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1
Higgs, Paul G. "Biological and synthetic polymer networks." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306415.
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Li, Weiyao. "Understanding UV Protection Mechanism of Natural and Synthetic Eumelanin." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1491930546268438.
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Fuller, Kristin M. "Bridging the Gap: Developing Synthetic Materials with Enzymatic Levels of Complexity and Function." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1595941048642725.
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Corradi, Roberto. "Conducting polymer-silica colloidal composites." Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263866.
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Minett, William T. "Cell adhesion on synthetic polymer substrates." Thesis, Aston University, 1986. http://publications.aston.ac.uk/14512/.
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Vokata, Tereza. "Synthetic Approaches to Flexible Fluorescent Conjugated Polymers." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/1910.
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Conjugated polymers (CPs) are intrinsically fluorescent materials that have been used for various biological applications including imaging, sensing, and delivery of biologically active substances. The synthetic control over flexibility and biodegradability of these materials aids the understanding of the structure-function relationships among the photophysical properties, the self-assembly behaviors of the corresponding conjugated polymer nanoparticles (CPNs), and the cellular behaviors of CPNs, such as toxicity, cellular uptake mechanisms, and sub-cellular localization patterns.
Synthetic approaches towards two classes of flexible CPs with well-preserved fluorescent properties are described. The synthesis of flexible poly(p-phenylenebutadiynylene)s (PPBs) uses competing Sonogashira and Glaser coupling reactions and the differences in monomer reactivity to incorporate a small amount (~10%) of flexible, non-conjugated linkers into the backbone. The reaction conditions provide limited control over the proportion of flexible monomer incorporation. Improved synthetic control was achieved in a series of flexible poly(p-phenyleneethynylene)s (PPEs) using modified Sonogashira conditions. In addition to controlling the degree of flexibility, the linker provides disruption of backbone conjugation that offers control of the length of conjugated segments within the polymer chain. Therefore, such control also results in the modulation of the photophysical properties of the materials.
CPNs fabricated from flexible PPBs are non-toxic to cells, and exhibit subcellular localization patterns clearly different from those observed with non-flexible PPE CPNs. The subcellular localization patterns of the flexible PPEs have not yet been determined, due to the toxicity of the materials, most likely related to the side-chain structure used in this series.
The study of the effect of CP flexibility on self-assembly reorganization upon polyanion complexation is presented. Owing to its high rigidity and hydrophobicity, the PPB backbone undergoes reorganization more readily than PPE. The effects are enhanced in the presence of the flexible linker, which enables more efficient π-π stacking of the aromatic backbone segments. Flexibility has minimal effects on the self-assembly of PPEs. Understanding the role of flexibility on the biophysical behaviors of CPNs is key to the successful development of novel efficient fluorescent therapeutic delivery vehicles.
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Glennon-Alty, Laurence Jerome. "Developing synthetic polymer substrates for stem cell." Thesis, University of Liverpool, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590053.
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Stem cells hold great promise for use in regenerative therapies. However, current obstacles to their use include the ability to culture them under defined conditions, and the ability to differentiate them cost effectively. Over recent years there has been a great deal of interest in designing artificial substrates that are able to regulate stem cell behaviour, and there is now much evidence to suggest that the chemical composition of the substrate plays an important role in this regulation. The use of chemically defined substrates represents simple and cheap solutions to the effective culturing of stem cells. -----.. - In this study, the surface properties of poly-acrylate substrates were altered to enact control over the self-renewal and differentiation of stem cells. Specifically, chemically defined substrates were designed and tested for their ability to support mouse embryonic stem cell (mESC) self-renewal and direct the differentiation of mouse and human mesenchymal stem cells (MSCs) to chondrocytes. Poly-acrylate substrates were designed with Biomer Technology Limited (BTL), which has developed novel synthetic accelerate ™ polymeric coatings for use as biomaterials. The surface of these poly-acrylate substrates presented a combination of amine, carboxylic acid and hydroxyl functional groups at controllable density and proportion. These functionalities are known to influence stem cell behaviour and differentiation; however their combined influence is less studied. Substrates were further developed by modelling the functional group composition and distribution found at common integrin binding sites of key extracellular matrix proteins. The poly-acrylate substrates were able to modulate stem cell behaviour through alterations in surface chemistry. Results of the mESC studies indicated that while some of the poly-acrylate substrates could support the expansion of undifferentiated mESC colonies in defined serum-free culture medium over the short-term, population expansion was significantly reduced compared with control substrates. Further investigation demonstrated that this was likely due to deficient attachment of cells to the poly-acrylate substrates. The MSC studies indicated that poly-acrylate substrates modelled on the functional composition and distribution of the RGD integrin-binding motif of fibronectin were able to promote chondrogenesis in mouse and human MSCs, without need of additional stimuli. MSCs began to aggregate following seeding onto substrates, with QPCR and immunostaining confirming the presence of chondrocyte markers within aggregates, reminiscent of limb-bud formation. The mechanism of chondrogenesis induction was thought to occur directly via an RGD-integrin-like interaction. This work is the first to show that biomaterials designed to mimic specific sites of ECM molecules have the potential to direct MSC chondrogenesis without need of additional stimuli. More broadly, this thesis demonstrates that the surface properties of biomaterials can be tailored to regulate the self-renewal or differentiation of stem cells cultured in contact with them.
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Richter, Dieter, Ralf Biehl, Michael Monkenbusch, Bernd Hoffmann, and Rudolf Merkel. "Polymer dynamics from synthetic to biological macromolecules." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193062.
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In soft materials entropic and enthalpic contributions are of similar magnitude and balance each other. Therefore, the macroscopic mechanical and rheological properties and the phase changes are determined to a high degree by thermal motion of the atoms
and molecules. Most of the relevant dynamics takes place on mesoscopic length and time scales in between the picosecond atomic scale and the macroscopic frame. Allowing for the proper space time observation window, neutron spin echo (NSE) spectroscopy
uniquely allows to address these motions. Here we briefly present some key experimental results on the mesoscopic dynamics of polymer systems, starting from the standard model of polymer motion - the Rouse model. We briefly touch the role of topological
confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement. In the second part we touch on some new developments relating to large scale internal dynamics of proteins by neutron spin echo. We will report results of some pioneering studies which show the feasibility of such experiments on large scale protein motion which will most likely initiate further studies.
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Richter, Dieter, Ralf Biehl, Michael Monkenbusch, Bernd Hoffmann, and Rudolf Merkel. "Polymer dynamics from synthetic to biological macromolecules." Diffusion fundamentals 7 (2007) 10, S. 1-16, 2007. https://ul.qucosa.de/id/qucosa%3A14167.
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In soft materials entropic and enthalpic contributions are of similar magnitude and balance each other. Therefore, the macroscopic mechanical and rheological properties and the phase changes are determined to a high degree by thermal motion of the atoms
and molecules. Most of the relevant dynamics takes place on mesoscopic length and time scales in between the picosecond atomic scale and the macroscopic frame. Allowing for the proper space time observation window, neutron spin echo (NSE) spectroscopy
uniquely allows to address these motions. Here we briefly present some key experimental results on the mesoscopic dynamics of polymer systems, starting from the standard model of polymer motion - the Rouse model. We briefly touch the role of topological
confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement. In the second part we touch on some new developments relating to large scale internal dynamics of proteins by neutron spin echo. We will report results of some pioneering studies which show the feasibility of such experiments on large scale protein motion which will most likely initiate further studies.
10
Gaitonde, Vishwanath Venkatesh. "Carbohydrate-Based Synthetic Methodology and Polymer Development." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1438939333.
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Buckley, Craig D. "Non-synthetic polymer biomodification using gold nanoparticles." Connect to resource, 2009. http://hdl.handle.net/1811/37282.
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Luruli, Nyambeni. "New synthetic and characterization strategies for polyolefins." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/21672.
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Thesis (PhD)--University of Stellenbosch, 2006.ENGLISH ABSTRACT: Metalloxycarbene complexes [(CO)5M1=O(R)M2(Cl)L2] (M1 = Cr , W; M2 = Zr, Hf; L = Cp, Cp*) were synthesized from the reaction between anionic Fischer-type carbene complex salts [(CO)5M1=C(O)R][NEt4] and metallocene chlorides. The molecular and crystal structures of [(CO)5W=C(Me)OZr(Cp)2Cl], [(CO)5Cr=C(Me)OZr(Cp)2Cl] and [(CO)5W=C(Ph)OHf(Cl)Cp2] determined by X-ray methods, show a short Ccarbene-O and relatively long O-Zr and O-Hf separations. Metalloxycarbene complexes in the presence of MAO are active catalysts for homo- and copolymerization of -olefins and produce polymers with heterogeneous properties. 1-Pentene oligomers, homopolymers of ethylene and ethylene/1-pentene copolymers were successfully synthesized using metalloxycarbenes/MAO and the results obtained were critically compared with those synthesized with metallocene/MAO catalysts. The GC and GPC show that 1-pentene oligomers produced with both metalloxycarbenes and metallocenes catalysts range from simple dimers to more complicated high molecular weight (2 600 g/mol) products. The properties of polyethylene and ethylene/1-pentene copolymers were evaluated by, among others, GPC, SEC-FTIR, preparative molecular weight fractionation and HPer DSC. Generally the polymers obtained using metalloxycarbene/MAO catalysts have broad and bimodal molecular weight distributions. The copolymers have higher concentration of 1- pentene in the lower molecular weight fraction than those produced with metallocene/MAO as shown by SEC-FTIR. Consequently, HPer DSC shows a decrease of melting and crystallization temperature towards the low molecular weight fractions.
