A series of new, well-defined poly(ether ether sulfone), poly(ether ether ketone) and polyimide derivatives containing the diphenylethylene moiety were prepared by step-growth polymerization methods. Poly(ether ether sulfone) derivatives were prepared by two step-growth polymerization methods: (a) The cesium fluoride catalyzed polycondensation reactions of 4,4´-difluorodiphenylsulfone with different mole percentage ratios of silylated bisphenol derivatives, 2,2-bis(4-tbutyldimethylsiloxyphenyl) propane and 1,1-bis(4-t-butyldimethylsiloxyphenyl)ethylene in N-methyl-2-pyrrolidone at 150 °C. (b) The potassium carbonate catalyzed nucleophilic aromatic substitution polycondensation reactions of 4,4´-difluorodiphenylsulfone with different mole percentage ratios of bisphenol A and 1,1-bis(4-hydroxyphenyl)ethylene in N,N-dimethylacetamide and toluene at 165 °C. Poly(ether ether ketone) derivatives were prepared by the cesium fluoride catalyzed polymerization reactions of 4,4´-difluorobenzophenone with different mole percentage ratios of 2,2-bis(4-t-butyldimethylsiloxyphenyl)propane and 1,1-bis[4-(t-butyldimethylsiloxy)- phenyl]ethylene in N-methyl-2-pyrrolidone at 150 °C. Polyimide derivatives were prepared by step-growth polymerization methods by the polycondensation reactions of 4,4´-oxydiphthalic anhydride with different mole percentage ratios of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 1,1-bis(4-aminophenyl)ethylene. The intermediate polyamic acids were subjected to thermal imidization processes to provide the corresponding polyimide derivatives. Due to the regiospecific introduction of the 1,1-diphenylethylene group along the polymer backbone, the different poly(ether ether sulfone), poly(ether ether ketone) and polyimide derivatives were subjected to post-polymerization sulfonation reactions via the thiol-ene reaction using sodium 3-mercapto-1-propane sulfonate as sulfonating agent and AIBN as initiator in N-methyl-2-pyrrolidone/dimethylsulfoxide at 75 °C for 5 days. The 1,1- diphenylethylene derivatives and the different polymeric compounds were characterized by size exclusion chromatography, dilute solution viscometry, 1H NMR and 13C NMR spectrometry, FTIR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, atomic force microscopy, transmission electron microscopy, elemental analysis, energy dispersive spectroscopy and ion exchange capacity measurements. / Chemistry / M.Sc.(Chemistry)

Thesis (Ph.D.)--Brown University, 2008. / Vita. Advisor : Edith Mathiowitz. Includes bibliographical references (leaves 70-71).

<p> The primary focus of the first portion of this study is to compare physical and mechanical properties of a model epoxy that has been toughened with one of three different types of rubber-based modifier: a traditional telechelic oligomer (phase separates into micro-size particles), a core-shell latex particle (preformed nano-scale particles) and a triblock copolymer (self-assembles into nano-scale particles). The effect of modifier content on the physical properties of the matrix was determined using several thermal analysis methods, which provided insight into any inherent alterations of the epoxy matrix. Although the primary objective is to study the role of particle size on the fracture toughness, stiffness and strength were also determined since these properties are often reduced in rubber-toughened epoxies. It was found that since the CSR- and SBM-modified epoxies are composed of less rubber, thermal and mechanical properties of the epoxy were better maintained. In order to better understand the fracture behavior and mechanisms of the three types of rubber particles utilized in this study, extensive microscopy analysis was conducted. Scanning transmission electron microscopy (STEM) was used to quantify the volume fraction of particles, transmission optical microscopy (TOM) was used to determine plastic damage zone size, and scanning electron microscopy (SEM) was used to assess void growth in the plastic zone after fracture. By quantifying these characteristics, it was then possible to model the plastic damage zone size as well as the fracture toughness to elucidate the behavior of the rubber-modified epoxies. It was found that localized shear yielding and matrix void growth are the active toughening mechanisms in all rubber-modified epoxies in this study, however, matrix void growth was more prevalent. The second portion of this study investigated the use of three acrylate-based triblocks and four acrylate-based diblocks to modify a model epoxy system. By varying block lengths and the polarity of the epoxy-miscible blocks, a variety of morphologies were generated (such as spherical micelles, layer particles and worm-like micelles). It was found that in some cases, the epoxy-miscible block did not yield domains substantial enough to facilitate increases in toughness. Overall, the thermal and mechanical properties of the acrylate-based triblock- and diblock-modified epoxies were found to be similar to CTBN-modified epoxy, which was used as a control. However, there were properties that were improved with the acrylate-based diblock-modified epoxies when compared to the acrylate-based triblock modified epoxies. Specifically, the viscosity penalty of the diblock-modified epoxies was shown to be a marked improvement over the triblock-modified epoxies, especially given that the fracture toughness values are similar. This reduction in the viscosity penalty becomes an important criterion when considering processing procedures and applications. Additionally, comparing the morphology of the resulting modified-epoxies utilizing atomic force microscopy (AFM) and scanning electron microscopy (SEM) led to a better understanding of the relationship between the particle morphology obtained and the physical properties of the acrylate-based rubber-modified epoxy systems in this research.</p>

Thesis (Ph. D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7608. Adviser: Jeffrey S. Moore. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--Lehigh University, 2006. / Advisers: Li Jia; Robert Flowers.

