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1
Jin, Shu-Rong. "Cinetiques de formation de reseaux polymeres interpenetres a base de polyurethanne et de poly (methacrylate de methyle)." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13328.
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Etude par spectrometrie ftir. La reaction est probablement controlee par la vitesse de dissociation de l'amorceur. La polymerisation du mma est acceleree en presence du reseau polyurethanne. Le reseau elastomere peut etre considere comme "solvant" de viscosite infinie dans lequel on prepare le deuxieme reseau. Influence de la cinetique sur les proprietes dynamomecaniques
2
Bardot, Anne. "Modélisation acoustique basses fréquences de cavités en présence d'absorbants sur parois rigides ou élastiques." Compiègne, 1992. http://www.theses.fr/1992COMP0424.
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Ces travaux concernent l'amélioration de la compréhension physique et la modélisation des phénomènes vibro-acoustiques de cavités en présence de matériaux absorbants en vue d'améliorer la modélisation vibro-acoustique d'un habitacle automobile pour des problèmes de bourdonnement [50-200Hz]. La caractérisation acoustique des matériaux absorbants, plus particulièrement des matériaux polyuréthanes est basée sur une procédure originale associant mesures et modèle de Biot pour caractériser l'impédance acoustique des matériaux en basses fréquences, sous l'incidence d'ondes planes normales ou obliques. La validation du modèle de Biot par les mesures directes en conduit (incidence normale) nous permet d'extrapoler les résultats sous l'incidence oblique dans l'hypothèse d'un matériau considéré isotrope. La modélisation acoustique des cavités a été réalisée à l'aide des méthodes par éléments finis de frontière. La prise en compte de ces matériaux passe par une notion originale "d'impédance acoustique modale" associée à la répartition spatiale du champ acoustique dans la cavité. Cette approche ne permet pas de définir le champ acoustique exact mais tient compte des variations d'impédance en se basant sur un modèle de boite parallélépipédique. La condition liùite des matériaux absorbants sur parois élastiques peut être représentée à l'aide d'un modèle associant vitesse de la paroi élastique et impédance acoustique du matériau sur fond rigide pour le problème spécifique des basses fréquences. La validation expérimentale du modèle a permis de comprendre les mécanismes de couplage fluide-structure mis en jeu. Ces premiers résultats contribuent à la modélisation acoustique de cavités et ouvrent des perspectives d'application pour le modèle acoustique d'habitacle en présence des matériaux d'habillage.
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Bardot, Anne. "Modélisation acoustique basses fréquences de cavités en présence d'absorbants sur parois rigides ou élastiques." Compiègne, 1992. http://www.theses.fr/1992COMPD424.
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Ces travaux concernent l'amélioration de la compréhension physique et la modélisation des phénomènes vibro-acoustiques de cavités en présence de matériaux absorbants en vue d'améliorer la modélisation vibro-acoustique d'un habitacle automobile pour des problèmes de bourdonnement [50-200Hz]. La caractérisation acoustique des matériaux absorbants, plus particulièrement des matériaux polyuréthanes est basée sur une procédure originale associant mesures et modèle de Biot pour caractériser l'impédance acoustique des matériaux en basses fréquences, sous l'incidence d'ondes planes normales ou obliques. La validation du modèle de Biot par les mesures directes en conduit (incidence normale) nous permet d'extrapoler les résultats sous l'incidence oblique dans l'hypothèse d'un matériau considéré isotrope. La modélisation acoustique des cavités a été réalisée à l'aide des méthodes par éléments finis de frontière. La prise en compte de ces matériaux passe par une notion originale "d'impédance acoustique modale" associée à la répartition spatiale du champ acoustique dans la cavité. Cette approche ne permet pas de définir le champ acoustique exact mais tient compte des variations d'impédance en se basant sur un modèle de boite parallélépipédique. La condition liùite des matériaux absorbants sur parois élastiques peut être représentée à l'aide d'un modèle associant vitesse de la paroi élastique et impédance acoustique du matériau sur fond rigide pour le problème spécifique des basses fréquences. La validation expérimentale du modèle a permis de comprendre les mécanismes de couplage fluide-structure mis en jeu. Ces premiers résultats contribuent à la modélisation acoustique de cavités et ouvrent des perspectives d'application pour le modèle acoustique d'habitacle en présence des matériaux d'habillage.
4
Cobaj, Anisa. "The Effects of Urethane Methacrylates on the Film Properties of Acrylic-Urethane Hybrid Latexes." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1560335362557041.
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Gerard, Eric-Jack. "Synthese, caracterisation et comportement de polyurethannes hydrophiles : etude du mecanisme de la polycondensation reticulante." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13192.
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Synthese d'hygrogels, constitues de chaines elastiques de polydioxolanne. Les reticulats sont synthetises en milieu organique par couplages multiples des extremites hydroxylees, du polydioxolanne precurseur avec un compose isocyanate plurifonctionnel. Apres reaction, un echange progressif du solvant organique par l'eau permet d'obtenir les hydrogels
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Laguerre, Albert. "Oligomerisation et fonctionnalisation en serie methacrylique : greffage d'acides alpha amines." Le Mans, 1987. http://www.theses.fr/1987LEMA1017.
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Oligomerisation anionique du methacrylate de methyle. Modification des fonctions ester en fonctions plus reactions (alcool, chloroformiate, acide). Greffage d'aminoacides dont une seule fonction est libre pour eviter leur oligocondensation. Caracterisations des produits obtenus par rmn**(13)c, **(1)h et ir. Utilisation de ces produits pour la synthese de polyamides et de polyurethannes optiquement actifs
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François, Patrice. "Le fibrinogène : contribution dans l'infection sur corps étrangers." Paris 13, 1996. http://www.theses.fr/1996PA132032.
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Les staphylocoques reconnaissent certaines proteines plasmatiques adsorbees sur les biomateriaux grace a des recepteurs specifiques appeles adhesines, presents a leur surface. Nous avons etudie la composante d'adherence au fibrinogene de staphylococcus aureus (nommee clfa), qui jusqu'ici n'etait pas caracterisee. En collaboration avec un laboratoire de biologie moleculaire, nous avons selectionne des bacteries mutantes, incapables de former des amas en presence de fibrinogene soluble ou d'adherer au fibrinogene depose sur une surface. L'etude de ces mutants a permis de cloner et de sequencer le gene de l'adhesine du fibrinogene. Dans un circuit extra-corporel de circulation sanguine chez l'animal, nous avons determine que le fibrinogene depose sur les materiaux artificiels stimulait l'adherence bacterienne. Un modele d'endocardite experimentale chez le rat a revele que l'adhesine du fibrinogene favorise la colonisation des valves cardiaques par les staphylocoques. Deux strategies visant a reduire l'adherence ou la colonisation des catheters par les staphylocoques ont ete etudiees: (a) une modification de la surface des catheters en polyurethanne, par un traitement a la polyvinylpyrrolidone, reduisant la deposition des proteines plasmatiques sur les materiaux ; (b) l'impregnation des catheters par des agents antimicrobiens ayant un effet bactericide sur les bacteries adherentes. L'importance des resultats obtenus sur la caracterisation de l'adhesine de s. Aureus au fibrinogene et sa contribution, in vitro et in vivo, a l'attachement bacterien permet d'envisager des strategies anti-adhesives specifiques. Ces strategies pourraient devenir une precieuse alternative aux antibiotiques, surtout en presence de souches multiresistantes a ces composes
8
Signoret, Christian. "Réseaux polyuréthannes classiques et contenant des motifs furanniques pour le confinement de déchets radioactifs : relations structure-propriétés." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0088.
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Etude des proprietes mecaniques, de la stabilite thermique de la diffusion de l'eau et de sels radioactifs dans des polyurethannes. Les polyetherurethannes souples ont un comportement moyen a la temperature et a la diffusion. Les polyesterurethannes ont un meilleur comportement mais sont hydrolyses rapidement les polyetherurethannes rigides (tv=20 a 40#oc) sont le meilleur compromis; amelioration de la tenue en temperature vers 350-500#oc par addition de derives furanniques
9
Meng, Lei. "Investigation of non-isocyanate urethane functional latexes and carbon nanofiller/epoxy coatings." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1445733724.
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Clayton, Anthony Brian. "Photopolymerised urethane acrylates /." Title page, contents and summary only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phc622.pdf.
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Abd, Elrehim Mona Hassan Mohammed. "Synthesis and characterization of hyperbranched poly(urea-urethane)s." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1091096011203-44194.
