Tesis sobre el tema "Polymer tip"
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Xie, Shaoxiong. "COMPARATIVE STUDY ON TIP/TIA/ZRP/TEOS MODIFIED EPOXIDES RESIN: ANTI-CORROSION PERFORMANCE". University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1534159109126582.
Texto completoAgapov, Rebecca L. "Advanced Scanning Probe Techniques for the Study of Polymer Surfaces". University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1352922649.
Texto completoRice, Reginald H. "Atomic force microscopy studies of thermal, mechanical and velocity dependent wear of thin polymer films". Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/14955.
Texto completoDepartment of Physics
Robert Szoszkiewicz
Nanoscale modifications of polymer surfaces by scratching them with sharp tips with curvature radii of tens of nanometers and at variable temperatures are expected to provide wealth of information characterizing wear response of these polymers. Such studies are important in the light of understanding the nanoscale behavior of matter for future applications in advanced polymer coatings. This thesis describes how Atomic Force Microscopy (AFM) and hot-tip AFM (HT-AFM) methods were used to characterize thermal and mechanical properties of a 30 nm thick film of poly(styrene-block-ethylene oxide), PS-b-PEO, and modify its lamellar surface patterns. Additionally, it is revealed how contact AFM and HT-AFM methods can efficiently characterize the wear response of two popular polymer surfaces, poly(methyl methacrylate), PMMA, and polystyrene, PS. The AFM and HT-AFM studies on PS-b-PEO copolymer were aimed at producing spatial alignment of respective PS and PEO parts. Instead, however, surface ripples were obtained. These measurements are explained using mode I crack propagation model and stick-and-slip behavior of an AFM tip. In addition, HT-AFM studies allowed extraction of several thermo-physical properties of a PS-b-PEO film at local volumes containing about 30 attograms of a polymer. These thermo-physical quantities are: PEO melting enthalpy of, 111 ± 88 J g[superscript]-1, PS-b-PEO local specific heat of 3.6 ± 2.7 J g[superscript]-1K[superscript]-1, and molecular free energy of Helmholtz of 10[superscript]-20 J nm[superscript]-2 for the PEO within PS-b-PEO. Utilizing a spiral scan pattern at constant angular speed and at various temperatures at the AFM tip-polymer interfaces, the wear response of PS and PMMA polymers was characterized. Cross-sections along the obtained spiral wear patterns provided plots of polymer corrugation as a function of scanning speed. From these studies it was found that the corrugation of the modified polymer surface decays exponentially with linear velocity of the scanning tip.
Hazra, Sumit Kumar. "Crazing and yielding in polyethylene under impact". Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369223.
Texto completoLeón, Albiter Noel. "On the fracture behavior of ductile polymer films : notch quality, essential work of fracture, J-integral, and crack tip opening displacement". Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/565501.
Texto completoLos materiales poliméricos poseen un amplio rango de aplicaciones. Su habilidad de adquirir múltiples formas hace posible obtener películas de polímero, las cuales son altamente usadas en industrias como la de alimentos y productos farmacéuticos. La caracterización de dichas películas de polímero usando propiedades mecánicas clásicas se encuentra bien definido; sin embargo, este no es el caso con las propiedades a fractura. El objetivo general de este trabajo fue analizar en detalle el comportamiento a fractura de películas de polímero dúctiles mediante la aplicación de los enfoques adecuados de la mecánica de la fractura. La primera parte de la tesis investiga las relaciones existentes entre el trabajo esencial específico de fractura, el valor de la integral J de iniciación del crecimiento de la grieta y el desplazamiento crítico para la apertura de la punta de la grieta, ademas de encontrar pruebas claras que hacen al trabajo esencial específico de fractura la energía específica necesaria para el crecimiento de grieta, es decir, un valor de iniciación. Para hacer esto, se aplicó la técnica de correlación de imágenes digitales a probetas de doble entalla sometidas a tracción. Esta técnica permite medir el desplazamiento y la longitud de ligamento al mismo tiempo, lo que hace posible que el trabajo esencial de fractura, la integral J y el desplazamiento de apertura en la punta de la grieta se puedan realizar en un único conjunto de probetas de doble entalla sometidas a tracción. La segunda parte de la tesis se centró en analizar la influencia de la calidad de la entalla en el comportamiento a la fractura. La preparación de la muestra, particularmente la técnica de agudización empleada en la entalla, se ha estudiado con mas profundidad. Con el propósito de ver la influencia del procedimiento de agudización de la entalla, se han utilizado varias técnicas, entre las que se incluyen la ablación con láser de femtosegundo, agudización con cuchilla de afeitar sobre muestras a temperatura ambiente y congeladas con nitrógeno líquido, entallas realizadas con corte de sierra, entallas realizadas con corte de sierra deformadas plásticamente, agudización con bisturí y agujeros taladrados usados como entallas. los resultados revelaron que todas las entallas agudizadas con femtolaser eran muy consistentes y agudas, sin deformación plástica en frente de la punta de la grieta. En cambio, la técnica con cuchilla de afeitar produjo grietas muy agudas, tan agudas como las del femtolaser, pero diferencias en la fuerza compresiva usada por parte del operador al momento de aplicar la técnica, generó entallas con diferentes niveles de deformación plástica por delante de la punta de la grieta. Ya que las diferentes técnicas de agudización producen diferentes niveles de deformación plástica en la punta de la grieta, también se esperarían diferencias en la forma y el tamaño de la curvas tensión - desplazamiento. En la tercera parte de la tesis, la forma y el tamaño de curvas tensión - desplazamiento de especímenes que fueron entallados de diversas maneras fueron analizadas con el objetivo de clarificar su comportamiento a fractura. También, en la región de propagación se identifica la forma parabólica de las curvas tensión - desplazamiento, la cual modelada relaciona el trabajo especifico no esencial de fractura con la tensión de iniciación de crecimiento de grieta y la razón de extensión durante el crecimiento de grieta
Pham, Thi Nhung. "Fabry-Perot interferometer based on end-of-fiber polymer microtip for chemical sensing". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0006.
