Дисертації: "Polymer solutions Elastic properties"

1

Farmer, David John. "Elastic measurements in ultra-thin polymer structures." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33073/.

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This thesis contains details of a series of experiments performed to investigate the acoustic and elastic properties of ultra-thin polymer structures. Three main investigations were conducted. The first involved studying quantised vibrations in ultra-thin (∼100 nm) polystyrene films on silicon substrates. These films were vibrated via the picosecond acoustic technique, an optical pump-probe method. Quantised, harmonic vibrations were observed in the films with frequencies of the order of 10 GHz. The polymer films were then loaded by evaporating small thicknesses (2.5 - 30 nm) of gold. The frequencies of loaded areas were observed relative to the unloaded films. This frequency shift is described via a theory that considers the elastic wave equation in the structure with appropriate boundary conditions. Excellent agreement between experiment and theory is achieved, suggesting the potential for using these films as ultra-sensitive mass sensors. The second experimental chapter deals with experiments performed on polymer Bragg reflectors. These multilayer structures were again investigated via the picosecond technique. The reflected intensity of the probe laser beam was observed to be modulated by the strain pulse as it travelled through the structure. These results were compared to theoretically generated signals and this comparison suggests that, in the polymer structures considered here, the modulation can be described almost exclusively by the photo-elastic effect. Although the modulation is small it opens up the possibility of using similar structures in combinations with micro-cavities to act as high frequency optical components. The final experimental chapter details attempts to develop a new metrology for elastic properties in ultra-thin polymer films floated on a water surface. The films were cut into annuli and placed on a Langmuir-Blodgett trough before surfactant was placed around the outside. By moving the barriers of the trough, a surface pressure difference between the inside and outside of the annulus could be controlled and a wrinkling pattern induced around the annulus. A system for imaging and counting the wrinkles as a function of the surface pressure difference was developed and a theory that attempts to describe this is detailed. While the experimental technique is successful in producing highly controlled, reproducible wrinkles, the theoretical analysis currently overestimates the Young's modulus of the films. The reasons for this as well as avenues for further work are considered. The results of these three investigations all demonstrate the rich physics accessible in ultra-thin polymer films. Furthermore, it points to their potential to b e a key material as devices are more commonly manufactured at the nano-scale.

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2

Whang, Kyu-ho. "Static and Flow Properties of Dilute Polymer Solutions." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc501073/.

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Small weight percentages of certain high-molecular weight polymers added to liquids in turbulent flow through conduits can result in dramatic friction reduction. Although many current and potential uses of the drag reduction phenomenon exist, there is a fundamental problem: drag reduction efficacy decreases rapidly with flow time due to the mechanical degradation in flow of the added polymer. In this thesis study, dilute aqueous solutions of polyacrylamide were tested under turbulent flow conditions in an attempt to determine where mechanical degradation in flow occurs.

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3

Gutsul, O. V. "The rheological and electrical properties of polymer-colloid solutions." Thesis, БДМУ, 2020. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18320.

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4

Eastman, John. "The shear and extensional flow properties of polymer/surfactant solutions." Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319075.

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5

De, Joannis Jason. "Equilibrium properties of polymer solutions at surfaces Monte Carlo simulations /." [Florida] : State University System of Florida, 2000. http://etd.fcla.edu/etd/uf/2000/ane5947/dissertation%5Fdone.pdf.

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Thesis (Ph. D.)--University of Florida, 2000.
Title from first page of PDF file. Document formatted into pages; contains ix, 242 p.; also contains graphics. Vita. Includes bibliographical references (p. 232-241).

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6

Sukhadia, Tejas. "Prediction of phase equilibria in solutions : an associative reformulation of thermodynamic theories of solutions." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/11886.

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7

Baranowski, Roman. "The properties of polymer/solvent systems at surfaces and interfaces." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25767.pdf.

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8

Mueller, A. J. "Extensional flow of macromolecules in solution." Thesis, University of Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234875.

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9

Omowunmi, Sunday Chima. "Modelling the nonlinear dynamics of polymer solutions in complex flows." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/modelling-the-nonlinear-dynamics-of-polymer-solutions-in-complex-flows(3230a688-0ea4-4620-bda1-396346feb645).html.

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The flow of polymer solutions in the high Elasticity number, El, regime in complex geometries may lead to strong viscoelastic behaviour and eventually become unstable as the Weissenberg number, Wi, is increased beyond a critical level. So far, the success of numerical simulations in predicting the highly non-linear behaviour of polymer solutions in complex flows has been limited. In this thesis, selected constitutive models are evaluated under the high El flow regime in the cross-slot and contraction benchmark flows using a numerical technique based on the finite volume method. The numerical technique is implemented within the OpenFOAM framework and thoroughly validated in the benchmark flow. A modification to the FENE dumbbell model based on the non-affine deformation of polymer solutions is proposed, which enabled the prediction of some non-linear material functions and also enhanced numerical stability, allowing a higher Wi to be attained. Asymmetric flow instability in the cross-slot flow has been studied. Time-dependent stability diagrams were constructed based on Wi and the strain, ε, both of which govern the stretching of a polymer chain. In the contraction flow, elastic instability is simulated for the first time in this geometry. Substantial time-dependent asymmetric flow patterns were predicted as seen in experiments. The effect of the contraction ratio is investigated through a stability diagram. Three-dimensional finite element simulations were also carried out to study the effect of the aspect ratio in the contraction flow of a Phan-Thien-Tanner fluid. The simulations suggest that a lip vortex mechanism is a signature for the onset of strong viscoelastic behaviour.

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10

LaRiviere, Daniel John Christopher. "Viscometric properties of dilute lubricating oil-polymer solutions over a wide temperature range." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ30961.pdf.

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11

Furuya, Tsutomu. "Structure Formation and Physical Properties of Aqueous Polymer Solutions and Hydrogels with Additives." Kyoto University, 2019. http://hdl.handle.net/2433/236625.

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12

Ashrafi, Behnam. "Theoretical and experimental investigations of the elastic properties of carbon nanotube-reinforced polymer thin films." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21910.