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The thesis aims to synthesize hyperbranched poly(urea-urethane) polymers (HPU) in one-pot method using commercially available monomers which are 2,4-toluylene diisocyanate (TDI) as aromatic diisocyanate and isophorone diisocyanate (IPDI) and 2(3-isocyanatopropyl) cyclohexylisocyanate (IPCI) as aliphatic diisocyanates. Those proposed diisocyanates were reacted with diethanolamine (DEA) or diisopropanolamine (DIPA). Conditions of polymerisation reactions were optimised. Complete structural analysis using 1H and 13C NMR for the obtained aromatic polymers was carried out. Degree of branching up to 70% was calculated. Aliphatic polymers have spectra with overlapped signals therefore, no full structural analysis was possible. Molar masses were determined using SEC/RI detector which shows that the prepared polymers have Mw values between 1600 g/mol and 106000 g/mol. Thermal analysis for different polymer systems showed that aliphatic HPU are more thermally stable and have values of glass transition temperature higher than aromatic ones. Modification of the end groups in the prepared hyperbranched polymers was carried out using three different modifiers and degree of modification up to 100%. Linear polymers based on the same diisocyanate monomers were prepared to compare the properties of hyperbranched systems with their linear analogs. Measurements of solution viscosity showed that HPU have lower solution viscosity values than their linear analogs of comparable molar masses. Rheological measurement of some polymer samples of different systems were carried out and showed that our hyperbranched systems exhibit a more elastic behavior than the linear polymers. Surface studies for thin films prepared from different polymer systems (hyperbranched, linear and modified) were carried out and the obtained thin films were characterized using light microscope, microglider, GC-MS, and AFM. Contact angle measurements showed that HPU have a relatively hydrophilic character. The modified polymers have higher contact angle values than the unmodified ones due to the lack of OH end groups. Networks based on aliphatic and aromatic HPU were prepared through the reaction of HPU with trimer of 1,6-diisocyanatohexane and characterised by DSC, GC-MS, DMA and AFM. The domain size in aromatic networks was found to be larger than in aliphatic networks. Tensile test was carried out and it was found that aliphatic network is more elastic than aromatic one.
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Alshuiref, Abubaker. "Synthesis and characterization of two novel urethane macromonomers and their methacrylic/urethane graft copolymers." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4022.
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Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Polymethacrylates are well known adhesives and can carry specific functionality, but have the disadvantage that their flexible backbones impart limited thermal stability and mechanical strength. Polyurethanes (PUs) are finding increasing application and use in many industries due to their advantageous properties, such as a wide range of flexibility combined with toughness, high chemical resistance and excellent weatherability. PUs do however have some disadvantages, for instance, PU is considered an expensive polymer, especially when considered for solvent based adhesives. the focus of this study was to consider a largely unstudied area of PU chemistry, namely combining PUs with polymethacrylates. Two types of linear urethane macromers (UMs) UM1 and UM2 were synthesized by the polyaddition polymerization of 4,4'-methylenediphenyl diisocyanate (MDI) with ethylene glycol (EG), and MDI with neopentylglycol (NPG), via a pre-polymer method, followed by termination with 2-hydroxy ethylacrylate (2-HEA) and methanol (MeOH) to yield UMs having specific urethane chain lengths, and which have to be predominantly monofunctional. Structural identification of the UMs was verified by MALDI-TOF-MS, FTIR, 13C-NMR and 1HNMR spectroscopy.Various percentages of the respective UMs (0_55 wt % of methacrylate monomers) were then incorporated into polymethyl methacrylate (PMMA) and poly n-butyl methacrylate (PnBMA) backbones via solution free-radical copolymerization. The resulting methyl methacrylate-g-urethane and n-butyl methacrylate-g-urethane copolymers were characterized by 1H-NMR,13C-NMR, FTIR, SEC with double detectors (UV and RI), light scattering, UV-Vis, HPLC, TGA, DSC, DMA and TEM. Weight percentages of UM incorporated into the methyl methacrylate-g-urethane copolymers were calculated using FTIR, UV-Vis and 1H-NMR techniques. Phase separation which occurred between the urethane segment and methacrylate segment in the graft copolymerization products was investigated by DMA, DSC and TEM analysis. Microphase separation occurred in all PMMA-g-UM1 and PnBMA-g-UM1 copolymers: two glass transitions temperatures corresponding to the PMMA or PnBMA and UM1 fractions, respectively, were observed. On the other hand, DMA and DSC results showed that in most graft copolymer products the two respective component parts PMMA-g-UM2 or PnBMA-g- UM2 were compatible, because only one Tg was observed. Two glass transitions occurred for PMMA or PnBMA and UM2 when the amount of UM was increased to 55 wt % during copolymerization and microphase separation was evident in DSC, DMA and TEM measurements. Thermal stability and storage modulus (stiffness) of all the synthesized PMMA-g-urethane and PnBMA-g-urethane copolymers increased as the concentration of urethane macromonomer in the copolymerization feed increased, as confirmed in TGA and DMA results. The surface and adhesive properties of the synthesized graft copolymer were studied by measuring the static contact angle and peel strength. Adhesion increased as the content of UMs increased in the graft copolymer. The graft copolymers prepared using a high UM2 feed for both PMMA and PnBMA showed improved in adhesion compared to the pure methacrylate polymers. The adhesion was better for both leather and for vinyl.
AFRIKAANSE OPSOMMING: Polimetakrilate is bekende kleefstowwe. Hulle het egter die tekortkoming dat hulle buigbare ruggraat beperkte termiese en meganiese stabliteit besit. Poliuretane (PUs) word deesdae al hoe meer gebruik in baie nywerhede as gevolg van hulle baie voordele, insluitend hul wye buigsaamheid tesame met sterkte, hoë chemiese weerstand en uitstekende weerbaarheid. PUs het egter ’n paar nadele: hulle is baie duur, veral wanneer hulle gebruik word in oplosmiddel-gebaseerde kleefstowwe. Die doel van hierdie studie is om die kombinering van PUs met polimetakrilate te bestudeer, 'n onderwerp wat tot dusver baie min aandag-getrek het. Twee tipes liniêre uretaanmakromere (UMs), UM1 en UM2, is gesintetiseer deur gebruik te maak van poliaddisiepolimerisasie van 4,4'-metileendifeniel diisosianaat (MDI) met etileenglikol (EG), en MDI met neopentielglikol (NPG), via ‘n prepolimeermetode, gevolg deur terminering met 2-hidroksiëtielakrilaat (2-HEA) en metanol (MeOH). Die produk hiervan is UMs met spesifieke kettinglengtes (hoofsaaklik monofunksioneel). Die samestelling van die UMs is met behulp van die volgende gevorderde analitiese tegnieke bepaal: MALDI-TOFMS, FTIR, 13C-NMR en 1H-NMR. Verskillende hoeveelhede van die UMs (0_55 gewIing% metakrilaatmonomere) is dan in die polimetielmetakrilaat (PMMA) en poli-n-butielmetakrilaat (PnBMA) ruggrate geïnkorporeer deur middel van oplossing-vryradikaalpolimerisasie. Die samestelling van die kopolimeerprodukte, metiel-metakrilaat-g-uretaan en n-butiel-metakrilaat-g-uretaan, is met behulp van die volgende gevorderde analitiese tegnieke bepaal: 1H-NMR, 13C-NMR, FTIR, SEC met dubbele detektors (UV en RI), ligverstrooiing UV-Vis, HPLC, TGA, DSC, DMA en TEM. Die hoeveelheid UM geïnkorporeer in die metielmetakrilaat-g-uretaan kopolimere is bereken deur gebruik te maak van FTIR, UV-Vis en 1H-NMR data. Die faseskeiding wat plaasgevind het tussen die uretaansegment en die metakrilaatsegment in die produkte van die entpolimerisasie is met behulp van DMA, DSC en TEM ondersoek. In alle PMMA-g-UM1 en PnBMA-g-UM1 kopolimere het mikrofaseskeiding plaasgevind: twee verskillende glasoorgangstemperature vir die PMMA of PnBMA en UM1 fraksies is waargeneem. Hierteenoor het DMA en DSC resultate getoon dat in die meeste entkopolimeerprodukte (PMMA-g-UM2 of PnBMA-g-UM2) was die twee komponente verenigbaar, aangesien net een Tg waargeneem is. In die geval van die kopolimere waar die hoeveelheid UM in die kopolimerisasiereaksies tot 55 gew% verhoog is, is twee glasoorgangstemperature vir PMMA of PnBMA, en UM2 waargeneem. Mikrofaseskeiding is met behulp van DSC, DMA en TEM bewys. Termiese stabiliteit en stoormodulus (styfheid) van alle gesintetiseerde PMMA-g uretaan en PnBMA-g-uretaan kopolimere het toegeneem namate die uretaankonsentrasie in die kopolimerisasiereaksie toegeneem het soos deur middel van TGA en DMA resultate bewys is. Die oppervlakte- en kleefeienskappe van die bereide entkopolimere is bestudeer deur die statiese-kontakhoek en skilkrag te meet. Adhesie het toegeneem namate die UMinhoud toegeneem het. Die entkopolimere berei met hoë PMMA en PnBMA inhoud het uiteindelik beter adhesie getoon as die suiwer metakrilaatpolimere. Die adhesie was beter vir beide leer en viniel.
