Materials Chemistry Commons^™

Investigation Of Novel Thiol "Click" Reactions, Justin William Chan

Dissertations

The thio-Michael addition reaction is traditionally considered a base catalyzed reaction which involves high catalyst concentrations and long reaction times. This reaction utilizes potent, simple nucleophiles to catalyze the reaction, decreases the catalyst concentration and greatly increases the reaction times. The free radical mediated thiol-ene click reaction uses light or heat and an initiator to catalyze the rapid and quantitative addition of thiols to most electron rich enes without the formation of side products and in the absence of solvent. Recently, the thiol-ene click reaction has been exploited for these reasons in materials science and organic synthesis. The research herein …

Investigation Of The Relationship Between Polymer Structures And Thermal, Mechanical, Viscoelastic Properties, Ethem Kaya

Dissertations

The research presented in this dissertation involves four distinct areas: physical crosslinking systems, UV curable coatings for enhanced oxygen and carbon dioxide barrier properties, synthesis, and investigation of melting behavior/crystallinity relations of linear polyamides with long alkyl chains, and synthesis and characterization of cyclic diamides as precursors to linear polyamides 6 4.

The physical crosslinking section involves synthesis of monomers and polymers bearing cyclodextrin and adamantane pendent groups, and investigation of non-covalent interactions between these polymers (Chapter II). Two methacrylate monomers bearing cyclodextrin and adamantane were synthesized, and copolymerized with poly(ethylene glycol) methyl ether methacrylate. The specific interaction between copolymers …

Random And Block Copolymers Of Poly(Dodecamethyleneterephthalamide), Theodore Frank Novitsky Jr.

Dissertations

The following dissertation focuses on the synthesis and characterization of poly(dodecamethylene terephthalamide) (PA-12,T) and novel copolymers. Chapter I details the synthesis of PA-12,T homopolymer by melt condensation polymerization. A series of homopolymers with different molecular weights were obtained by adjusting the stoichiometry of the polymerization using 1,12-diaminododecane, terephthalic acid and benzoic acid. End group 13C NMR spectroscopy resonances were obtained by correlating peak intensities with intrinsic viscosity values. From the NMR data, total end group concentrations and molecular weights were determined for each sample. The data exhibited a linear trend when plotting log (IV) versus log (Mn), and previously unknown …

Preparation And Characterization Of Thiol Based Polymeric Materials, Junghwan Shin

Dissertations

The thiol click-type reaction is one of the most efficient chemical processes that can undergo at room temperature in the benign organic solvent providing excellent opportunity in the fabrication of new materials as well as development of new manufacturing processes. Moreover, the versatility of thiol click-type reactions with many different functional groups such as ene, yne, epoxy, isocyanate, and alkyl halide is the important aspect that should be differentiated from the classic azide-alkyne click chemistry. Although, there are tremendous studies on many areas using thiol click-type reactions, the efficiency and utilities for the material applications have been barely explored. Especially, …

Studies Of Titanium Dioxide Nanoparticles And Surfactants Effects, Singly And In Combinations, On Luminescence Intensity Of Some Aromatic Compounds., Charles Anim Odame-Ankrah

Electronic Theses and Dissertations

Luminescence techniques are sensitive, selective, and widely used in analysis. Luminescence intensity is attenuated by quenchers. This research has focused on the use of surfactants such as CTAB, SDS, and TX-100 singly or together with TiO₂ nanoparticles to evaluate their individual and combined effects on some fluorescent aromatic compounds such as pyrene, fluoranthene, anthracene, phenanthrene, and carbazole. Rutile phase TiO₂ was synthesized using the low temperature sol-gel method. Carbazole and phenanthrene were severely quenched by all surfactants singly or in combination with TiO₂. Anthracene and fluoranthene showed some enhancement in their luminescence intensity. The most dramatic …

The Use Of Fourier Transform (Ft) Surface-Enhanced Raman Scattering For Biochemical Analysis, Robert Butler Jeffers

Chemistry & Biochemistry Theses & Dissertations

Surface-enhanced Raman scattering (SERS) is a powerful spectroscopic technique that has created exciting opportunities in the field of bioanalytical chemistry, where it combines ultrasensitive detection of biologically relevant molecules with vibrational spectroscopy. Due to the difficulties in preparing reproducible SERS active substrates, SERS has been mainly used as a qualitative tool. In order for SERS to be utilized as a viable tool for quantitative analysis, simple, facile SERS substrates which generate clean, highly reproducible signals must be developed. This dissertation deals with the evaluation of three different methods of SERS that led to the development of a novel substrate for …

Evaluation Of Low-Temperature Fluoride Routes To Synthesize Actinide Nitrides And Oxide Solid Solutions, Gunanda Waduge Chinthaka Silva

UNLV Theses, Dissertations, Professional Papers, and Capstones

Actinide mononitrides have been considered as a possible nuclear fuel for the Generation-IV nuclear reactor systems. In the process of evaluating these actinide mononitrides as nuclear fuel, it is important to study different chemical and physical characteristics of these compounds. Synthesis of the materials is thus important. Carbothermic reduction is one of the techniques that have been used to synthesize actinide mononitrides. In this method, a mixture of actinide oxide such as UO ₂ and excess carbon is heat treated at temperatures greater than 1700 °C under a nitrogen atmosphere. The technique is however not promising in synthesizing the actinide …

The Synthesis And Systematic Evaluation Of Modified Polymeric Foams And Electrically Conductive Polyimide/Carbon/Metal Films, John Macharia Kinyanjui

UNLV Theses, Dissertations, Professional Papers, and Capstones

Thermally processed PU foams are examined as a function of processing temperatures (25, 45, 65, and 85°C) at the side, middle, and center of a simple cylindrical mold. The PU foams show both chemical and morphological differences as a function of the processing temperature and radial position within the mold. Thermal degradation of uretoneimine structures, the emergence of carbodiimide structures, and extent of reaction of isocyanate groups are measured using photoacoustic FTIR spectroscopy. Chemical gradients and morphology differences between the side, middle, and center of the molded foam are observed for all processing temperatures. The data indicate that thermal activation …

Influence Of Functional Components On The Film Formation Of Colloidal Dispersions, Kevin Lee Rhudy

Dissertations

A number of colloidal dispersions were synthesized to advance knowledge and gain understanding regarding interactions between individual components and for elucidation of complex processes governing their film formation. These studies show that for methyl methacrylate/n-butyl acrylate (MMA/nBA) colloidal dispersions, the presence of functional components significantly affects film formation. The incorporation of polyvinyl alcohol (PVOH) into pMMA/nBA colloidal dispersions creates competing environments between the copolymer particle surfaces, aqueous phases, and dispersing agents which results in migration with self-induced stratification occuring during coalescence. pMMA/nBA/PVOH films stratify to form sodium dodecyl sulfate (SDS) rich film-air (F-A) interfaces, and the -SO3" moieties exhibit preferential …

Magnetic And Dielectric Properties Of Sulfonated (S) Poly[(Styrene)-(Ethylene-Co-Butylene)-(Styrene)] (Sebs) Block Copolymer/Magnetic Metal Oxide Nanocomposites Synthesized Via An In-Situ Precipitation Method, Sateesh Kumar Peddini

Dissertations

Block copolymer/magnetic metal oxide nanocomposites were synthesized by growing metal oxide nanoparticles (cobalt ferrite, CoFe204 and iron oxide, a-Fe203) in sulfonated (s) poly (styrene) (PS) block domains of sulfonated poly [(styrene)-(ethyleneco- butylene)-(styrene)] (SEBS) BCP preformed films via an in-situ precipitation method by dissolving the salts of respective metal chloride (s) in a suitable solvent that selectively swells the sPS regions. Inorganic uptake was determined using thermogravimetric analysis (TGA), and it was observed that none of the samples incorporated more than 5 wt % of the inorganic component. Dynamical mechanical analysis was used to observe the changes in the glass transition …

Design, Synthesis, And Film Formation Of Fluorine Containing Colloidal Dispersions, Anuradha Misra

Dissertations

Fluoropolymers (FPs) have been subject of interest for many years, however due to extreme synthetic and processing conditions their applications have been limited. This dissertation focuses on design and synthesis of fluorine containing colloidal dispersions to advance limited knowledge and to gain further understanding of fluorine containing colloidal dispersions. Fluoroacrylates and fluoro methacrylates consisting of varying chain length of perfluoroalkyl side chain were copolymerized with methylmethacrylate (MMA) and n-butylacrylate (n-BA) under aqueous environment utilizing phospholipids (PLs) as dispersing agent. Morphologies of colloids, coalescence, and film formation processes after water evaporation was investigated using various microscopic probes such as transmission electron …

Investigation Of Electrical And Optical Properties Of Bulk Iii-V Ternary Semiconductors, Travis C. Gomez

Theses and Dissertations

Bulk grown III-V ternary semiconductors of In_0.08Ga_0.92Sb and In_0.15Ga_0.85As were investigated through Hall-effect and photoluminescence measurements to determine carrier concentration, mobility, sheet resistivity, and luminescence spectrum. In the past, epitaxial layers of ternary compounds have been grown on binary compound substrates, and thus very limited lattice matched ternary alloys were available. Recently, bulk grown ternary substrates have been developed, and it has presented a renewed interest in using these substrates to grow high quality ternary compounds for use in many next generation optoelectronic devices. The results of photoluminescence (PL) study for the …

Advanced Radiometry For High Discrimination Explosive Fireball Discrimination, Steven E. Slagle

Theses and Dissertations

The high explosive fireball phenomenological model for the mid wave infrared spectrum, developed by AFIT, performs classification from spectral signatures was modified to use radiometric intensities. Five bands were sequentially fit to derive the five physical fit parameters describing the fireball's temperature, size, soot absorption coefficient within 16% and emissions from the H₂O and CO₂ concentrations within 333% of the spectral model. This was improved by changing the model's band sizes, center, and fitting methods where all five fit parameters were matched to within 17% of spectral model. This demonstrated that a combination of radiometric intensities could …

Synthesis Of 5-Methoxy-7-Methylbicyclo[3.2.0]Hept-2-En-6-Ol, Harlan Reid

Theses, Dissertations and Capstones

In order to generate a chiral metallocene ligand similar to Kaminsky-Sinn catalysts, a multistep synthesis for the production of 6,7-dimethylbicyclo[3.2.0]hepta-1,3-dienyl anion was proposed. Experiments directed at the initial phase of the proposal are included, ending with the characterization of new alcohols in compounds 9 through 12. Two steps from the synthesis were successfully combined, leading to improved recovery of the alcohols.