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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Mechanistic studies of the copolymerization of epoxides with carbon dioxide and ring-opening polymerization of cyclic esters

Zhou, Zhiping, January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xix, 193 p.; also includes graphics. Includes bibliographical references (p. 181-193).
2

Synthesis of functional polyesters by lipase-catalyzed ring-opening polymerization /

Panova, Anna A. January 2003 (has links)
Thesis (Ph.D.)--Tufts University, 2003. / Director: David L. Kaplan. Submitted to the Dept. of Chemistry. Includes bibliographical references (leaves 160-175). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
3

Synthesis and photophysical properties of phthalocyanine-containing poly(norbornenes).

January 2002 (has links)
by Man-Wai Woo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 77-81). / Abstracts in English and Chinese. / ABSTRACT --- p.i / ACKNOWLEDGMENT --- p.iii / CONTENTS --- p.iv / LIST OF FIGURES --- p.vi / LIST OF TABLES --- p.ix / ABBREVIATIONS --- p.x / Chapter 1. --- INTRODUCTION / Chapter 1.1 --- General Background of Phthalocyanines --- p.1 / Chapter 1.2 --- Previous Examples of Phthalocyanine-containing Polymers --- p.5 / Chapter 1.2.1 --- Poly(phthalocyanines) Linked Via Peripheral Substituents --- p.5 / Chapter 1.2.2 --- Poly(phthalocyanines) Linked Via Axial Ligation --- p.7 / Chapter 1.2.3 --- Poly(phthalocyanines) Attached Laterally to a Polymer Backbone --- p.11 / Chapter 1.3 --- Ring Opening Metathesis Polymerization (ROMP) --- p.15 / Chapter 1.4 --- ROMP of Norbornene Substituted Porphyrazine --- p.18 / Chapter 2. --- RESULTS AND DISCUSSION / Chapter 2.1 --- Phthalocyanines Substituted with Four Poly(norbornene)s --- p.20 / Chapter 2.1.1 --- Preparation of Tetra(norbornene) Phthalocyanines --- p.20 / Chapter 2.1.2 --- Polymerization of Tetra(norbornene) Phthalocyanines --- p.30 / Chapter 2.1.3 --- Characterization of Polymers --- p.39 / Chapter 2.1.4 --- Photophysical Properties of the Polymers --- p.43 / Chapter 2.2 --- Phthalocyanines Substituted with One Poly(norbornene) --- p.49 / Chapter 2.2.1 --- Preparation and Polymerization of Mono(norbornene) Phthalocyanines --- p.49 / Chapter 2.2.2 --- Characterization of the Polymers 41 - 44 --- p.56 / Chapter 2.2.3 --- Fluorescence Quenching of 40 Polymers 41 -44 --- p.61 / Chapter 2.2.4 --- Preparation of Water-soluble Poly(7-oxanorbornene) --- p.63 / Chapter 2.3 --- Conclusion --- p.65 / Chapter 3 --- EXPERIMENTAL SECTION --- p.66 / Chapter 3.1 --- General Methods --- p.66 / Chapter 3.2 --- Photophysical Measurements --- p.67 / Chapter 3.3 --- Synthesis of Phthalocyanines with Four Poly(norbornene) Substituents --- p.68 / Chapter 3.4 --- Synthesis of Phthalocyanines with One Poly(norbornene) Substituent --- p.74 / Chapter 4. --- REFERENCES --- p.77
4

Synthesis Of Novel Amphiphilic Copolymers Based On Sugar Moieties: Development Of New Architectures And Biomedical Applications