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Nanocomposites are a promising new class of materials for the mechanical components of microstructures such as microactuators and microresonators. This work presents a combination of theoretical and experimental investigations of the utility of carbon nanotube-reinforced composites for designing microstructures. In the theoretical part of this research, the effects of nanotube aspect ratio, dispersion, alignment, and volume fraction on the elastic modulus and longitudinal wave velocity are analyzed by recourse to the Mori-Tanaka theory. The calculated bounds on Young's modulus and wave velocity capture the trend of the experimental results reported in the literature. Polymer-matrix nanocomposites reinforced with aligned, dispersed single-walled carbon nanotubes are identified as excellent candidates for small structures with properties rivaling those of metallic- and ceramic-structures used in the current generation of microelectromechanical systems (MEMS). The experimental part of this research focuses on the manufacture and characterization of carbon nanotube-reinforced polymer thin films. A novel nanoindenter-based bending test is developed for characterizing the elastic properties of nanocomposite thin films. This technique is first numerically verified using finite element methods. Polymer thin films with known mechanical properties are then utilized to validate the technique experimentally. Next, epoxy-matrix and vinyl ester epoxy-matrix nanocomposite films (ranging from 50 to 70 μm in thickness) reinforced with low concentrations (<1% by weight) of single-walled carbon nanotubes are successfully manufactured and characterized. Finally, using carbon nanotube sheets (buckypaper), polymer-matrix nanocomposite films with high volume fractions of carbon nanotubes (30-40%) are manufactured by using two different techniques: vacuum infiltration and hot press. This relatively high content of carbon nanotubes results in a three- to four-fold increase in the elasti
Les nano-composites sont une nouvelle classe de matériaux prometteurs pour les composants mécaniques de microstructures telles que les micro-actuateurs et micro-résonateurs. Ce travail présente une combinaison d'études théoriques et expérimentales sur l'utilité de composites renforcés par des nanotubes de carbone pour la conception de microstructures. Dans la partie théorique de cette recherche, les effets du rapport de forme, de la dispersion, de l'alignement et de la fraction volumique des nanotubes sur le module élastique et la vitesse d'onde longitudinale ont été analysés en utilisant la théorie de Mori-Tanaka. Les limites calculées du module d'Young et de la vitesse d'onde capturent la tendance des résultats expérimentaux rapportés dans la littérature. Les nano-composites à matrice polymère renforcée avec des SWNT alignés et dispersés ont été identifiés comme d'excellents candidats pour de petites structures dont les propriétés rivalisent avec les structures métalliques ou céramiques utilisées dans la présente génération de systèmes micro-électro-mécaniques (MEMS). La partie expérimentale de cette recherche focalise sur la fabrication et la caractérisation de films polymères minces renforcés avec des nanotubes de carbone. Du aux difficultés rencontrées avec les techniques traditionnelles pour la caractérisation du module élastique de films polymère minces, une nouvelle technique, un test en flexion par nano-indentation, a été développée avec succès. La technique a été d'abord vérifiée numériquement par la 00 méthode d'éléments finis. Puis des films polymère minces avec des propriétés connues ont été utilisés pour vérifier cette technique expérimentalement. Par la suite, des films minces (épaisseur variant de 50 à 70 μm) de nano-composite à matrice époxy et vinyle-ester renforcées avec de faibles concentrations de SWNT (1% par masse) ont été fabriqués et caractérisés avec succès

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13

Desruisseaux, Claude. "The electrophoretic properties of end-labeled DNA molecules in gels, polymer solutions and free-solutions, a theoretical and experimental study." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/NQ48096.pdf.

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14

Ladin, Dmitry. "Study of the rheological properties of polymer/gas solutions based on a foam extrusion system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0017/MQ49787.pdf.

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15

Raviprasad, Muniyamuthu. "Influence of Molecular Interactions on Elastic Properties and Oxygen Diffusion in PolyButylene Terephthalate Polymer: A Molecular Dynamics Study." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26732.

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In most barrier applications, both mechanical and diffusion properties of the material are important. In this thesis the evaluation of molecular mechanisms responsible for the enhanced elastic properties of Polymer Clay Nanocomposites (PCNs) and the molecular mechanisms of Oxygen diffusion in PolyButylene Terephthalate polymer are presented. Interaction energy between PCN constituents, conformational changes of polymer, interaction energy between Oxygen molecule and polymer, rate of Oxygen and Oxygen diffusion coefficient are evaluated. Molecular simulation studies of PolyButylene Terephthalate (PBT) clay nanocomposite and Nylon6 clay nanocomposite show that a higher crystallinity polymer such as PBT would require higher attractive and repulsive interactions with organic modifier in order to make significant change in the crystallinity of PBT in the nanocomposite and in turn enhance the elastic modulus and hardness. Molecular interactions energy between Oxygen molecule and polymer, change in polymer conformation caused by thermal energy assist the Oxygen molecule to diffuse through polymer.
NSF-EPSCoR FlexEM Grant

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16

Park, Simon S. "On-line measurement of the PVT properties of polymer/CO¦2 solutions using a gear pump." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0003/MQ46081.pdf.

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17

Smith, Steven Richard. "Equilibrium and dynamic properties of side-chain liquid-crystalline polymers in dilute nematic solutions." Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1058202738.

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18

Nanavati, Hemant. "Molecular modeling of the elastic and photoelastic properties of crosslinked polymer networks: a statistical segment approach / by Hemant Nanavati." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8227.

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19

Li, Yumeng. "Multiscale Modeling of the Effects of Nanoscale Load Transfer on the Effective Elastic Properties of Carbon Nanotube-Polymer Nanocomposites." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51197.

