hexyl isocyanate)and Poly(diisopropyl fumarate)." Kyoto University, 2019. http://hdl.handle.net/2433/242545.
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Reeves, Benjamin D. "Processable disubstituted poly(propylenedioxythiophenes)." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012924.
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Hsu, Chen-Ming. "Electrospinning of Poly(£`-Caprolactone)." Digital WPI, 2003. https://digitalcommons.wpi.edu/etd-theses/485.
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The objectives of the present work are to produce porous polymeric scaffolds with Poly (ƒÕ-Caprolactone), PCL, by electrospinning. The structure in the electrospun polymer has been characterized by scanning electron microscopy. The effects of process variables such as voltage, solution concentration and deposition distance on the structure have been studied. The physical phenomena associated with the electrospinning process have been highlighted through high speed digital photography. The feasibility of using additives to the solution to control the structure of the porous construct has been examined. The data indicate that a range of structural morphologies can be produced in the electrospun polymer. Solid and hollow sub-micron beads can be produced by electrospraying of dilute solutions. Beyond a critical solution concentration of about 4 wt% PCL, elongational flow stabilizes the fibrous structure and a web of interconnected sub-micron fibers may be obtained. The average fiber diameter increases with concentration. A combination of elongated beads and fibers, known as the bead-on-string morphology is also observed under many conditions. The fibrous structure is stabilized at high voltages. The fiber diameter in the electrospun polymer typically exhibits a bimodal distribution. The addition of DMF (N,N-dimethylformamide) to the solution increases the deposition rate significantly and leads to extensive splaying, thereby reducing the fiber diameter to about 150 nm. DSC data indicate that electrospinning may lower the degree of crystallinity in the polymer. The wide of range of structural characteristics that may be obtained in the electrospun polymer make it suitable for many biomedical applications including medical textiles, drug delivery, membrane separation, tissue engineering and organ regeneration.
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Ji, Jing. "Poly(vinylidene fluoride) membranes." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/43532.
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Poly(vinylidene fluoride) (PVDF) membranes have been intensively investigated and commercialised with broad applications in water purification and wastewater treatment for decades due to its outstanding properties. Currently, PVDF membranes are mainly produced by the phase inversion technique, which is predominant in both laboratory research and industrial manufacturing. Various modification methods based on the phase inversion technique have also been developed to improve the membrane performances, but these improvements are incremental and there have been no important breakthroughs during the past decade. This thesis first explores the preparation of reinforced PVDF flat sheet membranes by blending nanoclay followed by the phase inversion process. Although the membranes showed improved water permeation flux and enhanced abrasion resistance, further improvements are limited by the phase inversion technique itself. Consequently, a new concept of membrane manufacturing procedure has been proposed by combining unidirectional crystallisation of green solvent and polymer diffusion. The new method uses crystallites of a solvent dimethyl sulfoxide with controlled sizes as pore templates to create enormous nanosized flow passages. It follows a completely different pore formation mechanism and therefore overcomes the drawbacks of the phase inversion technique. The resultant PVDF membranes have an asymmetric structure composed of a highly porous separation layer and gradually opened micro-channels. Due to the unique structure, the prepared membranes showed excellent permeation performances and mechanical properties overwhelming commercial PVDF membranes prepared by the phase inversion technique. The filtration performance of the PVDF membranes can be further improved by modification of the membrane material, for example, by blending polyethylene glycol in the dope solution. The obtained membrane with pore size of 36 nm showed extraordinary high flux of 1711 L/m2h and could withstand 35 bar in the test. Moreover, the new manufacturing process is of much fewer influencing factors compared to the phase inversion approach and thus highly reliable and repeatable. In principle, it is also applicable to other common polymeric membrane materials such as polyethersulfone and cellulose acetate.
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Petruš, Josef. "Funkcionalizace poly(mléčné kyseliny)." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-234572.
