Dissertations / Theses: 'Polymer Composites - Inorganic Oxides'

1

Alfinaikh, Reem. "Preparation and Characterization of Poly(Ethylene Oxide)(MW 35K and 100K)/ Silica Nanoparticle Composites." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2017. http://digitalcommons.auctr.edu/cauetds/109.

Full text

Abstract:

In recent years, polymer-inorganic nanoparticle compositions have been a subject of considerable interest in order to achieve desired chemical, physical properties and mechanical properties. In this study a polymer nanocomposites have been prepared by incorporating silica nanoparticles (~20 nm) as fillers into poly(ethylene oxide) matrix. The composites of poly(ethylene oxide) and silica nanoparticles were prepared by solution blending. The product composites were powders. The thermal properties of the composites were investigated using the Differential Scanning Calorimetry. The Nuclear Magnetic Resonance (13C solid state, T1ρ), Atomic Force Microscopy, X-ray diffraction and Fourier Transform Infrared Spectroscopy were used to investigate the effect of the nanoparticles on the polymer matrix. The results suggest that the silica nanoparticles were reasonably well dispersed in the PEO 35K. The dispersion was accompanied by slightly reduced the crystallinity. However, with increasing the SiO2 nanoparticles the aggregation Phenomenon appears. Moreover, with increase in the MW of the PEO to 100K the dispersion of the nanoparticles decreased and aggregation phenomenon is observed even at lower of SiO2 contents.

APA, Harvard, Vancouver, ISO, and other styles

2

Bhaway, Sarang M. "Fabrication of Block Copolymer Templated Mesoporous Metal Oxide Composites for Energy Storage Applications." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468417723.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Carvalho, Thaís. "Preparação e caracterização de compósitos com matriz de poliuretano e híbridos fibrosos modificados com óxido de magnésio hidratado." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/97/97136/tde-20112017-123925/.

Full text

Abstract:

A versatilidade das espumas poliuretanas permite sua aplicação em inúmeros setores industriais, devido à possibilidade de se obter diferentes conjuntos de propriedades apenas alterando sua formulação básica. Um tipo recorrente de alteração é a incorporação de diferentes tipos de fibras em matrizes de poliuretano, vastamente estudada com o objetivo de gerar materiais compósitos com melhores propriedades mecânicas do que a matriz original. Inúmeros autores reportaram a utilização de celulose cristalina como uma alternativa renovável aos agentes de reforço e revelaram que a celulose utilizada como aditivo em matrizes poliméricas afetou as propriedades mecânicas da matriz original e, em menor escala, exerceu influência sobre a estabilidade térmica do compósito. O presente trabalho dedicou-se a isolar a celulose cristalina contida nas fibras de bananeira mediante tratamento com ácido acético concentrado. Os tratamentos químicos são necessários para modificar a superfície do material e melhorar a adesão do agente de reforço à matriz. Tendo em vista os resultados associados à estabilidade térmica dos compósitos de poliuretano reforçados com celulose, buscou-se sintetizar materiais híbridos de celulose e MgO.nH2O. Foi observado que, mesmo em pequenas quantidades, a presença do óxido hidratado de magnésio afetou significativamente a estabilidade térmica do HB 98:2. Estudos térmicos indicam que os materiais compósitos estudados apresentaram comportamento semelhante ao da matriz PU. Estudos das propriedades compressivas dos materiais poliméricos gerados mostraram que a incorporação do HB 98:2 ao PU afetou positivamente as propriedades mecânicas do material, sendo que o compósito PU + 1 HB 98:2 apresentou desempenho mecânico superior ao da matriz pura.
The versatility of polyurethanes foams allows its application in numerous industries because of the possibility of obtaining different sets of properties just by changing its basic formulation. A recurrent type of modification is the incorporation of different types of fibers in polyurethane matrices widely studied with the objective of generating composite materials with better mechanical properties than the original matrix. Numerous authors have reported the use of crystalline cellulose as a renewable alternative to fillers and showed that the cellulose used as additive in polymer matrices affect the mechanical properties of the original matrix and, to a lesser extent, influence upon thermal stability of the composite. This work was dedicated to isolate the crystalline cellulose contained in banana fibers by treatment with concentrated acetic acid. The chemical treatments are needed to modify the surface of the material and improve adhesion of the filler to the matrix. In view of the results associated with the thermal stability of the composite polyurethane reinforced with cellulose, sought to synthesize hybrid materials cellulose and MgO.nH2O. It has been observed that even in small quantities, the presence of hydrated magnesium oxide significantly affect the thermal stability of HB 98: 2. thermal studies indicate that the studied composites showed similar behavior to the PU matrix. Studies of the compressive properties of polymeric materials generated showed that the incorporation of HB 98: 2 to PU positively affect the mechanical properties of the material, and the composite PU + HB 98 1: 2 had mechanical performance superior to that of pure matrix.

APA, Harvard, Vancouver, ISO, and other styles

4

Thomson, James Burgess. "Structural studies of new inorganic oxides and polymer electrolytes." Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/15523.

Full text

Abstract:

A knowledge of structure is crucial to the understanding of inorganic solids and polymers. Neutron and X-ray powder diffraction are two powerful complementary techniques which can be used in the structural characterisation of a variety of crystalline materials. Chemical and electrochemical oxygen intercalation techniques involving both aqueous and non-aqueous systems, have been investigated for a number of crystalline inorganic oxides. The pyrochlore structure has been discovered to be a new class of host for the chemical intercalation of oxygett and the interstitial solid solution of Ce2Zr2O7+x based on this structure-type has been investigated. Intercalation in this system is found to involve an unusual mechanism of oxygen displacement. The structures of other complex metal oxides have also been elucidated using a combination of X-ray and neutron powder diffraction, including those of Li29Zr9Nb3O40 and Li29Zr9.6Ta2.4O40. The doping behaviour of magnesium into the technologically important material lithium niobate has also been studied using these techniques. Polymer electrolytes are a class of ionically conducting solid phases formed by the dissolution of salts in ion co-ordinating macromolecules. The relationship between the crystalline and amorphous phase of the polymer-salt complex PEO3.LiCF3SO3 has been examined by variable-temperature powder X-ray diffraction. This has shed new light on the relationship between the crystalline and amorphous structures of polymer electrolytes. Finally, the crystal structure of the polymer-salt complex PEO4:RbSCN has been determined.

APA, Harvard, Vancouver, ISO, and other styles

5

Keum, Dong-ki. "Organic-inorganic composites of CaCO3 particles by organic polymer templates." 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147661.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Chang, Kaiguo. "Synthesis and characterization of conducting polymer-inorganic composite materials /." View online ; access limited to URI, 2000. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3108646.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Brennan, Daniel P. "Small molecule and polymer templating of inorganic materials." Diss., Online access via UMI:, 2006.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

8

Han, Y. "Structural modelling of the organic/inorganic interface in polymer nanotube composites." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603639.

Full text

Abstract:

This thesis describes an investigation of various polymer/nanotube composite systems, using computer simulation. Firstly, pure polymer melts composed of linear homopolymers, polyethylene (PE) and poly(ethylene oxide) (PEO), were studied by a multiscale modelling approach. A Monte Carlo coarse-grained lattice model was employed to generate initial equilibrated chain configurations. A process of ‘reverse-mapping’ was then used to recover atomistic details from the coarse-grained model. After that, fully atomistic molecular dynamic (MD) simulations have been performed on samples of PE and PEO melts. Our results suggest good agreement of structural and dynamical properties between current MD results and experimental and theoretical results. Next, we discussed the application of this multiscale modelling approach to the study of PE/CNT (carbon nanotube) composite system. The presence of CNT causes a clear structuring of the polymer chains around the nanotube surface. Furthermore, structural relaxations of the interfacial PE chains were found to be slower than that of the pure PE melt. MD method and effective fibre theory were used for the calculation of composite mechanical properties, and results agree with experimental data. Finally, we attempted to study the organic/inorganic interface. A composite model containing an inorganic TiO₂ nanotube embedded in a PEO matrix was generated and results are compared with the PEO/CNT system. Much stronger structuring and ordering of PEO chains were found in the vicinity of the TiO₂ surface. In addition, the PEO conformation was more coiled in order to better adapt to the TiO₂ nanotube. Evidence for chain immobilization is more obvious in the PEO/TiO₂ system, which contributes to the improvement of interfacial properties of the composite.

APA, Harvard, Vancouver, ISO, and other styles

9

Livingstone, Veronica Jean. "One-Pot In-Situ Synthesis of Conductive Polymer/Metal Oxide Composites." University of Toledo / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=toledo158860469194691.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Robertson, Duncan J. "Inorganic organic composite polymer coatings based on functionalised polyhedral oligomeric silsesquioxanes." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2155.