Texto completoFabry−Perot interferometers (FPIs) have received a significant attention for their use in sensor applications. FPIs consist of an optical cavity with separate parallel reflecting surfaces which reflect incident light, resulting in an optical interferometric signal. The FPI signal depends on the distance between the reflecting surfaces and the refractive index of the cavity medium, which are sensitive to variation of environment humidity, temperature, pressure, and material. FPIs can be attached to optical fibers to form compact fiber optic FPI-based sensors in which the optical fiber works as a waveguide for both incident and reflected signal. This thesis presents FPI-based chemical sensors incorporating a polymer microtip located at the end of an optical fiber and characterizes their sensing capabilities for humidity, water, and chemical targets.Firstly, we develop a pentaerythritol triacrylate (PETA) tip on the facet of an optical fiber by a self-guiding photopolymerization. One end of the optical fiber is placed inside a PETA droplet and the self-guiding photopolymerization of PETA is actuated by a 375 nm laser injected to the other end of the fiber. The optimal conditions to form a straight and mechanically stable PETA tip are 1.0 μW of laser power × 1.0 second of exposure time. However, the PETA chains do not completely polymerize during this self-polymerization, leading to an unstable dynamic resonant frequency of the tip. Thus, the tip needs a post-polymerization under a UV 365 nm lamp to achieve a stable dynamic characteristic, which is applicable for further sensing applications.Secondly, we demonstrate the PETA tip as an effective sensor to detect humidity. The PETA tip acts as an optical cavity formed between the fiber-core/PETA and the PETA/environment interface, resulting in a clear interferometric signal. The FPI signal of the tip is highly sensitive to humidity in the air. This is due to hydroxyl groups within the PETA structure, which strongly absorb water molecules in the humid air and significantly swell the tip. The length and/or the refractive index of the tip are therefore changed, resulting in a FPI shift. The tip exhibits a consistent sensitivity of 90pm/%RH, equivalent to a relative sensitivity of 104 ppm/%RH in the humidity range from 30 to 80%. The sensing performance is highly reproducible and stable. Furthermore, the cross effect of the temperature is negligible, indicating a great practical potential for the devices.Next, we apply the FPI-based PETA tips to determine the water content in glycerol and ethylene glycol solutions. The FPI signal of the PETA tip shifts nonlinearly towards longer wavelengths as the water content increases from 0 to 100 wt.%. The shift in the FPI signal occurs due to the contraction in the tip length, which is linked to the loss of water inside the PETA structure caused by the hydrophilic solutions. When the water contamination is below 10 wt.%, the tip shows a sensitivity of 394 pm/wt.% and 226 pm/wt.% for glycerol and ethylene glycol solutions, respectively. Therefore, the FPI-based PETA tip shows a great potential in determining water content in hydrophilic aqueous solutions, including hydrocarbons.Finally, a tip consisting of a PETA core and a shell of molecularly imprinted polymers (MIPs) is developed for detecting Dansyl-L-phenylalanine. The PETA tip is initially fabricated using the self-guiding polymerization and MIPs are then copolymerized to form a thin shell layer around the PETA tip. Upon the selective binding of Dansyl-L-phenylalanine, the refractive index of the MIP layer changes, leading to the change in the FPI signal of the whole PETA/MIP tip. This straightforward and affordable method offers new innovative possibilities for creating FPI-based MIP fiber optic sensors, which can be applied for a wide range of analytes, including both non-fluorescent and fluorescent targets
Shi, Xian [Verfasser] y Achim [Akademischer Betreuer] Hartschuh. "Tip-enhanced near-field optical microscopy of single-walled carbon nanotube/polymer conjugates and improvements of the image contrast / Xian Shi ; Betreuer: Achim Hartschuh". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1151447404/34.