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A multiscale model is proposed to study the influence of interfacial interactions at the nanoscale in carbon nanotube(CNT)-polymer nanocomposites on the macroscale bulk elastic material properties. The efficiency of CNT reinforcement in terms of interfacial load transferring is assessed for the non-functionalized and functionalized interfaces between the CNTs and polymer matrix using force field based molecular dynamic simulations at the nanoscale. Polyethylene (PE) as a thermoplastic material is adopted and studied first because of its simplicity. Characterization of the nanoscale load transfer has been done through the identification of representative nanoscale interface elements for unfunctionalized CNT-PE interface models which are studied parametrically in terms of the length of the PE chains, the number of the PE chains and the "grip" position. Referring to the non-functionalized interface, CNTs interact with surrounding polymer only through weakly nonbonded van der Waals (vdW) forces in our study. Once appropriate values of these parameters are deemed to yield sufficiently converged results, the representative interface elements are subjected to normal and sliding mode simulations in order to obtain the force-separation responses at 100K and 300K for unfunctionalized CNT-PE interfaces. To study the functionalization effects, atomistic interface representative elements for functionalized CNT-PE interface are built based on non-functionalized interface models by grafting functional groups between the PE matrix and the graphene sheet. This introduces covalent bonding forces in addition to the non-bonded vdW forces. A modified consistent covalent force field (CVFF) and adaptive intermolecular reactive empirical bond order (AIREBO) potentials, both of which account for bond breaking, are applied to investigate the interfacial characteristic of functionalized CNT-PE interface in terms of the force-separation responses at 100K in both normal opening and sliding mode separations. In these studies, the focus has been on the influence of the functionalization density on the load transfer at the nanoscale interface. As an important engineering material, Epon 862/DETDA epoxy polymer,a thermoset plastic, has also been used as the polymer matrix material in order to see the difference in interfacial load transfer between a network structured polymer and the amorphous entangled structure of the PE matrix. As for thermoset epoxy polymer, emphasis has been put on investigating the effects of the crosslink density of the epoxy network on the interfacial load transfer ability for both non-functionalized and functionalized CNT-Epoxy interface at different temperatures(100K and 300K) and on the functionalization effect influenceing the interfacial interactions at the functionalized CNT-Epoxy interface. Cohesive zone traction-displacement laws are developed based on the force-separation responses obtained from the MD simulations for both non-functionalied and functionalized CNT-PE/epoxy interfaces. Using the cohesive zone laws, the influence of the interface on the effective elastic material properties of the nanocomposites are observed and determined in continuum level models using analytic and computational micromechanics approaches, allowing for the assessment of the improvement in reinforcement efficiency of CNTs due to the functionalization. It is found that the inclusion of the nanoscale interface in place of the perfectly bonded interface results in effective elastic properties which are dependent on the applied strain and temperature in accordance with the interface sensitivity to those effects, and which are significantly diminished from those obtained under the perfect interface assumption for non-functionalized nanocomposites. Better reinforcement efficiency of CNTs are also observed for the nanocomposites with the functionalized interface between CNTs and polymer matrix, which results in large increasing for the effective elastic material properties relative to the non-functionalized nanocomposites with pristine CNTs. Such observations indicates that trough controlling the degree of functionalization, i.e. the number and distribution of covalent bonds between the embedded CNTs and the enveloping polymer, one can tailor to some degree the interfacial load transfer and hence, the effective mechanical properties. The multiscale model developed in this study bridges the atomistic modeling and micromechanics approaches with cohesive zone models, which demonstrates to deepen the understanding of the nanoscale load transfer mechanism at the interface and its effects on the effective mechanical properties of the nanocomposites. It is anticipated that the results can offer insights about how to engineer the interface and improve the design of nanocomposites.
Ph. D.

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20

Vlattas, Cosmas. "A study of the mechanical properties of liquid crystal polymer fibres and their adhesion to epoxy resin using Laser Raman Spectroscopy." Thesis, Queen Mary, University of London, 1995. http://qmro.qmul.ac.uk/xmlui/handle/123456789/25566.

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A number of high performance fibres (aramid, PBZT and PBO) spun from liquid crystal polymer solutions were examined in this work. In particular, a thorough investigation of the mechanical response of these fibres under tensile and compressive deformations was carried out. The major experimental tool employed was the technique of Laser Raman Spectroscopy. It was found that stress-induced changes of these fibres at molecular level are proportional to the macroscopic deformation applied. This correlation is unique for the fibres. A method for converting spectroscopic data to predicted stress-strain curves in tension and compression was proposed. An estimation of their compressive strength was derived and an understanding of the nature of their compressive failure was discussed. The adhesion of these fibres to epoxy resin was also investigated by monitoring in situ the interfacial stresses developed along the interface/interphaseo f model single fibre composite coupons. The strength of the interfacial bond was measured. The effect of various parameters such as fibre modulus, fibre diameter and fibre nature upon the interfacial strength of the various systems was evaluated. The mechanisms of stress transfer along with the nature of interfacial damage was examined accurately. It was found that the major parameter controlling the above mechanisms was interfacial yielding in shear. A numerical appoximation (using Finite Element Analysis) was employed in order to evaluate the experimental results. Finally, general conclusions concerning the performance of these fibres were drawn.

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21

Woelfle, Caroline. "Study of Nanoparticle/Polymer Composites: I) Microstructures and Nonlinear Optical Solutions Based on Single-Walled Carbon Nanotubes and Polymers and II) Optical Properties of Quantum Dot/Polymer Composites." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/26657.

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The overall research theme of this dissertation was the study of nanoparticle/polymer composites. Two types of nanoparticles were utilized: Single-Walled Carbon Nanotubes and quantum dots. Chapter 1 of this thesis comprises an extensive literature review on Carbon Nanotubes, which presents theoretical aspects relevant to the structure and properties of CNTs, methods of purifying and solubilizing CNTs in aqueous and organic solvents and selected applications. This literature review is followed by the study and comparison of the optical limiting performances of different Single-Walled Carbon Nanotubes/conjugated polymer dispersions (Chapter 2). The results obtained are discussed in terms of dispersion of the SWNTs in the polymer solutions and resulting SWNT bundle diameters. Chapter 3 presents the spontaneous assembly of dendrimer patterns induced by SWNTs. Finally, chapter 4 presents a new method for fabricating quantum dot/polymer composites, which uses the extraction of positively charged quantum dot into a hydrophobic liquid. The resulting solution is used as a compatible polymerization medium for poly(methylmethacrylate ) networks enabling the formation of transparent and fluorescent composites.
Ph. D.

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22

Rodrigues, Ferreira Elizabete. "Finite-amplitude waves in deformed elastic materials." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210464.

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Le contexte de cette thèse est la théorie de l'élasticité non linéaire, appelée également "élasticité finie". On y présente des résultats concernant la propagation d'ondes d'amplitude finie dans des matériaux élastiques non linéaires soumis à une grande déformation statique homogène. Bien que les matériaux considérés soient isotropes, lors de la propagation d'ondes un comportement anisotrope dû à la déformation statique se manifeste.