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Van, Clack Ralph Vincent. "Non-isocyanate routes to urethane-polymers." Thesis, University of Central Lancashire, 2007. http://clok.uclan.ac.uk/20700/.
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The conventional synthetic route to urethane polymers involves the use of hazardous dflsocyanates which are synthesised using phosgene, the use of which produces a significant chlorine-waste stream. The processing of high molecular mass specialty polyurethanes regularly requires the use of organic solvents. This research aims to address these issues by separately employing enzyme-catalysis in order to synthesise high molecular mass polyurethanes and by investigating the use of high pressure CO2 as an alternative to the use of organic solvents in the synthesis of urethane polymers. The main building blocks in the enzyme-catalysed synthesis of urethane polymers are based on di-functional carbamate-blocks, synthesised by reaction of diamines with ethylenecarbonate or dimethylcarbonate. In addition to the more conventional di-functional carbamate-blocks, the synthesis of a novel mono-carbamate based on an amino acid has been investigated. The mechanism of the polymerization of adipic acid and hexane diol was investigated. The reaction was optimised for the high vacuum reaction in bulk and solution, as well as for the polymerisation under Dean-Stark distillation conditions. Although the dimethylcarbonate-based carbamate-compounds proved to be too resistant against enzymatic cleavage, the enzyme-catalysed co-polymerisation of ethylene-based carbamate-blocks with adipic acid and hexane diol eventually led to the synthesis of high molecular mass segmented urethane polymers in excess of 30000 g moi1. The crystallisation behaviour of both enzyme-catalysed polyesters and polyurethanes has been investigated and the differences in crystallisation for the polyesters have been shown to be caused by the presence of small quantities of residual enzyme. The enzyme appears to act as a nucleating agent for the crystallisation and increases the uniformity of crystallisation and the rate at which a crystalline structure was obtained upon cooling. The thermal properties of the enzyme-catalysed polyurethanes have been determined and compared to conventional polymers. Although the molecular mass of the enzyme-catalysed urethane polymers are comparable to those obtained via the conventional route, it has not been possible to reproduce their physical p rope rties. The use of high pressure CO2 to eliminate the need of a solvent in the synthesis of a urethane polymer was studied. The use of a pressure of 4.5 bar 002 has been shown to enhance the reaction rate for this reaction procedure. GPC analysis confirmed that polyurethanes with a molecular mass of approximately 53000 g moi1 were synthesised in 200 minutes, whereas the same reaction under atmospheric conditions required a longer reaction time (260 minutes) before the same molecular mass polyurethane was obtained.
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Hunt, Jason Patrick. "Synthesis and dynamic mechanical studies of a urethane-based polyrotaxane." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/8553.
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Todd, Jordana Louise. "UV-initiated synthesis of novel urethane polymers." Thesis, University of Central Lancashire, 2007. http://clok.uclan.ac.uk/20200/.
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The Barton reaction involves the photoinitiated rearrangement of nitrite esters and is used primarily in the synthesis of complex steroidal structures. The rearrangement results in the introduction of active hydrogen atoms into the molecule and a novel use of this reaction for the production of polyurethane coatings through a photopolymerisation reaction with isocyanates has been discovered. The nitrite esters were synthesised from nitrous acid produced in situ from sodium nitrite and sulfuric or nitric acid. Yields of 79.5 and 76.4% were obtained in the synthesis of the mononitrite esters butyl- and hexyl-nitrite, however lower yields of 55.1 and 53.4% were obtained in the synthesis of butane-1,4- and hexane-1,6-dinitrite respectively. It was found that the nitrite esters are very rapidly hydrolysed and loss of product through hydrolysis occurs during the synthesis because of the aqueous environment in which it is carried out therefore a position of equilibrium is reached. The kinetics of the hydrolysis reaction was studied by monitoring the change in pH over time for both butyl- and butane-I,4-di-nitrite. The sensitivity of the nitrite esters to hydrolysis not only makes the synthesis of nitrite esters problematic but it also means that storage above the critical pH of 6.8 and at a temperature of 2-8°C is crucial to maximise the storage stability of the samples. The stability of the nitrite esters mixed with isocyanates was determined, the results indicated that the two reagents did not react and therefore the compounds could be stored together prior to irradiation. An extensive study on the reactions occurring after the photolysis of a series of nitrite esters was undertaken. The optimum wavelength range of 3 10-385 nm was confirmed for the occunence of the Barton reaction and results showed that the competing reaction of disproportionation also occurred after irradiation. The structure of the starting nitrite was found to have a significant effect on the reactions occurring after photolysis. A chain length of greater than 4 carbon atoms was found necessary for the Barton reaction to dominate over disproportionation because the intramolecular hydrogen abstraction 111 step involved a secondary hydrogen atom, whereas when a nitrite ester with only a 4 carbon chain was subjected to photolysis the disproportionation reaction was the dominant reaction because a primary hydrogen atom was abstracted. However this trend was not observed during the photolysis of dinitrite esters, the Barton reaction occurred to a greater extent than the disproportionation reaction even when a primary hydrogen atom was abstracted due to the second nitrite group which facilitates its removal. A series of coatings were produced from solutions of nitrite esters and isocyanates. It was found that a catalyst was essential to drive the reaction towards the Barton reaction and prevent the occurrence of the disproportionation reaction in order to ensure the formation of highly cured coatings. An excess of nitrite was required to compensate for the loss of nitrite ester through evaporation that prevented the production of highly cured coatings. The occurrence of a post-curing reaction was observed due to the continuation of the reaction of the isocyanate with residual active hydrogen compounds. The film thickness, nitrite ester, isocyanate and catalyst used were all found to have an effect on the rate of the polymerisation reaction. The photolysis reaction was also affected by the conditions under which the photopolymerisation reaction was undertaken. In a heated system an oxime compound was formed after photolysis whereas when a cooled curing oven was used a dimer was produced. The formation of the dimer also resulted in coatings with inferior properties; this is because the absence of oxime groups and the lower temperature reduces the rate of the polymerisation reaction resulting in increased formation of by-products. The properties of the coatings produced were tested and were found to have good solvent resistance (over 100 MEK double rubs), pencil hardness (7H), resistance to deformation (3mm pass in the bend test), adhesion (cross-cut value of 0) and weathering resistance. The properties of the coatings were also comparable to standard coatings indicating that they may have commercial importance.
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Alshuiref, Abubaker. "Synthesis and characterization of urethane-acrylate graft copolymers." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/491.
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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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Maître, Anne. "Les peintures polyuréthanes en réparation automobile : développement de méthodes d'évaluation des niveaux d'exposition et approche de la toxicité humaine." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10147.
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L'asthme aux isocyanates represente la premiere cause d'asthme chimique professionnel, et les peintres en reparation automobile constituent la population la plus exposee. Si la grande reactivite chimique des isocyanates explique leurs nombreuses applications industrielles, elle est egalement la cause de la diversite des mecanismes d'action toxique et de la meconnaissance des transformations metaboliques chez l'homme. La methode retenue pour evaluer les niveaux d'exposition atmospherique aux polyisocyanates est le barbotage de l'air dans une solution de methoxyphenylpiperazine, suivi d'une analyse par chromatographie liquide avec une detection ultraviolette. Alors que le dosage urinaire de l'hexane diamine a pu etre valide en tant qu'indicateur biologique d'exposition a l'hexamethylene diisocyanate, aucune surveillance biologique aux polyisocyanates n'est actuellement possible. Pendant l'application au pistolet des peintures polyurethanes, l'exposition des peintres aux isocyanates est tres elevee. La performance technique de la ventilation de la cabine, mais egalement le volume et la position des subjectiles par rapport aux grilles d'extraction jouent un role primordial. Le port d'une protection respiratoire individuelle nous semble indispensable pour diminuer l'incidence de l'asthme aux isocyanates.
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Hsu, Tze-Chien Jeffrey. "Urethane-based IPNs and polyureas in reactive polymer processing /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487331541711679.
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Kiziltay, Aysel. "Biodegradable Poly(ester-urethane) Scaffolds For Bone Tissue Engineering." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613811/index.pdf.