Suriano, Fabian 07 October 2009 (has links)
Synthesis of novel amphiphilic copolymers based on sugar moieties: development of new architectures and biomedical applications As early as in the 50’s, amphiphilic copolymers started to attract much interest in the frame of polymer science thanks to their self-assemblies as organized nano-structures in a selective solvent. The resulting micelles or vesicles have emerged as potentially useful materials in the biomedical field such as drug delivery systems when matching the specific conditions of size, coating nature and functionalization,… Moreover, active cell-targeting increases the therapeutic effect by selectively delivering the drug to the required cells. Accordingly, carbohydrates have drawn much attention due to the cell recognition processes they can mediate. Carbohydrates are thus incorporated in polymer backbones to mimic the naturally occurring substrate for the adapted cell receptors. The originality of this thesis is based on the use of sugar moieties as potential multi-hydroxylated initiators for the polymerization of various lactones. This leads to well-defined amphiphilic polymer architectures along with the development of a more facile route for the incorporation of carbohydrates in polymer chains to promote active cell-targeting of the as-obtained nano-structures. The first part of the thesis aims at describing the synthesis of novel amphiphilic brush-like polymers via two pathways. A first approach relies upon the synthesis of polyester arms initiated from the alcohol groups of pending sugars distributed along a preformed hydrophilic polymethacrylate backbone obtained by controlled radical polymerization (via ATRP). Various metal-based and organic catalysts/activators have been studied to lead to the desired architectures using this “grafting from” technique. In another synthetic strategy, the lactone polymerization using a carbohydrate initiator has been carried out, followed by end-chain derivatization reactions yielding brush-like copolymers via a “grafting through” technique. Slight modifications of the end-chain functionalities have also afforded the possibility to synthesize amphiphilic mikto-arm copolymers which self-assemble in aqueous medium in micelles characterized by interesting size features affording promising applications as new drug delivery systems. On the other hand this thesis also focuses on the use of carbohydrate moieties in amphiphilic diblock copolymers such as poly(ε-caprolactone)-b-poly(methacrylate-graft-poly(ethylene oxide)-co-6-O-methacryloyl-D-galactopyranose) or poly(ε-caprolactone)-b-poly(methacrylate-graft-poly(ethylene oxide)-co-1-O-methacryloyl-D-mannofuranose), using the combination of lactone ring-opening polymerization with ATRP of the respective functionalized comonomers, followed by selective post-polymerization sugar deprotection. Next to these copolymers based on polylactones and polymethacrylates, fully degradable amphiphilic block copolymers composed of a polycarbonate backbone have been originally designed. To that end, a multi-step procedure involving the synthesis of sugar-substituted cyclic carbonates, block copolymerization reactions and ultimate selective sugar deprotection, has been investigated. The self-organization of the resulting copolymers, e.g., poly(trimethylene carbonate)-b-poly(3-O-(5’-methyl,5’-carboxy-1’,3’-dioxan-2’-one)-D-glucopyranose), has been studied in aqueous medium. Interestingly, the so-formed polymeric micelles proved to display remarkable living cell-targeting properties. Fabian Suriano
5

Polymer bionanocomposites reinforced by functionalized nanoparticles: impact of nanofiller size, nature and composition

Goffin, Anne-Lise 28 September 2010 (has links)
The aim of this research was to prepare high performance and fully biodegradable polymer nanocomposites. The most representative polymers classified as biodegradable are poly(!-caprolactone) (PCL) (issued from petrochemistry) and polylactide (PLA) (issued from renewable bio-resources). Biodegradable nanoparticles purposely extracted from biomass were selected, namely Cellulose NanoWhiskers (CNW) and Starch NanoCrystals (SNC). CNW are rod-like nanoparticles with 2 nanometric dimensions while SNC consists in nanosheets, thus with 1 nanometric dimension. A 3 nanometric-dimension particle often considered as “silica- type nanocage” was selected to complete this study, namely Polyhedral Oligomeric Silsesquioxane (POSS). The addition of such nanoparticles was expected to enhance several properties of the filled polymer matrix, especially thermo-mechanical performances and extent of crystallinity. In this field, the quality of the nanoparticle dispersion throughout the matrix is an essential parameter to produce nanocomposite materials with largely improved properties. One of the most cited techniques to overcome nanofiller aggregation and even agglomeration relies upon the creation of strong chemical bonds between the nanoparticle and the polymer matrix, leading to the preparation of so-called nanohybrids. For that purpose, the surface of the nanoparticles was first modified by chemical grafting and polymerization reactions. The ring-opening polymerization (ROP) of e-caprolactone and L,L-lactide catalyzed by tin(II) 2- ethylhexanoate (tin octoate, Sn(Oct)2) was initiated from functional groups available on the nanoparticle surface. The grafting efficiency was demonstrated for the three investigated nanofiller/polyester systems. Different characterization techniques were approached depending on the nanofiller nature. In a second step, the so-formed nanohybrids were used as “masterbatches” and dispersed in their corresponding commercial polyester matrices, i.e. PCL and PLA, by melt-compounding using a mini-lab twin screw extruder. The nanocomposite materials were fully characterized, correlating morphological observations with thermal, mechanical and rheological properties. To highlight the beneficial effect of the surface covalent grafting, simple melt-blends, i.e., containing unmodified nanofillers and polyester matrices (PCL or PLA) were prepared. The level of property improvement was most of the time directly related to the degree of nanofiller dispersion, and proved systematically better in case of masterbatch-based materials. Keeping in mind the effect of the nanoparticle geometry, as well as its mechanical modulus, crystallinity or extent of dispersion within the polyester matrix, the rod-like 2D-nanofiller, namely cellulose nanowhiskers extracted from ramie, appeared as the most efficient candidate for polyester reinforcement. The incorporation of PCL chains surface-grafted onto CNW contributed to substantially increasing the overall thermo- mechanical properties, most likely due to the formation of a strong physical chain network between surface- grafted chains and chains composing the matrix. Additionally, CNW-based nanohybrids revealed their potential as both nucleating sites dramatically increasing the crystallization rate of PLA matrix and compatibilizing PCL/PLA immiscible blends.
6