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Teoretická část předložené dizertační práce popisuje princip radikálového roubování a faktory ovlivňující reakční průběh. Radikálové roubování poly(mléčné kyseliny) (PLA) reaktivní modifikací je vhodnou technikou přípravy biodegradabilních polymerních materiálů s rozličnými vlastnostmi. Současný stav problematiky modifikace poly(mléčné kyseliny) radikálovým roubováním v tavenině je obsahem literární rešerše včetně možných aplikací. Experimentální část se zabývá modifikací PLA anhydridem kyseliny itakonové (IAH) radikálovým roubováním v tavenině. Reakce byla iniciována 2,5-bis(tert-butylperoxy)-2,5-dimethylhexanem (L101). V první části je průběh radikálového roubování pozorován “in situ” pomocí diferenciální kompenzační kalorimetrie (DSC) a termogravimetrické analýzy (TGA). Exotermní pík na DSC záznamu odpovídá průběhu radikálové reakce, na jehož základě lze definovat aktivační energii reakce. Průběh TGA křivky “in situ” radikálové reakce umožňil detekovat vedlejší produkty vznikající v průběhu radikálové modifikace. Ve druhé části byla PLA funkcionalizována reakcí v diskontinuálním laboratorním mixéru za reakčních podmínek navržených dle poločasu rozpadu zvoleného iniciátoru a zpracovatelských podmínek PLA. Reakční teplota 190 °C byla stanovena výpočtem z Arrheniovy rovnice pro reakční čas 6 min. Uvedené reakční parametry byly zvoleny s ohledem na kinetiku rozkladu L101 a potlačení degradace PLA. Infračervená spektroskopie (FTIR) potvrdila navázání IAH na PLA řetězec na základě výskytu –CH2 vibrací s absorpčními pásy při vlnočtu 2860 a 2920 cm-1. Vzrůstající intensita absorpčního pásu 1750 cm-1 potvrdila přítomnost minoritních C=O vibrací anhydridového kruhu překrytých dominantními C=O vibracemi PLA řetězce. Nukleární magnetická rezonance (1H-NMR) nepotvrdila roubování oligomerního IAH na PLA. Koncentrace reaktantů ve zvoleném rozsahu (0.5–10 hm % IAH, 0.1–2 hm % L101) byla použita pro posouzení jejího vlivu na obsah naroubovaného IAH a míru vedlejších reakcí, např. -štěpení, větvení a síťování. Při vysoké koncentraci IAH a L101 byla potvrzena homopolymerace IAH i přes její zanedbávání v tématicky podobných studiích. Tvrzení o IAH homopolymeraci bylo podpořena výsledky kolorimetrické analýzy, charakterizací vzorků připravených polymerací IAH za podmínek radikálového roubování a termickou stabilitou frakcí extrahovaných z PLA-g-IAH. Radikálovou modifikací PLA došlo ke zvýšení flexibility polymerních řetězců díky objemné struktuře IAH navázané na PLA řetězci, což se projevilo poklesem teploty skelného přechodu (Tg). Zvýšený obsah amorfní fáze, hydrofilní chování, rozvětvená struktura a štěpení řetězců má pozitivní vliv na zvýšenou biodegradabilitu PLA-g-IAH v porovnání s nemodifikovanou PLA. Neradikálová degradace, probíhající v průběhu zpracování PLA, byla prokázána změnou tokových vlastností taveniny. Tento nežádoucí jev byl potlačen přídavkem tzv. “prodlužovače řetězců” obsahujícího reaktivní epoxy skupiny. Reakce mezi epoxy skupinami a karboxylovými skupinami byla potvrzena pomocí FTIR a změnou reologických vlastností PLA-g-IAH.
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Barnes, Suzanne R. "Size Exclusion Chromatography of Poly(2-ethyl-2-oxazoline) Homopolymers and Poly(ethylene oxide)-b-Poly(2-ethyl-2-oxazoline) Copolymers." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/24907.