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During last decade, polyurethanes (PUs) which are able to degrade into harmless molecules upon implantation have received a significant level of attention as a biomaterial in tissue engineering applications. Many studies are focused especially on development of PUs based on amino acid derivativeshowever, there are only few applications of amino acid based PUs in tissue engineering. In this study, a biocompatible and biodegradable thermoplastic poly(ester-urethane) (PEU) based on L-lysine diisocyanate (LDI) and polycaprolactone diol (PCL) was synthesized and used for the preparation of two dimensional (2D) films and three dimensional (3D) scaffolds. The resulting polymer was casted as 2D films for full characterization purpose and it was found that it is highly elastic with modulus of elasticity ~12 MPa. Surfaces of 2Ds were modified via micropatterning and fibrinogen coating to check the material-cell interaction. The 3D scaffolds were obtained by salt leaching and rapid prototyping (bioplotting) techniques. The 3D scaffolds had various pore size and porosity with different mechanical strength. The bioplotted scaffolds had uniform pore size of ~450 µ
m and exhibited higher compressive modulus (~4.7 MPa) compared to those obtained by salt leaching (~147 kPa). Salt leached 3D scaffolds had inhomogenous pore size distribution in the range of 5 µ
m - 350 µ
m and demonstrated greatest degradation profile compared to 2D films and 3D bioplotted samples under enzymatic condition. Rat bone marrow stem cells (BMSCs) were used to investigate the biocompatibility of the polymer and suitability of fabricated scaffolds for osteogenesis. Presence of micropatterns on 2D matrices did not show any influence on osteoblastic function, but presence of fibrinogen enhanced cell attachment and proliferation. All of the fabricated 3D PEU matrices supported proliferation, osteoblastic differentiation and extracellular matrix (ECM) deposition with highest osteoblastic activity on bioplotted scaffolds which confirmed by von Kossa staining and EDX analysis. The results indicated that the synthesized PEU based scaffolds were able to induce osteoblastic differentiation and mineralization of BMSC and therefore these scaffolds can be good candidates to be used in bone tissue engineering
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Nishioka, Marcia G. "Identification of Carcinogenic Di-amines in the Indoor Environment from Common Urethane Polymer Products." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu148344608670484.
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Suzuki, Shinya. "Rheological Properties of Telechelic Associative Polymer in Aqueous Solution." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/200500.
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Bass, Roger Wesley. "Synthesis and Characterization of Self-Healing Poly (Carbonate Urethane) Carbon-Nanotube Composites." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/2999.
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Synthesis of high molar mass polycarbonate polyurethanes using a novel polyol is described. The resulting elastomers demonstrate excellent mechanical properties as well as the capability to re-heal after rupture without the addition of additives or imbedded healing agents. The self-healing functionality is shown to greatly improve with the addition of up to 1% single and multi-walled carbon nanotubes. The interface of the carbon nanotubes and self-healing polymer are probed using Raman techniques and provide an insight into how the self-healing actions are improved with the addition of carbon nanotubes.
Synthesis of polycarbonate polyurethanes and carbon nanotube composites using a novel casting method is described and compared to the more traditional solution casting method. The dispersion of the carbon nanotubes is evaluated as well as the effect of effective dispersion on the composites through tensile testing, rheometry and hardness testing. Although complete agglomeration avoidance could not be achieved, significant size decrease was observed. Over 200% improvement in tensile strength is shown with conventional solution casting method which is further improved by the described novel solution casting method.
Contact angle measurements on our novel self-healing poly (carbonate urethane) and CNTs composites show that surface energies are drastically changed when CNTs are used. The most revealing finding is that f×svp increases in CNT composite materials from ~30% of the surface energy on average for the samples tested, to ~80%. We have shown that surface free energies increase most likely as a result of exposing hydrogen bonding sites typically found within the bulk in polyurethanes. Our polyurethane differs from traditional polyurethanes in that it has both novel soft segments made from a novel polycarbonate polyol discussed in chapter 2 and relatively soft ¡§hard¡¦ segments resulting from the use of H12MDI, all leading to increased ability to hydrogen bond within the material. The availability of the hydrogen bonding sites is demonstrated by FTIR absorbance bands for associated and unassociated hydrogen bonding sites, which do not seem to be accessible to a large until the PCPU¡¦s surface is disrupted. Once disrupted, the exposed hydrogen bonding sites are able to bond with other bonding sites of adjacent ruptured surfaces. This would explain why our material is non-blocking, e.g. won¡¦t stick to itself, until the surface is ruptured. It would also explain why any two ruptured surfaces of our material will reheal, even if they were not attached previously.
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Asplund, Basse. "Biodegradable Thermoplastic Elastomers." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7434.
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Nelsen, Tyler S. "Performance of Concrete Bridge Deck Surface Treatments." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/314.
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The purpose of this research was to identify the types of surface treatments available for use on concrete bridge decks and to determine which materials are most capable of providing long-term protection from contamination by chloride ions. The products addressed in this report primarily include urethanes, silicon-based sealers, and epoxies. An extensive literature review was conducted to document common overlay distresses, performance histories, and properties of specific surface treatment products currently available in the industry. In addition, three reports summarizing in-house experiments performed by the Utah Department of Transportation between 1995 and 2003 regarding various types of surface treatments were reviewed as part of this research. Finally, a nationwide questionnaire survey was conducted to investigate the state-of-the-practice with regard to surface treatment applications on bridge decks by state departments of transportation throughout the United States. Of the three types of materials addressed in this research, epoxy-based products have the greatest ability to protect concrete and remain uncracked with an acceptable level of skid resistance. Silicon-based products do not crack because they seep into the pores of the concrete, but they do not protect the concrete from the wearing effects of traffic or improve skid resistance. Published field studies indicate that urethane surface treatments do not resist the effects of traffic as well as epoxy-based materials, nor do they offer a substantial decrease in expense or health risk when compared to epoxy-based products. The results of the nationwide questionnaire clearly indicate that bridge deck surface treatments are valuable as both chloride barriers and skid-resistant wearing courses. No standard practice appears to exist with regard to timing of surface treatments, however. Some states arbitrarily apply surface treatments at 10 to 12 years after construction, other states wait until cracking has become fairly considerable before action is taken, and still other states apply surface treatments when the chloride content of the concrete reaches a certain level. Because concrete decks with significant cracking are not ideal substrates for polymer applications, surface treatments should be applied as preventive measures early in the service lives of bridge decks to effectively prevent chloride concentrations from reaching critical levels. This research suggests that epoxy-based surface treatments should be specified for concrete bridge decks when both a chloride barrier and improved skid resistance are desired. If a chloride barrier is all that is needed or desired, a silane surface treatment should be considered; silane treatments are less expensive and easier to apply than epoxy treatments. When a large amount of epoxy is to be mixed, automatic proportioning equipment that can precisely monitor and control the ratios of components should be employed.
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Julien, Tamalia. "Synthesis, Modification, Characterization and Processing of Molded and Electrospun Thermoplastic Polymer Composites and Nanocomposites." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7631.
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This dissertation focuses on the versatility and integrity of a novel, ultrasoft polycarbonate polyurethane (PCPU) by the introduction of nanoparticles and lithium salts. Additionally, the research takes into account the use of electrospinning as a technique to create PCPU and polyimide (PI) fibers. These polymers are of interest as they offer a wide range of properties and uses within the medical and industrial fields.
An industrial batch of an ultrasoft thermoplastic polyurethane (TPU) was synthesized using a two-step process. The first was to create an end capped pre-polymer from methylene bis (4-cyclohexylisocyanate), and a polycarbonate polyol made up of 1,6- hexanediol and 3-methyl-1,5-pentanediol. The second step was done by reacting the pre-polymer with an excess of the polycarbonate polyol with a chain extender, 1,4-butanediol. Biocompatibility testing such as USP Class VI, MEM Elution Cytotoxicity and Hemolysis toxicology reported that PCPU showed no toxicity. This novel type of polyurethane material targets growing markets of biocompatible polymers and has been used for peristaltic pump tubing, but also can be utilized as balloon catheters, enteral feeding tubes and medical equipment gaskets and seals. This material is ideal for replacing materials such as soft plastisols containing diethylhexyl phthalate for use in biomedical and industrial applications. After extensive characterization of this polymer system another dimension was added to this research.
The addition of nanoparticles and nanofillers to polyurethane can express enhanced mechanical, thermal and adhesion properties. The incorporation of nanoparticles such as nanosilica, nanosilver and carbon black into polyurethane materials showed improved tensile strength, thermal performance and adhesion properties of the PCPU. Samples were characterized using contact angle measurements, Fourier transform spectroscopy (FTIR), differential scanning calorimetry (DSC), parallel plate rheology and tensile testing.
The second chapter entails the fabrication and characterization of PCPU nanofibers and nanomembranes through a process known as electrospinning. The resulting PCPU nanomembranes showed a crystalline peak from the WAXS profile which is due to electrospun and solution strain induced crystallinity. The PCPU nanocomposite nanomembranes displayed increased thermal stability and an increase in tensile performance at higher weight percent. The nanomembranes were investigated using contact angle measurements, thermogravimetric analysis (TGA), DSC, WAXS, SAXS and tensile testing.