Thesis (Ph.D.)--Lehigh University, 2008.

A series of new, well-defined poly(ether ether sulfone), poly(ether ether ketone) and polyimide derivatives containing the diphenylethylene moiety were prepared by step-growth polymerization methods. Poly(ether ether sulfone) derivatives were prepared by two step-growth polymerization methods: (a) The cesium fluoride catalyzed polycondensation reactions of 4,4´-difluorodiphenylsulfone with different mole percentage ratios of silylated bisphenol derivatives, 2,2-bis(4-tbutyldimethylsiloxyphenyl) propane and 1,1-bis(4-t-butyldimethylsiloxyphenyl)ethylene in N-methyl-2-pyrrolidone at 150 °C. (b) The potassium carbonate catalyzed nucleophilic aromatic substitution polycondensation reactions of 4,4´-difluorodiphenylsulfone with different mole percentage ratios of bisphenol A and 1,1-bis(4-hydroxyphenyl)ethylene in N,N-dimethylacetamide and toluene at 165 °C. Poly(ether ether ketone) derivatives were prepared by the cesium fluoride catalyzed polymerization reactions of 4,4´-difluorobenzophenone with different mole percentage ratios of 2,2-bis(4-t-butyldimethylsiloxyphenyl)propane and 1,1-bis[4-(t-butyldimethylsiloxy)- phenyl]ethylene in N-methyl-2-pyrrolidone at 150 °C. Polyimide derivatives were prepared by step-growth polymerization methods by the polycondensation reactions of 4,4´-oxydiphthalic anhydride with different mole percentage ratios of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 1,1-bis(4-aminophenyl)ethylene. The intermediate polyamic acids were subjected to thermal imidization processes to provide the corresponding polyimide derivatives. Due to the regiospecific introduction of the 1,1-diphenylethylene group along the polymer backbone, the different poly(ether ether sulfone), poly(ether ether ketone) and polyimide derivatives were subjected to post-polymerization sulfonation reactions via the thiol-ene reaction using sodium 3-mercapto-1-propane sulfonate as sulfonating agent and AIBN as initiator in N-methyl-2-pyrrolidone/dimethylsulfoxide at 75 °C for 5 days. The 1,1- diphenylethylene derivatives and the different polymeric compounds were characterized by size exclusion chromatography, dilute solution viscometry, 1H NMR and 13C NMR spectrometry, FTIR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, atomic force microscopy, transmission electron microscopy, elemental analysis, energy dispersive spectroscopy and ion exchange capacity measurements. / Chemistry / M.Sc. (Chemistry)

<p>HDAC inhibitors are known to have anti-inflammatory properties. HDAC inhibitors are used in combination with Oct4 to generate induced pluripotent stem cells. I hypothesized that polyesters based on simple aliphatic HDAC inhibitors like valproic acid (VPA) and phenylbutyric acid (PBA) can serve as alternatives to existing polyester biomaterials with improved anti-inflammatory properties and as scaffolds for generation of iPSCs when used in combination with layer-by-layer thin films delivering reprogramming transcription factors. Vinyl ester of phenylbutyric acid (VEPA) and vinyl ester of valproic acid (VEVA) were synthesized from their carboxylic acid precursors using an iridium complex catalyst at yields as high as 97% and 73%, respectively. Amorphous poly(VEPA) and poly(VEVA) polymers were prepared by free radical solution polymerization and characterized for molecular weight and glass transition temperature. Poly(VEPA) and poly(VEVA) microparticles of 20-40 um diameter were prepared by an emulsion-solvent evaporation method and examined under scanning electron microscopy (SEM). Their hydrolytic degradation was studied by dry weight loss and HDAC inhibitor release via high performance liquid chromatography (HPLC) in the presence of varied pH and lipase-containing buffers. No significant degradation occurred within 5 days, and an MTT assay conducted on HeLa cells in the presence of these microparticles confirmed an absence of cytotoxicity. Poly(VEPA) and poly(VEVA) microparticles were not found to be a suitable biomaterial for hypothesized applications in light of their poor degradation characteristics in vitro.

No description available.

<p> The realization of nanostructured functional materials by self-assembly in polymers and polymer nanocomposites is adversely affected by persisting structural defects which greatly diminish the performance of the material. The use of magnetic fields to impose long-range order is investigated in three distinct systems - ion-conducting block copolymers, semiconducting nanowire-polymer composites and lyotropic surfactant mesophases. The alignment process is quantitatively studied with X-ray scattering and microscopic methods. Time and temperature resolved data collected <i>in situ</i> during the magnetic experiments provide an insight into the thermodynamic and kinetic aspects of the process. These data together with simultaneous electrical conductivity measurements allow relating fundamental structural properties (e.g., morphology and long-range order) to transport properties (i.e., conductivity). In particular, it is demonstrated that magnetic fields offer a viable route for improvement of electric conductivity in these systems. More than an order of magnitude increase in conductivity is recorded in magnetically-annealed materials. The resulting aligned nanostructured systems are attractive for ordered solid polymer electrolyte membranes, heterojunction photovoltaic devices and generally help to understand charge transport mechanisms in anisotropic heterogeneous systems.</p>