Après un rappel des équations de base de l'élasticité non linéaire (Chapitre 1), on considère tout d'abord la classe générale des matériaux incompressibles. Pour ces matériaux, on montre que la propagation d'ondes transversales polarisées linéairement est possible pour des choix appropriés des directions de polarisation et de propagation. De plus, on propose des généralisations des modèles classiques de "Mooney-Rivlin" et "néo-Hookéen" qui conduisent à de nouvelles solutions. Bien que le contexte soit tri-dimensionnel, il s'avère que toutes ces ondes sont régies par des équations d'ondes scalaires non linéaires uni-dimensionelles. Dans le cas de solutions du type ondes simples, on met en évidence une propriété remarquable du flux et de la densité d'énergie.

Dans les Chapitres 3 et 4, on se limite à un modèle particulier de matériaux compressibles appelé "modèle restreint de Blatz-Ko", qui est une version compressible du modèle néo-Hookéen.

En milieu infini (Chapitre 3), on montre que des ondes transversales polarisées linéairement, faisant intervenir deux variables spatiales, peuvent se propager. Bien que la théorie soit non linéaire, le champ de déplacement de ces ondes est régi par une version anisotrope de l'équation d'onde bi-dimensionnelle classique. En particulier, on présente des solutions à symétrie "cylindrique elliptique" analogues aux ondes cylindriques. Comme cas particulier, on obtient aussi des ondes planes inhomogènes atténuées à la fois dans l'espace et dans le temps. De plus, on montre que diverses superpositions appropriées de solutions sont possibles. Dans chaque cas, on étudie les propriétés du flux et de la densité d'énergie. En particulier, dans le cas de superpositions il s'avère que des termes d'interactions interviennent dans les expressions de la densité et du flux d'énergie.

Finalement (Chapitre 4), on présente une solution exacte qui constitue une généralisation non linéaire de l'onde de Love classique. On considère ici un espace semi-infini, appelé "substrat" recouvert par une couche. Le substrat et la couche sont constitués de deux matériaux restreints de Blatz-Ko pré-déformés. L'onde non linéaire de Love est constituée d'un mouvement non atténué dans la couche et d'une onde plane inhomogène dans le substrat, choisies de manière à satisfaire aux conditions aux limites. La relation de dispersion qui en résulte est analysée en détail. On présente de plus des propriétés générales du flux et de la densité d'énergie dans le substrat et dans la couche.

The context of this thesis is the non linear elasticity theory, also called "finite elasticity".

Results are obtained for finite-amplitude waves in non linear elastic materials which are first subjected to a large homogeneous static deformation. Although the materials are assumed to be isotropic, anisotropic behaviour for wave propagation is induced by the static deformation.

After recalling the basic equations of the non linear elasticity theory (Chapter 1), we first consider general incompressible materials. For such materials, linearly polarized transverse plane waves solutions are obtained for adequate choices of the polarization and propagation directions (Chapter 2). Also, extensions of the classical Mooney-Rivlin and neo-Hookean models are introduced, for which more solutions are obtained. Although we use the full three dimensional elasticity theory, it turns out that all these waves are governed by scalar one-dimensional non linear wave equations. In the case of simple wave solutions of these equations, a remarkable property of the energy flux and energy density is exhibited.

In Chapter 3 and 4, a special model of compressible material is considered: the special Blatz-Ko model, which is a compressible counterpart of the incompressible neo-Hookean model.

In unbounded media (Chapter 3), linearly polarized two-dimensional transverse waves are obtained. Although the theory is non linear, the displacement field of these waves is governed by a linear equation which may be seen as an anisotropic version of the classical two-dimensional wave equation. In particular, solutions analogous to cylindrical waves, but with an "elliptic cylindrical symmetry" are presented. Special solutions representing "damped inhomogeneous plane waves" are also derived: such waves are attenuated both in space and time. Moreover, various appropriate superpositions of solutions are shown to be possible. In each case, the properties of the energy density and the energy flux are investigated. In particular, in the case of superpositions, it is seen that interaction terms enter the expressions for the energy density and the energy flux.

Finally (Chapter 4), an exact finite-amplitude Love wave solution is presented. Here, an half-space, called "substrate", is assumed to be covered by a layer, both made of different prestrained special Blatz-Ko materials. The Love surface wave solution consists of an unattenuated wave motion in the layer and an inhomogeneous plane wave in the substrate, which are combined to satisfy the exact boundary conditions. A dispersion relation is obtained and analysed. General properties of the energy flux and the energy density in the substrate and the layer are exhibited.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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23

Seidel, Gary Don. "Micromechanics modeling of the multifunctional nature of carbon nanotube-polymer nanocomposites." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1881.

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24

Ingremeau, François. "Solutions de polymères sous écoulement : liens entre propriétés microscopiques et manifestations macroscopiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00912345.

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Анотація:

Ce manuscrit présente les résultats d'expériences illustrant différentes manifestations de la présence de polymères dans un écoulement. Pour chacune d'elles, nous étudions l'interaction entre la structure microscopique et l'écoulement.Lorsqu'une goutte se détache d'un capillaire, la colonne de liquide liant la goutte au capillaire doit se rompre. Pour les liquides simples, l'amincissement suit des lois universelles bien établies. La dynamique de détachement d'une goutte de fluide complexe est très différente. Pour les solutions de polymères, après une phase de décroissance rapide du diamètre de cette colonne, il se forme un long filament cylindrique entre la goutte et le capillaire. Afin de mieux comprendre comment les polymères présents en solution donnent naissance à ce filament, nous avons observé leurs conformations au cours du détachement. Ces observations confirment que l'étirement des polymères est à l'origine du ralentissement du processus de détachement. Cependant, lors de l'amincissement du filament, la distribution des longueurs reste inchangée. Ce résultat inattendu, nous a amené à mettre en place une nouvelle méthode pour estimer la viscosité élongationnelle.D'autres expériences sont présentées, l'une porte sur un effet de déplétion qui apparait lors de l'écoulement confiné d'une solution de polymères, alors que l'autre porte sur l'écoulement instable d'une solution concentrée de polymères dans une conduite rectiligne.

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25

White, Christopher Cleaveland. "High frequency viscoelastic properties of polymer solutions." 1994. http://catalog.hathitrust.org/api/volumes/oclc/32426410.html.

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26

Radtke, Douglas Robert. "High frequency viscoelastic properties of polymer solutions." 1986. http://catalog.hathitrust.org/api/volumes/oclc/13959796.html.

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Анотація:

Thesis (Ph. D.)--University of Wisconsin--Madison, 1986.
Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 298-305).

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27

BEARDEN, DANIEL WESLEY. "A QUASI-ELASTIC NEUTRON SCATTERING STUDY OF HYDROGEN DYNAMICS IN AQUEOUS POLYMER SOLUTIONS." Thesis, 1986. http://hdl.handle.net/1911/16036.

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We have used quasi-elastic neutron scattering techniques to study the dynamics of solvent water protons in H$\sb 2$O solutions of deuterated poly(ethylene oxide) (Polyox) at room temperature. Using a slightly modified technique, we also have obtained values for the mean-square vibrational amplitude of polymer protons in powder and D$\sb 2$O solutions of Polyox and trypsin at temperatures between 300K and 75K. To study the dynamics of solvent water in deuterated Polyox (dPolyox) solutions, we used a high energy-resolution spectrometer ($\Gamma\sb{\rm res}\approx$ 100$\mu$eV) so that we could measure the width of the quasi-elastic line for various values of the momentum transfer, Q. The Q-dependence of the quasi-elastic linewidth shows that the diffusive properties of water in these Polyox/water solutions is slightly affected at low (5 polymer wt%) and intermediate (10-20 wt%) polymer concentrations. At high polymer concentration (38 wt%), the water clearly has a reduced diffusion coefficient and an increased residence time compared to bulk water and this may be attributed to the nature of the interaction of the water molecules with the polymer. We were motivated to study the mean-square vibrational amplitude of protons in powder and D$\sb 2$O solutions of Polyox and trypsin because of recent computer simulations on biological macromolecules. We measured the vibrational mean-square amplitude by using a low energy-resolution spectrometer ($\Gamma\sb{\rm res}\approx$ 700$\mu$eV) to measure the intensity of the quasi-elastic peak in a relatively short time compared to standard high energy-resolution techniques. Our results on these 20 wt% solutions at 300K are consistent with conventional quasi-elastic neutron scattering results on the Polyox and with computer simulations of trypsin in solution. The vibrational amplitude was proportional to temperature throughout the temperature range studied, and the proportionality constant is interpreted in terms of an effective spring constant for the motion of the hydrogens. These spring constants are smaller than those for some common chemical bonds indicating that there are significant contributions to the motion of the hydrogens besides vibrational motion.

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28

Rahman, Shamsur. "Shear & Extensional Effects in Internal Flows of Dilute Polymer Solutions." Thesis, 2011. http://hdl.handle.net/1807/31400.

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Shear and extensional flows of dilute polymer solutions were studied experimentally in an attempt to understand the mechanism of polymer-induced drag reduction. A flowcell capable of simulating the dynamics of a turbulent boundary layer, involving the motion of counter-rotating vortices, was designed and fabricated. The pressure drop across the flowcell was measured for different flow arrangements, first with a Newtonian fluid and then with drag reducing, dilute polymer solutions. The pressure drop in excess of the Newtonian baseline, after accounting for viscous effects, was used as a measure of elastic effects. With the dilute polymer solutions, elastic effects were observed both in shear, extensional, as well as presheared extensional flows. These effects can be attributed to additional normal stresses generated by shearing. For extensional flows, the observed effects were independent of elongation rates, indicating that a conclusion regarding the mechanism of drag reduction cannot be made from the flowfield investigated.

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29

"Interaction of polymer chains in solution." 2003. http://library.cuhk.edu.hk/record=b6073531.

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Анотація:

Ngai To.
"May 2003."
Thesis (Ph.D.)--Chinese University of Hong Kong, 2003.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.

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30

Tuan, Yu-Chun, and 段友竣. "P-V-T Properties of Polymer Blend Solutions at Elevated Pressures." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/14845623823414079024.

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Анотація:

碩士
國立臺灣科技大學
化學工程系
89
P-V-T data have been measured for binary and ternary mixtures composed of anisole, PEG-200, PPG-425, and PEGME-350 with a high-pressure densimeter in a temperature range of 298.15 K to 348.15 K and the pressures up to 50 MPa. The variations of densities and excess volumes with composition, temperature, and pressure were investigated. The excess volumes were found to change from positive to negative with increasing the mole fraction of PPG-425 in the PPG-425 + anisole and PPG-425 + PEGME-350. The Redlich-Kister model correlated well the excess volumes at fixed temperature and pressure. The Tait equation correlated accurately the density data over the entire pressure range. The isothermal compressibilities were calculated with the aid of the Tait equation. The magnitudes of the isothermal compressibility follow the order of anisole > PPG-425 > PEGME -350 >PEG-200. Both the FOV( Flory-Orwoll-Vrij ) and the Schotte equations of state were also employed to correlate the P-V-T data. The values of the binary interaction parameters were determined from the specific volumes of binary mixtures. The equations of state with those determined binary interaction parameters predicted the P-V-T properties to within acceptable accuracy for the three ternary mixtures composed of anisole with polymer blends of PEG-200, PPG-425 or PEGME-350.

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31

"Thermally induced association/dissociation of polymers in dilute solutions." Thesis, 2008. http://library.cuhk.edu.hk/record=b6074635.

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Chapter 1 briefly introduces the theoretical background of the association and dissociation of polymer chains or colloidal particles are briefly introduced, including thermodynamic consideration and viscoelastic effect on the formation of mesoglobular phase in dilute polymer solutions, as well as some basic theories and universal models of fractal aggregates.
Chapter 2 details the theories of static and dynamic laser light scattering (LLS) as well as the instrumental set-up. In addition, the invention and set-up of differential refractometer are briefly discussed.
Chapter 3 summarizes laser light-scattering (LLS) and stopped-flow studies of association of cyclic- and linear-poly( N-isopropylacrylamide) (c-PNIPAM and l-PNIPAM) chains in dilute aqueous solutions. Dynamic and static LLS results reveal that the heating leads to a microphase transition. Resultant structures of interchain aggregates depend on the heating rate and the chain structure. In comparison with l-PNIPAM chains, a slow heating of c-PNIPAM chains in the solution results in stable mesoglobules with a lower average aggregation number, a looser structure and a smaller average size (∼290 nm). The temperature-jump induced association of c -PNIPAM chains in the stopped-flow measurement reveals two kinetic stages; namely, the loose packing of contracted c-PNIPAM chains and further contraction-induced fragmentation of initially packed c-PNIPAM chains due to the lack of interchain entanglements. On the other hand, for l-PNIPAM chains, the intrachain contraction and interchain penetration/entanglement simultaneously occur as the temperatures increases, leading to larger and more compact aggregates whose size increases with the solution temperature.
Chapter 4 discusses the association of water-soluble PNIPAM-monolayer-protected gold particles in dilute dispersions induced by heating the dispersions to different final temperatures higher than the lower critical solution temperature (LCST) of PNIPAM chains via the slow and fast processes. LLS was used to trace and characterize the association process, supplemented by transmission electron microscopy (TEM) measurements. The slow heating-and-cooling cycle reveals that the association and dissociation of PNIPAM-protected gold nanoparticles can be easily induced by altering the solution temperatures and the association and dissociation are fully reversible. Fast heating the dispersion to three different temperatures reveals that both the aggregation rate and average aggregation number increase with the dispersion temperature. Furthermore, the fast heating leads to the formation of fractal aggregates. The fractal dimensions of such formed aggregates continuously increases as the time evolves, which can be ascribed to the simultaneous dissociation that leads to the restructuring and rearrangement of the aggregates, resulting in denser structures. It is interesting to note that the structure of aggregate always remains fractal during the whole process.
Chapter 5 shows how water-dispersible nanosized semiconductor CdS particles (quantum dots, QDs) can be synthesized with a protective layer of covalently grafting linear thermally sensitive PNIPAM chains as well as how these CdS particles can be induced into reversible association and dissociation via an alteration of the dispersion temperature. The formation and fragmentation of these QDs aggregates were systematically investigated by laser light scattering (LLS) and confirmed by transmission electron microscopy (TEM). There exists a hysteresis in one heating-and-cooling cycle. The CdS particles stabilized with shorter PNIPAM chains (Mn = 15,000 g/mol) can associate to form larger and denser spherical aggregates with a much higher aggregation number than those grafted with longer PNIPAM chains ( Mn = 31,000 g/mol) in the heating process. The dissociation (fragmentation) in the cooling process has two stages: initially, the aggregates dissociate as the temperature decreases, and then, the fragmentation stops over a wider temperature range before its final complete dissociation at a lower temperature. We attribute such a two-stage fragmentation to a balanced effect of inter- and intra-chain hydrogen bonding as well as to the hydrophobic interaction between PNIPAM chains and CdS particles.
In this Ph.D. thesis, temperature-induced association and dissociation of various polymeric systems were systematically investigated by a combination of static and dynamic laser light scattering (LLS), supplemented by other methods, such as stopped-flow temperature jump, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR).
Ye, Jing.
Adviser: Wu Chi.
Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3533.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.

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32

CHIEN, WANG MENG, and 王孟堅. "PVT Properties of Polymer Solutions of Oligomeric Propylene Glycols at Elevated Pressures." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/03147839633058066084.

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Анотація:

碩士
國立臺灣科技大學
化學工程系
91
Abstract In this study, the densities of polymer solutions were measured with a high-pressure vibrating tube densimeter at temperatures from 298.15 K to 348.15 K and pressures up to 50 MPa. The investigated mixtures include two binary and three ternary systems, containing 1-octanol, acetophenone, anisole, PEGME-350, and PPG-425. The Tait model and a semi-empirical model can correlate accurately the experimental density data over the entire pressure range. The experimental density data were used to calculate the excess volumes, which showed that the excess volumes change from positive to negative as the mole fraction of PPG-425 increasing from zero to unity for 1-octanol + PPG-425 and acetophenone + PPG-425 systems. The excess volumes can be correlated with the Redlich-Kister model. The experimental binary PVT data were also correlated with the FOV, the Schotte, and the Polymer CPHC equations of state, respectively, to determine the binary interaction parameters. By using the parameters determined from experimental data of pure components and binary mixtures, the equations of state predicted the specific volumes of the ternary polymer solutions to within reasonable accuracy.

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33

Ho, Kuan-Li, and 何寬澧. "PVT Properties for Polymer Solutions of PEG and PEGME at Elevated Pressures." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/74320316410957594360.

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Анотація:

碩士
國立臺灣科技大學
化學工程系
90
In this study, we measured the densities for mixed solvents and polymer solutions by a high-pressure densimeter. The mixtures include two binary and three ternary systems, containing anisole, acetophenone, PEG-200, and PEGME-350. Operating temperatures were in a range of 298.15 K to 348.15 K and the pressures were up to 50 MPa. Tait model and a choosed semi-empirical model can correlate accurately the density data. The isothermal compressibilities were calculated with the aid of Tait constants. The magnitudes of the isothermal compressibility follow the order of anisole＞acetophenone＞PEGME-350＞PEG-200. The R-K model was applied to correlate the excess volumes of each binary system. The FOV and the Schotte equations of state were also applied to correlate the PVT data. Both models correlated well the specific volumes of each binary system. With the parameters determined from pure materials and binary systems, the equations of state were used to predict the specific volumes for multi-component polymer solutions. However, the predicted results appear to be larger than the experimental values.

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34

Kuang, Lee Cheng, and 李正光. "Coarse-Grained Molecular Dynamics Simulation of the Aggregation Properties in Conjugated Polymer Solutions." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/09502101302967051096.

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Анотація:

碩士
國立中正大學
化學工程研究所
93
Coarse-grained molecular dynamics simulation, which has been developed consistently from atomistic molecular dynamics simulation and retains the information of chemical structure, is utilized to investigate the aggregation properties of conjugated polymer solutions. Essential single-chain structural parameters including self-diffusivity, radius of gyration, and persistent length are reported. Representative aggregation realizations in two distinct solvent are contrasted and discussed in view of related experimental findings.

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35

Koh, Andrew Yew Chiang. "Preparation, characterisation and properties of thermally-responsive copolymers and emulsions : a thesis submitted towards the degree of Doctor of Philosophy / by Andrew Yew Chiang Koh." 2003. http://hdl.handle.net/2440/21984.

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Анотація:

"May 2003"
Includes bibliographical references (leaves 261-270)
xvi, 271, [16] leaves : ill. ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, 2003

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36

Koh, Andrew Yew Chiang. "Preparation, characterisation and properties of thermally-responsive copolymers and emulsions : a thesis submitted towards the degree of Doctor of Philosophy / by Andrew Yew Chiang Koh." Thesis, 2003. http://hdl.handle.net/2440/21984.

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37

Crain, Patrick Michael. "Polymer/solvent interactions as revealed by dynamic viscoelastic and oscillatory flow birefringence properties for polystyrene solutions." 1991. http://catalog.hathitrust.org/api/volumes/oclc/25662306.html.

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Анотація:

Thesis (Ph. D.)--University of Wisconsin--Madison, 1991.
Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 295-300).

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38

"Laser light scattering studies of some special polymers in solution." 1997. http://library.cuhk.edu.hk/record=b5889179.

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by Kwan Chi Man Simon.
Abstract also in Chinese.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.
Includes bibliographical references.
Abstract --- p.i
Abstract (Chinese) --- p.iii
Acknowledgment --- p.iv
Contents --- p.v
Abbreviations --- p.viii
List of Figures --- p.xiv
List of Tables --- p.xvii
Chapter 1. --- Introduction --- p.1
Chapter 2. --- Theoretical background --- p.4
Chapter 2.1 --- Static laser light scattering --- p.5
Chapter 2.2 --- Dynamic laser light scattering --- p.5
Chapter 2.3 --- Gel Permeation Chromatography --- p.6
Chapter 2.4 --- Chain Flexibility --- p.9
Chapter 2.4.1 --- Flexible chains --- p.9
Chapter 2.4.2 --- Stiff chains --- p.12
Chapter 2.5 --- Calibration between translational diffusion coefficient D and molar mass M --- p.14
Chapter 2.5.1 --- Conversion between line-Width and molar Mass distributions --- p.14
Chapter 2.5.2 --- Using a set of Narrowly Distributed Standards --- p.15
Chapter 2.5.3 --- Using Two or More Broadly Distributed Samples --- p.16
Chapter 2.6 --- "Calibration by off-line GPC, Static and Dynamic LLS" --- p.16
Chapter 2.7 --- References --- p.19
Chapter 3. --- Experimental --- p.21
Chapter 3.1 --- Laser Light Scattering Instrumentation --- p.21
Chapter 3.2 --- Refractive index increment measurement --- p.23
Chapter 3.3 --- Gel permeation chromatography --- p.24
Chapter 3.4 --- References --- p.25
Chapter 4. --- Laser Light Scattering Studies of Soluble High Performance Fluorine- containing Polyimides --- p.26
Chapter 4.1 --- Introduction --- p.26
Chapter 4.2 --- Sample Preparation --- p.28
Chapter 4.3 --- Results and Discussion --- p.28
Chapter 4.4 --- Conclusion --- p.40
Chapter 4.5 --- References --- p.42
Chapter 5. --- Characterization of novel optically active conjugated polyarylenes and poly(aryleneethynylene)s by a combination of Laser Light Scattering and Gel Permeation Chromatography --- p.45
Chapter 5.1 --- Introduction --- p.45
Chapter 5.2 --- Sample Preparation --- p.48
Chapter 5.3 --- Results and Discussion --- p.48
Chapter 5.4 --- Conclusion --- p.56
Chapter 5.5 --- References --- p.61
Appendix --- p.62
Chapter A.1 --- Static laser light scattering --- p.62
Chapter A.1.1 --- Scattering from a small particle --- p.62
Chapter A. 1.2 --- Scattering from a large particle --- p.62
Chapter A. 1.3 --- Scattering by macroscopic systems and Theory of Fluctuations --- p.65
Chapter A.1.3.1 --- Scattering by gases and liquids --- p.67
Chapter A. 1.4 --- Scattering by solutions of small molecules --- p.68
Chapter A. 1.4.1 --- Scattering from polymer solution --- p.70
Chapter A.2 --- Dynamic laser light scattering --- p.71
Chapter A.2.1 --- Line-width measurement --- p.75
Chapter A.2.2 --- Data analysis --- p.77

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39

Ayranci, Cagri. "Predicting the Elastic Properties of Two Dimensionally Braided Tubular Composite Structures Towards the Design of Braid-Reinforced Polymer Medical Catheters." Phd thesis, 2010. http://hdl.handle.net/10048/1169.

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Two-dimensionally (2D) braided tubular composites have been utilized in a wide range of applications including medical equipment such as braided stents and catheters. Catheters are long flexible tubes used in catheterization procedures, such as angiography and ablations. In this thesis, angiographic catheters were specifically targeted; which are referred as catheters for the remaining of the document. Catheters are typically used with guidewires which provide structural support to the often low rigidity catheters. In some catheterization procedures, it may be beneficial to use a 2D braided catheter for increased control and maneuverability in the body. The 2D braided catheter, if designed properly, may provide all the required rigidities for a successful procedure and decrease the dependency to the guidewire compared to conventional catheters. Hence, use of 2D braided catheters may decrease the procedure time, may provide superior control of the device due to its design, and may also decrease the inherent patient discomfort. A thorough understanding of 2D braided composites is of absolute necessity considering the delicate use of medical equipment, such as catheters, in the human body. The aim of this PhD thesis is to address the shortcomings of the available models in the literature by developing an analytical model geometrically consistent with small braided tubular structures and provide all the necessary tools possible to design a target specific braided catheter. An analytical model that accounts for the effect of diameter of a braided tubular product on the elastic properties, needed for catheter design, was developed. Parametric studies were conducted to highlight the effects of the change in radius on elastic properties of braided composites. Case studies that underline the important geometrical parameters that affect predictions were conducted and findings discussed. Effect of increased undulation length on elastic properties of braided composites was also investigated. The findings were compared to experimental work using three different fiber/matrix system composites. As predicted by the model, a decrease in the properties was observed experimentally; however, this decrease was found to be more important than predicted. Possible reasons for this behavior are discussed in the view of composite materials and geometrical factors. The experimental findings of the open-mesh composites were also used to further validate a regression based model available in the literature. Lower linearity limit values for the regression based model were calculated for longitudinal elastic and shear moduli predictions.

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40

Chang, Chih-Shun, and 張智舜. "The Aggregation and Gelation Behavior and Its Effect on the Photophysical Properties of Polyfluorenes Conjugated Polymer in Solutions." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/05975675913493408263.

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Анотація:

碩士
國立臺灣科技大學
高分子系
98
In this work, we provided insights into effect of the concentration, aging time, temperature, and blended conjugated polymers on the aggregation, gelation mechanism and its effect on the photophysical properties of polyfluorenes conjugate polymer in solutions with Static light scattering (SLS), Dynamic light scattering (DLS), Polarized optical microscopy(POM), Wide-angle X-ray diffraction (WAXD) UV-visble absorption(UV-vis), and Photoluminescence (PL) spectra. Firstly, Poly(9,9-dioctylfluorene-2,7-diyl) (PF8), in a good solvent toluene. The conformational structure characterized by the radius of gyration (Rg) and the persistence length (lp) of PF8 in the dilute toluene solution depended strongly on temperature, where the conjugated chains exhibited a more extended conformation as the temperature was raised. The inter-chain interaction above the overlap concentration induced aggregation of PF8 to form network clusters in the solution. Gelation took place when the semidilute PF8 solutions were cooled and subsequently aged at -20 oC. The gel composed of the dynamically arrested PF8-enriched phase and the isotropic phase due to the occurrence of a phase-separation at the subambient temperature. The PF8-enriched phase was mesomorphic, consisting of sheetlike aggregates or membranes. A fraction of the PF8 chains or segments within these sheetlike aggregates formed the beta-phase which dominated the photoluminescence of the gel. The gel structure could be disrupted by heating to ca. 45 oC, above which the corresponding PL spectra displayed a blue shift because of reduced amount of the beta-phase. Then, we provided insights into effect of the concentration, temperature, and aging time on the aggregation, and gelation mechanism and its effect on the photophysical properties of poly(9,9-dioctylfluorene) (PF8), with a poor solvent, methylcyclohexane (MCH), induced by aging and spinning rate at room temperature. Light scattering and optical microscopy revealed that the gelation was driven by a phase-separation occurred through a spinodal decomposition mechanism. Although the spinodal decomposition could proceed to the late stage, the interconnected morphology was arrested to give rise to the gel property of the system. The liquid crystalline phase was further found to consist of sheetlike aggregates as revealed by polarized optical microscopy(POM), in which a fraction of the PF8 chains formed the beta-phase that dominated the photoluminescence (PL) spectrum of the gel. The PF8/MCH gel could be disintegrated by moderate heating to ca. 70 oC. This gel-to-sol transition was accompanied with the disruptions of the sheetlike aggregates and the ??phase that led to homogenization of the solution. In the solid state, the photophysical spectra and crystallinity of thin films changed with increasing spinning rate at spin-coat film attested that the beta-phase in PF8/MCH thin film was deformed accompanied by shear force. Finally, we provided a constant weight content (1.0wt%) but various ratios of PF2/6 in PF8/PF2/6 blended conjugated polymer, aging time, and temperature on the gelation mechanism of Poly(9,9-dioctylfluorene)/Poly[9,9-di-(2-ethylhexyl)-fluorenyl] (PF8/PF2/6) in MCH solution. At PF8/PF2/6/MCH solutions and gels, dynamic light scattering revealed that the sheetlike aggregates (beta-phase) of PF8 conjugate polymer restricted by PF2/6. However, the gelation mechanism of PF8/PF2/6/MCH solutions was driven by the phase-separation occurred through a spinodal decomposition. Herein, the spinodal decomposition temperature, Tsp, gel-to-sol transition temperature, Tg-s, and gelation temperature, Tgel of PF8/PF2/6/MCH solutions decreased as PF2/6 was increased. The fraction of the PF8 chains formed the beta-phase that dominated the photoluminescence (PL) spectrum of the gel was revealed by Avrami equation to prove that the scale of beta-phase from 2-D to 1-D as PF2/6 was increased. The beta-phase of PF8/PF2/6/MCH gel could be disintegrated by moderate heating and increase PF2/6. These results proved that disrupted the sheetlike aggregates and the beta-phase by PF2/6 that led to reduce the intensities at 470 and 490 nm of the PL spectrum.

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41

Chuang, Ching-Heng, and 莊靖恆. "Morphology and Electronic Properties of Semiconducting Polymer and Branched Polyethylene Blends and the synthesis of Self-Healing and elastic random copolymer." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8wkqrq.

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42

Stokich, Theodore M. "The influence of polymer/solvent interactions on the viscoelastic and oscillatory flow birefringence properties of polystyrene and polyisoprene solutions." 1988. http://catalog.hathitrust.org/api/volumes/oclc/19759530.html.

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43

Sharma, Rati. "Theoretical Approaches to the Study of Fluctuation Phenomena in Various Polymeric Systems." Thesis, 2013. http://etd.iisc.ernet.in/2005/3338.

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Анотація:

The goal of this thesis has been to throw light on a selection of open problems in chemical and biological physics using the general principles of statistical mechanics. These problems are all broadly concerned with the role of fluctuations in the dynamics of macromolecular systems. More specifically, they are concerned with identifying the microscopic roots of a number of interesting and unusual effects, including fractional viscoelasticity, anomalous chain cyclization dynamics in crowded environments, subdifffusion in hair bundles, symmetries in the work distributions of stretched polymers, heterogeneities in the geometries of reptation channels in polymer melts, and non-Gaussianity in the distributions of the end products of gene expression. I have shown here that all these effects are expressions of essentially the same underlying process of stochasticity, which can be described in terms of the dynamics of a point particle or a continuous curve that evolves in simple potentials under the action of white or colored Gaussian noise [8]. I have also shown that this minimal model of time-dependent behavior in condensed phases is amenable to analysis, often exactly, by path integral methods [13-15], which are naturally suited to the treatment of random processes in many-body physics. The results of such analyses are theoretical expressions for various experimentally measured quantities, comparisons with which form the basis for developing physical intuition about the phenomena under study. The general success of this approach to the study of stochasticity in biophysics and molecular biology holds out hopes of its application to other unsolved problems in these fields. These include electrical transport in DNA [143], quantum coherence in photosynthesis [144], power generation in molecular motors [145], cell signaling and chemotaxis [146], space dependent diffusion [147], and self-organization of active matter [148], to name a few. Most of these problems are characterized by non-linearities of one kind or another, so they add a new layer of complexity to the problems considered in this thesis. Although path integral and related field theoretic methods are equipped to handle such complexities, the attendant calculations are expected to be non-trivial, and the challenge to theory will be to devise effective approximation schemes for these methods, or to develop new and more sophisticated methods altogether.

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Дисертації з теми "Polymer solutions Elastic properties"

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