Full text

Abstract:

A study has been undertaken with the aim of preparing appropriately functionalised polyhedral oligomeric silsesquioxane (POSS) compounds to be used in ambient-cure chemistry. Numerous epoxy-functionalised compounds have been designed and synthesised and these materials have been characterised in order to determine their chemical structure. These compounds have also been incorporated into existing polymerisation reactions to test whether these materials could be used in the protective coatings industry. A glycidyl-functionalised POSS compound was prepared and reacted with a series of amines to produce ambient-cured polymers which could be used in the coatings industry. There were also a series of experiments undertaken on these polymers to identify the processes at work and to test how they compare to industry standards. As a direct comparator to this work, another set of results was obtained with a cyclic-siloxane material incorporated into the systems in place of the POSS. A linear analogue was also tested. The reactions proved to be a success and an appropriate data-set was yielded. During the synthesis of POSS precursors there are a series of residual materials produced. These materials have also been studied in this project. It was anticipated that these would behave in a similar way to the POSS compounds however the same functionality was never achieved as had been with the POSS. Ambient-cured polymers have also been targeted from a basic hydride-functionalised POSS compound and a polybutadiene system. The appropriate reactions unfortunately never took place as anticipated but there were a series of tests undertaken to identify the processes at work. A study has also been undertaken using near-I.R. to track the curing reactions. From this data, the extent of cure could be studied and the make-up of the reaction could be investigated in more detail.

APA, Harvard, Vancouver, ISO, and other styles

11

Nunnery, Grady A. "The influence of surface curvature on polymer behavior at inorganic surfaces." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33929.

Full text

Abstract:

Nanoscale surfaces were examined in order to determine the influence of surface curvature on polymer behavior at polymer-ceramic interfaces, as well as the influence of nanoparticles in cellulosic media. Poly(methyl methacrylate) and block copolymers thereof were adsorbed onto porous alumina substrates of various pore sizes in order to determine how polymer and copolymer adsorption behavior at nanoscale surfaces differs from adsorption onto flat surfaces. It was determined that chain density on concave surfaces dramatically decreases as curvature increases in much the same way that it does on convex surfaces (e.g. on the surface of nanoparticles), and physical models are provided to explain this similarity. Diblock copolymer adsorption is observed to vary dramatically with solvent quality and block asymmetry and can be correlated with the surface curvature very similarly to the adsorptive behavior of homopolymers on those same surfaces. The addition of nanoparticles to cellulosic media was investigated as a means to significantly modify the properties of cellulosic composites with minimal additions of nanoparticles. Although cellulose is among the most abundant polymers on earth, its primary uses are limited to bulk commodity goods, such as paper and textiles. This work demonstrates a simple means to control cellulosic fluid viscosity, thereby increasing the versatility of these biopolymers in additional applications with higher value-added potential. The formation of iron-cellulosic nanocomposites by the in-situ thermolysis of metal carbonyls to form metallic nanoparticles was performed and was analyzed by viscometry among other techniques. It was determined that the nanocomposites that were formed exhibited significantly increased viscosity, up to the point of gelation. Additionally, an introduction to the expansive field of nanocomposites is provided, including how and why composite properties change abruptly as filler size approaches the nanoscale. An extensive background on this diverse field as it relates to the current work is provided with an emphasis on cellulosic nanocomposites and the dependence of curvature on polymer-surface interactions. A detailed account of the experimental work relevant to this work is provided, including materials and characterization methods. Future work is proposed for both cellulosic nanocomposites as well as for curvature-dependent polymer adsorption. Finally, conclusions are drawn from the entire work and its implications to the greater field of nanocomposites.

APA, Harvard, Vancouver, ISO, and other styles

12

Karabulut, Meryem. "The Effect Of Inorganic Composites On The Thermal Degradation Of Polymethylmetacrylate (pmma)." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613752/index.pdf.

Full text

Abstract:

Metal coordinated polymer nanocomposites have gained great attention due to their superior characteristics. Polymethylmethacyrlate (PMMA) is the most commonly used polymer since it is easily processed. In this study, modified TiO2 nanoparticles prepared by insitu and exsitu methods were embedded into PMMA in order to improve its thermal stability and the effects of TiO2 nanoparticles on thermal characteristics of PMMA were investigated by direct pyrolysis mass spectrometry. The insitu method which is a sol gel method, TiO2/SiO2 nanoparticles were synthesized by mixing titanium(IV) tetraisopropoxide, TTIP, with silane coupling agent, 3-(3-methoxysilyl)methylmetacrylate, MSMA in absolute ethanol. In exsitu method, TiO2 powder was directly mixed with silane coupling reagent. TiO2/SiO2 nanoparticles were embedded into the PMMA by direct mixing resulting in exsitu and insitu TiO2/SiO2/PMMA nanocomposites. The synthesized TiO2/SiO2/PMMA nanocomposites were characterized by TEM, ATR-FT-IR and analyzed for the investigation of their reaction mechanism and thermal characteristics by pyrolysis mass spectroscopy. iv TEM images confirmed the formation of TiO2/SiO2 nanoparticles and TiO2/SiO2/PMMA nanocomposites and indicated that the average particle size of TiO2/SiO2 nanoparticles was around 6 nm whereas average particle size of SiO2/TiO2/PMMA nanocomposites were around 25 nm. The increase in the size of nanoparticles is associated with incorporation of TiO2/SiO2 nanoparticles into PMMA matrix. ATR-FTIR spectrum of 5% TiO2/SiO2/PMMA nanocomposites showed the formation of TiO2/SiO2 nanopartciles clearly. Pyrolysis mass spectrometry analysis revealed that incorporation of TiO2/SiO2 nano- particles into PMMA resulted in higher thermal stability only for low weight percentage insitu TiO2/SiO2/PMMA. At high weight percentages a decrease in thermal stability was detected. On the other hand, in case of exsitu TiO2/SiO2/PMMA, contrary to our expectations a decrease in thermal stability was detected. The decrease in thermal stability was attributed to evolution of methacrylic acid during thermal degradation of silane groups.

APA, Harvard, Vancouver, ISO, and other styles

13

Bambalaza, Sonwabo Elvis. "An investigation into the use of a ceramifiable Ethylene Vinyl Acetate (EVA) co-polymer formulation to aid flame retardency in electrical cables." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/d1020159.

Full text

Abstract:

The concept of a unique ceramifiable Ethylene vinyl acetate (EVA) based polymer composite was based on the incorporation of inorganic compounds such as aluminium hydroxide, calcium carbonate, muscovite mica, and calcined kaolinite within a 95 percent EVA/ 5 percent Polydimethylsiloxane (PDMS) polymer matrix such tha t upon heating to elevated temperatures of about 1000 oC, a solid end-product with ceramic-like properties would be formed. The ceramifiable EVA based polymer composite was developed to be used as electric cable insulation or sheath as the formation of a ceramic based material at elevated temperatures would provide flame retardant properties during fire situations. The flame retardant properties at elevated temperatures would ensure that the insulation remains at such temperatures due to some of the properties of the resultant ceramic such as reasonably high flexural strength, high thermal stability, non-reactivity and high melting point. During a fire this would ensure that flames would not be propagated along the length of the cable and also protect the underlying conducting wires from being exposed to the high temperatures of the fire. Its application as a cable insulation also required that the material functions as a cable insulator under ambient temperature conditions where the ceramifiable polymer composite should retain certain polymer properties such as the post-cure tensile strength (MPa), degree of polymer elongation (percent), thermal expansion, thermal slacking, limited oxygen index and electrical insulation. This study made use of a composite experimental design approach that would allow for the optimization of the amounts of the additives in the ceramifiable polymer composite giving both the desired mechanical properties of the material under normal operating temperatures as a polymer and also as a ceramic once exposed to elevated temperatures. The optimization of additives used in the ceramifiable polymer composite was done by using a D-optimal mixture design of experiments (DoE) which was analyzed by multiple linear regression.

APA, Harvard, Vancouver, ISO, and other styles

14

Akbarian-Tefaghi, Sara. "Microwave-Assisted Topochemical Manipulation of Layered Oxide Perovskites: From Inorganic Layered Oxides to Inorganic-Organic Hybrid Perovskites and Functionalized Metal-Oxide Nanosheets." ScholarWorks@UNO, 2017. http://scholarworks.uno.edu/td/2287.

Full text

Abstract:

Developing new materials with desired properties is a vital component of emerging technologies. Functional hybrid compounds make an important class of advanced materials that let us synergistically utilize the key features of the organic and inorganic counterparts in a single composite, providing a very strong tool to develop new materials with ”engineered” properties. The research presented here, summarizes efforts in the development of facile and efficient methods for the fabrication of three- and two-dimensional inorganic-organic hybrids based on layered oxide perovskites. Microwave radiation was exploited to rapidly fabricate and modify new and known materials. Despite the extensive utilization of microwaves in organic syntheses as well as the fabrication of the inorganic solids, the work herein was among the first reported that used microwaves in topochemical modification of the layered oxide perovskites. Our group specifically was the first to perform rapid microwave-assisted reactions in all of the modification steps including proton exchange, grafting, intercalation, and exfoliation, which decreased the duration of multi-step modification procedures from weeks to only a few hours. Microwave-assisted grafting and intercalation reactions with n-alkyl alcohols and n-alkylamines, respectively, were successfully applied on double-layered Dion-Jacobson and Ruddlesden-Popper phases (HLaNb2O7, HPrNb2O7, and H2CaTa2O7), and with somewhat more limited reactivity, applied to triple-layered perovskites (HCa2Nb3O10 and H2La2Ti3O10). Performing neutron diffraction on n-propoxy-LaNb2O7, structure refinement of a layered hybrid oxide perovskite was then tried for the first time. Furthermore, two-dimensional hybrid oxides were efficiently prepared from HLnNb2O7 (Ln = La, Pr), HCa2Nb3O10, HCa2Nb2FeO9, and HLaCaNb2MnO10, employing facile microwave-assisted exfoliation and post-exfoliation surface-modification reactions for the first time. A variety of surface groups, saturated or unsaturated linear and cyclic organics, were successfully anchored onto these oxide nanosheets. Properties of various functionalized metal-oxide nanosheets, as well as the polymerization of some monomer-grafted nanosheets, were then investigated for the two-dimensional hybrid systems.