The final chapter focuses on investigating the rheological properties of PCPU/lithium electrolytes as well as transforming an unprocessable polyimide powder into a nanomembrane. The PCPU/ lithium composite electrolyte showed an increase in the activation energy and conductivity, while the PI/lithium showed increased conductivity over time. Dynamic mechanical analysis and four-point probe was used to investigate the samples.
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Kaiser, Ricky L. "Synthesis and Characterization of ABA Block Polyurethanes and Block Poly(Ether Urethanes) Containing Pendant-Functionalized DIol Monomers." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1418317693.
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Leadbitter, J. "Structure-property relationships in reaction injection moulded polymers and polymer composites : Structure-property studies of reaction injection moulded polyurethanes, polyesters, polyacrylates and novel acrylic-urethane blends and of composites of these." Thesis, University of Bradford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384311.
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Bell, Tyler J. "Development and Implementation of Dispersion Phase Diagrams (DPDs) for Four Different Hydrophobically Modified Ethoxylated Urethane (HEUR) Based Acrylic Paint Systems." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1210.
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Latex polymers serve as binders in a wide range of architectural paints and coatings. A latex is an aqueous colloidal dispersion of polymer particles that when dried above the polymer’s film formation temperature coalesces into a dry polymer film (Dragnevski, Routh, Murray, & Donald, 2010). The other main components of paint include associative thickeners, surfactants, pigments and fillers with the thickener being the primary area of focus for this study.
The relatively simple system of latex, associative thickener and surfactant has been studied extensively. These studies have shown the mechanism of thickening for the associative thickener, and surfactant effects on both latex and thickener; however, there are few studies conducted for a fully-formulated system. The introduction of pigments, fillers, coalescing aids, functional amines, and other additives greatly increases the difficulty of research in this area. The addition of many additives ultimately affects the stability and physical properties of the end-product. Phase separation of the paints, also called syneresis, is a major concern of paint formulators because paints need to be as stable when left sitting in a paint-can for an extended period of time. The goal of this project is to essentially probe the areas of phase separation for some hydrophobically modified ethoxylated urethane (HEUR) thickened paint systems that are very similar to commercially used paint formulations. The probing of these phase separated regions includes the careful preparation of each paint sample, physical property testing, as well as new experimental development in the area of syneresis, rheology, followed by statistical analysis of data.
Dispersion phase diagrams (DPDs) were first reported by Kostansek (2003) in a simple system of HEUR thickener, surfactant, and latex. They are a plot of the three possible dispersion states for an associative thickened system. These states include bridging flocculation which occurs at low levels of HEUR in which 50% or less of the latex particle surface is covered by the associative thickener. The second state is a good dispersion, which does not show any signs of flocculation. The third state is a mode of flocculation called depletion flocculation that occurs when the particle surfaces of the system are covered mostly with surfactant. The free associative polymer in the system is excluded from the free space in between particles, and the latex particles form aggregates (Otsubo, 1995). The three dispersion phases are then plotted with wt% HEUR on the continuous phase versus wt% surfactant on the continuous phase. The ideal end product for this project would be to use various combinations of latex, surfactant, and associative thickeners (ATs) to create multiple DPDs, which then could be used to troubleshoot formulations and samples in which flocculation is present.
Each formulation was made using a thickening package of two non-ionic HEURs: a low-shear and high-shear thickener. Surfactant additions were made after the HEUR in small incremental amounts. Each DPD would consist of one surfactant, the previously stated combination of HEURs, and an all-acrylic latex. Three different surfactants were used in the study: two non-ionic surfactants, and an anionic surfactant. The first non-ionic surfactant was not studied in full as the other two surfactants due to time constraints. Two different all-acrylic latexes were used which varied in the particle size. The first latex studied, Acrylic-A, has an average particle size of 105 nm, and the second latex was Acrylic-B with 150 nm particle size. The TiO2 used in each DPD was surface treated and used in powder form. By the end of the project, 4 full-scale DPDs were made with the following combinations: Acrylic-A and a non-ionic surfactant, Acrylic-A and an anionic surfactant, Acrylic-B and a non-ionic surfactant, and Acrylic-B and an anionic surfactant. From these DPDs the mechanistic interactions of various components of the system could be made. The DPDs could also be used to troubleshoot problematic paints and even hypothesize new formulations.
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Kull, Kenneth. "Synthesis and Characterization of Novel Polyurethanes and Polyimides." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6530.
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Four novel high performance soft thermoplastic polyurethane elastomers utilizing methylene bis(4-cyclohexylisocyanate) as a hard segment, 1,4 butanediol as a chain extender and modified low crystallinity carbonate copolymer as a soft segment were synthesized. The samples were characterized by infrared spectroscopy (FTIR), tensile, elongation, hardness, abrasion resistance and atomic force microscopy (AFM). SAXS data shows evidence of an interdomain "center-to-center" distance of 45Å. DSC traces show evidence of one glass transition temperature and a weak melting region. DMA analysis reveals a low temperature secondary relaxation and the glass to rubber transition followed by a rubbery plateau. All samples demonstrated the ability to maintain excellent physical and mechanical properties in hardness below 70 Shore A. Thermoplastic polyurethanes in this study do not possess surface tackiness usually observed in soft polyurethanes. Biocompatability testing showed no toxicity of these samples as indicated by USP Class VI, MEM Elution Cytotoxicity and Hemolysis toxicology reports. This novel type of polyurethane material targets growing markets of biocompatible polymers and can be utilized as peristaltic pump tubing, balloon catheters, enteral feeding tubes and medical equipment gaskets and seals.
Polyimides are a family of engineering polymers with temperature stability, high polarity and solvent resistance. These high-performance materials are used in aerospace applications, in the production of semi-dry battery binders, and in a host of other high temperature demanding situations. However, their glass transition and melt temperatures are characteristically very high and close to one another, making them difficult to melt process and limiting them to thin film formulations from their polyamic acid precursors. Here, a new series of thermoplastic polyether-polyimides (PE-PIs) are synthesized by incorporating a polyetherdiamine monomer to reduce rigidity and break up an otherwise fully aromatic backbone as seen with most conventional polyimides. It will be shown that control of the stoichiometric ratio between the aromatic 4,4'-methylenebis(2,6-dimethylaniline) and aliphatic polyetherdiamines relative to PMDA (pyromellitic dianhydride), along with the molecular weight of the polyetheramine, can be used to tune the Tg to best balance between temperature performance and processability.
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Rahimi, Alireza. "Investigation of Novel Approaches for Improved Amphiphilic Fouling-Release Coatings." Diss., North Dakota State University, 2020. https://hdl.handle.net/10365/32075.
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Marine biofouling has troubled mankind, both environmentally and economically, since they set sail, resulting in many undesired consequences such as increased drag, reduced maneuverability, increased fuel consumption and greenhouse gas emissions, and heightened maintenance costs. This problem is highly complex as it involves more than 4000 marine organisms with varying modes of adhesion and surface preferences as well as many aquatic environments. The common state-of-the-art approaches to contend with marine biofouling on the submerged surfaces of ships in seawater has antifouling (AF) and fouling-release (FR) surfaces.
As AF coating systems utilize biocides which are often toxic to the environment to prevent settlement of biofoulants, the endeavors have been shifted towards non-toxic FR marine system. Many FR systems take advantage of low surface energy and modulus polydimethylsiloxane (PDMS) on their surface, while the recent attempts explored the simultaneous effect of PDMS and hydrophilic moieties (i.e. polyethylene glycol (PEG) or zwitterionic polymers) on an FR surface, known as amphiphilic surfaces. Thus, the work in this dissertation focused on attaining amphiphilic surfaces with desirable FR performance.
The studies in this dissertation were investigated to deliver two goals: 1) Enhancing the (FR) fouling-release performance of previously developed coating systems; 2) Introducing novel fouling-release marine coatings with set criteria. To address the former, a series of amphiphilic additives containing PDMS and hydrophilic polymers (zwitterionic-based or PEG) were prepared in chapters two-five. These additives were incorporated in several previously developed FR coating systems in order to modify their surfaces and enhance their FR performance. To address the latter, two amphiphilic marine coating systems were explored for accessing durable, non-toxic, and effective FR surfaces using epoxy-amine crosslinking chemistry. Overall, the studies in this dissertation not only demonstrated viable FR surfaces with desirable performance against several representative marine organisms such as N. incerta, U. linza, C. lytica, barnacles, and mussels but also contributed a deeper understanding about the effect of amphiphilicity concentration/balance on surface and FR properties.
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Nar, Mangesh. "Structural, Thermal and Acoustic Performance of Polyurethane Foams for Green Buildings." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699971/.