AFRIKAANSE OPSOMMING: Metaaloksikarbeenkomplekse [(CO)5M1=C(R)OM2(Cl)L2] (M1 = Cr , W; M2 = Zr, Hf; L = Cp, Cp*] is gesintetiseer in die reaksie tussen anioniese Fischer-tipe karbeenkomplekssoute, [(CO)5M1=C(O)R][NEt4], en metalloseen dichloriedes. Die molekulêre- en kristalstrukture van [(CO)5W=C(Me)OZr(Cp)2Cl], [(CO)5Cr=C(Me)OZr(Cp)2Cl] en [(CO)5W=C(Ph)OHf(Cl)Cp2] bepaal deur X-straalkristallografiese metodes, toon die aanwesigheid van kort Ckarbeen-O- en relatief lang O-Zr- en O-Hf-bindings. Metaaloksikarbeenkomplekse, in die aanwesigheid van MAO, is aktiewe katalisatore vir die homo- en ko-polimerisering van α-olefiene en is verantwoordelik vir die vorming van polimere met heterogene eienskappe. 1-Penteen oligomere, homopolimere van etileen en etileen/1-penteen ko-polimere is suksesvol gesintetiseer met metaaloksikarbeenkomplekse/MAO en die resultate sodoende verkry, is krities vergelyk met produkte gesintetiseer vanuit metalloseen/MAO prekatalisatore. Die GC en GPC resultate toon dat die 1-penteen oligomere, geproduseer met beide metaaloksikarbeenkomplekse en metallosene, kan wissel van eenvoudige dimere tot meer komplekse, hoë molekulêre massa (2 600g/mol) produkte. Die polietileen en etileen/1- penteen ko-polimere is gekarakteriseer deur onder andere gevorderde, GPC, SEC-FTIR, preparatiewe molekulêre massa fraksionering en HPer DSC. In die algemeen het die polimere verkry met metaaloksikarbeen/MAO katalisatore, breë en bimodale molekulêre massaverspreidings. Die ko-polimere bevat hoër konsentrasies van 1-penteen in die lae molekulêre massa fraksie in vergelyking met dié gevorm vanuit metalloseen/MAO–gekataliseerde mengsels, soos aangedui deur SEC-FTIR-analise. HperDSC wys 'n verlaging in smelt- en kristallisasietemperature in die laer molekulêre massa fraksies.
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Sirichaisit, Jutarat. "Deformation processes in synthetic and natural polymer fibres." Thesis, University of Manchester, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488312.
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Jesudason, Jeyarajan Joseph. "Synthetic analogues of bacterial polyesters : preparation and properties." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41256.
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The in situ, equimolar, trimethylaluminum/H$ sb2$O catalyst was used for the ring opening polymerization of racemic $ beta$-butyrolactone, $ beta$-heptanolactone and $ beta$-nonanolactone to form synthetic analogues of the naturally occurring family of biodegradable poly((R) -$ beta$-hydroxyalkanoate) polymers. This catalyst was found to produce both a better yield and a higher molecular weight of a high isotactic, primarily crystalline fraction of poly($ beta$-(R,S) -hydroxybutyrate) than the conventional in situ, equimolar triethylaluminum/H$ sb2$O catalyst. A mechanically tougher, less isotactic and less crystalline fraction of lower molecular weight and a largely amorphous fraction of even lower molecular weight were also isolated and characterized.Biodegradation of solid films of synthetic poly($ beta$-(R,S) -hydroxybutyrate) in the presence of an "extracellular" poly($ beta$-(R) -hydroxybutyrate) depolymerase was found to be dependent on accessibility of the enzyme to the (R) linkages along the polymer chain. The semicrystalline fraction was the most susceptible to degradation whereas the high crystallinity fraction showed little degradation and the low crystallinity fraction only showed limited degradation early in the incubation period.
Synthetic poly($ beta$-(R,S) -hydroxyheptanoate) and poly($ beta$-(R,S) -hydroxynonanoate) polyesters were prepared for the first time and the whole product was predominantly isotactic. It was found to have comparable physical properties as the biosynthetic materials, which are only available as terpolymers. Evidence for paracrystalline ordering relating to the organization of the side chains and formation of liquid crystalline-like phases was observed.
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Carey, Michelle Jocelyn. "The photophysics of naphthalene containing synthetic polymers." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320273.
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Bones, Simeon Joseph. "Synthetic structural and kinetic studies of polyethoxy-silanes." Thesis, Royal Holloway, University of London, 1987. http://repository.royalholloway.ac.uk/items/881e8bf8-5a34-409e-8b0b-afc2127e2727/1/.
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Polyethoxy-silanes are of considerable commercial interest in Brake Fluid formulations. The synthesis of a polymeric Brake Fluid base material, known industrially as Silane Racing Fluid (SRF) isreported, along with the preparation of a series of reference compounds. The fluid contained a mixture of polymeric glycol silanes with theformula andn = 0,1,2, etc. The molecular weights of these compounds weredistributed over a range from 164 to at least 1200. The referencecompounds synthesised were monomeric, with the structure MenSi(OR1 where n = 0,1 ,2 and -OR1 represents varying chain length glycol units, including. The compounds prepared were characterised using a variety of analytical techniques including Si NMR, Size Exclusion Chromatography (SEC) and Mass Spectrometry. The partial hydrolysis of SRF and several of the reference compounds, including is also described. Reactions were monitored qualitatively by Si NMR spectroscopy. Molar ratios of water to si lane were in the range of 2:1 to ~14:1. The technique allowed the identification 'in situ' of labile partial hydrolysis products, before they condensed to more stable siloxanes. In further studies the hydrolysis of several polyethoxy-silanes is reported, in dilute aqueous solution. The reactions were monitored quantitatively by two techniques, ultra-violet spectrophotometry and an extraction method. In the spectrophotometric experiment the hydrolysis of was studied. Pseudo first order kinetics was observed, which was found to be specific Acid/Base catalysed over the pH range studied (4-9). The extraction method relied upon n-hexane specifically extracting the starting material. An Infra-red spectrometer was used to determine the quantity of starting material present after extraction, by monitoring the Si-O-C stretching frequency ~1100 cm. Pseudo first order rate constants were obtained for the hydrolysis of and (0Me)3 . The results indicated specific Acid/Base catalysis over the pH range studied (5-9). The kinetic results described are in good agreement with recent studies reported using Trialkoxysilanes.
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Seamen, P. J. "Investigation into the biocompatibility of modified synthetic polymer surfaces." Thesis, University of Salford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381699.
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Walczak, Ryan Michael. "Synthetic methodology as a basis for conducting polymer design." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013725.
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Giguere, Marie-Soleil. "Sequencing synthetic copolymers using electrospray ionization mass spectrometry." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26485.
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The dissociation of gas-phase synthetic homopolymers poly(butyl acrylate) (PBA), poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) ionized by Li+ or Na+ was investigated by electrospray-ionization tandem mass spectrometry. Based on these results it was possible to use tandem mass spectrometry to sequence three copolymers produced by free radical polymerization (PBA/PVAc, PBA/PMMA and PMMA/PVAc). In the case of PVAc containing copolymers, tandem mass spectrometry yielded partial sequence information including the number of VAc monomers and consecutive BA or MMA monomers while the complete sequence (and mixture of sequences) could be deduced for PBA/PMMA.
The poly(vinyl acetate) ions lose acetic acid molecules from the polymer side chain, and ultimately metal acetate, to form a polyene with a positive charge on the carbon backbone while PBA and PMMA fragment along the polymer backbone. An extensive study was made of the dissociation characteristic of PVAc. Collision-induced dissociation (CID) was performed at different center-of-mass collision energies to study the sequential appearance of the fragment ions. Molecular mechanics/molecular dynamics (MM/MD), Hartree-Fock, semi-empirical and density functional calculations were employed to model the lowest energy dissociation processes.
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Xiao, Hui. "Design, synthesis and characterization of bis-azobenzenes - their synthetic applications and incorporation into polymer." Thèse, Université de Sherbrooke, 2018. http://hdl.handle.net/11143/11954.