APA, Harvard, Vancouver, ISO, and other styles

15

Ravarian, Roya. "The Effect of Nano-Scale Interaction on the Physico-Chemical Properties of Polymer-Bioactive Glass Composites." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10147.

Full text

Abstract:

Polymer-bioglass composites are favourable materials for bone repair. However, early failure in the interface of components is a common problem in physical mixtures. The aim of this project was to address the issue of phase separation by creating a hybrid material in which the polymer is bonded to bioglass. Synthetic non-biodegradable poly(methyl methacrylate) (PMMA) and natural biodegradable chitosan were selected as two types of polymers for fabrication of hybrid with bioglass. PMMA and chitosan were functionalised with appropriate silane coupling agents and covalently bonded to bioglass. The polymer and bioglass were then co-condensed during sol-gel method to form hybrid. The results of molecular scale analyses demonstrated that at optimum condition (0.1 coupling agent:MMA mol ratio, 60:40 vol% polymer:bioglass), the covalent bond between PMMA and bioglass occurred and resulted in the fabrication of hybrid. The presence of nano-scale interaction resulted in improved physico-chemical and biological properties compared with physical mixtures and bioglass. Furthermore, by manipulating process parameters such as replacing tetrahydrofuran with ethanol, increasing the temperature to 70 °C and adding sodium bicarbonate as catalyst, the gelation time was reduced and a more condensed structure was produced. The chitosan-bioglass hybrid was optimized for the volume ratio of chitosan:bioglass and coupling agent. Furthermore, a new method was developed for the creation of porosity in polymer-bioglass composites in which sodium bicarbonate was used as a gas foaming agent and a biocompatible alternative for the commonly used hydrofluoric acid during sol-gel method. In conclusion, the presence of nano-scale interaction significantly improved the physico-chemical properties of polymer-bioglass hybrids via promoting the homogenous distribution of phases. These hybrids open an avenue for the applications of polymers-bioglass composites for bone replacement and tissue engineering.

APA, Harvard, Vancouver, ISO, and other styles

16

Kaleli, Kadir. "Nano Structural Metal Composites: Synthesis, Structural And Thermal Characterization." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609674/index.pdf.

Full text

Abstract:

In this work , metal functional polymers, namely Cr-PS-b-P2VP, Co-PS-b-P2VP, Au-PS-b-P2VP, Fe-PS-b-P2VP and Mo-PS-b-P2VP were prepared by thermal reaction of hexacarbonylchromium, Cr(CO)6, octacarbonyldicobalt,Co2(CO)8, hydrogentetrachloroaurate(III), H(AuCl4).4H2O, trichloroiron(III), FeCl3.6H2O, molybdenum(VI)oxide, MoO3 and PS-b-P2VP. TEM images indicated formation of AuIII, Cr and Co nanoparticles. On the other hand, crystalline structures were detected for Fe-PS-b-P2VP and Mo-PS-b-P2VP. Samples involving nanoparticles were further characterized by FTIR, UV-Vis and direct pyrolysis mass spectroscopy techniques. FTIR analysis indicated dissapearance of characteristic carbonyl peaks of Cr(CO)6 and Co2(CO)8 for Cr-PS-b-P2VP and Co-PS-b-P2VP samples. The appearance of a peak at about 467 cm-1 supported the formation of metal-nitrogen bond. Pyrolysis mass spectrometry analysis showed an increase in the thermal stability of P2VP chains involving coordinated pyridine units. The thermal stability of these chains increased in the order Co<
Cr <
Au3+ indicating stronger coordination in the same order.

APA, Harvard, Vancouver, ISO, and other styles

17

Orhan, Tugba. "Nano Structural Metal Nano Composites: Synthesis, Structural And Thermal Characterization." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610799/index.pdf.

Full text

Abstract:

Recently, the use of block copolymers in preparation of nanocomposites has received great attention as they form well-defined micelles. In this work, the synthesis of different metal functional copolymers, nano structural metal composites and investigation of their reaction mechanism and thermal characteristics by pyrolysis mass spectroscopy have been aimed. Namely, polyisoprene-block-poly2vinylpyridine, (PI-b-P2VP) and poly2vinylpyridine-block-polymetylmethacrylate, (PMMA-b-P2VP) were used as block copolymers and the thermal reaction of these copolymers with two different transition metal complexes Cr(CO)6 and HAuCl4.3H2O were investigated which mostly lead to the coordination of metal through nitrogen atom of the pyridine ring which then degrates to form nano particles. The samples were further characterized by TEM, ATR-FT-IR, UV-Vis and Direct-Pyrolysis Mass Spectroscopy techniques. TEM images proved the formation of nanoparticles and the results showed that synthesized Au nanoparticles have 2 to 3 fold larger size than Cr nanoparticles. ATR-FT-IR spectrum of metal functional copolymers showed that the disappearance of characteristic peaks of pyridine stretching and bending mode when metal coordinates to the pyridine nitrogen. Furthermore, the spectrum indicated the appearance of a new absorption peak at around 740 cm-1 which may be a clue for the coordination of gold(III) ion to the pyridine nitrogen. Different from chromium case, in the spectrum of Au3+-(PMMA-b-P2VP), CO stretching frequency of PMMA which may appear at around 1720&ndash
1718 cm-1 decreased in intensity while a new absorption peak appeared at around 1600 cm-1. This results reveals that electron deficient gold (III) ion prefers the coordination from both donor atoms namely carbonyl oxygen PMMA and pyridine nitrogen of P2VP in order to compensate its electron deficiency. In the UV-Vis spectrum of copolymers, Cr-functional copolymers showed a sharp absorption peak appeared at around 290 nm is attributed to a MLCT transition from chromium atom to * orbital of pyridine group. Furthermore, Au-functional copolymers showed a completely new absorption band at around 320 nm which can be associated again with a LMCT transition since gold is electron deficient and more willing to accept electrons from the ligand. Pyrolysis mass spectrometry analysis showed that poly2vinylpyridine blocks for each copolymers were affected similarly but polyisoprene block was not affected much from the coordination of metal compared to poly(methyl methacrylate) block in copolymers. For (PI-b-P2VP), Au3+ coordination to copolymer resulted in the higher thermal stability compared to Cr coordination. For (PMMA-b-P2VP), different from Cr, Au3+ coordination to P2VP nitrogen atom was extensive and PMMA based products changed drastically due to the coordination of electron deficient Au3+ to PMMA carbonyl group.

APA, Harvard, Vancouver, ISO, and other styles

18

Bandi, Suneel A. "HIGH PERFORMANCE BLENDS AND COMPOSITES: PART (I) CLAY AEROGEL/POLYMER COMPOSITES PART (II) MECHANISTIC INVESTIGATION OF COLOR GENERATION IN PET/MXD6 BARRIER BLENDS." online version, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1152638697.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Motoc, Dana. "Development of green composites based on epoxidized vegetable oils (EVOs) with hybrid reinforcements: natural and inorganic fibers." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90399.