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Decreasing the carbon footprint through use of renewable materials has environmental and societal impact. Foams are a valuable constituent in buildings by themselves or as a core in sandwich composites. Kenaf is a Southeast USA plant that provides renewable filler. The core of the kenaf is porous with a cell size in a 5-10 micrometer range. The use of kenaf core in foams represents a novel multiscalar cellular structural composite. Rigid polyurethane foams were made using free foaming expansion with kenaf core as filler with loadings of 5, 10 and 15 %. Free foaming was found to negatively affect the mechanical properties. An innovative process was developed to introduce a constraint to expansion during foaming. Two expansion ratios were examined: 40 and 60 % (decreasing expansion ratio). MicroCT and SEM analysis showed a varying structure of open and closed cell pores. The mechanical, thermal insulation, acoustic properties were measured. Pure PU foam showed improved cell size uniformity. Introducing kenaf core resulted in decreasing the PU performance in the free expansion case. This was reversed by introducing constraints. To understand the combined impact of having a mixed close cell and open cell architecture, finite element modeling was done using ANSYS. Models were created with varying percentages of open, closed, and bulk cells to encompass entire range of foam porosities. Net zero energy building information modelling was conducted using EnergyPlus was conducted using natural fiber composite skins. Environmental impacts for instance global warming potential, acidification, eutrophication, fossil fuel consumption, ozone depletion, and smog potential of the materials used in construction was studied using life cycle assessment. The results showed improvement on energy consumption and carbon footprint.
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Ho, Wing-hang Angela, and 何穎恆. "Biocompatibility and efficacy of five-channel and eight-channel crosslinked urethane-doped polyester elastomers (CUPEs) as nerve guidance conduit for reconstruction of segmental peripheral nerve defect using rat model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193523.
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Introduction
Peripheral nerve injury is common in clinical practice. The usual etiologies are penetrating injury, stretch, compression, crush and ischemia. Outcome of nerve injury depends on the etiology and also the management. Nerve defect is a challenging scenario. The current gold standard of managing a nerve defect is autologous nerve graft.
However, due to the selection of nerve graft and donor site morbidity, artificial nerve conduits are gaining popularity. However, there are drawbacks of single hollow conduit such as lack of internal support to prevent conduit collapse and inability so as to recreate the proper native spatial arrangement of cells and extracellular matrix within the conduit. In this study, the biocompatibility and efficacy of five-channel and eight-channel Crosslinked Urethane-doped Polyester Elastomers (CUPEs) as nerve guidance conduit will be evaluated through a rat model with reconstruction of segmental peripheral nerve defect.
Material and method
Eighteen adult Sprague-Dawley rats were used. Tthey were randomly allocated to three groups: autograft group, five-channel conduit group and eight-channel conduit group with each consisted of six rats. A 10mm nerve defects were created at the right sciatic nerve. They were bridged with reverse autograft, 5-channel conduit and 8-channel conduit. After eight weeks the rats were euthanized and the reconstructed nerves were harvested for histomorphometric analysis.
Results
All conduits showed regenerated nerve tissue inside. There was no collapse of the conduits. There were no severe tissue reaction or scarring near the reconstructed nerve. No neuroma was formed. Histomorphometric analysis showed nerve regeneration was enhanced with increasing number of channels inside conduit. There was overall drop in fiber density between proximal and distal segment among all groups.
Conclusions
CUPE nerve guidance conduit is biocompatible and shows good nerve regeneration in reconstructing nerve defect.published_or_final_version
Obstetrics and Gynaecology
Master
Master of Medical Sciences
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Borth, David J. "Non-Destructive Evaluation of Urethane-Ester Coating Systems Using the Scanning Kelvin Probe Technique." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1524749968517527.
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Yip, Siu-leung, and 葉紹亮. "Biocompatibility and efficacy of a new synthetic polymer, crosslinked urethane-doped polyester elastomers (CUPEs), as nerve conduit forreconstruction of segmental peripheral nerve defect using rat model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45153759.
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Nelsen, Tyler. "Performance of concrete bridge deck surface treatments /." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd810.pdf.
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Shmelin, George. "A new rheological polymer based on boron siloxane cross-linked by isocyanate groups." Thesis, University of Hertfordshire, 2012. http://hdl.handle.net/2299/13901.
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The research described in this thesis originated from an idea to develop new body protection for the sport of fencing. The ultimate goal is to develop body armour which would be flexible, wearable, washable, light and breathable, offer protection from injuries and cover the entire body of a sportsman. A new material which exhibits shear thickening behaviour has been specially developed for this purpose in the process of this investigation. The material was designed and synthesised as a soft polymeric system which is flexible, chemically stable and able to increase the value of its modulus of elasticity upon impact at a high strain rate, while remaining in its soft gel-like elastomeric state when low strain rate deformation is applied. The polymeric system that has been developed is based on interpenetrating polymeric networks (IPN) of immiscible polyurethane/urea-ester/ether and poly(boron)n(dimethylsiloxane)m (where on average m ≈ 16 n). In addition, as the polydimethylsilane (PDMS) based polymeric system strongly tends to phase separation, the siloxane polymeric network was chemically cross-linked to the polyurethane polymeric network through polyurethane chemical cross-link-bridges. In order to introduce polyurethane cross-links to a siloxane-based polymeric network, some of the attached methyl groups in the PDMS polymeric backbone were substituted by ε-pentanol groups. The resulting polymeric system combines properties of an alternating copolymer with IPN. The actual substitution of the methyl groups of PDMS into alternating ε-pentanol groups was performed by Grignard reaction of trifunctional chlorosilane monomers, magnesium and 1,5-dibromopentane. Chemical analytical techniques like FT-IR, 13C NMR and 1H NMR spectroscopy were used to reveal the chemical structure of the synthesised polymeric network. The mechanical and dynamical properties of the obtained polymeric system were analysed by dynamic mechanical analysis (DMA). This part of the investigation indicated that the novel polymeric system exhibited shear thickening behaviour, but only at a narrow diapason of deformations (i.e., deformations between 2 to 3 % of the length of the sample). At this limited diapason of deformation an effective increase of the modulus of elasticity from 6 MPa (at lower frequencies, i.e., up to ≤6 Hz of the applied oscillating stress) to 65 MPa (at frequencies between 12.5 to 25 Hz) was obtained. However, no increase in the modulus of elasticity was recorded at deformations below 1.5 % or above 3.5 % of length of the sample at the same frequencies (0 to 25Hz) of the applied oscillating stress.
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Iurzhenko, Maksym. "Electrical, thermomechanical and sorption properties of hybrid organic-inorganic systems based on urethane oligomers and silicates." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00689865.
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L'objectif de cette recherche est d'établir des mécanismes de formation de la structure des systèmes hybrides organique-inorganique à base des oligomères uréthane et silicates en fonction de la réactivité de la composant organique, d'identifier l'impact de l'organisation structurelle du OIS obtenue sur leurs propriétés électriques et thermomécaniques, de sorption et de l'activité du capteur. La signification pratique des résultats est la détermination de l'impact de la réactivité composant organique sur la structure des systèmes hybrides polymère organique-inorganique avec la possibilité d'obtenir des matériaux avec des propriétés spéciales prévisibles. Les résultats peuvent être utilisés comme base scientifique pour comprendre l'interconnexion de la structure, les propriétés et les moyens de leur régulation en direction de systèmes hybrides polymère organique-inorganique. La sensibilité très élevée pour les différents types de solvants, qui, combiné avec une haute sélectivité, a été révélé pour les systèmes de synthèse, la possibilité de leur utilisation pratique en tant que matières capteur existe.
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Pavier, Claire. "Oxypropylation de la pulpe de betterave à sucre et utilisation des polyols obtenus pour la préparation de nouveaux matériaux polyuréthanes." Grenoble INPG, 1998. http://www.theses.fr/1998INPG0041.