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Abstract: Owing to the light-induced switching between their trans- and cis-isomers, azobenzenes display a wide range of applications including stimuli-responsive polymers, acid-base indicators, colorful systems, liquid crystals, and bio-medicals. In the past decades, much research on azobenzenes has been carried out and they have become a growing research topic. Particularly, the synthetic methodology of azobenzene derivatives has become mature. However, a general synthetic method of furnishing the bis- and tris-azobenzene compounds in one step is still lacking, and the study of bis-azobenzene is nearly blank including the solution properties and applications. In this thesis, we focus on the design, and preparation of bis-, tris- and small cyclic azobenzene derivatives; followed by a further investigation of their properties in solution. We also explore the preparation and applications of azobenzene-based stimuli-responsive polymeric materials. The first chapter describes an efficient strategy for the synthesis of bis- and tris-azobenzene derivatives. In this synthetic pathway, the bis- and tris-azobenzenes could be obtained in one pot, together with mono-azobenzene side products. By modifying the reaction conditions, the yields of the azobenzene compounds were mainly dependent on the substituents on the phenols and diazonium salts, and the molar ratio of starting materials. Compared with the unsubstituted aniline, the use of anilines with electron-withdrawing groups, leading to electron-deficient diazonium salts, favors the formation of mono-azobenzenes, rather than bis-azobenzenes. Whereas, anilines with electron-donating groups are not efficient during the first step leading to the formation of mono-azobenzene and thus favor the generation of bis-azobenzenes. Large amounts of anilines (over two-fold and three-fold excess), are the best choice to obtain bis- and tris-azobenzenes in good yields. In Chapter 2, we describe a novel method for the cyclization of mono- and bis-azobenzenes without ultraviolet light to form seven-membered heterocycles. The starting materials contain ortho-fluoro atom and ortho-phenol groups on the phenyl rings of the azobenzene systems. The role of the fluoro substituent is twofold. It promotes the stability of the cis-form of the azobenzene and it acts as a leaving group when its carbon atom neighbor is attacked by the phenolate. The nature of solvents was found to have a pronounced effect on the spontaneous cyclization reaction by stabilizing the intermediate complex. The cyclization rate could be accelerated under the UV irradiation and by using more polar solvents. Due to the competing keto-enol tautomerizations and cyclizations, we observed complicated changes in UV-vis absorption and color of solutions over time. It was revealed that, for ortho-hydroxyl azobenzenes with ortho-fluorine atom in polar solvents, the trans-to-cis isomerization and cyclization happened under daylight, and keto-enol tautomerization occurred in the dark. In Chapter 3, we studied a class of novel dual-responsive (photo- and thermo-) copolymers by modifying Poly(N-isopropylacrylamide) (PNIPAM) with bis-azobenzene moieties. The copolymers were prepared from a free radical copolymerization of N-isopropylacrylamide (NIPAM) and bis-azobenzenes bearing electron-donating or electron-accepting substituents. It was found that bis-azobenzene moieties could influence the cloud point of aqueous copolymer solution due to the photoisomerization of bis-azobenzenes and the conformation of polymer chain upon the photoreactions. Varying substituents on bis-azobenzene moieties, the copolymer solutions displayed an opposite cloud point shift after the photoreactions of the chromophores. When the substituents on azobenzene have push-pull feature, the polymer chains prefer aggregation after UV irradiation, which decreases the cloud point. By contrast, the cloud point shifts to higher temperature upon UV light irradiation when the bis-azobenzenes bears the donors, which is caused by cis-isomer being more hydrophilic than the trans-isomer. However, the effect of photoisomerization of azobenzene on the cloud point shift appears to be greater on PNIPAM containing mono-azobenzene pendent groups.En raison de la commutation induite par la lumière entre leurs isomères trans et cis, les azobenzènes affichent une gamme étendue d'applications. On y retrouve des polymères sensibles aux stimuli, des indicateurs acido-basiques, des systèmes colorés, des cristaux liquides et des matériaux aux applications biomédicales. Dans les dernières décennies, de nombreuses recherches sur les azobenzènes ont été menées et ils sont devenues un sujet de plus en plus important. En particulier, la méthodologie de synthèse des dérivés d'azobenzène est devenue mature. Cependant, une méthode synthétique générale pour l’obtention des composés bis- et tris-azobenzène en une seule étape est encore manquante, et l'étude du bis-azobenzène est presque vierge, y compris les propriétés et les applications en solution. Dans cette thèse, nous nous concentrons sur la conception et la préparation de bis-, tris- et de petits dérivés cycliques de l'azobenzène. Ce premier volet est suivi d'une étude plus poussée de leurs propriétés en solution. Nous explorons également la préparation et l'application de matériaux polymères d'azobenzène, réagissant à plusieurs stimulations. Le premier chapitre décrit une stratégie efficace pour la synthèse des dérivés bis- et tris-azobenzène. Dans cette voie de synthèse, les bis- et tris-azobenzènes peuvent être obtenus dans un pot réactionnel, avec des produits secondaires mono-azobenzène. En modifiant les conditions de réaction, les rendements des composés azobenzène dépendent principalement des substituants sur les phénols et les sels de diazonium, et du rapport molaire des produits de départ. Par rapport à l'aniline non substituée, l'utilisation d'anilines avec des groupes électroattracteurs, conduisant à des sels de diazonium déficients en électrons, favorise la formation de monoazobenzènes plutôt que de bis-azobenzènes. En revanche, les anilines à groupements donneurs d'électrons ne sont pas efficaces au cours de la première étape conduisant à la formation de monoazobenzènes et favorisent ainsi la génération de bis-azobenzènes. De grandes quantités d'anilines (excès de plus de deux et trois fois) sont le meilleur choix pour obtenir des bis- et tris-azobenzènes avec de bons rendements. Dans le chapitre 2, nous décrivons une nouvelle méthode de cyclisation des mono- et bis-azobenzènes, sans lumière ultraviolette, pour former des hétérocycles à sept chaînons. Les produits de départ contiennent des groupes ortho-fluoro et orthophénol sur les cycles phényle des systèmes azobenzène. Le rôle du substituant fluoro est double. Il favorise la stabilité de la forme cis de l'azobenzène et agit comme un groupe partant lorsque son atome de carbone voisin est attaqué par le phénolate. La nature des solvants s'est avérée avoir un effet prononcé sur la réaction de cyclisation spontanée en stabilisant le complexe intermédiaire . La vitesse de cyclisation peut être accélérée sous l'irradiation UV et en utilisant des solvants plus polaires. En raison des tautomérisations céto-énol et des cyclisations en compétition, nous avons observé que l’évolution des spectres d'absorption UV-vis et de la couleur des solutions au fil du temps était compliqué. Il a été révélé que, pour les ortho-hydroxyl azobenzènes avec un atome d'ortho-fluor dans les solvants polaires, l'isomérisation et la cyclisation trans-cis se produisaient à la lumière du jour et que la tautomérisation céto-énol se produisait dans l'obscurité. Dans le chapitre 3, nous avons étudié une classe de nouveaux copolymères biosensibles (photo- et thermo-) en modifiant le poly(N-isopropylacrylamide) (PNIPAM) avec des portions bis-azobenzène. Les copolymères ont été préparés à partir d'une copolymérisation radicalaire de N-isopropylacrylamide (NIPAM) et de bis-azobenzènes portant des substituants donneurs ou accepteurs d'électrons. Il a été constaté que les fragments bis-azobenzène pouvaient influencer le point de trouble de la solution aqueuse de copolymère en raison de la photoisomérisation des bis-azobenzènes et de la conformation de la chaîne polymère lors des photoréactions. En changeant les substituants sur les fragments bis-azobenzène, les solutions de copolymères présentaient un décalage du point de trouble opposé après les photoréactions des chromophores. Lorsque les substituants sur l'azobenzène ont une influence «push-pull», les chaînes polymères préfèrent l'agrégation après l'irradiation UV, ce qui diminue le point de trouble. En revanche, le point de trouble passe à une température plus élevée lors de l'irradiation par la lumière UV lorsque les bis-azobenzènes portent des donneurs, ce qui est dû au fait que l'isomère cis est plus hydrophile que l'isomère trans. Cependant, l'effet de la photo-isomérisation de l'azobenzène sur le décalage du point de trouble semble être plus important sur les groupes pendants mono-azobenzène contenant du PNIPAM.
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Bruckner, Eric P. "Integrated Synthetic and Computational Techniques For The Design of Poly[3]Rotaxanes." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459286768.
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Tateyama, Miho. "Development of polymer-supported synthetic procedure for Heyns rearrangement products." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ55092.pdf.
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Fuller, C. S. "Cellulosic-synthetic polymer blends : molecular interaction and controlled drug release." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599257.
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A compressed matrix incorporating poly(ethylene oxide) (PEO) and hydroxypropyl methylcellulose (HPMC) has been developed by Pfizer Ltd., and found to exhibit a pulsed drug release profile. This thesis presents work carried out on this and other polymer combinations that might also be useful in controlling the rate of drug release from oral dosage forms. Direct investigations of the hydration of compressed matrices were carried out using x-ray scattering, environmental scanning electron microscopy and differential scanning calorimetry. The molecular interactions and miscibility of HPMC-PEO, cellulose acetate-PEO and HPMC-poly(vinyl alcohol) (PVA) were investigated using microscopy, DSC, wide angle x-ray scattering and spectroscopy. HPMC-PEO and cellulose acetate-PEO were shown to be miscible due to the presence of attractive intermolecular interactions such as hydrogen bonds, whereas HPMC-PVA was found to be immiscible. The presence of attractive interactions and hence the miscibility of each blend combination is rationalised in terms of the chemical compositions and stereochemistries of the cellulosic component of the blends. The ability of the mixed polymer systems to control release when applied as coatings to drug-loaded non-pareils (beads), rather than as compressed matrices, was assessed. HPMC-PEO powder mixtures were applied successfully to drug-loaded non-pareils using powder layering. This technique avoids the use of potentially harmful organic solvents. The drug release was fast, but when the powder layer was prevented from detaching from the non-pareils using an overcoat of cellulose acetate, release of a soluble drug could be prolonged of up to 8 hours. The PEO increased the time it took for a continuous gel layer to form within the powder layer, at which point, the release rate slowed via a mechanism similar to that governing the pulsed release found in compressed matrices.
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Connell, Louise Stephanie. "Natural and synthetic polymer-based hybrid materials for tissue regeneration." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24820.
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The world's population is aging and cases of debilitating degenerative diseases are increasing. Bone is the second most transplanted tissue after blood but natural bone grafts are in short supply. Bioglass, which is a particular composition of bioactive glass, stimulates more bone repair than other synthetic bone grafts. However, it is brittle so cannot be used in cyclically loaded sites. A promising solution is the use of hybrid materials that can potentially combine the toughness of polymers with the stiffness and bioactivity of the glass through interpenetrating inorganic-organic networks. Hybrids have the unique feature of tuneable mechanical properties and degradation rates. In this thesis, two very different polymers were investigated as the organic component of hybrids; chitosan and poly(2-hydroxyethyl methacrylate-co-(3-trimethoxysilane)propyl methacrylate). The natural polymer chitosan was incorporated into the silica sol-gel process to produce hybrids and scaffolds were fabricated using freeze drying and foaming techniques. The chemical, morphological, mechanical and degradation properties of the scaffolds were studied. In order to covalently bond the organic and inorganic components, the chitosan was functionalised with an alkoxysilane crosslinker, 3-glycidoxypropyl trimethoxysilane. Using NMR and FTIR, the functionalisation reaction and side-reactions were characterised, discovering that the reaction was only 20% efficient at all pH values. To avoid the inefficient functionalisation reactions and concerns over the reproducibility of natural polymers, the synthetic co-polymer poly(2-hydroxyethyl methacrylate-co-(3-trimethoxysilane)propyl methacrylate) was synthesised by controlled polymerisation techniques (ATRP and ARGET ATRP) and typical free radical polymerisation (FRP). ATRP gave good control over molecular weight distributions, but the copper catalyst had serious implications on the chemical and architectural structure of the polymers. An NMR kinetics study was used to identify alternative polymerisation routes that could avoid the problems associated with the copper catalyst. The polymers were introduced into the sol-gel process to produce entirely synthetic hybrids with non-brittle (tough) behaviour and dissolution rates controlled by the polymer composition. The hybrids also exhibited hydroxyapatite precipitation in simulated body fluid, indicative of potential bioactivity in vivo. Hence, the aim of producing non-brittle, bioactive materials with controllable degradation rates was achieved.
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Mankoci, Steven Gerald. "The Investigation of Water-Soluble Polyurethanes that Mimic Antimicrobial Peptides." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1524649965130039.
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Barghi, Hamidreza. "Functionalization of Synthetic Polymers for Membrane Bioreactors." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3688.
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Membrane bioreactors (MBRs) show great promise for productivity improvement and energy conservation in conventional bioprocesses for wastewater reclamation. In order to attain high productivity in a bioprocess, it is crucial to retain the microorganisms in the bioreactors by preventing wash out. This enables recycling of the microorganisms, and is consequently saving energy. The main feature of MBRs is their permeable membranes, acting as a limitative interface between the medium and the microorganisms. Permeation of nutrients and metabolites through the membranes is thus dependent on the membrane characteristics, i.e. porosity, hydrophilicity,and polarity. The present thesis introduces membranes for MBRs to be used in a continuous feeding process, designed in the form of robust, durable, and semi-hydrophilic films that constitute an effective barrier for the microorganisms, while permitting passage of nutrients and metabolites. Polyamide 46 (polytetramethylene adipamide), a robust synthetic polymer, holds the desired capabilities, with the exception of porosity and hydrophilicity. In order to achieve adequate porosity and hydrophilicity, bulk functionalization of polyamide 46 with different reagents was performed. These procedures changed the configuration from dense planar to spherical, resulting in increased porosity. Hydroxyethylation of the changed membranes increased the surface tension from 11.2 to 44.6 mJ/m2. The enhanced hydrophilicity of PA 46 resulted in high productivity of biogas formation in a compact MBR, due to diminished biofouling. Copolymerization of hydrophilized polyamide 46 with hydroxymethyl 3,4-ethylenedioxythiophene revealed electroconductivity and hydrophilic properties, adequate for use in MBRs. To find either the maximal pH stability or the surface charge of the membranes having undergone carboxymethylation, polarity and the isoelectric point (pI) of the treated membranes were studied by means of a Zeta analyzer. The hydroxylated PA 46 was finally employed in a multilayer membrane bioreactor and compared with hydrophobic polyamide and PVDF membranes. The resulting biogas production showed that the hydroxylated PA 46 membrane was, after 18 days without regeneration, fully comparable with PVDF membranes.
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Zhou, Min. "Affinity precipitation using thermo-responsive, water-soluble polymers as matrix; synthetic studies toward the ageliferins." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1578.
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Isolated from marine sponges, many bromopyrrole alkaloids have become natural products of intense scientific interest. The oroidin-derived class of dimeric bromopyrrole alkaloids that include ageliferin, bromoageliferin, and dibromoageliferin exhibit interesting biological properties, including actomycin ATPase, antiviral and antibacterial activities.
As a prelude to the total synthesis of ageliferin, an intramolecular Diels-Alder (IMDA) reaction was explored as a means to introduce the three contiguous stereocenters. Toward this end, various IMDA precursors were synthesized, and several strategies for the synthesis of IMDA substrates were devised and explored.
Affinity chromatography is a powerful technique that enables the purification of a specific protein from a complex mixture. However, traditional affinity chromatography techniques are somewhat limited due to the solid state of the matrix. To overcome these limitations, the utility of a soluble polymer as an alternative affinity matrix was explored for the isolation of natural product receptors. This polymer displays physical properties that make it an ideal matrix for protein isolation and purification. The parent polymer is soluble in aqueous solution at 4 °C and precipitates once the mixture reaches 32 °C. Furthermore, employing this polymer for affinity chromatography may limit the nonspecific binding of proteins. It is also possible to determine the ligand loading using standard analytical techniques such as 1H and 13C NMR. For proof of concept, a dexamethasone-containing macroligand was synthesized to isolate the known glucocorticoid receptor. In addition, a cyclosporin A-containing macroligand was synthesized and employed to isolate the well known and more robust cyclophilins. In this work, it was demonstrated that indeed the ligand loading can be determined by 1H NMR technique. In addition, it was established, as expected, that the water solubility of the macroligands varies based on the hydrophilicity and hydrophobicity of the ligand and degree of ligand loading.
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Simmons, Gregory F. "Synthetic lubricants and polymer composites for large full film journal bearings." Licentiate thesis, Luleå tekniska universitet, Maskinelement, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26740.
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The rapid build-up of variable renewable power sources such as wind and solar are leading to increased instability in the electrical grid. Many methods of controlling this instability have been proposed but existing hydroelectric power plants in many cases already been enlisted to fill the regulating power needs of industry and the population. Filling this regulating power role necessitates that a machine changes load state more often and experiences an increase in starts and stops. Likewise, the push for a less environmentally intrusive society has raised the importance of utilizing equipment with reduced impact.This situation has created a host of opportunities to improve existing power plants and upgrade designs of new power plants to allow for reduced impact, better reliability, and increased efficiency. As one of the most critical and failure prone components of the power plant, the bearings hold great potential for improvements that together can reduce impact while increasing efficiency and reliability.To accomplish these opportunities, this work investigates the potential of new, environmentally adapted, lubricants to improve power plant efficiency. It then continues by developing guidelines for power plant operators when considering changing lubricants. Finally, the potential of polymer faced bearings to improve plant reliability at start up is investigated.A journal bearing test machine was constructed to investigate a number of new synthetic lubricants and polymer bearing materials. These tests found that a significant reduction in power loss could be accomplished without significantly affecting the bearing's minimum film thickness by changing from a traditional mineral oil based lubricant to a high viscosity index lubricant of much lower base viscosity grade.Further experimental work led to the development of practical guidance for power plant operators contemplating a lubricant change. This technique focuses on the importance of maintaining equivalent viscosity in the minimum film thickness region after a lubricant change. Efficiency improvements can then be calculated by comparing the viscosity in the bulk of the bearing to that with the original lubricant.Experimental work with polymer bearing facing materials demonstrated the dramatic reductions in break away friction that these materials can provide. A number of polymer composite materials were investigated for their friction characteristics at the moment of the start of sliding, finding that PTFE based materials were far superior to traditional Babbitt metal. The break away friction of PTFE materials was much lower than that of Babbitt and furthermore, the PTFE materials provided a much more stable friction than Babbitt through large variations in both pressure and oil bath temperature.Finally, experimental work with a full scale polymer faced bearing provided insight into the function of polymer faced bearings as well as valuable lessons in the further development of these bearings and their monitoring systems.Godkänd; 2011; 20110204 (gresim); LICENTIATSEMINARIUM Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Gregory F. Simmons Ämnesområde: Maskinelement/Machine Elements Uppsats: Synthetic Lubricants and Polymer Composites for Large Full Film Journal Bearings Examinator: Professor Sergei Glavatskih, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: Professor Patrick De Baets, Soete Laboratory, Ghent University, Belgium Tid: Måndag den 14 mars 2011 kl 10.00 Plats: E231, Luleå tekniska universitet
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Taylor, Michael. "To F-SIMS/XPS chemical depth profiling of synthetic polymer hydrogels." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/38755/.
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Over the last decade the beneficial properties of hydrogels as artificial cell culture supports have been extensively investigated. Certain synthetic hydrogels have been proposed to be similar in composition and structure to the native extracellular matrix of the stem cell niche, their in vivo cell habitat, which is a powerful component in controlling stem cell fate. The stem cell differentiation pathway taken is influenced by many factors. When culturing cells within or upon hydrogels the choice can be strongly dependent on the underlying 3D hydrogel chemistry which strongly influences hydrogel-cell interactions. The interrelationship between hydrogel chemistry and that of biomolecules in controlling cellular response ideally requires analysis methods to characterise the chemistry without labels and normally in 3D. Time-of-flight secondary ion mass spectrometry (ToF SIMS) has the potential to be utilised for through thickness characterisation of hydrogels. The frozen-hydrated sample format is well suited to minimise changes associated with dehydration or the complication of chemical ‘fixation’. There is however significant challenges associated with this sample format. Frost formation occurs on cold samples in the ambient atmosphere affecting the quality of chemical information acquired from depth profiling frozen hydrogel samples. We develop a simple method to remove this frost by blowing with gas prior to entry into the instrument which is shown to produce remarkably good profiles on a poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel film where a model protein, lysozyme, is incorporated to demonstrated how biomolecule distribution within hydrogels can be determined. A comparison of lysozyme incorporation is made between the situation where the protein is present in the polymer dip coating solution and lysozyme is a component of the incubation medium. It is shown that protonated water clusters H(H2O)n+ where n=5-11 that are indicative of ice are detected through the entire thickness of the pHEMA and the lysozyme distribution through the pHEMA hydrogel films can be determined using the intensity of characteristic fragment secondary ions. Quantitative TOF-SIMS analysis is highly desirable in biomaterial analysis as the amount and type of molecule in the material analysed may be determined. This has significant interest in hydrogel chemical analysis as cellular development on or within hydrogels may be highly influenced by the concentration and type of soluble molecule. Unfortunately, the matrix effect in SIMS changes the measured signal intensity of the analyte, preventing accurate quantitation. For this reason, we apply X-Ray Photoelectron Spectroscopy (XPS) on the equivalent samples as the ToF-SIMS in an attempt to correlate molecular ion yields to exact elemental concentrations. Similarly to ToF-SIMS the frozen-hydrated format in XPS is however still relatively unexplored. We apply the developed preparatory procedure in 3D XPS analysis of pHEMA/lysozyme hydrogel films in a hydrated state. We show that this format is suitable for alternative high vacuum analysis techniques. Furthermore, we show that lysozyme ingression and concentration can be determined through XPS. This work describes the first example of the characterisation of a hydrogel by ToF-SIMS and XPS in a frozen hydrated format, characterising hydrogels in a format most reflecting its native hydrated state at culture conditions. The described procedure allows for the mapping of biomolecules in a label free manner in 3D, furthermore allowing quantitative determination of biomolecule concentrations in hydrogels.
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Chen, Hao. "Effective Synthetic Way of Making Mannose-Based Linear and Truly Hyperbranched Glyco-Polymer via Reverse ATRP." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1428341905.
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Hoberg, Anne-Mette. "Intricacies regarding matrix-assisted laser desorption/ionisation of synthetic polymers." Thesis, University of Warwick, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342522.
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Ge, Xianlong. "Synthetic and mechanistic studies of poly(vinyl chloride) and some other chlorinated polymers." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539623417.
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Unlike vinyl chloride, 1,2-dichloroethylene (DCE) experienced dimerization under free-radical conditions. Chain transfer to DCE by beta-Cl elimination was shown to be the major reason for its nonpolymerization.;During the chlorination of alkyl chlorides with molecular chlorine, the involvement of a bridged intermediate led to the formation of vicinal chlorides as the major products. The yields of geminal chlorides increased significantly in the presence of solvents that form complexes with chlorine atoms, but such solvents also decreased the reactivity of the chlorination. Thus the chlorination of poly(vinyl chloride) (PVC) in the presence of complexing solvents was not a useful method for the synthesis of poly(1,2-dichloroethylene).;Polyacetylene (PA) was prepared by the methods of both Shirakawa and Luttinger. The PA's were chlorinated with Cl2 to form white polymers that were, however, not chlorinated completely, in that double bonds were invariably left in the polymer backbone. The chlorinated PA's had a much higher glass transition temperature than PVC but were much less thermally stable, apparently owing to the presence of allylic chloride groups.;Ring-opening metathesis polymerization (ROMP) followed by addition chlorination with Cl2 provided an approach to the preparation of a series of new polymers that could be interesting technologically. However, experiments with model compounds showed that the addition chlorination of conjugated double bonds or the double bonds of allylic dichlorides is frequently slow and incomplete. The chlorination of ROMP polymers made from cyclopentadiene, 1,3-cyclooctadiene, and 1,3,5-cyclooctatriene also did not proceed to completion, and the chlorination of the -(CH=CHCHClCHCl)n- polymer made from cis-3,4-dichlorocyclobutene did not occur at all.;Polyene sequences formed during the thermal degradation of PVC were found to interact with HCl in order to form an ion pairs whose thermal excitation produces triplet cation diradicals. These diradicals abstract methylene hydrogen atoms from PVC, and the ensuing beta-Cl scission forms internal allylic chloride structural defects that quickly lose HCl. as a result, the autoacceleration of thermal dehydrochlorination occurs.;A "Plasticizer thiol", 2-ethylhexyl 3-mercaptobenzoate, was confirmed to be an excellent thermal stabilizer for PVC and was suggested by preliminary experiments to function via a mechanism involving both the nucleophilic displacement of labile chloride and addition to double bonds.
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Jacobs, Nokwindla Valencia. "Optimising the polymer solutions and process parameters in the electrospinning of Chitosan." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1010762.
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Electrospinning is a technique, which can be used to produce nanofibrous materials by introducing electrostatic fields into the polymer solution. Due to their intrinsic properties, such as small fiber diameter, small pore size and large surface area, nanofibres are suitable for use in a variety of applications including wound dressing, filtration, composites and tissue engineering. The study demonstrates the successful and optimised production of Poly(ethylene oxide) (PEO) and chitosan nanofibres by electrospinning. The biocidal effects of chitosan, chitosan-silver nanofibres and silver nanoparticles were successfully investigated. To set up a functional electrospinning apparatus, the PEO solution parameters (concentration, molecular weight, solvent, and addition of polyelectrolyte) and applied potential voltage on the structural morphology and diameter of PEO nanofibres were studied. At lower PEO concentrations, the fibres had morphology with a large variation in fibre diameter, whereas at the higher concentrations, the nanofibres exhibited ordinary morphology with uniform but larger fibre diameters. Higher molecular weight showed larger average diameters when compared to that obtained with the same polymer but of a lower molecular weight. The addition of polyelectrolyte to the polymer solution had an influence on the structural morphology of the PEO. Flow simulation studies of an electrically charged polymer solution showed that an increase in the flow rate was associated with an increase in poly(allylamine hydrochloride) (PAH) concentration for the low molecular weight polymer, the shape and size of the Taylor cone increasing with an increase in PAH concentration for the low molecular weight polymer. During optimization of the PEO nanofibres, based on statistical modelling and using the Box and Behnken factorial design, the interaction effect between PAH concentration and the tip-to-collector distance played the most significant role in obtaining uniform diameter of nanofibres, followed by the interaction between the tip-to-collector distance and the applied voltage and lastly by the applied voltage. The production and optimization of chitosan nanofibres indicated that the interactions between electric field strength and the ratio of trifluoroacetic acid (TFA) and dichloromethane (DCM), TFA/DCM solvents as well as between electric field strength and chitosan concentration had the most significant effect, followed by the concentration of chitosan in terms of producing nanofibres with uniform diameters. Chitosan and chitosan-silver nanofibres could be successfully electrospun by controlling the solution properties, such as surface tension and electrical conductivity with the silver nanoparticles in the chitosan solutions affecting the electrospinnability. The silver nanoparticles in the chitosan solution modified the morphological characteristics of the electrospun nanofibres, while the conductivity and the surface tension were elevated. The fibre diameter of the chitosan and chitosan-silver nanoparticles decreased with an increase in the silver content. The electrospun chitosan nanofibres had a smooth surface and round shape as compared to the silver-chitosan nanofibres with a distorted morphology. The chitosan and chitosan-silver nanofibres as well as the silver nanoparticles exhibited antimicrobial or inhibition activity against S. aureus than against E. coli. S. aureus bacterial culture showed good cell adhesion and spreading inwards into the chitosan nanofibrous membrane. The chitosan-silver nanofibres exhibited a greater minimum inhibitory concentration (MIC), followed by silver nanoparticles and then chitosan nanofibres; suggesting a synergistic effect between the chitosan and silver nanoparticles.
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Fouquet, Thierry. "Mass spectrometry of synthetic polysiloxanes : from linear models to plasma-polymer networks." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4756/document.
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Contrairement aux méthodes de polymérisation par voie humide, la « plasma-polymérisation » de précurseurs siliconés (typiquement l'hexaméthyldisiloxane) fournit des couches minces peu solubles, considérées comme riches en chaines courtes et ramifiées, structures cycliques et réticulées, à mi-chemin entre un poly(diméthylsiloxane) (PDMS) et une silice. Ces caractéristiques confèrent des propriétés barrières, électriques ou mécaniques uniques aux substrats traités mais sont autant de difficultés pour leur analyse par spectrométrie de masse. La caractérisation fine d'un plasma polymère serait pourtant d'autant plus utile qu'elle permettrait – indirectement – de proposer ou de valider des mécanismes d'activation et d'oligomérisation du précurseur en phases plasma et solide, connaissance essentielle s'il en est pour la maîtrise des caractéristiques d'un dépôt. Cependant, l'interprétation de données MS/MS en vue de relier un comportement dissociatif à des caractéristiques structurales nécessite l'établissement préalable de règles de fragmentation à partir de modèles pertinents. En l'absence d'étalons plasma-polymère de structure contrôlée, il s'agit donc d'explorer différents modèles potentiels afin d'établir des relations structure/fragmentation pour comprendre les données MS/MS obtenues pour des échantillons réels. Ces études contribueront d'ailleurs à enrichir la littérature sur la fragmentation de polymères siliconés, très réduite en comparaison de polymères à chaine carbonée.A partir des données obtenues depuis les parties solubles de plasma-polymères, les comportements MS/MS d'un ensemble de polymères de référence dument choisis ont été explorés et explicitésThis thesis work aimed at describing the molecular and structural composition of silicon-based plasma-polymers (ppHMDSO) by mass spectrometry. Deposited under a micro-discharge regime at atmospheric pressure, these plasma-polymers exhibit a very low solubility in common solvents, assigned to their highly cross-linked structures, and are hence not easily amenable to ionization. Moreover, structural information cannot be readily deduced from fragmentation data obtained from species extractable from the studied thin films due to the lack of appropriate rules to understand dissociation of the observed gas-phase ions. This research work has thus consisted of developing an analytical strategy to address both of these challenging issues.Owing to the very limited number of articles dealing with tandem mass spectrometry of silicon-containing oligomers, mechanistic investigations were performed on the collision-induced decomposition of selected polymer standards holding different end-groups, expected to be relevant to characterize oligomers suspected to be present in the soluble part of the ppHMDSO samples. Focusing on ammonium adducts, fragmentation routes have first been established for symmetric poly(dimethylsiloxane) (PDMS) polymers holding trimethylsilyl, hydride, or methoxy terminations. POSS molecules were also investigated to understand the influence of cross-linked structures on PDMS adduct dissociation. Some discrepancies between MS/MS spectra of the standards and of the analytes were evidenced, assigned to random branching which could not be modeled by any commercially available compounds
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He, Jinbo. "Directing synthetic and bio-nanoparticle self-assembly at liquid and polymer interfaces." Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/dissertations/AAI3349725/.
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Ghadge, V. B. "Synthetic polymer based affinity matrices: separation of penicillin g acylase and penicillinase." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2001. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2419.
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Kaner, Jake. "Early polymeric materials encountered in furniture, 1880-1920 : their chemistry, conservation, history and manufacture." Thesis, Bucks New University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342084.
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Casiano-Maldonado, Madalis. "Mass Spectrometry Techniques for the Characterization of Synthetic Polymers, Biopolymers, Biodegradation Products and Their Interactions." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1332962590.
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Tsimpos, Kleomenis. "Τοwards a Synthetic Tryptophan Aminotransferase." Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-97548.
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The synthesis and evaluation of a molecularly imprinted polymer has been undertaken using an oxazine-based tryptophanamide transition state analogue (TSA) as template. An efficient route to the synthesis of oxazine-based TSAs for the reaction of pyridoxamine and indole-3-pyruvic acid has been established, with yields of up to 80%. NMR titration studies were performed to examine the interactions between the functional monomer, methacrylic acid and the template. Complexation of the template by functional monomer in the presence of crosslinker showed an apparent KD of 0.63-0.79 ± 0.04 M (293 K, acetonitrile-d3) based upon the chemical shift of the template amide protons. TSA-imprinted and non-imprinted reference polymers were synthesized by free radical polymerization in acetonitrile. Polymer monoliths were ground and fractionated into a 25-63 μm size range. Polymer-ligand recognition studies were conducted using the polymers as HPLC stationary phases. An imprinting factor (IF) of 2.93 was observed for the TSA, indicating the selectivity of the imprinted sites for the template. Studies using the D- and L-enantiomers of the phenylalaninamide analogue of the template showed enantioselectivity in the case of the imprinted polymer, α = 1.10, though not in the case of the non-imprinted reference polymer (1.00). Using UV-spectroscopy based polymer-ligand binding studies, a maximum theoretical capacity (Bmax) of 0.059 ± 0.004 mmol·g-1 was observed for the imprinted polymer. Conclusively, an imprinted polymer with binding sites selective for the TSA was successfully prepared and shall subsequently be studied with respect to its capacity to catalyse the transamination reaction between pyridoxamine and indole-3-pyruvic acid to yield pyridoxal and tryptophan.
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Musch, Janelle C. Riemersma. "Design optimization of sustainable panel systems using hybrid natural/synthetic fiber reinforced polymer composites." Diss., Connect to online resource - MSU authorized users, 2008.
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Thesis (M.S.)--Michigan State University. Dept. of Civil and Environmental Engineering, 2008.Title from PDF t.p. (viewed on Aug. 3, 2009) Includes bibliographical references (p.129-132). Also issued in print.
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Guckian, Lynley H. "Synthesis of styrene and acrylic emulsion polymer systems by semi-continuous seeded polymerization processes /." Online version of thesis, 2004. http://hdl.handle.net/1850/11796.
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Haigh, Russell. "Biological responses to synthetic hydrogels : the effect of polymer hydration and water distribution." Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289298.
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Parris, Juanita M. "X-ray diffraction analyses of synthetic polymers in the 3,3-substituted polyoxetane family and their copolymers." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39373.
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A series of crystalline, substituted polyoxetanes were studied using X-ray fibre diffraction as the primary investigative tool. Three systems were probed, each presenting a unique facet of structure analyses.The structure of poly(3,3-bis(hydroxymethyl)oxetane) using X-ray fibre diffraction was proposed. Modelling studies and FT-IR have been used to arrive at a probable conformation in which the backbone was found to be planar zigzag and the hydroxyls in the sidechain were extended. Few reflections were observed and it was not possible to grow lamellar single crystals for electron diffraction.
The preliminary structure of poly(3,3-bis(hydroxymethyl)oxetane) diacetate using X-ray fibre diffraction on films and fibres and electron diffraction on lamellar single crystals provided a tentative packing scheme based on the most intense equatorial reflections. CP/MAS $ sp{13}$C NMR indicates slight deviations in the environments for the acetate groups on the same residue.
X-ray fibre diffraction of atactic P(MHMO) resulted in a unit cell of comparable dimensions as in P(BHMO). The intensity and quality of the fibre patterns suggest identical structures. P(BHMO-co-MHMO) is a random copolymer in which the MHMO units are incorporated into the crystalline lattice of P(BHMO). One melting endotherm is observed for all compositions and decreases linearly with increasing content of MHMO. These data support a phenomenon known as isomorphism.
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Naidoo, Venthan B. "The supramolecular chemistry of novel synthetic biomacromolecular assemblies." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50196.
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Dissertation (PhD)--Stellenbosch University, 2004ENGLISH ABSTRACT: Over the past decade peptide bola-amphiphiles have been the subject of much attention because of their role as potential models of functionalised membranes and as new generation surfactants. In the quest for new surfactants a peptidomimetic-based approach was used to design a library of novel 'hybrid' bola-amphiphilic peptide surfactants derived from sapecin B and a model symmetrical oligo-glycine bola-amphiphile. The library was divided into different series, each one purpose-built; first, to investigate hierarchal supramolecular architecture and, second, to investigate potential antimicrobial activity. The bola-amphiphiles were synthesised using Fmoc-polyamide based solid phase peptide synthesis and purified via high performance liquid chromatography. The peptide hybrids were characterised using electro spray mass spectrometry, nuclear magnetic resonance, different modes of electron microscopy, Fourier-transform infrared spectroscopy and, in some cases, further studies were done using circular dichroism and bioactivity tests. The model bola-amphiphile suberamide(GGh was synthesised using peptide fragment condensation based on solid phase peptide synthesis. The synthesis is bi-directional (N~C and C~N) and versatile, making it possible to synthesis new dicarboxylic oligopeptide bola-amphiphiles and other analogous compounds. The product, suberarnide(GG)2, was purified using its inherent ability to self-assemble in an acidic solution. Novel asymmetrical bola-amphiphiles composed of dipeptide head groups linked via an aliphatic (I)-amino acid, serving as a hydrocarbon spacer, were also synthesized. Two small libraries of bola-amphiphiles were established - the first involved variation in to-amino acid length and the other variation in the C-terminal amino acid. The bolaamphiphiles were self-assembled in either 0.1% trif1uoroacetic acid or 0.1% triethylamine. Electron microscopy revealed the formation of a variety of higher order supramolecular architectures based on ~-sheet self-assembly. FT-IR spectrometry indicated that interlayer and intralayer hydrogen bond networks, together with strong selfassociation, promoted by the hydrophobic effect and, in certain instances, electrostatic interactions, are responsible for the variety of supramolecular architectures. Variations in the higher order structures can be attributed to amino acid composition, specifically length of m-amino acid, nature of the C-terminal amino acid and the optimised solvent conditions used for the self-assembly process. A third library of novel 'hybrid' bola-amphiphilic peptide surfactants, in which a cationic tripeptide motif from antimicrobial peptides was combined in a hybrid molecule containing a oi-amino acid residue, was established. These bola-amphiphiles displayed potent antimicrobial activity against both Gram-positive and Gram-negative bacteria; the analogues were as active or more active than the leader peptides yet, remarkably, displayed little or no appreciable haemolytic activity. These organopeptide bolaamphiphiles thus demonstrated selective toxicity towards bacteria. The hydrophobicity imparted by the co-amino acid has contrasting effects on haemolysis and antimicrobial activity of the peptide analogues. The other unique feature of these peptides and their analogues is the fact they self-assembled into complex supramolecular architectures, composed primarily of ~-sheets. Their self-assembly is primarily governed by hydrophobic interactions together with inter and intralayer hydrogen bonding. Electron microscopy clearly revealed higher order structures for both peptides and analogues. The generation of higher order supramolecular architecture is dependent on optimisation of ~- sheet self-assembly whereas antimicrobial activity is dependent on the balance between net positive charge and optimum hydrophobicity of the peptide hybrids. This study has demonstrated that it is possible to design hybrid peptide surfactants capable of producing higher order supramolecular architecture and improving the antimicrobial activity whilst reducing the haemolytic effect. The study and design of these versatile 'purpose-built' bio-inspired surfactants heralds a novel approach, one that shows tremendous potential.
AFRIKAANSE OPSOMMING: Die afgelope dekade het bola-amfifiliese peptiede baie aandag geniet weens hulle rolle as potensiële modelle van gefunksionaliseerde membrane en as 'n nuwe generasie surfaktante. In die soeke na nuwe surfaktante is 'n peptiedornimetiese benadering gevolg om 'n biblioteek van nuwe "hibried" bola-amfifiliese peptiedsurfaktante van sapesien B en 'n simmetriese oligoglisien bola-amfifil af te lei. Die biblioteek is in verskillende reekse onderverdeel. Elke reeks is doelmatig vervaardig om ondersoek in te stel na twee aspekte, nl. die rangorde van die supramolekulêre strukture en die potensiële antirnikrobiese aktiwiteit. Fmoc-poliamied gebaseerde soliedefase-peptied-sin-tese is aangewend vir die sintese van die bola-amfifile en hulle is met behulp van hoë doeltreffendheid vloeistofchromatografie gesuiwer. Die peptiedhibriede is gekarakteriseer met behulp van elekrosproei massaspektrometrie, kern-magnetiese resonansie, verskillende modusse elektronrnikroskopie, Fourier-transform infrarooispektrometrie en, in sommige gevalle is verdere studies met sirkulêre dichroïsme en bioaktiwiteitstoetsing uitgevoer. Die bola-amfifilsuberamiedtflfij--model is met behulp van peptiedfragment-konden-sasie gesintetiseer gegrond op soliedefase-peptiedsintese. Dit sintese vind in twee rigtings plaas (N~C en C~N) en is veelsydig aangesien dit die sintese van sowel nuwe dikar-boksielbola- amfifile as ander analoë verbindings moontlik maak. Die produk, suber-arnied(GG)2, is gesuiwer met behulp van die verbinding se inherente vermoë tot self-montering in suur oplossings. Nuwe assimetriese bola-amfifile, saamgestel uit dipeptiedkopgroepe, gekoppel via 'n alifatiese ro-aminosuur, wat as koolwaterstofspasieerder dien, is ook gesintetiseer. Twee klein bola-amfifilbiblioteke is saamgestel - die een het variasies in die ro-aminosuur se lengte omvat en die ander een variasies in die C-terrninale aminosuur. Selfmontering van die bola-amfifile het plaasgevind in of 0,1 % trifluorasynsuur Of 0,1 % trietielamien. Elektronrnikroskopie het die bestaan van 'n verskeidenheid hoërorde supramolekulêre strukture, gegrond op p-plaatselfmontering, aangetoon. Uit FT-IR-spektrometrie blyk dit dat inter - en intralaag waterstofbinbdingsnetwerke en sterk selfassosiasie, 19. word bevorder deur die hidrofobiese effek en, in sekere gevalle, elektrostatiese interaksies, is verantwoordelik vir die verskeidenheid supramolekulêre strukture. Variasies in die hoërorde strukture kan toegeskryf word aan aminosuursamestelling, in besonder die lengte van die ro-aminosuur, die aard van die C-terminale aminosuur en die geoptimiseerde oplosmiddelkondisies wat gebruik is vir die selfmonteringsproses. 'n Derde biblioteek nuwe "hibried" bola-amfifiliese peptiedsurfaktante, waarin 'n kationiese tripeptiedmotief uit antimikrobiale peptiede gekombineer is met 'n m-aminosuurresidu, is geskep. Sommige van hierdie bola-amfifile het 'n kragtige antimikrobiese aktiwiteit teenoor sowel Gram-positiewe as Gram-negatiewe bakterieë gertoon. Die analoë strukture was aktief, of selfs meer aktief as die voorste peptiede maar het, verbasend genoeg, nie 'n beduidende hemolitiese aktiwiteit vertoon nie. Hierdie organopeptied bola-amfifil het dus 'n selektiewe toksisiteit teenoor bakterieë vertoon. Die hidrofo-bisiteit, as gevolg van die ui-aminosuur, het 'n resiproke effek op hemolise en die antimikrobiese aktiwiteit van die peptiedanaloë. Die ander uitstaande kenmerk van die peptiede en hulle analoë is die vermoë om te selfmonteer en komplekse supramolekulêre strukture, bestaande hoofsaaklik uit ~-plate, te vorm. Hierdie selfmontering word in hoofsaak beheer deur hidrofobiese interaksies asook inter - en intralaagwaterstofbinding. Elektronmikroskopie het duidelik hoërorde strukture getoon by sowel dié peptiede as hulle analoë. Die ontwikkeling van hoërorde supramolekulêre struktuurvorms is afhanklik van die optimalisering van die ~-plaatselfmontering. Daarteenoor is die antimikro-biese aktiwiteit afhanklik van die balans tussen die netto positiewe lading en die opti-male hidrofobisiteit van die peptiedhibriede. Hierdie studie het getoon dat dit moontlik is om hibriedsurfaktante te ontwerp wat hoërorde supramolekulêre strukture te produseer en om die antimikrobiese aktiwiteit te verbeter terwyl die hemolitiese effek verminder word. Die studie en ontwerp van hier-die veeldoelige, "doelmatig-gesintetiseerde" biogeïnspireerde surfakante stel 'n unieke benadering daar, wat oor groot potensiaal beskik.
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Sprong, Ewan. "Synthesis, characterization and evaluation of macromonomers used to prepare rheology modifiers for possible improvement of the pigmentation of decorative coatings." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51929.
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Thesis (MSc)--Stellenbosch University, 2000.ENGLISH ABSTRACT: There is a decrease in viscosity when universal colorants are added to the latex coating system. Two different routes were taken to investigate this problem. The first was to investigate the thickening mechanism of the coating system. For this purpose six different hydrophobically modified alkali-soluble (HASE) thickeners were synthesized. The second was to compile new color concentrate formulations. The HASE thickeners consist of acrylic acid and a second associative monomer. The associative monomer (macromonomer) contained a long chain hydrophilic segment, terminated with a hydrophobic group. The hydrophilic segment consists of polyethoxylation, situated between the ethylenic unsaturation at one end of the molecule and the terminal hydrophobe at the other end. Three different macromonomers were prepared by coupling the hydroxyl end groups of three commercially available nonionic surfactants with either acrylic acid or acryloyl chloride. A much higher yield of macromonomer was obtained when the nonionic surfactants were reacted with the acryloyl chloride. Six HASE thickeners were synthesized by means of free radical addition polymerization. The first three HASE thickeners had the same backbone length and each thickener containing one type of hydrophobic macromonmer. The hydrophobic macromonomers differed in the length of their repeating oxyethylene units. They contained either 20, 50 or 100 oxyethylene units. The next three HASE thickeners were very similar to the first three except that 5% of the acrylic acid in the backbone was substituted with a second, phosphated, macromonomer, meaning that these thickeners each contained two types of macromonomers. These thickeners were then introduced into a standard latex coating formulation. By comparing the rheology profiles of the different coatings it was possible to determine the thickening efficiencies of the different thickeners. These coatings were also evaluated for their viscosity stability when tinted with a universal colorant. The HASE thickeners containing the second phosphated macromonomer showed superior thickening efficiency. All six coatings showed excellent stability on tinting with a universal colorant. Following the second route of investigation, eight universal colorant formulations consisting of only one polymeric dispersant in each of the formulations as sole wetting and dispersing additive were made up. A commercially available universal colorant was used as standard against which the new formulations were tested. The colorants were tested for color strength, their compatibility with the different coating groups, and the rheology profiles of the tinted vs. untinted coating systems. The two colorant formulations that contained EFKA 4550 as the polymeric dispersant performed very well in all the coating groups.
AFRIKAANSE OPSOMMING: Daar is 'n afname in viskositeit wanneer universele kleurstowwe by die lateks-bedekkingsisteem gevoeg word. Twee verskillende roetes is gevolg om die probleem te ondersoek. Die eerste was om die verdikkingsmeganisme van die bedekkingsisteem te ondersoek. Vir die doel is ses verskillende hidrofobies gemodifiseerde alkali-oplosbare (HASE)-verdikkers gesintetiseer. Die tweede was om nuwe kleurkonsentraatformulerings saam te stel. Die HASE-verdikkers bestaan uit akrielsuur en 'n tweede assosiatiewe monomeer. Die assosiatiewe monomeer (makromonomeer) bevat 'n langketting-hidrofiliese segment, met 'n hidrofobiese endgroep. Die hidrofiliese segment bestaan uit herhalende oksi-etileen eenhede, tussen die etileniese onversadigdheid aan die een punt van die molekuul en die hidrofobiese endgroep aan die ander punt. Drie verskillende makromonomere is voorberei deur die koppeling van die hidroksiel-endgroepe van drie kommersieel beskikbare anioniese sepe met akrielsuur of akriloielchloried. 'n Baie hoër opbrengs van makromonomere is verkry toe die anioniese sepe met die akriloielchloried gereageer is. Ses HASE-verdikkers is gesintetiseer deur middel van vrye radikaal addisie polimerisasie. Die eerste drie HASE-verdikkers het dieselfde ruggraatlengte en elke verdikker bevat een tipe hidrofobiese makromonomeer. Die hidrofobiese makromonomere verskil in die lengte van hul herhalende oksi-etileen eenhede. Die hidrofobiese makromonomere bevat of 20, 50 of 100 oksietileen eenhede. Die volgende drie HASE-verdikkers stem baie ooreen met die eerste drie behalwe dat 5% van die akrielsuur in die ruggraat vervang is deur 'n tweede, fosfaatbevattende makromonomeer, wat beteken dat hierdie verdikkers elk twee tipes makromonomere bevat. Hierdie verdikkers is in 'n standaard lateks bedekking formulering gevoeg. Deur die vergelyking van die reologie profiele van die verskillende bedekkings was dit moontlik om die verdikkings effektiwitiet van die verskillende verdikkers te bepaal. Hierdie bedekkings is ook geevalueer vir hulle viskositeits stabiliteit as dit met 'n universele kleurstof gekleur word. Die HASE-verdikkers wat die tweede fosfaatbevattende makromonomeer bevat, het uitstekende verdikkings effektiwiteit getoon. Al ses bedekkings het uitstekende stabiliteit getoon tydens kleuring met 'n universele kleurstof. Deur die tweede roete van ondersoek te volg, is agt universele kleurstof formulerings wat bestaan uit slegs een polimeriese dispergeermiddel opgemaak. 'n Kommersieel beskikbare universele kleurstof is gebruik as standaard waarteenoor die nuwe formulerings getoets is. Die kleurstowwe is getoets vir kleursterkte, hul verenigbaarheid met die verskillende bedekkingsgroepe, en die reologie profiele van die gekleurde teenoor die ongekleurde bedekkingsisteme. Die twee kleurstof formulerings wat EFKA 4550 as die polimeriese dispergeer middel bevat, het baie goed gevaar in al die bedekkingsgroepe.
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Niu, Jia. "Translation of DNA into Evolvable Sequence-Defined Synthetic Polymers." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11351.
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Laboratory directed evolution have enabled the discovery of numerous functional natural and synthetic macromolecules with tailor-made functions. However, approaches that use enzymes to effect the crucial translation from an information carrier molecule such as DNA or RNA to synthetic polymers are limited to producing close analogs of nucleic acids, either due to a strict requirement to hybridize with a nucleic acid template or as a consequence of the limited substrate scope of polymerase enzymes.Chemistry and Chemical Biology
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No, Young Jung. "Development and characterization of synthetic injectable biomaterials incorporated with doped calcium silicate ceramics." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16949.
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Injectable biomaterials that are able to set in situ provide clinicians a valuable tool in treating patients with clinically relevant tissue defects, as these can be administered via minimally invasive procedures and able to fill complex-shaped tissue defects. Injectable biomaterials also allow for novel fabrication techniques that aid in developing complex structures that mimic biological tissue. However, clinically-used injectable biomaterials that are currently available possess critical and inherent shortcomings that are difficult to address. The aim of this thesis was to develop and characterize new synthetic injectable biomaterials to address some of these shortcomings. To achieve this aim, the works in this thesis combined two distinct strategies: (1) utilize injectable material platforms not currently established for clinical use, but proven to be biocompatible and exhibit promising properties for filling musculoskeletal tissue defects; and (2) further improve the physicochemical and biological properties of these injectable materials, by incorporating bioactive doped calcium silicate ceramics. In particular, this thesis focused on the development and characterization of three such novel injectable biomaterials: (1) thermoplastic polycaprolactone composited with baghdadite (Ca3ZrSi2O9); (2) strontium-hardystonite (Sr-Ca2ZnSi2O7, Sr-HT)-phosphate cement; and (3) self-setting polyvinyl alcohol hydrogel composited with Sr-HT. All the synthetic injectable materials developed in this thesis possess sets of simultaneous ideal physicochemical and biological properties that address the limitations of injectable biomaterials currently established in the clinical setting. This thesis demonstrates that the physicochemical and biological properties of various injectable material platforms can be improved significantly by incorporating DCSC such as baghdadite and Sr-HT in order to render these materials ideal for filling various musculoskeletal tissue defects.
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Kokubo, Shinsuke. "Characterization of Physical and Chemical Properties of Synthetic Polymer using Ion Mobility-Mass Spectrometry." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3FAC-5.
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Mowat, Ian A. "Synthetic polymer analysis using matrix assisted laser desorption/ionization time-of-flight mass spectrometry." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/12128.
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The aim of the work described in this thesis was to assess 'Matrix Assisted Laser Desorption/Ionization' (MALDI) Time-of-Flight mass spectrometry as a possible technique for the analysis of synthetic polymers. A compact home-built time-of-flight mass spectrometer of cylindrically symmetrical geometry was used to carry out all the mass spectrometry detailed described in this thesis. A survey of the literature describing the development of matrix assisted laser desorption/ionization spectrometry and also the previous analysis of polymers by laser mass spectrometry was carried out. Experiments comparing the performance of the apparatus with published data on peptides and proteins were carried out, followed by experiments to assess the possibility of analyzing synthetic polymers. Initially polar polymers were investigated, since they could be anlayzed using sample preparations very similar to those developed for peptide and protein analysis. Later investigations were carried out on non-polar polymers such as polystyrene. The attachment of a range of transition metals to a low mass polystyrene was investigated using laser desorption/ionization time-of-flight mass spectrometry, without the use of matrices to increase the ion yield. Systematic investigations into the effects of sample spot composition, i.e. the amounts of matrix, polymer and salt present, were carried out, and used to suggest possible models for the processes leading to the generations of large gas phase ions. The effects of sample spot composition on the size and shape of the polymer molecular weight distributions obtained was also investigated. Liquid polymers such as polysiloxanes and perfluorinated polyethers were investigated using laser desorption/ionization and matrix assisted laser desorption/ionization. Carbon cluster generation from such polymers was investigated, and fullerene and polycyclic aromatic hydrocarbon analysis was also briefly studied. Novel new molecules such as aryl ester dendrimers were investigated, since they could not be successfully analyzed by other mass spectrometric techniques. Single molecular ions were obtained, helping to confirm the expected masses of these molecules. Novel new polymers such as hyperbranched aromatic polyesters were also analyzed, and molecular weight distributions were successfully obtained for a number of samples, showing the utility of MALDI for the analysis of new materials.
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Huang, Xiao. "Conducting Redox Polymers for Electrode Materials : Synthetic Strategies and Electrochemical Properties." Doctoral thesis, Uppsala universitet, Organisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-334562.
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Organic electrode materials represent an intriguing alternative to their inorganic counterparts due to their sustainable and environmental-friendly properties. Their plastic character allows for the realization of light-weight, versatile and disposable devices for energy storage. Conducting redox polymers (CRPs) are one type of the organic electrode materials involved, which consist of a π-conjugated polymer backbone and covalently attached redox units, the so-called pendant. The polymer backbone can provide conductivity while it is oxidized or reduced (i. e., p- or n-doped) and the concurrent redox chemistry of the pendant provides charge capacity. The combination of these two components enables CRPs to provide both high charge capacity and high power capability. This dyad polymeric framework provides a solution to the two main problems associated with organic electrode materials based on small molecules: the dissolution of the active material in the electrolyte, and the sluggish charge transport within the material. This thesis introduces a general synthetic strategy to obtain the monomeric CRPs building blocks, followed by electrochemical polymerization to afford the active CRPs material. The choice of pendant and of polymer backbone depends on the potential match between these two components, i.e. the redox reaction of the pendant and the doping of backbone occurring within the same potential region. In the thesis, terephthalate and polythiophene were selected as the pendant and polymer backbone respectively, to get access to low potential CRPs. It was found that the presence of a non-conjugated linker between polymer backbone and pendant is essential for the polymerizability of the monomers as well as for the preservation of individual redox activities. The resulting CRPs exhibited fast charge transport within the polymer film and low activation barriers for charge propagation. These low potential CRPs were designed as the anode materials for energy storage applications. The combination of redox active pendant as charge carrier and a conductive polymer backbone reveals new insights into the requirements of organic matter based electrical energy storage materials.