Texto completoBarrios, Carlos A. "Modified Scanning Probes for the Analysis of Polymer Surfaces". University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1249315424.
Texto completoSolomão, Zenaide. "Desenvolvimento e caracterização de compósitos de Poli (E-Caprolactona) PCL e ß-Fosfato Tricálcico (ß-TCP) para uso em biomateriais". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263534.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: A utilização de biomateriais para substituir, reparar tecidos e órgãos lesados dos seres humanos tem aumentado muito ultimamente devido a diversos fatores como o crescimento da população e a sua maior expectativa de vida. A engenharia tecidual é um campo interdisciplinar que integra princípios da biologia celular e molecular, química, genética, ciências dos materiais e engenharia biomédica, para produzir compósitos tridimensionais inovativos, capazes de substituir tecidos biológicos. O desenvolvimento de novo biomaterial pode ajudar a solucionar este problema, utilizando o método de evaporação de solvente. Este trabalho teve como objetivos: sintetizar e caracterizar o ß-TCP através do método via seca; desenvolver e caracterizar as membranas de poli ('epsilon'-caprolactona) densas e porosas (scaffolds) utilizando dois solventes; preparar e caracterizar os compósitos densos e porosos PCL/ß-TCP; fazer uma avaliação da biocompatibilidade in vitro desses materiais. As seguintes técnicas de caracterização foram utilizadas: MO, MEV, EDS, DRX, TGA,DSC, ensaios mecânicos de tração, teste de viabilidade celular e atividade de fosfatase alcalina. Foi também analisada a sua degradação hidrolitica em solução tampão fosfato (PBS). Essas técnicas foram adequadas para diferenciar as amostras preparadas com os dois solventes utilizados: clorofórmio e diclorometano. Os ensaios mostraram que o último forneceu amostras mais resistentes mecanicamente, mantendo as propriedades térmicas do PCL puro sem alterações, com a adição das partículas do ß-TCP. A biocompatibilidade foi analisada através das normas conhecidas (ASTM e ABNT) e foi possível concluir que os materiais confeccionados são biocompativeis e a atividade de fosfatase alcalina (ALP) favoreceu o crescimento celular na membrana porosa. As avaliações in vitro não mostraram mudanças significativas nas composições preparadas com o solvente clorofórmio. Os materiais estudados possuem um grande potencial para aplicação em substitutos do tecido ósseo
Abstract: The use of biomaterials to replace, repair damaged tissues and organs of humans has greatly increased lately due to various factors such as population growth and greater life expectancy. Tissue engineering is an interdisciplinary field that incorporates principles of molecular and cellular biology, chemistry, genetics, materials science and biomedical engineering to produce innovative three-dimensional composites, capable of replacing tissue. The development of new biomaterial can help solutions this problem by using on whole of evaporation of solvent. This work aimed to synthesize and characterize the ß-TCP by the dry method; develop and characterize the membranes of poly ('épsilon'-caprolactone) porous and dense (scaffolds) using two solvents, to prepare and characterize the dense and porous PCL composites / ß-TCP, perform an evaluation of in vitro biocompatibility of these materials. The following characterization techniques were used: OM, SEM, EDS, XRD, TGA, DSC, mechanical testing, testing cell viability, alkaline phosphatase activity. We also analyzed its hydrolytic degradation in phosphate buffer solution (PBS). These techniques were adequate to differentiate the samples prepared with two solvents used, chloroform and dichloromethane. The tests showed that the samples provided last more mechanically resistant, keeping the thermal properties of pure PCL unchanged with the addition of particles of ß-TCP. The biocompatibility was determined by known standards (ASTM and ABNT) and we can conclude that the materials are biocompatible and made (ALP), promoted cell growth in the porous membrane. The in vitro evaluations showed no significant changes in the compositions prepared with the solvent chloroform. The materials studied have a great potential for application in bone tissue substitutes
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
Liang, Wenfeng. "Metal Organic Composites Derived Tin Dioxide/C Nanoparticles For Sodium-Ion Battery". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460304081.
Texto completoJin, Changqing. "FTIR studies of TiO₂ : pigmented polymer photodegradation". Thesis, University of Newcastle Upon Tyne, 2004. http://hdl.handle.net/10443/1056.
Texto completoLiu, Ruofan. "Assessment of Composite Railroad Tie Cracking". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1386688325.
Texto completoScherger, Jacob D. "Expanding Tip Enhanced Raman Spectroscopy: Blinking Measurements and Alternative Probe Materials". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1510657402180872.
Texto completoHall, David Steven. "Metal polymer adhesion for packaging materials". Thesis, Oxford Brookes University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245702.