Full text

Abstract:

The main aim of this work id to provide integral methods to predict and characterize the properties of composite structures based on hybrid polymers and reinforcements, that could lead to useful results from an industrial point of view. This is addressed, if possible, by theoretical predictions of the effective properties by using the available experimental data. The first part is focused on the scientific achievements of the author that allowed a quantitative characterization of the main effective properties of several composite architectures from hybrid polymers and reinforcements, based on bio matrices, tailor-made matrices and different theoretical and simulation methods using computer software to allow good comparison. The second part defines the future research lines to continue this initial investigation. The main objectives are clearly defined to give the reader a sound background with the appropriate concepts that are specifically discussed in the following chapters. As a main objective, this research work makes a first attempt to provide a systematic analysis and prediction of composite hybrid structures.
El objetivo general del trabajo es proporcionar medios integrales para predecir y caracterizar las propiedades de las estructuras de compuestos basados en polímeros y refuerzos híbridos, principales que pueden producir resultados de utilidad práctica simultáneamente. Esto se logra comparando, siempre que sea posible, las predicciones teóricas de las propiedades efectivas con los datos experimentales disponibles. Una primera parte se ocupa de los logros científicos del autor que permitieron caracterizar cuantitativamente las principales propiedades efectivas de las arquitecturas de compuestos basados en polímeros y refuerzos híbridos, basados en matrices bio, auto-desarrollados y diferentes métodos teóricos y de simulación por ordenador utilizados para la comparación. La segunda parte identifica las orientaciones futuras para la evolución y desarrollo de la ciencia y la investigación. Los objetivos generales fueron subrayados y concisos para dar al lector una visión previa de los conceptos que serán discutidos específicamente en los siguientes capítulos. Indirectamente, apuntan hacia uno de los objetivos principales de este trabajo, a saber, proporcionar una dirección para el análisis sistemático de materiales compuestos a base de refuerzos híbridos.
L'objectiu general d'aquest treball es proporcionar els mitjos integrals per tal de predir i caracteritzar les propietats d'estructures de compòsits basats en polímers i reforçaments híbrids, que poden produir resultats amb utilitat pràctica simultàniament. Aquest objectiu s'aconsegueix comparant, sempre que és possible, les prediccions teòriques de les propietats efectives amb les dades experimentals disponibles. Una primera part es centra en els temes científics en què ha treballat l'autor que han permès caracteritzar quantitativament les principals propietats efectives de les arquitectures de compòsits basades en polímers i reforçaments híbrids, derivats de matrius bio, auto-desenvolupats i diferents mètodes teòrics i de simulació informàtica per a una correcta comparació. La segona part identifica les orientacions futures per tal d'establir l'evolució i desenvolupament de la ciència i investigació lligada a la temàtica de la tesi. Els objectius generals han sigut clarament definits per tal de donar-li al lector una visió prèvia i sòlida dels conceptes que es discuteixen en capítols venidors. Indirectament, apunten cap a un dels objectius principals d'aquest treball, a saber, proporcionar una direcció per a l'anàlisi sistemàtica de materials compòsits a base de polímers i reforçaments híbrids.
Motoc, D. (2017). Development of green composites based on epoxidized vegetable oils (EVOs) with hybrid reinforcements: natural and inorganic fibers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90399
TESIS

APA, Harvard, Vancouver, ISO, and other styles

20

MacLachlan, Mark John. "New directions in inorganic polymer and materials chemistry, studies of metal germanium sulfides, ferrocene-containing materials, and mesoporous silica - poly(ferrocenylsilane) composites." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0030/NQ63819.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Gorka, Joanna. "Polymer-based mesoporous carbons: soft-templating synthesis, adsorption and structural properties." Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1290460109.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

BRUNENGO, ELISABETTA. "Engineered poly(vinylidene fluoride) based composites containing inorganic inclusions as materials for energy-related applications: process-structure-properties correlations." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1041104.

Full text

Abstract:

In recent years the continuous and rapid development of the electronic industry together with the need for more efficient electric energy harvesting have notably increased the demand for: (i) high dielectric constant and breakdown strength materials for high energy density capacitors and (ii) piezoelectric flexible materials, with the ability to bend into diverse shapes, for powering low-power portable devices and self-powered electronic systems. Polymer-based composites and nanocomposites with inclusions of a ceramic active phase are very attractive for these applications because they combine materials with different characteristics, allowing the possibility to tune and optimize the dielectric and piezoelectric properties in the ensuing composite systems. In particular, many parameters can affect the material performance: (i) the nature of the polymer matrix and active component; (ii) the phases connectivity; (iii) the filler concentration, shape and dimensions; (iv) the filler/matrix interactions; (v) the preparation technique and processing. All this variability expands the possible applications of polymer-composites for energy-related purposes but also increases the difficulty in realistically predicting their ultimate properties. The design of polymer composites thus requires a rational selection of components, good interface engineering and proper processing optimization. To achieve this, a thorough comprehension of the process-structure-properties correlations is very important. This is the principal aim of this thesis work, which focus on the preparation of poly(vinylidene fluoride) homopolymer (PVDF) or poly(vinylidene fluoride-co-hexafluoropropylene) copolymer (PVDF-HFP) based composites with 0-3 connectivity containing different perovskite fillers, namely, BaTiO3 (BT), Pb(Zr,Ti)O3 (PZT) and Na0.5Bi0.5TiO3 - BaTiO3 (BNBT). The filler particles were used as prepared or properly surface modified and several techniques were employed for the composites preparation (i.e., solvent casting, melt blending, hot-pressing, compression moulding). Initially, a study of the neat polymer matrices was performed, by using, for the first time in literature, the compression moulding technique to tune the polymorphism of PVDF. A principal component analysis was performed on the infrared spectra of the moulded films to validate the equation usually employed for determining the electroactive phase amount (FEA) then multiple linear regression was applied to better understand how the processing parameters affect the FEA value. A double-step procedure was proven fundamental in inducing the formation of PVDF β phase and improving the dielectric properties of the ensuing polymer films. After this preparatory investigation, the study of the process-structure-properties correlations was extended to PVDF-based composites, addressing three main issues: (i) the influence of processing on the ultimate properties of the prepared samples; (ii) the influence of particles dimensions and surface modification on the dielectric behaviour of the composite materials; (iii) the response of flexible piezoelectric composites. The preparation technique affects the microstructure at different levels, but it was found that not always a flawless particles dispersion necessary leads to the best final performance of the composite. Whereas, a proper moulding method, by affecting the polymorphism of the polymer matrix and the compactness of the film, can improve significantly the dielectric response. The presence of an inorganic shell around BT particles allows a modulation of the effective permittivity of the composites; if intrinsic factors (i.e., the permittivity of the components) prevail on extrinsic ones (i.e., interfacial polarization), the composites response can be predicted by FEM calculations. However, in these conditions, the reduction in the dielectric constant compensates for the increase of the breakdown strength promoted by the shell and, as a whole, the stored energy decreases. It is worth noting that the composites containing core-shell particles are characterized by low tunability, a condition which is important for application as dielectric capacitors. The functionalization of the ceramic particles with the tested coupling agents, despite decreasing to a certain extent the dielectric permittivity of the ensuing composites (due to the intrinsic low permittivity of the silane moieties), increases the maximum electric field, thus leading to an energy recovering capability comparable or slightly higher than that of the composite containing pristine BT particles. The dielectric response of the composites is affected by the particles dimensions even though the films containing pristine BT and those containing TiO2-coated particles exhibit a different trend of dielectric permittivity with filler size; this suggests a not negligible contribution of the interfaces, which varies with the method of particles synthesis. As concerns the piezoelectric composites, the piezoelectric coefficient (d33), in general, increases if the filler dimensions increase significantly. The higher response of the samples containing sintered and crushed PZT or BNBT particles (with respect to simply calcined powders) probably derived from the higher particles connectivity inside the agglomerates, which in turn leads to higher local stresses inside the material. As far as we know, the piezoelectric properties of composites made of fluorinated polymer matrices and BNBT filler had not been studied yet. The obtained d33 are in line with those of many flexible lead-free composites made with particles different from BNBT, suggesting the potentiality of these composites in the field of energy harvesting. As principal achievements, I obtained: (i) an alternative and smart method to tune the polymorphism of PVDF homopolymer and its copolymers, by exploiting a simple and easily-scalable processing technique; (ii) solvent-free fabrication of polymer-based composites with dielectric properties improved by the moulding process; (iii) a better comprehension about the role of the interfaces, useful to tune the final performance of the dielectric composites; (iv) flexible lead-free polymer-based composites with a good piezoelectric response for potential application as safe energy harvesting devices.

APA, Harvard, Vancouver, ISO, and other styles

23

Bernard, Alexandre. "Green Polymers: Part 1: Polylactide Growth on Various Oxides: Towards New Materials Part 2: Poly(epoxides-co-anhydrides) from porphyrin catalysts." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343059362.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Michalak, Franck. "Étude d'électrodes composites polymères/oxydes colloidaux : application aux systèmes électrochromes sur supports souples." Grenoble INPG, 1995. http://www.theses.fr/1995INPG0091.

Full text

Abstract:

Au cours de ce travail, nous avons etudie des electrodes composites polymeres/oxydes colloidaux en vue d'application aux systemes electrochromes sur supports souples. Ces composites sont constitues d'un materiau electrochrome colloidal (wo#3, iro#2) et d'un polymere ionique (nafion) ou neutre (polyacrylamide, polymethylmetacrylate, polyvinylbutyral). Nous avons etudie la synthese de ces oxydes dans le but d'obtenir un materiau colloidal stable de taille inferieure a 100 nm. Nous avons obtenu des sols de wo#3 stables contenant des particules ayant un diametre moyen de 10 nm. Les composites wo#3 - polymere contiennent jusqu'a 90% en poids de wo#3 et restent transparents. Ils constituent l'electrode electrochrome de nos systemes. Les particules d'iro#2 obtenues sont trop grosses pour les applications visees (100nm). Nous avons alors utilise la polyaniline comme materiau de contre electrode. La polyaniline a ete deposee sous forme d'un film mince par polymerisation galvanostatique sur un substrat en polyethylene terephtalate recouvert d'une fine couche d'or. Le systeme electrochrome complet comprenant l'electrode composite wo#3/polymethylmetacrylate, la contre electrode en polyaniline et l'electrolyte polymere (bpei-1. 5 h#3po#4) a un contraste de 35% a 700 nm

APA, Harvard, Vancouver, ISO, and other styles

25

Stanciu, Nicoleta Doriana. "Compozite polimer-organice şi polimer-anorganice obţinute prin polimerizare radicalică „in situ”." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10006.