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Size exclusion chromatography is the method of choice for characterizing molecular weights and molecular weight distributions of polymers. An important advancement in SEC is multidetection SEC which includes multi-angle laser light scattering, viscometry, refractive index and UV spectroscopy to analyze block and graft copolymers as well as polymers with oligomeric molecular weights. Oligomeric molecular weights present special challenges since the light scattering and viscosity detectors are more sensitive to higher molecular weights and both detectors have low molecular weight threshold values.
The molecular weights and distributions of poly(2-ethyl-2-oxazoline) oligomers and block copolymers as well as poly(2-ethyl-2-oxazoline) were investigated by SEC using multiple detectors. Both a universal calibration method and light scattering were used to determine molecular weights and molecular weight distributions. The solvent was N-methylpyrrolidone that contained 0.05M LiBr used to minimize interactions among the polymers and solvent. SEC was used to establish that the diblock copolymers had heterogeneous compositional distributions. The low molecular weights of the diblock and homopolymer made it necessary to use the universal calibration method with combined refractive index and viscometry detectors to determine absolute molecular weights.Master of Science
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Hurcom, Jamie. "Probing the behaviour of poly(ethylene oxide) : poly(propylene oxide)-poly(ethylene oxide) surfactants in the formation of hydrophilic polyurethane foam." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/73463/.
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Polyurethane (PU) foams are widely used in the medical industry in the treatment of chronic wounds but the role of surfactants in the reaction process, which strongly influences foam structure and properties, is not well understood. In this research, a homologous series of non-ionic poly(ethylene oxide)-poly(propylene oxide)- poly(ethylene oxide) (Pluronic) block copolymer surfactants were studied, in order to elucidate the influence of surfactant structure on PU foam performance. The behaviour of aqueous surfactant stabilised foams was investigated using a combination of surface science techniques (foaming ability/stability, surface tension) and small-angle neutron scattering (SANS). SANS has been successfully implemented to probe the adsorbed Pluronic surfactant layer of dynamic foams in-situ in the neutron beam. We propose the air-water interface comprises a paracrystalline stack consisting of a minimum of 5 adsorbed surfactant layers, with thickness ranging from 80-200Å interspersed with somewhat thicker (200Å) films of water. Total adsorbed layer thickness correlates directly with aqueous foam stability. Correlations of aqueous behaviour to the cell structure and performance of PU foams manufactured on an industrial line were made in an attempt to determine the features of surfactant necessary to produce ‘ideal’ PU foam wound dressings. Analysis of foam cell size and fluid absorption properties demonstrated that greatest absorption was observed for small, fine cell size. This was typically produced by the smallest molecular weight,most hydrophobic surfactants of the series implying that the surface activity of the surfactant (i.e. its ability to reduce the surface tension of the system) is more important than its foaming behaviour. This study should provide a more rational approach when designing surfactant formulations for polyurethane foam systems.
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Botta, Davide. "Strategies for structural studies of poly(ADP-ribose) glycohydrolase: Towards the validation of a novel therapeutic target." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/145718.
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Poly(ADP-ribosyl)ation is a reversible post-translational modification of histones and nuclear proteins rapidly stimulated by DNA damage. Its homeostasis is a dynamic process regulated by the synthesizing enzymes poly(ADP-ribose) polymerases (PARPs) and the degrading enzyme poly(ADP-ribose) glycohydrolase (PARG). PARP-1, the first-discovered and major PARP, has been the focus of many studies aimed at clarifying the biological function of poly(ADP-ribose) (PAR). This abundant nuclear enzyme plays key roles in a variety of cellular processes, including the regulation of chromatin structure, transcription and genomic integrity. Its multifunctionality has made it an attractive and potential target for therapy, as evidenced by the numerous PARP-1 inhibitors currently undergoing clinical trials. The transient nature of PAR, explained by the close coordination between PARP-1 and PARG, has also highlighted the potential of targeting PARG for diseases of inappropriate cell death. A number of obstacles, however, have prevented PARG from being studied as extensively as PARP-1. The extreme sensitivity of PARG to proteases and its insolubility at high concentrations have limited structure-activity relationship analyses and structural studies of PARG, and the unavailability of high-throughput activity assays has stalled the discovery and development of specific and cell permeable PARG inhibitors, subsequently slowing down the validation of PARG as a therapeutic target. The work presented in this dissertation describes in detail strategies devised to overcome these difficulties. First, a novel colorimetric high-throughput assay for PARG was evaluated and its sensitivity and precision were compared to a widely-used radiolabelling assay. Second, several expression and purification systems were constructed in order to obtain high quantities of soluble human PARG protein adequate for in vitrostructural studies. The efficacy of these strategies was demonstrated in structure-activity analyses of PARG which led to the identification of a regulatory segment far removed linearly from the catalytic site of PARG. This region, necessary for catalytic activity, corresponds with a recently identified mitochondrial targeting sequence (MTS) and was thus named the ‘regulatory segment/MTS’ (REG/MTS). Finally, based on structural data obtained, secondary structure predictions were made to provide insight into the molecular composition of the different domains of PARG, whose structures still remain to be determined.