Metal Complexes of Chelating Phenolate Phosphine Ligands

Hsu, Yu-lin 13 July 2010 (has links)
Aluminum complexes, [O3PMe]AlR(R = OtBu, OPh), containing tris-(3,5-di-tert-butyl-2-hydroxy-phenyl)phosphine ([O3P]H3) which is a novel tridentate ligand have been synthesized and characterized by NMR, X-ray diffraction and elemental analysis. Theses complexes were used as catalysts for ring-opening polymerization of £`-caprolactone. We suggested that the stereo effect of catalysts is the main factor in the ring-opening polymerization and compared the mechanism with DFT. In additional, we studied the electronic states and electronic chemistry of [O3PMe]AlR by DFT, UV and PLE. The novel ligand, bis(3,5-tert-butyl-2-phenoxy) tert-butylphosphine ([tBuOPO]H2), reacted with alkali metals such as n-BuLi, NaH and KH to form a series metal complexes, [tBuOPO]M2(Solvent)x (M = Li, Na, K). These metal complexes are all dimeric molecules characterized by X-ray diffraction, NMR and elemental analysis. Moreover, we reacted {[tBuOPO]Li2(DME)}2 with metal complexes of group 4, TiCl3 and MCl4(THF)2 (M = Ti, Zr, Hf), and we received [tBuOPO]2M and [tBuOPO]MCl2(THF) (M = Ti, Zr, Hf). We also synthesized alkoxide complexes of the series metal complexes and studied the catalytic reactivity for ring-opening polymerizations. Furthermore, tantalum complexes, [tBuOPO]2TaX (X = F, Cl) and [tBuOPO]TaCl3, have been synthesized and characterized. Especially synthesizing [tBuOPO]TaCl3 should be carefully controlled by lowering the concentration of TaCl5.
7

Metal Complexes of a Chelating Diphenolate Phosphine Ligand

Chang, Yu-Ning 12 September 2006 (has links)
A tridentate diphenolate phosphine ligand H2[OPO] (bis(3,5-di-tert-butyl-2-hydroxyphenyl)phenylphosphine) has been synthesized in high yield. Treatment of H2[OPO] with Ti(OEt)4 in toluene at room temperature produced reddish orange crystalline Ti[OPO]2. The bis-ligand complex Ti[OPO]2 also be obtained from the in situ lithiation of H2[OPO] in THF or toluene followed by addition of TiCl4(THF)2. The reactions of MCl2[N(SiMe3)2]2 (M = Zr, Hf) with H2[OPO] in pentane at room temperature generated cleanly [OPO]2Zr(H2O) and [OPO]2Hf(H2O), respectively, in high yield. Treatment of TiCl4(THF)2 with Ti[OPO]2 in toluene afforded [OPO]TiCl2(THF). The solution and solid-state structures of Ti[OPO]2, [OPO]TiCl2(THF), [OPO]2Zr(H2O) and [OPO]2Hf(H2O) were studied by multinuclear NMR spectroscopy and X-ray crystallography. lithiation of H2[OPO] with n-BuLi in DME solution afforded [OPO]Li2(DME)2. The metathetical reactions of H2[OPO] with NaH or KH in DME solutions, respectively, produced the corresponding complexes [OPO]Na2(DME)2 and {[OPO]K2(DME)2}2. Both [OPO]Li2(DME)2 and [OPO]Na2(DME)2 are highly active catalysts for ring-opening polymerization of caprolactone. A series of tetravalent tin complexes [OPO]SnX2 (X = Cl, Me, n-Bu) also be obtained from the in situ lithiation of H2[OPO] in THF followed by addition of SnCl2X2. A divalent tin complexe [OPO]Sn also be obtained by analogous way from the in situ lithiation of H2[OPO] in pentane followed by addition of SnCl2.
8

Towards polymeric helicenes the chemistry of poly(divinyl-m-phenylene)s /

Bonifacio, Margel C. January 2007 (has links)
Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "December, 2007." Includes bibliographical references. Online version available on the World Wide Web.
9

Chemistry of a new trispyrazolylborate ligand with some group 1 group 2 ions

Yaman, Gülşah , January 2008 (has links)
Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 190-197).
10

Surface grafting of synthetic hydrophilic polymers via ring opening metathesis polymerization for biomedical applications /

Stoddart, Stephanie S. January 2005 (has links) (PDF)
Undergraduate honors paper--Mount Holyoke College, 2005. Dept. of Chemistry. / Includes bibliographical references (leaves 62-65).

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