Texto completoZeiner, Tim [Verfasser]. "Phase- and Interfacial Behaviour of Hyperbranched Polymer Solutions / Tim Zeiner". München : Verlag Dr. Hut, 2011. http://d-nb.info/1010446754/34.
Texto completoTas, Huseyin. "Coordination Polymerization Of Cyclic Ethers By Metal Xanthates And Carbamates". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1225028/index.pdf.
Texto completohigh molar mass, crystalline (K-polymer) and low molar mass (D-polymer). Formation of double bonds in D-polymer was thought to be due to as an anionic process. Polymerization reactions were studied by changing polymerization conditions and reacting catalyst with predetermined amount of water. It&
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s found that Sn(isoPr)Xt have considerably low efficiency than that of Zn(isoPr)Xt catalyst. The yield linearly increases by increasing catalyst concentration. The propagation is competed by termination or transfer process hence overall activation energy is negative. Some mechanistic features of this system was also discussed. The catalytical activity of carbamates in this field has also been reported, without any information about catalytical efficiency and stereoregularity of the process. Therefore zinc diethyl dithiocarbamate was also studied and found as an active catalyst in stereoregular polymerization but it showed weaker efficiency in the PO polymerization than that of Zn(isoPr)Xt catalyst (about 12 times weaker).
Bahrami, Sanaz. "Low-Profile Polymer Actuator Fabrication for Spastic Hand Exoskeletons". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37953.
Texto completoLounis, Sebastien Dahmane. "The influence of dopant distribution on the optoelectronic properties of tin-doped indium oxide nanocrystals and nanocrystal films". Thesis, University of California, Berkeley, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3686398.
Texto completoColloidally prepared nanocrystals of transparent conducting oxide (TCO) semiconductors have emerged in the past decade as an exciting new class of plasmonic materials. In recent years, there has been tremendous progress in developing synthetic methods for the growth of these nanocrystals, basic characterization of their properties, and their successful integration into optoelectronic and electrochemical devices. However, many fundamental questions remain about the physics of localized surface plasmon resonance (LSPR) in these materials, and how their optoelectronic properties derive from their underlying structural properties. In particular, the influence of the concentration and distribution of dopant ions and compensating defects on the optoelectronic properties of TCO nanocrystals has seen little investigation.
Indium tin oxide (ITO) is the most widely studied and commercially deployed TCO. Herein we investigate the role of the distribution of tin dopants on the optoelectronic properties of colloidally prepared ITO nanocrystals. Owing to a high free electron density, ITO nanocrystals display strong LSPR absorption in the near infrared. Depending on the particular organic ligands used, they are soluble in various solvents and can readily be integrated into densely packed nanocrystal films with high conductivities. Using a combination of spectroscopic techniques, modeling and simulation of the optical properties of the nanocrystals using the Drude model, and transport measurements, it is demonstrated herein that the radial distribution of tin dopants has a strong effect on the optoelectronic properties of ITO nanocrystals.
ITO nanocrystals were synthesized in both surface-segregated and uniformly distributed dopant profiles. Temperature dependent measurements of optical absorbance were first combined with Drude modeling to extract the internal electrical properties of the ITO nanocrystals, demonstrating that they are well-behaved degenerately doped semiconductors displaying finite conductivity at low temperature and room temperature conductivity reduced by one order of magnitude from that of high-quality thin film ITO.
Synchrotron based x-ray photoelectron spectroscopy (XPS) was then employed to perform detailed depth profiling of the elemental composition of ITO nanocrystals, confirming the degree of dopant surface-segregation. Based on free carrier concentrations extracted from Drude fitting of LSPR absorbance, an inverse correlation was found between surface segregation of tin and overall dopant activation. Furthermore, radial distribution of dopants was found to significantly affect the lineshape and quality factor of the LSPR absorbance. ITO nanocrystals with highly surface segregated dopants displayed symmetric LSPRs with high quality factors, while uniformly doped ITO nanocrystals displayed asymmetric LSPRs with reduced quality factors. These effects are attributed to damping of the plasmon by Coulombic scattering off ionized dopant impurities.
Finally, the distribution of dopants is also found to influence the conductivity of ITO nanocrystal films. Films made from nanocrystals with a high degree of surface segregation demonstrated one order of magnitude higher conductivity than those based on uniformly doped crystals. However, no evidence was found for differences in the surface electronic structure from one type of crystal to the other based on XPS and the exact mechanism for this difference is still not understood.
Several future studies to further illuminate the influence of dopant distribution on ITO nanocrystals are suggested. Using synchrotron radiation, detailed photoelectron spectroscopy on clean ITO nanocrystal surfaces, single-nanoparticle optical measurements, and hard x-ray structural studies will all be instructive in elucidating the interaction between oscillating free electrons and defect scattering centers when a plasmon is excited. In addition, measurements of temperature and surface treatment-dependent conductivity with carefully controlled atmosphere and surface chemistry will be needed in order to better understand the transport properties of ITO nanocrystal films. Each of these studies will enable better fundamental knowledge of the plasmonic properties of nanostructures and improve the development of nanocrystal based plasmonic devices.