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Letavaj, Emil. "Bioresorbovatelné polyuretany s říditelnými mechanickými vlastnostmi." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-295722.
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Presented diploma thesis deals with preparation of bioresorbable polyurethanes (PUR) and their characterization. The theoretical part describes the feedstocks used for the PUR preparation and summarizes the knowledge about PUR used in medical applications. Experimental part presents characterization of bioresorbable PUR films prepared by reactive casting in one step without the use of organic solvents. The absence of solvents represents a great advantage due to their toxicity and subsequent removal from the resulting product. The synthesis of PUR was conducted under an inert atmosphere by polyaddition reaction of hydrophobic poly(e-caprolactone) (PCL) and hydrophilic poly(ethylene glycol) (PEG) with hexamethylene diisocyanate (HDI). Synthesis under an inert atmosphere was necessary due to a side reaction of isocyanate with atmospheric humidity, which causes the formation of porous films instead of continuous ones. Prepared PUR films were characterized for different PCL/PEG ratios and different isocyanate index (ratio of NCO/OH reacted groups). PUR (isocyanate index 1.05) with PCL content 90 wt. % and higher demonstrated tought behavior in mechanical tests. Increase of isocyanate index and decrease of PCL content under 90 wt. % caused fragile sample behavior. The reason of such behavior was the different ability of PCL to crystallize in the structure of the polyurethane network. Increasing the PEG content has improved the ability of PUR films to absorb water and enhanced the rate of hydrolytic degradation. By adjusting the PCL/PEG ratio and the amount of isocyanate, solvent free bioresorbable PUR with suitable mechanical (flexibility, toughness) and physical properties (swelling, degradation) can be obtained. Prepared PUR films could be used in biomedicine e.g. as vascular grafts.
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Bannemann, Beate. "Herstellung von Poly(methylmethacrylat) und Poly(n-butylacrylat) Polymerblends durch in-situ Mikroemulsionspolymerisation." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967697263.
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El-Anani, Anas. "Pervaporation dehydration of isopropanol/water using poly(hema)/poly acrylic acid composite membranes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0019/MQ58451.pdf.
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Lambert, James M. "Synthesis and basic characteristics of segmented poly(arylene ether sulfone)-poly(arylate) copolymers." Diss., This resource online, 1986. http://scholar.lib.vt.edu/theses/available/etd-07282008-135252/.
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Hallett, Andrew Jon. "The chemistry of poly(pyrazolyl)borate and poly(pyrazolyl)methane transition metal complexes." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251095.
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El-Aufy, Afaf Khamis Ko Frank K. "Nanofibers and nanocomposites of poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate) by electrospinning /." Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/282.
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Rippey, Julie M. "Spectroscopic investigations of acrylodan dye interactions with poly(amidoamine) and poly(propyleneimine) dendrimers." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/6107.
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Thesis (M.S.)--University of Missouri-Columbia, 2008.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed July 13, 2009). Includes bibliographical references.