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L'industrie sucriere, basee sur la betterave a sucre, donne une quantite importante de pulpe, un dechet dont il n'a pas encore ete trouve d'utilisation en tant que source de materiaux. Cette pulpe de betterave est compose essentiellement de polysaccharides et est particulierement riche en fonctions hydroxyles. Alors que l'oxypropylation de la cellulose, de la lignine et plus recemment du chitosane, aient ete etudiees, aucune investigation equivalente sur la pulpe de betterave n'a ete conduite avant ce travail. Le but de cette etude a ete de transformer un solide insoluble dans tous les solvants en un polyol liquide visqueux adapte a l'elaboration de polyurethanes apres melange avec des polyisocyanates. La premiere etape de ce travail consistait a examiner la faisabilite puis a optimiser la reaction d'oxypropylation de la pulpe de betterave a sucre. La reaction a ete menee en suspendant la pulpe dans de l'oxyde de propylene (op) en presence de differents catalyseurs basiques et en chauffant ce melange sous pression. En faisant varier differents parametres, on obtient des polyols possedants des viscosites et des indice d'oh differents. Il s'avere que ces liquides visqueux sont en fait des melanges homogenes de pulpe oxypropylee et d'homopolymeres de op. Ces polyols ont ete utilises seuls ou en combinaison avec des extenseurs de chaines (diols d'origines diverses) pour l'elaboration de polyurethanes a la fois sous forme de materiaux pleins (en utilisant le procede rim) et de mousses. Les cinetiques de ces polymerisations ainsi que la caracterisation des materiaux obtenus ont ete correlees avec la composition du melange reactionnel. Les proprietes de ces nouveaux polyurethanes suggerent que la pulpe de betterave a sucre peut constituer un dechet agroindustriel viable, base sur l'exploitation agricole d'une ressource renouvelable, pour l'elaboration de materiaux polymeres originaux.
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Niddam-Mercier, Pascale. "Matériaux macromoléculaires à conduction ionique pour générateurs électrochimiques au lithium." Grenoble INPG, 1990. http://www.theses.fr/1990INPG0134.
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Cette recherche concerne la synthese et l'etude de reseaux de polyethers en vue de leur utilisation comme electrolytes solides dans les generateurs electrochimiques au lithium. Trois reseaux de polyethers de nuds de reticulation differents ont ete synthetises: 1) un reseau a nuds urethanne; 2) un reseau a nuds urethanne-siloxane; 3) un reseau a nuds siloxane. La synthese de reseau a nuds siloxane a permis de mettre en evidence la presence de reactions secondaires lors de l'hydrosilylation du poly(oxyethylene) (poe) diallyle, de masse 2000, par le triethoxysilane. Il a ete egalement montre l'influence de la masse du poe et de la nature du silane sur le rendement de l'hydrosilylation. L'etude comparative des proprietes de transport des trois reseaux a montre l'influence de la nature chimique du nud de reticulation sur la temperature de transition vitreuse et sur la solvatation du sel de lithium. Un ensemble d'equilibres de dissociation du sel a ete propose afin d'expliquer le mecanisme d'ionisation du sel dans les reseaux de polyethers
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Shen, Hang. "Development of functional biopolymers with controlled architecture." Thesis, Saint-Etienne, 2013. http://www.theses.fr/2013STET4027/document.
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Des polyacides lactiques hydroxy téléchélique de masses molaires variées ont été synthétisés par polymérisation par ouverture de cycle du LLA en présence de 1,4 -butane diol. Des polyhydroxybutyrate hydroxy téléchéliques ont été préparés transesterification du PHB et du 1,4-butanediol catalysée par l'acide p-toluène sulfonique .Ces oligomères ont été utilisés pour préparer des polyesters amides fonctionnalisés acrylates ou mercaptans. Dans une approche parallèle, du PCL multi acrylate a été préparé avec succès par copolymérisation par ouverture de cycle de méthacrylate de glycidyle avec du caprolactone. Des copolymères (GMA -co- CL) ayant des masses molaire et de la fonctionnalité variables, ont été préparés en modifiant les paramètres de la réaction tels que le catalyseur, la nature du co-amorceur et le rapport des stœchiométriques des différents réactifs. Les polymères multi acrylates ont été copolymérisés principalement avec l'HEMA sous irradiation UV pour obtenir des réseaux PLA, PHB et PCL segmentés. Les mécanismes de dégradation de ces réseaux ont été étudiés en examinant particulièrement les décompositions des liaisons uréthanes et esters. Des dépolymérisations du PHEMA ont été détectées avec TGA -FTIR à plus haute température (450°C). Pour les réseaux à base de PCL, les propriétés thermo -mécaniques ont été étudiées. Le résultat montre que les phases riches en PCL ont une bonne compatibilité avec le poly HEMA. Les modules caoutchoutiques et l’étendue des températures des zones d’amortissement peuvent être contrôlées en fonction des paramètres réactionnels. Les Polymères multifonctionnels Thiols du PCL, PHA et PLA ont été utilisés pour faire croître des chaines méthacrylates et construire des polymères de type étoileHydroxyl telechelic polylactic acids of various molecular weights were synthesized by ring opening polymerization in the presence of LLA and 1,4-butanediol. Telechelic hydroxy polyhydroxybutyrate were prepared transesterification of PHB and 1,4- butanediol catalyzed by p- toluene sulfonic acid. These oligomers were used to prepare polyesteramides functionalised acrylates or mercaptans. In a parallel approach, the PCL multi acrylate was successfully prepared by ring-opening copolymerization of glycidyl methacrylate with caprolactone. Copolymers (GMA-co-CL) with variable molar masses and functionality were prepared by changing the reaction parameters such as catalyst, the nature of the co-initiator and the ratio of different stoichiometric reagents. Multi-acrylated polymers were copolymerized with HEMA under UV irradiation to obtain PLA, PHB and PCL segmented networks. Degradation mechanisms of these networks have been studied by examining particular decomposition of urethane bonds and esters. Depolymerization of the PHEMA was detected with TGA -FTIR at higher temperature (450°C). For PCL based networks, the thermo- mechanical properties were studied. The result shows that the PCL-rich phases have good compatibility with poly HEMA. The rubber and the working temperature range of the damping zones modules can be controlled as a function of reaction parameters. Multi mercapto functionalized polymers with PCL, PLA and PHA segments were used to grow methacrylate polymer chains and build star type
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Jonquières, Anne. "Influence de la structure des matériaux et perméants sur les propriétés de sorption et de transfert dans des systèmes polymère / liquides organiques : application à la séparation par pervoration de mélanges alcool-éther à l'aide de polyuréthaneimides (PUI) et modélisation du transfert dans le cas d'un système ternaire." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL095N.
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Ce mémoire résume les résultats d'une étude systématique concernant les propriétés d'une importante série de polyuréthaneimides (PUI) copolymères à blocs à structure évolutive lors de la pervaporation de mélanges exclusivement organiques avec un intérêt particulier pour la séparation du mélange azéotropique EtOH/ETBE. Environ 40 polyuréthaneimides ont été synthétisés par une méthode permettant le contrôle de la structure du matériau. Les résultats obtenus en pervaporation ont montré une nette tendance de relations propriétés-structure très utile pour la recherche d'une membrane d'intérêt industriel. Restreinte à des PUI ne différant que par leur segment flexible, cette étude permet d'établir une corrélation quantitative entre la sélectivité en pervaporation et un paramètre de sélectivité d'interaction, défini à partir du paramètre de solubilité du segment flexible calculé à partir de méthodes par contribution de groupes. Une approche nouvelle permet ensuite de corréler les propriétés en pervaporation et en sorption à l'aide de paramètres de polarité. Les corrélations quantitatives sont établies pour de nombreux systèmes ternaires différant par les matériaux ou les perméants impliqués. L'étude de nombreuses données publiées sur la sorption d'un liquide pur dans un polymère montre par ailleurs la généralité de ce type de corrélation qui s'applique à des systèmes très variés. La dernière partie concerne la modélisation du transfert dans le cas d'un véritable système ternaire selon une loi de FICK thermodynamique qui considère la forte non-idéalité du système. Les lois décrivant l'équilibre thermodynamique de sorption sont particulièrement simples et mettent en évidence la saturation préliminaire des groupes uréthane par l'éthanol. La comparaison des différents paramètres calculés (modèle ou perméation différentielle) conduit à remettre en question la validité de la loi de FICK adoptée pour décrire le transfert en pervaporation
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Sousa, Kenia Garrido Marques de. "Estudo Viscosimétrico de Soluções de Pré-Polímeros Uretânicos à Base de Poli(Glicol Propilênico) e Diisocianato de Isoforona." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=104.
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Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de JaneiroNeste estudo, o comportamento em solução diluída de pré-polímeros uretânicos à base de poli(glicol propilênico) (PPG) e diisocianato de isoforona (IPDI) foi avaliado por medidas viscosimétricas a 30 C em dois tipos de solventes, com diferentes polaridades: isopropanol e tolueno. Os pré-polímeros foram sintetizados em massa, ou seja, na ausência de qualquer solvente, e nas formulações foram variadas as razões entre o número de equivalentes-grama de grupamentos isocianato e hidroxila [NCO/OH] e a massa molar do PPG. Os pré-polímeros foram caracterizados por espectrometria na região do infravermelho. No tratamento matemático dos dados viscosimétricos, foram empregadas cinco diferentes equações para determinar os valores de viscosidade intrínseca: Huggins; Kraemer e Schulz-Blaschke, por extrapolação gráfica; e Solomon-Ciuta; Deb-Chanterjee e; novamente, Schulz-Blaschke, para determinações por um único ponto. Os valores de viscosidade intrínseca obtidos pelos dois métodos (extrapolação gráfica e por um único ponto) foram comparados a fim de se verificar a validade da determinação por um único ponto para os sistemas analisados, bem como determinar qual equação seria a mais adequada para esse tipo de cálculo. Foram calculadas as constantes viscosimétricas de Huggins, Kraemer e Schulz-Blaschke, e foi feita uma análise da qualidade do solvente.