Potoczny, Grzegorz A. "Electro-mechanical behaviour of indium tin oxide coated polymer substrates for flexible electronics". Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3475/.
Texto completoLin, Feng. "Preparation and Characterization of Polymer TiO2 Nanocomposites via In-situ Polymerization". Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2849.
Texto completoThe objective of this work is to synthesize and characterize polymer-TiO2 hybrid nanocomposites. When dispersed at the nanoscale level TiO2 could act as visually transparent UV filters and high-thermomechanical-performance materials. The synthesis strategy involved two steps. Firstly, aggregated TiO2, as received, was modified by 3-trimethoxysilyl propylmethacrylate aimed at altering its surface characteristics. The effect of modifier concentration on changing the physicochemical properties of TiO2 surface was evaluated. Size distribution of unmodified and modified TiO2 nanopowders was measured using a particle size analyzer. The qualitative and quantitative grafting of vinyl groups on TiO2 surface was investigated with Fourier transform-infrared (FTIR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. Secondly, styrene monomer was then added to carry out copolymerization with vinyl groups on the modified TiO2 by free radical initiator 2,2-azobis isobutyronitrile (AIBN) in bulk medium. FTIR spectra confirmed the formation of nanocomposites with polystyrene chains chemically linked to the surface of TiO2 nanopowders. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the resulting nanocomposites displayed higher thermal stability and maintained similar glass transition temperatures (Tg) compared with pure PS. Ultraviolet ?visible spectroscopy (UV-Vis) investigated that these nanocomposites have improved optical properties potentially acting as visually transparent UV filters. Such incremented properties were attributed to the nancoscale dispersion (20-50nm size) of TiO2 into polystyrene matrix, which morphology was observed by scanning electron microscopy (SEM).
Ohenoja, K. (Katja). "Particle size distribution and suspension stability in aqueous submicron grinding of CaCO3 and TiO2". Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526205502.
Texto completoTiivistelmä Viimeisen kymmenen vuoden aikana alle yhden mikrometrin partikkelit ovat herättäneet kiinnostusta ja niille on kehitetty uusia sovelluksia niiden suuren pinta-alan ja lujuuden ansiosta. Ultrahienojauhatus märkähelmimyllyllä on useimmiten viimeinen prosessivaihe ennen partikkelien lisäämistä sovelluskohteeseen ja siinä saavutetaan partikkelien lopullinen partikkelikokojakauma. Helmimyllyjauhatuksen energiankulutus minimoidaan etsimällä optimioperointiparametrit kullekin jauhatusprosessille ja käyttämällä korkeinta mahdollista suspension kuiva-ainepitoisuutta. Suspension kuiva-ainepitoisuutta voidaan nostaa hallitsemalla partikkelien välisiä vuorovaikutuksia stabilointiaineilla, kuten polymeereillä. Tässä väitöskirjassa tutkittiin operointiparametrien ja jauhatusapuaineiden vaikutusta titaanidioksidin (TiO2) ja kalsiumkarbonaatin (CaCO3) partikkelikokojakaumaan ja lietteen stabiilisuuteen submikronijauhatuksessa. Tutkitut TiO2-partikkelit olivat aggregaatteja, jotka oli valmistettu sulfaattiprosessilla saostamalla, ja tutkitut CaCO3-partikkelit olivat primäärisiä mineraalipartikkeleita. TiO2-partikkeleille saavutettiin energiatehokkain jauhatus ja samalla toivottu partikkelikokojakauma, eli mediaani 300 nm ja mahdollisimman kapea jakauma, pienillä helmillä, jotka aiheuttavat partikkeleihin pienimmän puristusenergian. Elektrosteerinen stabilointi käyttämällä natriumpolyakrylaatteja stabilointiaineena havaittiin tehokkaaksi menetelmäksi hallita TiO2-partikkelien välisiä vuorovaikutuksia. Natriumpolyakrylaatti, jonka molekyylimassa oli 12500 g/mol, oli tehokkain TiO2-partikkeleille alentaen suspension viskositeettiä eniten. Myös CaCO3-partikkeleille elektrosteerinen stabilointi natriumpolyakrylaatteja käyttäen oli tehokkain stabilointimenetelmä. Myös natriumpolyakrylaattien polydispersiteetti-indeksin vaikutusta tutkittiin CaCO3-suspensioille. Tulokset osoittivat matalan polydispersiteetti-indeksin olevan tehokkaampi alentaen viskositteettia ja pienentäen partikkelikokoa tehokkaammin kuin natriumpolyakrylaatti, jolla oli korkeampi polydispersitetti-indeksi. Tämän vuoksi natriumpolyakrylaatti, jolla oli matala polydispersiteetti-indeksi, valittiin nanojauhatuskokeisiin. Kokeissa CaCO3-partikkelit saatiin jauhettua 26 nm kokoon, joka on pienin koskaan aiemmin jauhamalla saavutettu koko CaCO3-partikkeleille
Bassi, Mitchell Brian 1963. "The mechanism of the ring-opening polymerization of ε-caprolactone using tin(IV) carboxylates". Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/291748.
Texto completoKingdom, Rachel Michele. "Conducting Polymer Matrix Poly(2,2’-Bithiophene) Mercuric Metal Ion Incorporation". Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1259889438.
Texto completoLott, Joseph Robert. "Reversible addition-fragmentation chain-transfer (RAFT) polymerization in grafting polymer chains from TiO₂ nanoparticles /". Online version of thesis, 2006. https://ritdml.rit.edu/dspace/handle/1850/2878.
Texto completoJia, Huiying. "Anodized TiO2 Nanotube Film For Controllable Drug Delivery". Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1376435848.
Texto completoHarris, Jeff. "The influence of adsorption layers on percolation characteristics of electrically conducting antimony-tin oxide/PMMA composites". Thesis, Brunel University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363512.
Texto completoPost, Anthony William. "Thermal and fatigue testing of fiber reinforced polymer tie connectors used in concrete sandwich walls". [Ames, Iowa : Iowa State University], 2006.
Buscar texto completoHupfeld, Tim [Verfasser] y Stephan [Akademischer Betreuer] Barcikowski. "Nanoparticle-functionalized polymers for laser powder bed fusion / Tim Hupfeld ; Betreuer: Stephan Barcikowski". Duisburg, 2021. http://d-nb.info/1237221455/34.
Texto completoFreitas, Jilian Nei de. "Modulo de celulas solares de TiO/2 corante e eletrolito polimerico". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248622.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Investigaram-se células solares de TiO2/corante e eletrólito polimérico visando a construção de um módulo de 9 V. O filme de TiO2 depositado sobre substratos de FTO (fIuorine tin oxide) em vidro foi obtido a partir da modificação de uma suspensão comercial do óxido coloidal em água. Para obter um filme com bom desempenho, utilizou-se uma suspensão com 0,45 g mL à qual foi adicionado 33 % (m/m) de polietilenoglicol com massa molar 20000. O eletrólito empregado nas células consistiu de Nal e I2 dissolvidos em poli(óxido de etileno-co-epicloridrina) contendo os co-monômeros na proporção 87:13, respectivamente. A condutividade iônica máxima desse sistema ocorreu para uma concentração de sal de 15 % (m/m) em relação à matriz polimérica; 2,7 x 10 S cm sob umidade < 1,0 ppm e ~ 30°C. Com o objetivo de aumentar a condutividade iônica, adicionou-se g-butirolactona como plastificante, mantendo-se a concentração de sal em relação à massa de polímero. Observou-se um aumento de cerca de uma ordem de grandeza na condutividade iônica e no coeficiente de difusão das espécies eletroativas no eletrólito plastificado. A suspensão de TiO2 e o eletrólito otimizados foram utilizados na preparação de células solares com área ativa de 1,0 e 4,5 cm. As células menores foram irradiadas com uma lâmpada de Xe. Sob 10 mW cm foram obtidas eficiências de conversão de energia de 2-3 %. As células com área ativa maior foram caracterizadas diretamente sob o Sol e apresentaram eficiência média de 0,9 % (às 12 h). Estes dispositivos foram usados na montagem de módulos de16 células conectadas em série, produzindo 9 V de potencial e 183 mW (valor integrado em um dia). Em conclusão este trabalho demonstrou que, é possível construir um módulo com células solares de TiO2/corante preparadas com eletrólito polimérico plastificado. O desempenho do módulo excedeu as expectativas, sendo a estabilidade o principal desafio para permitir a sua futura aplicação em escala comercial.
Abstract: TiO2 dye-sensitized solar cells assembled with polymer electrolyte were investigated aiming at the construction of a 9 V module. The TiO2 film deposited on substrates of FTO (fluorine tin oxide) on glass was obtained through the modification of a colloidal oxide suspension in water . To obtain a film with good performance, a suspension containing 0.45 g mL of TiO2 and 33 wt % of polyethyleneglycol with molar weight of 20000 was employed. The electrolyte consisted of Nal and I2 dissolved in poly(ethylene oxide-co-epichlorydrin) containing the monomers in the molar ratio 87:13. The maximum ionic conductivity for this system occurred for a concentration of salt of 15 wt % in relation to the polymer matrix; 2.7 x 10 S cm under relative humidity lower than 1.0 ppm and 30°C. To increase the ionic conductivity, g-butyrolactone was added to the electrolyte as a plasticizer, maintaining the salt concentration constant in relation to the polymer. The measured ionic conductivity and diffusion coefficient for the plasticized electrolyte were both increased by ca. one order of magnitude. Both, optimized TiO2 suspension and electrolyte, were applied in solar cells assembled with active area of 1.0 or 4.5 cm. The smaller cells were investigated under 10 mW cm irradiation, with a Xe lamp, and the efficiency of energy conversion was 23 %. The larger cells were characterized directly under the Sun with an average efficiency of 0.9 % (at 12:00 h). These were used to assemble a 9 V module by connecting in series 16 cells. The integrated average daily power was 183 mW. In summary, this work demonstrated that it is feasible to assemble a module with dyesensitized solar cells employing a plasticized polymer electrolyte. The performance of the modules exceeded all expectations and their stability is the main challenge to allow a future commercial scale application.