Full text

Abstract:

Ce travail porte sur l'obtention et la caractérisation de composites polymères à charges organiques et inorganiques obtenus par polymérisation radicalaire in situ de monomères dans une matrice organique de type cellulose ou inorganique de type silicate. Avec la cellulose, les monomères retenus sont d'abord des dérivés vinyliques de type acide (méth)acrylique et de comonomères tels que l'anhydride maléique, le styrène et le chlorométhylstyrène. Les produits sont caractérisés notamment par ATG et XRD. La conductivité électrique de ces composites en fonction de leur gonflement a été étudiée. La copolymérisation de l'anhydride maléique avec le dicyclopentadiène est ensuite étudiée dans le toluène et le dioxane. Ce type de copolymère n'avait pas été étudié jusqu'à présent. L'influence du type de solvant sur la conduite de la réaction est étudiée. La caractérisation des composites est effectuée par IR, XRD et microscopie SEM. L'interaction entre les composants est mise en évidence par XRD. Les composites à base de silicate sont obtenus par polymérisation radicalaire contrôlée après greffage de l'amorceur sur le support inorganique. Le greffage est caractérisé par IR. Les analyses XRD et IR mettent en évidence la prédominance du greffage du polymère à la surface du silicate. L'étude de la copolymérisation chlorométhylstyrène - méthacrylate d'hydroxyéthyle a été effectuée qui montre in fine l'influence du support sur la structure des copolymères. De même, les analyses XRD et IR révèlent la modification de la structure du silicate. La microscopie SEM met en évidence des structures homogènes. Une étude complète de dégradation thermique a été menée par ATG qui montre l'influence des différents polymères
The synthesis of organic-polymer or inorganic-polymer composites was a real challenge within the last decades due to the difficulty of optimally dispersing the reinforcing agent into the polymeric matrix. A method to solve this problem is the "in situ "polymerization. The first part of the experimental study deals with the synthesis of the polymer-cellulose composites. Cellulose-containing composites based on copolymers of acrylic acid with styrene, 4-chloro-methyl-styrene and maleic anhydride or based on copolymers of methacrylic acid with styrene and 4-chloro-methyl-styrene were prepared for proton conducting membranes. Next, cellulose composites with maleic anhydride – dicyclopentadiene copolymer matrix were obtained by “in situ” free-radical polymerization. The syntheses were carried out in two different solvents: toluene and dioxane, aiming to determine their influence upon both the polymerization process and properties of the resulting materials. To the best of our knowledge, studies concerning the preparation of this composite have not been published in the literature until now. The second part of the original contributions section is dedicated to the investigation of some polymer-layered silicates composites, using a commercial layered silicate (Cloisite 30B), modified with OH-containing quaternary ammonium salts. First, a new ATRP-based procedure to synthesize polymer-layered silicate composites involving a simpler method than those published in the literature up to now, was studied. The novelty of the methods consists in the one-step preparation of the ATRP initiating sites anchored onto the layered silicate by reacting the OH groups of the quaternary ammonium salt with chloroacetic anhydride, followed by the "in situ” ATRP of the monomer. This way several intermediate stages are eliminated. The last experimental study concerns the synthesis and characterization of a composite with an inorganic support (Cloisite 30B) and a polymeric matrix synthesized by the copolymerization of two different monomers with high reactivity: 2-hydroxyethyl methacrylate and 4-chloro-methyl-styrene. To our knowledge, there are no studies published in the literature describing the preparation of this composite until now. The obtained composite materials were characterized both structurally by FT-IR, NMR, XRD and SEM, and from the thermal behavior point of view by TGA-DSC-MS

APA, Harvard, Vancouver, ISO, and other styles

26

Fourmentin, Aymeric. "Revêtements polyuréthane-acrylate organiques/inorganiques superhydrophobes." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI096/document.

Full text

Abstract:

Ce travail de thèse a porté sur le développement de revêtements organiques/inorganiques photopolymérisables superhydrophobes à partir de procédés d’élaboration simples associés à des produits commerciaux largement diffusés. Pour cela, des revêtements à matrice polyuréthane acrylate (PUA), intrinsèquement hydrophiles, incluant différents composés à base de silicium ont été élaborés par enduction ou pulvérisation. L’objectif a été d’apporter en surface des revêtements une structuration multi-échelle et une chimie à caractère hydrophobe nécessaires pour atteindre la superhydrophobie, c’est-à-dire un angle de contact avec l’eau supérieur à 150° et une hystérésis de mouillage inférieure à 10°. L’introduction de molécules de polysilsesquioxane polyédrique (POSS), présentant un ligand acrylate et sept ligands isobutyle, a apporté une nanostructuration et un comportement hydrophobe aux revêtements PUA à des concentrations très faibles (≤ 1% en masse.). Cependant, la rugosité apportée se révèle trop faible et cette stratégie ne peut aboutir à la superhydrophobie des revêtements. L’introduction de particules de silice pyrogénée, modifiées en surface par des chaînes polydiméthylsiloxane, a permis d’établir une structuration multi-échelle et une chimie à caractère hydrophobe à la surface des revêtements PUA, leur conférant ainsi la superhydrophobie. De plus, le procédé d’élaboration a joué un rôle majeur sur les modifications physico-chimiques de surface des revêtements : la superhydrophobie est obtenue à une concentration relativement élevée de 30 et 60% en masse de silice pyrogénée respectivement par pulvérisation et enduction. Afin de diminuer ces concentrations, la combinaison des deux stratégies précédentes, c’est-à-dire l’introduction simultanée de POSS et de silice pyrogénée, a été considérée. Ceci a permis d’exacerber le caractère hydrophobe des revêtements tout en préservant la rugosité établie par la silice pyrogénée. Cette approche a conduit à la diminution de la concentration de silice nécessaire pour obtenir la superhydrophobie dans le cas des revêtements élaborés par pulvérisation
This work deals with the development of organic/inorganic superhydrophobic UV-curable coatings manufactured through simple processes and from commercially available products. To achieve this goal, a hydrophilic polyurethane acrylate matrix (PUA) was used, in which several silicon-based compounds were introduced. The coatings were deposited using either bar- or spray-coating. The main objective was to structure the surface thanks to a multiscale roughness, while bringing a hydrophobic character, two properties needed to obtain a superhydrophobic coating (defined by a water contact angle superior to 150° and a water contact angle hysteresis inferior to 10°). The introduction of polyhedral oligomeric silsesquioxane molecules (POSS), presenting one acrylate and seven isobutyl ligands, brought a nanostructuration and a hydrophobic behavior to PUA coatings, even at low concentrations (≤ 1%wt.). However, the roughness obtained was not sufficient to bring the superhydrophobicity to the coatings.The introduction of fumed silica particles, functionalized by PDMS chains, established multiscale roughness and hydrophobic behavior at the surface, leading to superhydrophobic coatings. Moreover, the process had a high influence on physico-chemical modifications at the coatings’surface: superhydrophobicity is obtained for a relatively high concentration of fumed silica, 30%wt. and 60%wt. respectively for spray and bar-coating. In order to decrease these concentrations, we tried the combination of the two previous strategies: introduction of POSS molecules and fumed silica particles. This path raised the hydrophobic behavior of the coatings while keeping intact the roughness brought by fumed silica particles. This approach allowed to decrease the silica concentration needed to obtain superhydrophobicity for spray-coated coatings

APA, Harvard, Vancouver, ISO, and other styles

27

Deng, Yuanming. "Study on RAFT polymerization and nano-structured hybrid system of POSS macromers." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00770668.

Full text

Abstract:

This work is generally aimed to synthesize POSS based BCPs via RAFT polymerization, to study their self-assembly behaviors, to research on the effect of POSS self-assembly structure on the bulk properties and to prepare nanostructured hybrid epoxy via self-assembly of POSS based copolymer. In Chapter1, We studied the RAFT polymerization of POSS macromers and capable to synthesize well defined POSS based BCPs with high POSS fraction and different topology such as AB，BAB and (BA)3. The vertex group and the morphology effect on thermo-mechanical properties of POSS based BCPs as well as the structure-property relationship was investigated. Dispersion RAFT polymerization in apolar solvent was applied and various aggregates with different morphology in Chapter2. Cooling induced reversible micelle formation and transition was found and the pathway selection in vesicle formation was investigated. Nano-construction of O/I hybrid epoxy materials based on POSS based copolymers was investigated in Chapter4. The effect of functional group content on miscibility of POSS based statistic copolymer and epoxy was investigated. A novel method to nanostructure epoxy hybrid involving self-assembly of POSS based BCPs in epoxy was presented. High homogeneity and well size/morphology control of core-corona structure containing rigid POSS core and soluble PMMA corona in networks were obtained.