In this study the behavior of urethanes prepolymers based on poly(propylene glycol) (PPG) and isophorone diisocyanate (IPDI), in diluted solutions, were studied by viscosimetric measurements, at 30 C, in two types of solvents with different polarities: isopropyl alcohol and toluene. The prepolymers were synthesized in bulk, i.e, in the absence of solvent. In the formulations were varied the ratio between the equivalent-grams number of isocyanate functional groups and hydroxyl group [NCO/OH] and PPG molecular mass. The prepolymers were characterized by infrared spectrometry (FTIR). Five different equations were used to determine intrinsic viscosities values: Huggins; Kraemer and Schulz-Blaschke, by graphic extrapolation; and Solomon-Ciuta; Deb-Chanterjee and; again, Schulz-Blaschke, by a single point determination. The intrinsic viscosities values obtained by two methods (graphic extrapolations and through a single point determination) were compared in order to verify the validity of the single point determination for the systems studied, as well as the more accurate equation for this type of calculation. Viscometric constants from Huggins; Kraemer and Schulz-Blaschke equations were also determined to verify solvent quality.
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Sa-nguandekul, Sopee. "The intraction of associative polymer with inorganic pigment dispersion /." Diss., 1997. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9814987.
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WANG, HSING-LUNG, and 王興龍. "Study on Polyether Poly(urethane-urea) as Polymer Electrolyte." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/95147117805778380880.
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碩士國立成功大學
化學工程學系
88
The behaviors of lithium ions in a polyether poly(urethane urea) (PEUU) were investigated by Differential Scanning Calorimetry (DSC), Fourier Transform Infra-Red (FTIR) spectroscopy, AC Impedance and magic angle spinning (MAS) solid state NMR measurements. The PEUU, used in this study, is composed of polyethylene glycol (PEG, mol. wt. 1000) as the soft segment and 4,4’-methylene bis(cyclohexyl isocyanate) extened with ethylene diamine (EDA) as hard segment. DSC experiments indicate the formation of transient cross links between Li+ ions and the ether oxygens on complexation with LiClO4, resulting in an increase in soft segment Tg. From the FTIR study, an appreciable change in the free as well as both of the hydrogen bonded —NH stretching bands has been observed, which suggests possible interactions of Li+ ions with both hard and soft segments of PEUU. The Arrhenius-like behavior of AC conductivity with reciprocal temperature suggests an activated hopping mechanism for transport of the charge carriers where the charge-carriers are decoupled from the segmental motion of the polymer chains. Significant line broadening, slight upfield chemical shift and short TCH, observed in the 13C NMR spectra for the carbons attached to the ether oxygens as the dopant was added into the polymer, indicates that a coordination between the Li cation and the ether oxygens in the soft segments. A systematic modeling analysis for composite electrolytes prepared by impregnating the ternary composites consisting polyethylene glycol based poly(urethane-urea) (denoted as PEUU(PEG)), polytetramethylene glycol based poly(urethane-urea) (PEUU(PTMG)), and polyethylene oxide (PEO) with LiClO4-PC. The results of swollen weight and conductivity at ambient temperature for composite electrolytes were fitted as empirical regression equations by using mixture design. These empirical equations were plotted as contour diagrams. The results indicates the composite electrolytes showed appropriate conductivities (liquid-like)only when swollen weight were over than 25 %.
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Lin, Chia-Li, and 林佳利. "一.Anti-aldol Reactions of Polymer Supported Vinylogous Urethane." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/37755419810694887101.
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碩士朝陽科技大學
應用化學系碩士班
89
一.Anti-aldol Reaction Studies of Polymer Supported Vinylogous 一.Urethane and their Application in the synthesis of various vinylogous urethane lactones. Polymer Supported Vinylogous Urethane (VU)1, (VU)4 were reacted with aldehydes via Anti aldol reaction.The distributions of products were analyzed by HPLC. 二.Polymer Supported Vinylogous Urethane applied in Combinatorial chemistry Polymer Supported Vinylogous Urethane (VU)6 was applied in Combinatorial chemistry to react with aldehydes via Anti aldol reaction to form anti aldol products. The distributions of products were analyzed by HPLC.
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Tsang, Chou Li, and 周立蒼. "Studies on urethane-aniline coplymer and Polyurethane Interpenetrating Polymer Networks." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/01569664033202409180.
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碩士國立臺灣大學
化學工程學研究所
88
Abstract The aim of this study is to synthesize low molecular weight PANI for improving its solubility. The low molecular weight PANI can be copolymerized with polyurethane prepolymer to form polyurea coplymer. The copolymer was then direct doping with acid, the mechanical property of the resulting copolymer was slightly improved. Furthermore, The Linear blend and Semi Interpenetrating Polymer Networks(Semi-IPNs) of PU-co-PANI/PU were prepared in order to improve the mechanical property of the resulting polymer. The Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry(DSC) , thermogravimetric analysis(TGA),tensile property, scanning electron microscope(SEM) dynamic mechanical analysis(DMA),surface resistivity measurement were performed to investigate mechanical properties, thermal properties, compatibility, surface resistivity and hydrogen bonding of the resulting linear blends and Semi-IPNs. The surface resistivity is much higher than PANI as the PU content increase in the PU-PANI' linear blends or Semi-IPNs. The surface resistivity of the resulting PANI-containing polymers is about 107~1010Ω/sq which is still much lower than pure PU about 1016Ω/sq.The surface resistivity of high PANI-containing Semi-IPNs and linear blends can meet the requirement of the anti-electrostatic materials with the resistivity of 107~1010Ω/sq.The tensile strength of high the value of PANI-containing semi-IPNs and linear blends has been improved and reached the 9.9MPa. Keyword: Polyaniline, Polyurethane, Interpenetrating Polymer Networks, linear blend, anti-electrostatic
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Guo, Jin-ching, and 郭金清. "Polyurethane/Methccrylate-terminated urethane Interpenetrating Polymer Networks for Blood Compatible material." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/16107772487414535363.
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碩士國立臺灣大學
化學工程研究所
81
The HPU/PU IPNs were synthesized simultaneously by solution po- lymerization from different weight ratio of poly( oxytetramethyle- ne) glycol-based PU prepolymer and polyethylene oxide-based HPU prepolymer. As increasing the HPU content in the IPN membranes , the water adsorption of the membrane was increased rapidly. The swelling ratio and sol fraction of IPN membrane increased. The tensile strength increases initially and then decreases,the maxi- mun value in tensile strength is at the 10 wt% of the HPU content The blood compatibility of IPN membranes were measured by means of the relative index of platelet adsorption (RIPA) which were determined from dynamic clotting method at constant shaking speed and temperature. The IPN membranes with 10 wt% HPU content are more compatible to the blood.In general,all membranes have better blood compatibility than the glass. It was found the good blood compatibility for the membrane when the polar term (γsp) of the surface tension is little higher than the dispersion term (γsd) for the membrane .
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Song, Zhong-Guang, and 宋忠廣. "The study of membrane properties of poly-urethane-based interpenetrating polymer networs." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/92066488079032551644.
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Fernandes, Joana Gonçalves. "Writing/erasing 3D micro and nano wrinkles in flexible elastomers for volatile organic compounds sensor." Master's thesis, 2014. http://hdl.handle.net/10362/13930.
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Micro/nano wrinkled patterns on cross-linked urethane/urea polymeric flexible free standing films with two soft segments, polypropylene oxide and polybutadiene, can be induced by UV-irradiation. The ability to write/erase these 3D structures, in a controlled manner, is the main focus of this work. The imprinting of the wrinkled structures was accomplished by swelling in an appropriate solvent followed by drying the membranes after the cross-linking process and UV irradiation. The surface tailoring of the elastomeric membranes was imaged by optical microscopy, scanning electronic microscopy and by atomic force microscopy. To erase the wrinkled structures the elastomers were swollen. The swelling as well as the sol/gel fraction and the UV radiation were tuned in order to control the wrinkles characteristics. It was found that the wrinkles wavelength, in the order of microns (1±0,25μm), was stamped by the UV radiation intensity and exposure time while the wrinkles' amplitude, in the order of nanometers (150-450 nm), was highly dependent on the swelling and sol/gel fraction. A prototype for volatile organic compounds detection was developed taking advantage of the unique 3D micro/nano wrinkles features.