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Full-Text Articles in Physical Sciences and Mathematics
Functionalized Materials From Atom Transfer Radical Processes, Sean Fischer
Functionalized Materials From Atom Transfer Radical Processes, Sean Fischer
Electronic Theses and Dissertations
This work is focused on the synthesis, characterization, and application of functionalized materials prepared from atom transfer radical processes. Atom transfer radical processes encompass both atom transfer radical addition (ATRA) and polymerization (ATRP) reactions, both of which are catalyzed by ppm amounts of copper complexes. The synthetic efforts of ATRA include increasing adduct selectivity through optimization of reaction conditions to generate small molecules in high to moderate yields. ATRA provides retention of the halogen moiety, which is an attractive functional group that can be further modified with other transformations. Specifically, the copper-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) allows for the realization …
Control Of Corrosion On Ss316l Using Surface Initiated Polymers, Alexander Rupprecht
Control Of Corrosion On Ss316l Using Surface Initiated Polymers, Alexander Rupprecht
Electronic Theses and Dissertations
Pitting corrosion is arguably one of the most destructive and dangerous forms of corrosion, resulting in damage to structures, the environment, and public health. In addition, damage caused to structures such as bridges, pipelines, and boats, corrosion also has a profound effect on the biomedical community. Implanted metallic devices (i.e., vascular stents and artificial joints) are prone to pitting corrosion caused by aggressive ions present in extracellular fluid. To provide a corrosion-resistant surface on SS316L, films of poly(styrene), poly(methyl acrylate), and poly(methyl methacrylate) were formed using surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting hydrophobic polymer films had a fractional …
Silver-Polymer Nanocomposites, Anita N. Paul
Silver-Polymer Nanocomposites, Anita N. Paul
Electronic Theses and Dissertations
The objective of this research was the development of an efficient method for the preparation of silver-polymer nanocomposites containing finely dispersed silver nanoparticles. The surface of nanosilver was functionalized by thiolation with 2-aminoethanethiol. Amino-modified nanosilver was covalently bonded to polyacrylic acid, biodegradable polymers like acid terminated polylactic acid, ester terminated poly(DL-lactide-co-glycolide) and acid terminated poly(DL lactide-co-glycolide) in the presence of diisopropylcarbodiimide by carbodiimide method. Esterification of the carboxyl groups of Ag-polyacrylic acid by hydrochloric acid in methanol resulted in the formation of a stable colloidal dispersion of Ag nanoparticles in the polymer matrix. It was observed that not just acid …
Photochemistry And Applications Of Diels-Alder Adducts And Photoacids In Materials Science, Valentine Johns
Photochemistry And Applications Of Diels-Alder Adducts And Photoacids In Materials Science, Valentine Johns
Electronic Theses and Dissertations
In chapter I Photo-retro-Diels-Alder (PrDA) reactions of a variety of Diels Alder (DA) adducts were studied. Experimental results showed that the photoreactivity (quantum yield) depends on the electron-donating ability of the diene component and the electronwithdrawing ability of the dienophile component. The mechanism was studied by trapping the reaction intermediate, O2 quenching and femtosecond time-resolved absorption spectroscopy. All the results support a mechanism that involves a charge-separated intermediate generated from a singlet excited state. The PrDA reaction may find applications in photoresponsive materials, photolithography, drug delivery and mechanistic research. Chapter II shows two applications of the PrDA reaction. The first, …
The Fabrication Of Polymer-Derived Sicn/Sibcn Ceramic Nanostructures And Investigation Of Their Structure-Property Relationship, Sourangsu Sarkar
The Fabrication Of Polymer-Derived Sicn/Sibcn Ceramic Nanostructures And Investigation Of Their Structure-Property Relationship, Sourangsu Sarkar
Electronic Theses and Dissertations
Polymer-derived Ceramics (PDCs) represent a unique class of high-temperature stable materials synthesized directly by the thermal decomposition of polymers. This research first focuses on the fabrication of high temperature stable siliconcarbonitride (SiCN) fibers by electrospinning for ceramic matrix composite (CMC) applications. Ceraset™ VL20, a commercially available liquid cyclosilazane, was functionalized with aluminum sec-butoxide in order to be electrospinnable. The surface morphology of the electrospun fibers was investigated using the fibers produced from solvents. The electrospun fibers produced from the chloroform/N,N-dimethylformamide solutions had hierarchical structures that led to superhydrophobic surfaces. A “dry skin” model was proposed to explain the formation of …
Physicochemical And Thermochemical Properties Of Sulfonated Poly(Etheretherketone) Electrolyte Membranes, Stephen Rhoden
Physicochemical And Thermochemical Properties Of Sulfonated Poly(Etheretherketone) Electrolyte Membranes, Stephen Rhoden
Electronic Theses and Dissertations
Fuel cells have long been seen as an alternative to combustion powered and diesel powered engines and turbines. Production of energy via a fuel cell conversion method can generate up to 60% efficiency in comparison to 30% using a combustion powered engine, with low co-production of harmful side-products. The polymer electrolyte membrane (PEM) adapted for the fuel cell application is one of the main components that determines the overall efficiency. This research project was focused towards novel PEMs, such as sulfonated poly(etheretherketone) or SPEEK, which are cost-efficient and robust with high proton conductivities under hydrated conditions. The degree of sulfonation …