APA, Harvard, Vancouver, ISO, and other styles

28

Faulmann, Christophe. "Conducteurs derives de metaux de transition : complexes moleculaires, polymeres, oxydes de cuivre." Toulouse 3, 1988. http://www.theses.fr/1988TOU30160.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Lai, Peng-Ren, and 賴鵬仁. "Thermal Conductivity Enhancement of Polymer Composites by Surface Modification Inorganic Materials." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/79949253475416499711.

Full text

Abstract:

碩士
國立交通大學
平面顯示技術碩士學位學程
104
Highly thermal conductive inorganic materials (including BN and AlN) have been applied and well distributed in polymeric materials to improve the thermal conductivity of the polymer composites for advanced applications. Our previous results (1.5 years of NSC projects) demonstrate the effects of surface modification and addition ratio of BN on the thermal and mechanical properties of polymer composites (containing RTV rubber and inorganic BN) were investigated. The surface modification of BN enhances the interaction between RTV and BN in the polymer composites. The results show that the combination of BN particles with different sizes in RTV/BN composites can obtain the highest thermal conductivity of 0.73 W/mK. In this proposal, we focus on two different inorganic materials (boron nitride BN and aluminum nitride AlN with excellent thermal conductivities) surface-modified with three different kinds of sufactants containing various functional groups (including -OH, NH2 and -C=C). Different types, ratios, and surface modification of inoganic materials (boron nitride and aluminum nitride with various sizes) and polymers (containing –OH, -NH2, -C=C) were blended to produce various polymer composites. Therefore, according to the adjustment of previous parameters, polymer composites can be optimized to possess many iii different merits, such as packaging, thermal conductivity, thermal stress, and transparency, via the following characterization techniques: (1) Morphology: SEM; (2) Crystallinity: XRD (to investigate the crystallization of inorganic materials); (3) Thermal mechanical property: TMA; (4) Thermal conductivity: Thermal conductive equipments. Finally, we expect to obtain polymeric composites with the optimized thermal conductivities (promoted up to 1.14 W/mK), thermal stress, transparency, and mechanical properties.

APA, Harvard, Vancouver, ISO, and other styles

30

Peng, Chun-Tang, and 彭春棠. "Reflectivity Enhancement of Polymer Composites by Surface Modification of Inorganic Materials." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4p7t8t.

Full text

Abstract:

碩士
國立交通大學
平面顯示技術碩士學位學程
105
In this paper, we use inorganic thermal conductivity materials (ie, boron nitride BN) for (-C = C-) functional inorganic surface modification, the polymer silicone materials mixed with different sizes and proportions of inorganic thermal materials and different proportions (TiO2) powder, and the polymer composite samples were cured at 150 ° C for 0.5 hour, and the reflectivity of the polymer composites was discussed and studied. Through the modulation of the above parameters, coupled with the use of UV-vis spectral measurement instruments to measure different formulations of polymer composites we can obtain in the visible wavelength range (300 ~ 800nm) reflectivity of the high and low trends and explore the following changes: 1)Effect of boron nitride thermal powder (particle size) on the thermal conductivity and reflectivity of polymer composites. 2)Effect of Titanium Dioxide Reflective Powder Addition on thermal Conductivity and Reflectance of Polymer Composites. 3)Relationship between heat transfer performance and reflectivity of non-surface modified boron nitride thermal powder and titanium dioxide reflective powder blended on polymer composites. 4)Relationship between heat transfer performance and reflectivity of surface modified boron nitride thermal powder and titanium dioxide reflective powder blended on polymer composites. Keywords: Boron Nitride (BN) 、TiO2、Polymer composite sample、Heat transfer performance、Reflectivity

APA, Harvard, Vancouver, ISO, and other styles

31

JIANG, JUNG-SHIUN, and 江仲恂. "Rheological and Rheo-birefringence Investigations of Organic and Inorganic Polymer Composites." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g4a9y6.

Full text

Abstract:

博士
國立中正大學
化學工程研究所
107
Polymer composites consisting of inorganic or organic fillers have recently found widespread applications in electronics, optics, biomedicine, and green energy industries. The ability to tailor the multiscale/multiphase structures of a polymer composite over length scales from nanometer to micrometer is essential to systematically improve the material performance in the applications above. The widely varying nature of existing composite materials, however, permits no routine characterization methods to meet the practical requirements. This research focuses on developing rheological and rheo-optical protocols that can be utilized to aid the exploration of structure-performance relationship for representative polymer composite materials that have found important applications in the green-energy technology nowadays. Specifically, we have investigated (1) the front- and rear-side conducting silver pastes used in the fabrication of silicon-based solar cells, (2) carbon black pastes for producing fine-patterned electrodes for bio-sensors, and (3) a representative set of entangled polymer solution, polymer/nanorod suspension, and polymer dispersions for which rheo-birefringence characterizations can play a significant role in simultaneously revealing the rheological and structural properties central to the scientific understanding and technological applications.

APA, Harvard, Vancouver, ISO, and other styles

32

Gupta, Satyajit. "Development of Hybrid Organic/Inorganic Composites as a Barrier Material for Organic Electronics." Thesis, 2013. http://etd.iisc.ac.in/handle/2005/3408.

Full text

Abstract:

The ultra high barrier films for packaging find applications in a wide variety of areas where moisture and oxygen barrier is required for improved shelf-life of food/beverage products and for microbial free pharmaceutical containers. These materials also find applications in micro electro mechanical systems such as ICs, and for packaging in industrial and space electronics. Flexible and portable organic electronics like OLEDs (Organic Light Emitting Diodes), OPVDs (Organic Photo Voltaic Devices) and dye sensitized solar cells (DSSCs) have a good potential in next generation solar powered devices. In fact, organic insulators, semiconductors, and metals may be a large part of the future of electronics. However, these classes of materials are just an emerging class of materials mainly because of their life time constraints. Thus significant research is required to bring them into the forefront of electronic applications. If the degradation problems can be diminished, then these polymers could play a major role in the worldwide electronic industry. A flexible polymer film itself cannot be used as an encapsulation material owing to its high permeability. While a glass or metal substrate possesses ultra high barrier properties, it cannot be used in many electronic applications due to its brittleness and inflexibility. Polymer/ nanocomposites based hybrid materials are thus a promising class of material that can be used for device encapsulation. Chapter I summarizes some of the recent developments in the polymer/nanocomposites based materials for packaging and specifically its use in flexible as well as portable organic electronic device encapsulation. While the development of low permeable encapsulant materials is a chemistry problem, an engineering/instrumentation problem is the development of an accurate technique that can measure the low levels of permeability required for electronic application. Therefore, there is a keen interest in the development of an instrument to measure permeability at these limits. The existing techniques to measure the low permeabilities of barrier films, their importance and accuracy of measurements obtained by these instruments have been briefly discussed in this chapter. Different polymer based hybrid composite materials have been developed for the encapsulation of organic devices and their materials properties have been evaluated. Broadly, two diverse strategies have been used for the fabrication of the composites: in-situ curing and solution casting. Chapters II, III and IV discuss the fabrication of nanocomposite films based on in-situ curing while chapter V discusses fabrication based on solution casting. In chapter II, amine functionalized alumina was used as a cross-linking agent and reinforcing material for the polymer matrix in order to fabricate the composites to be used for encapsulation of devices. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used to elucidate the surface chemistry. Thermogravimetric and CHN analysis were used to quantify the grafting density of amine groups over the surface of the nanoparticles. Mechanical characterizations of the composites with various loadings were carried out with dynamic mechanical analyzer (DMA). It was observed that the composites have good thermal stability and mechanical flexibility, which are important for an encapsulant. The morphology of the composites was evaluated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The work presented in chapter III is a technique based on grafting between surface decorated γ-alumina nanoparticles and the polymer to make these nanocomposites. Alumina was functionalized with allyltrimethoxysilane and used to conjugate polymer molecules (hydride terminated polydimethylsiloxane) through platinum catalyzed hydrosilylation reaction. As in the previous chapter, the surface chemistry of the nanoparticles after surface modification was characterized by different techniques (FTIR, XPS and Raman). The grafting density of alkene groups over the surface of the modified nanoparticles was calculated using CHN analyzer. Thermal stability of the composites was also evaluated using thermogravimetric analysis. Nanoindentation technique was used to analyze the mechanical characteristics of the composites. The densities of the composites were evaluated using density gradient column and the morphology of composites was evaluated using SEM. All these studies reveal that the composites have good thermal stability and mechanical flexibility and thus can be potentially used for encapsulation of organic photovoltaic devices. In addition, rheological studies of the composites were carried out to investigate the curing reaction. The platinum-catalyzed hydrosilylation reaction was studied using both DSC and rheological measurements. The competitive reactions occurring in the system was also monitored in real time through DSC and rheology. Based on the curing curves obtained from these two studies, the mechanistic detail of the curing process was proposed. In addition, swelling studies and contact angle measurements of the composites were also carried out to determine the capability of these materials as encapsulants. Chapter IV deals with a thermally stable and flexible composite that has been synthesized by following a hydrosilylation coupling between silicone polymer containing internal hydrides and mesoporous silica. The results of the characterization of the composites indicates that the composites are thermally stable, hydrophobic, flexible and can be potentially used for encapsulating flexible electronic devices. Chapter V discusses the solution casting method for the development of composites. This chapter is divided into two parts: Part I discusses the synthesis and characterization of flexible and thermally stable composites using polyvinyl alcohol as the base polymer matrix and reactive zinc oxide nanoparticles as the dispersed phase. Various studies like thermal analysis, mechanical analysis, surface analysis and permeability studies were used to characterize the composite films for their possible use as a passivation material. The material was used to encapsulate Schottky structured devices and the performance of these encapsulated devices under accelerated weathering was studied. Part II of this chapter discusses the fabrication of hybrid organic/inorganic based polymer-composite films, based on polyvinylbutyral (PVB) and organically modified mesoporous silica. PVB and amine functionalized mesoporous silica were used to synthesize the composite. An additional polyol (‘tripentaerythritol’) component was also used to enhance the –OH group content in the composite matrix. The thermal, barrier and mechanical properties of these composites were investigated. The investigation of these films suggests that these can be used as a moisture barrier layer for encapsulation. Chapter VI gives the concluding remarks of the results presented. The advantages as well as disadvantages of the in-situ cured and solution casted films and the scope for future work is discussed in this chapter.