Mestrado
Quimica Inorganica
Mestre em Química
Hu, Qingchun. "Fabrication and characterization of poly(amide-imides)/TiO₂ nanocomposite gas separation membranes". Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-10022008-063009/.
Texto completoStander, Elzet. "Nuwe reaksies van gedeprotoneerde Fischer-tipe karbeenkomplekse". Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1222.
Texto completoLi, Zhi. "Three-Dimensional Optical Characterization of Heterogeneous Polymer Systems". Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5008.
Texto completoBarkhuysen, Shani. "High resolution 195Pt and 119Sn NMR characterization of platinum(II)-tin(II) complexes". Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17841.
Texto completoDoherty, Walter John. "POLYMER-MEDIATED ELECTROCHEMISTRY IN SOL-GEL THIN FILMS AND SPECTROELECTROCHEMICAL CHARACTERIZATION OF MOLECULAR ADLAYERS ON INDIUM-TIN OXIDE ELECTRODE SURFACES". Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1233%5F1%5Fm.pdf&type=application/pdf.
Texto completoSmith, Stuart Douglas. "Barrier properties of spray-coated epoxy-graft-acrylic films on tin-plate in corrosive environments". Thesis, Sheffield Hallam University, 1998. http://shura.shu.ac.uk/20375/.
Texto completoLin, Yijian. "Structure-Property Relationship of Polyolefins Used as Packages and Adhesives". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1290044976.
Texto completoWu, Kecheng. "Anatase TiO2 Nanotubes Electrode in Rechargeable Magnesium Battery: In Situ Infrared Spectroscopy Studies". University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1522509011455228.
Texto completoErdmann, Tim [Verfasser], Brigitte [Akademischer Betreuer] [Gutachter] Voit y Antonio [Gutachter] Facchetti. "High Charge Carrier Mobility Polymers for Organic Transistors / Tim Erdmann ; Gutachter: Brigitte Voit, Antonio Facchetti ; Betreuer: Brigitte Voit". Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/1128036657/34.
Texto completoErikson, Pontus. "The Interaction of Oil and Polymer in the Microporous Polyethylene Film when using a Thermally Induced Phase Separation Process". Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266155.
Texto completoBatteri separatorn är en komponent i det konventionella batteriet som länge har förbisetts. Bara för att den är en inaktiv komponent, betyder inte att den är mindre viktig för battericellens prestation. Trender idag pekar mot en enorm tillväxt inom elbils-industrin, och med det även litium-jon batteriseparatorns marknad. Det är för att litium-jon batteriet är det batteriet som vanligen används kommersiellt idag i elbilar. I en av de två stora industriella tillverkningsprocesserna används olja för att åstadkomma en porös film. Denna studie syftar på att utvärdera olika oljors interaktion med polymeren i denna tillverkningsprocess. Eftersom de flesta batteriseparator-industrier idag använder paraffinrik olja så testas oljor med olika mycket naftalensikt innehåll för att hitta korrelationer mellan oljornas egenskaper och kristalliniteten eller porositeten hos filmerna. Inga korrelationer för porositeten eller kristalliniteten kunde göras till oljornas egenskaper. Bilderna tagna med SEM var ej tillräckligt förstorade för att kunna studera vare sig porstorleken eller porstrukturen hos filmerna. För framtida studier rekommenderas att samla in mer data för att kunna utskilja ”outliers” i datan, för att erhålla mer korrekta värden. Metodiken måste även verifieras för att säkerställa att proceduren är reproducerbar. För att studera porerna och porstrukturen, borde en FE-SEM användas för att få mer förstorade bilder med bättre kvalité på filmernas yta.
Hoffmann, Sebastian Tim [Verfasser] y Anna [Akademischer Betreuer] Köhler. "Dynamik und Energetik von Triplettexzitonen in konjugierten Polymeren und Molekülen / Sebastian Tim Hoffmann. Betreuer: Anna Köhler". Bayreuth : Universitätsbibliothek Bayreuth, 2012. http://d-nb.info/1022434616/34.
Texto completoKaul, Pankaj B. "Thermal Transport in Tin-Capped Vertically Aligned Carbon Nanotube Composites for Thermal Energy Management". Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1383515941.
Texto completoCormier, Daniel. "Repair of Conductive Layer on Carbon Fibre Reinforced Polymer Composite with Cold Gas Dynamic Spray". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33160.
Texto completoSampaio, Alexandre Botelho. "Efeitos de um enxerto biofuncional e da terapia laser de baixa intensidade em defeitos ósseos induzidos em tíbias de ratos". Botucatu, 2019. http://hdl.handle.net/11449/183393.
Texto completoResumo: O objetivo do estudo foi avaliar os efeitos de um enxerto biofuncional isolado, ou combinado com a terapia laser de baixa intensidade no reparo de defeitos ósseos induzidos em tíbias de ratos. A hipótese foi que a qualidade do reparo ósseo pode ser incrementada a partir da associação destas terapias. Foram utilizados 40 ratos da linhagem Wistar, machos, três meses de idade, com massa corpórea variando entre 250 e 300 g, nos quais foi induzido defeito ósseo circular de 3 mm de diâmetro, nas tíbias direita e esquerda. Os ratos foram divididos, aleatoriamente, em quatro grupos experimentais equitativos: Grupo 1 – controle, Grupo 2 - enxerto biofuncional composto de beta fosfato tricálcico e poli(ácido lático-co-ácido glicólico) (β-TCP/PLGA), Grupo 3 – terapia laser de baixa intensidade, Grupo 4 – enxerto biofuncional composto de β-TCP/PLGA, e terapia laser de baixa intensidade. Os ratos foram submetidos à eutanásia aos 15 dias após a cirurgia. A irradiação laser (Ga-Al-As) foi iniciada no pós-operatório imediato e repetida três vezes por semana, sendo empreagado 6 J de energia em um único ponto sobre a região do defeito. Após a eutanásia, as tíbias direita e esquerda foram removidas, sendo que as tíbias direitas foram designadas para as análises histológicas e as tíbias esquerdas para as análises biomecânicas com ensaio de flexão em três pontos. Estatisticamente o Grupo 4 apresentou o menor escore de infiltrado inflamatório e o maior de tecido ósseo neoformado, sendo o maior esc... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This study aimed to assess the effects of a biofunctional graft alone, or in combination with low-level laser therapy (LLLT) on the repair of tibial bone defect in rats. The hypothesis was that the combination of therapy modalities could increase the quality of bone healing. Forty male Wistar rats, 3 months of age, weighing from 250 g to 300 g were used. A circular bone defect (3 mm diameter) was created in the right and left tibias. The rats were randomly distributed into four equal groups: G1 - control, G2 - biofunctional graft composed of β-tricalcium phosphate and poly(lactic-co-glycolic acid) (βTCP/PLGA), G3 - LLLT, G4 - biofunctional graft composed of β-TCP/PLGA and LLLT. The rats were euthanized on day 15 day after surgery. The LLLT (Ga-AlAs) was performed in the immediate postoperative period and three times per week. The application was at one point with energy 6J. After euthanasia, the right and left tibiae were removed. The right tibias were used for the histological analysis, and the left tibias were used for three-point bending tests. The statistical analysis showed lower inflammatory infiltrate score and higher newlyformed bone tissue in G4, and the higher granulation tissue score in G3. Highest values for maximum rupture force and maximum displacement occurred in G4. In conclusion, biofunctional graft composed of β-TCP/PLGA and LLLT was better in promoting the repair of bone defects induced in rat tibiae compared with each treatment alone, based on the histopat... (Complete abstract click electronic access below)
Doutor
Heinrich, Annika C. J. [Verfasser]. "New Synthetic Strategies for Semiconducting Polymers : Incorporation of Tin, Boron and Gold as Metalfunctionalities and Dinucleophile Synthesis / Annika C. J. Heinrich". Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/1169652751/34.
Texto completoVeselkova, Iuliia. "Gelové polymerní elektrolyty s retardéry hoření". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-319497.
Texto completoFinne, Anna. "Novel Possibilities for Advanced Molecular Structure Design for Polymers and Networks". Doctoral thesis, KTH, Polymerteknologi, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3623.
Texto completoQC 20100602
Damadzadeh, Behzad y Hamideh Jabari. "Biodegradable Composites : Processing of thermoplastic polymers for medical applications". Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19329.
Texto completoТульженкова, О. С., М. О. Рокицький y А. М. Шут. "Теплопровідність полімерних нанокомпозитів системи поліхлортрифторетилен – діоксид олова". Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/64317.
Texto completoTopuz, Burcu Berna. "Synthesis And Characterization Of Copper Phthalocyanine Deposited Mica Titania Pigment". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611519/index.pdf.
Texto completoThorud, Steinar. "Overganger mellom matematiske representasjoner : En studie om hvordan 1T-elever gjennomfører overgangen fra situasjon til grafiske og algebraiske representasjoner av polynomer". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25106.
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