APA, Harvard, Vancouver, ISO, and other styles

33

Gupta, Satyajit. "Development of Hybrid Organic/Inorganic Composites as a Barrier Material for Organic Electronics." Thesis, 2013. http://etd.iisc.ernet.in/2005/3408.

Full text

Abstract:

The ultra high barrier films for packaging find applications in a wide variety of areas where moisture and oxygen barrier is required for improved shelf-life of food/beverage products and for microbial free pharmaceutical containers. These materials also find applications in micro electro mechanical systems such as ICs, and for packaging in industrial and space electronics. Flexible and portable organic electronics like OLEDs (Organic Light Emitting Diodes), OPVDs (Organic Photo Voltaic Devices) and dye sensitized solar cells (DSSCs) have a good potential in next generation solar powered devices. In fact, organic insulators, semiconductors, and metals may be a large part of the future of electronics. However, these classes of materials are just an emerging class of materials mainly because of their life time constraints. Thus significant research is required to bring them into the forefront of electronic applications. If the degradation problems can be diminished, then these polymers could play a major role in the worldwide electronic industry. A flexible polymer film itself cannot be used as an encapsulation material owing to its high permeability. While a glass or metal substrate possesses ultra high barrier properties, it cannot be used in many electronic applications due to its brittleness and inflexibility. Polymer/ nanocomposites based hybrid materials are thus a promising class of material that can be used for device encapsulation. Chapter I summarizes some of the recent developments in the polymer/nanocomposites based materials for packaging and specifically its use in flexible as well as portable organic electronic device encapsulation. While the development of low permeable encapsulant materials is a chemistry problem, an engineering/instrumentation problem is the development of an accurate technique that can measure the low levels of permeability required for electronic application. Therefore, there is a keen interest in the development of an instrument to measure permeability at these limits. The existing techniques to measure the low permeabilities of barrier films, their importance and accuracy of measurements obtained by these instruments have been briefly discussed in this chapter. Different polymer based hybrid composite materials have been developed for the encapsulation of organic devices and their materials properties have been evaluated. Broadly, two diverse strategies have been used for the fabrication of the composites: in-situ curing and solution casting. Chapters II, III and IV discuss the fabrication of nanocomposite films based on in-situ curing while chapter V discusses fabrication based on solution casting. In chapter II, amine functionalized alumina was used as a cross-linking agent and reinforcing material for the polymer matrix in order to fabricate the composites to be used for encapsulation of devices. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used to elucidate the surface chemistry. Thermogravimetric and CHN analysis were used to quantify the grafting density of amine groups over the surface of the nanoparticles. Mechanical characterizations of the composites with various loadings were carried out with dynamic mechanical analyzer (DMA). It was observed that the composites have good thermal stability and mechanical flexibility, which are important for an encapsulant. The morphology of the composites was evaluated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The work presented in chapter III is a technique based on grafting between surface decorated γ-alumina nanoparticles and the polymer to make these nanocomposites. Alumina was functionalized with allyltrimethoxysilane and used to conjugate polymer molecules (hydride terminated polydimethylsiloxane) through platinum catalyzed hydrosilylation reaction. As in the previous chapter, the surface chemistry of the nanoparticles after surface modification was characterized by different techniques (FTIR, XPS and Raman). The grafting density of alkene groups over the surface of the modified nanoparticles was calculated using CHN analyzer. Thermal stability of the composites was also evaluated using thermogravimetric analysis. Nanoindentation technique was used to analyze the mechanical characteristics of the composites. The densities of the composites were evaluated using density gradient column and the morphology of composites was evaluated using SEM. All these studies reveal that the composites have good thermal stability and mechanical flexibility and thus can be potentially used for encapsulation of organic photovoltaic devices. In addition, rheological studies of the composites were carried out to investigate the curing reaction. The platinum-catalyzed hydrosilylation reaction was studied using both DSC and rheological measurements. The competitive reactions occurring in the system was also monitored in real time through DSC and rheology. Based on the curing curves obtained from these two studies, the mechanistic detail of the curing process was proposed. In addition, swelling studies and contact angle measurements of the composites were also carried out to determine the capability of these materials as encapsulants. Chapter IV deals with a thermally stable and flexible composite that has been synthesized by following a hydrosilylation coupling between silicone polymer containing internal hydrides and mesoporous silica. The results of the characterization of the composites indicates that the composites are thermally stable, hydrophobic, flexible and can be potentially used for encapsulating flexible electronic devices. Chapter V discusses the solution casting method for the development of composites. This chapter is divided into two parts: Part I discusses the synthesis and characterization of flexible and thermally stable composites using polyvinyl alcohol as the base polymer matrix and reactive zinc oxide nanoparticles as the dispersed phase. Various studies like thermal analysis, mechanical analysis, surface analysis and permeability studies were used to characterize the composite films for their possible use as a passivation material. The material was used to encapsulate Schottky structured devices and the performance of these encapsulated devices under accelerated weathering was studied. Part II of this chapter discusses the fabrication of hybrid organic/inorganic based polymer-composite films, based on polyvinylbutyral (PVB) and organically modified mesoporous silica. PVB and amine functionalized mesoporous silica were used to synthesize the composite. An additional polyol (‘tripentaerythritol’) component was also used to enhance the –OH group content in the composite matrix. The thermal, barrier and mechanical properties of these composites were investigated. The investigation of these films suggests that these can be used as a moisture barrier layer for encapsulation. Chapter VI gives the concluding remarks of the results presented. The advantages as well as disadvantages of the in-situ cured and solution casted films and the scope for future work is discussed in this chapter.

APA, Harvard, Vancouver, ISO, and other styles

34

Kamble, Ramesh B. "Tuning of electrical and magnetic properties in nanocomposites of conductive LaNiO3 and transition metal oxides." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/5450.

Full text

Abstract:

The discovery of new composites by integrating materials of different physical properties with optimal control is of immense interest to researchers at present. Today, there are several composites being used for several applications. The list of composites and their applications is endless from toys to space applications in today's life, as it is a very broad area of research. Composites are made up of the combinations of two or more materials in which one of the materials, so called reinforcing phase in the form of fibers, tubes and particles which are incorporated in the other called matrix phase. The main functions of the matrix are to transfer the stresses between the reinforcing fibers or particles, and to protect them from the mechanical and environmental damage. This enhances their mechanical properties like strength and stiffness. A composite is therefore one synergistic combination of two or more phases which is superior to their individual phases due to more physical and chemical properties. Ceramic composites have successfully replaced many traditional ceramics and metals in several applications due to their light weight and high strength, high tensile strength at elevated temperatures, high creep strength and toughness. Typically, composites can be properly designed and manufactured, by the appropriate combination of the strength of the reinforcing phase and the toughness of the matrix. Such ceramic composites can be more capable to give the desirable properties, which is not possible with a single conventional ceramic. Polymer matrix composites and metal matrix composites have a large number of applications in many fields. However, there are certain issues such as homogeneity of fillers (particles or fibers), recycling, lack of stability, low mechanical and thermal strength, very high coefficient of thermal expansion, etc. The disadvantages of these composites are the difficulty in the production of fiberreinforced composites and their increased labor cost. Ceramic matrix composites are more significant over single phase ceramics, metals matrix and polymer matrix composites in some applications due to their high fracture toughness and high resistant to thermal shocks. They are used in the field of automotive industry, renewable or alternative energies, healthcare, electronics and telecommunications, aerospace, gas sensors and in many high temperature applications. These are based on the combination of physical properties and are referred to as bio-ceramics, electroceramics, magneto˗ceramics, opto˗ceramic, multiferroics and catalysts, etc. Several materials like carbon, graphene and metal oxides have been used to produce composites with different combinations to get superior physical properties. In the present work, the conducting and magnetic metal oxide mixtures were preparation and examined as metal oxide composites. The electrically conductive lanthanum nickelate (LNO) was prepared as the conducting matrix. Ferrites of spinel cubic structure like CoFe2O4, Ni Fe2O4 and barium hexaferrite BaFe12O19 were prepared as magnetic phase. The synthesis, structural, morphological and compositional studies of lanthanum nickelate (LaNiO3) and Co, Ni, Ba ferrites were carried out. The electrical conductivity of LaNiO3 and the magnetic properties of ferrites were investigated at room temperature. Three nanocomposite systems of LaNiO3 with different ferrites were prepared. All composites were investigated for their structural, morphological and compositional studies. The electrical and magnetic properties of composites were investigated. The study of these composites was further extended for electromagnetic interference (EMI) shielding to test shielding effectiveness. The main results on electrical conductivity, magnetic properties and EMI shielding of nanocomposites are briefly summarized. In the thesis, major findings on this work are discussed. The composites of conducting and magnetic metal oxides have not yet been studied and reported. The electrical and magnetic properties of composite materials can be finely tuned by varying concentration of reinforcing phase into conducting matrix and these materials are explored in order to search possible application. This work mainly focuses on the i) Preparation of new composites using conductive and magnetic metal oxides, ii) Tuning of electrical conductivity and magnetic properties, iii) To study composites for EMI shielding, iv) To check the possibilities of applications in the field of electronics and v) To explore the surface and interface physics of hetero structure. Electromagnetic interference (EMI) is a fast growing problem in the modern era of electronics, telecommunication and in various instruments. It has become a critical area to be considered in electronic design and packaging. The increasing usage of large number of electronic devices and the need of increasing processor frequencies, the environment is becoming noisy due to the increasing electromagnetic fields. Therefore, it is necessary to prevent the unwanted EM waves with the adequate EMI shielding. The desire of high performance shields with the reduction in size, weight and price had been a great interest of researchers to discover new materials as suitable candidate for electronic housing. Presently, there are several types of housings and EMI shields are made up of polymer composites and thin metal or metal-alloy sheets work to protect devices from electromagnetic waves. As a part of present thesis work, we have studied all above composites for the EMI shielding measurements in the frequency range of 8 to 18 GHz. It is observed that each composite system showed a very high shielding effectiveness.

APA, Harvard, Vancouver, ISO, and other styles

35

Yong-YiLin and 林永溢. "Polymer/Inorganic Nanoparticle Composites with Asymmetric Trilayer Configuration as Functional Electrolyte Membrane for Full-cell Lithium Ion Battery." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/51504717528638951084.

Full text

Abstract:

碩士
國立成功大學
化學工程學系
104
Asymmetric trilayer membrane shall be first used in full cell lithium ion battery. By choosing the ceramic fillers of electrospinning solution during layer-by-layer deposition, acidic/basic property can be functionalized in individual layer. The transition from coordination complexes to free lithium ions is expected on the surface of SiO2 nanoparticles. On the other side, anions accumulated on the surface of nanoparticle can provide an efficient pathway for lithium ions. The pivotal concept of zeta potential difference for polarization behavior is stressed in the electrolyte and it is different from the case in conventional nanocomposite membrane. It is observed that the performance of electrolyte membranes has no direct relation with their ionic conductivity. Poly(acrylonitrile) based electrolyte membrane with asymmetric trilayer configuration can exhibit 1.60 mS cm−1 at 30 oC. It provides a capacity of 110 mAh g−1 at 5 C-rate and retain 87% initial capacity after 500 cycles. The rate capability of the battery is comparable to that assembled with commercial trilayer membrane. It can sustain at 0.5 mA cm−2 without internal short circuit during 270 h lithium stripping-plating process. With modern electrospray or electrospinning process, the unique configuration applications of this technology include full cell lithium ion batteries, supercapacitors and other battery systems made up of asymmetric electrode configuration.

APA, Harvard, Vancouver, ISO, and other styles

36

Bokel, Felicia. "Solution Assembly of Conjugated Polymers." 2013. https://scholarworks.umass.edu/open_access_dissertations/727.

Full text

Abstract:

This dissertation focuses on the solution-state polymer assembly of conjugated polymers with specific attention to nano- and molecular-scale morphology. Understanding how to control these structures holds potential for applications in polymer-based electronics. Optimization of conjugated polymer morphology was performed with three objectives: 1) segregation of donor and acceptor materials on the nanometer length-scale, 2) achieving molecular-scale ordering in terms of crystallinity within distinct domains, and 3) maximizing the number and quality of well-defined donor/acceptor interfaces. Chapter 1 introduces the development of a mixed solvent method to create crystalline poly(3-hexyl thiophene) (P3HT) fibrils in solution. Chapter 2 describes fibril purification and approaches to robust and functional fibrils, while chapters 3 and 4 demonstrate the formation of hybrid nanocomposite wires of P3HT and cadmium selenide (CdSe) nanoparticles by two methods: 1) co-crystallization of free and P3HT-grafted CdSe for composite nanowires and 2) direct attachment of CdSe nanoparticles at fibril edges to give superhighway structures. These composite structures show great potential in the application of optoelectronic devices, such as the active layer of solar cells. Finally, ultrafast photophysical characterization of these polymers, using time-resolved photoluminescence and transient absorption, was performed to determine the aggregation types present in suspended fibrils and monitor the formation and decay of charged species in fibrils and donor-acceptor systems

APA, Harvard, Vancouver, ISO, and other styles

37

Das, Barun. "Investigations Of Graphene, Noble Metal Nanoparticles And Related Nanomaterials." Thesis, 2011. https://etd.iisc.ac.in/handle/2005/2432.

Full text

Abstract:

The thesis consists of four parts of which part 1 presents a brief overview of nanomaterials. Parts 2, 3 and 4 contain results of investigations of graphene, nanofilms of noble metal nanoparticles and ZnO nanostructures respectively. Investigations of graphene are described in Part 2 which consists of six chapters. In Chapter 2.1, changes in the electronic structure and properties of graphene induced by molecular charge-transfer have been discussed. Chapter 2.2 deals with the results of a study of the interaction of metal and metal oxide nanoparticles with graphene. Electrical and dielectric properties of graphene-polymer composites are presented in Chapter 2.3. Chapter 2.4 presents photo-thermal effects observed in laser-induced chemical transformations in graphene and other nanocarbons system. Chapter 2.5 describes the mechanical properties of polymer matrix composites reinforced by fewlayer graphene investigated by nano-indentation. The extraordinary synergy found in the mechanical properties of polymer matrix composites reinforced with two nanocarbons of different dimensionalities constitute the subject matter of Chapter 2.6. Investigations of noble metal nanoparticles have been described in Part 3. In Chapter 3.1, ferromagnetism exhibited by nanoparticles of noble metals is discussed in detail while Chapter 3.2 deals with surface-enhanced Raman scattering (SERS) of molecules adsorbed on nanocrystalline Au and Ag films formed at the organic–aqueous interface. Factors affecting laser-excited photoluminescence from ZnO nanostructures are examined in great detail in Part 4.

APA, Harvard, Vancouver, ISO, and other styles

38

Das, Barun. "Investigations Of Graphene, Noble Metal Nanoparticles And Related Nanomaterials." Thesis, 2011. http://hdl.handle.net/2005/2432.

Full text

Abstract:

The thesis consists of four parts of which part 1 presents a brief overview of nanomaterials. Parts 2, 3 and 4 contain results of investigations of graphene, nanofilms of noble metal nanoparticles and ZnO nanostructures respectively. Investigations of graphene are described in Part 2 which consists of six chapters. In Chapter 2.1, changes in the electronic structure and properties of graphene induced by molecular charge-transfer have been discussed. Chapter 2.2 deals with the results of a study of the interaction of metal and metal oxide nanoparticles with graphene. Electrical and dielectric properties of graphene-polymer composites are presented in Chapter 2.3. Chapter 2.4 presents photo-thermal effects observed in laser-induced chemical transformations in graphene and other nanocarbons system. Chapter 2.5 describes the mechanical properties of polymer matrix composites reinforced by fewlayer graphene investigated by nano-indentation. The extraordinary synergy found in the mechanical properties of polymer matrix composites reinforced with two nanocarbons of different dimensionalities constitute the subject matter of Chapter 2.6. Investigations of noble metal nanoparticles have been described in Part 3. In Chapter 3.1, ferromagnetism exhibited by nanoparticles of noble metals is discussed in detail while Chapter 3.2 deals with surface-enhanced Raman scattering (SERS) of molecules adsorbed on nanocrystalline Au and Ag films formed at the organic–aqueous interface. Factors affecting laser-excited photoluminescence from ZnO nanostructures are examined in great detail in Part 4.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Polymer Composites - Inorganic Oxides'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles