Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 15 of 15
Full-Text Articles in Physical Sciences and Mathematics
The Selective Oxidation Of Beta-Cyclodextrin On The Secondary Face, Christine Evelyn Heath
The Selective Oxidation Of Beta-Cyclodextrin On The Secondary Face, Christine Evelyn Heath
Dissertations, Theses, and Masters Projects
No abstract provided.
Analysis Of Mercury Coordination Environments Of Tridentate And Tetradentate Nitrogen Based Ligands By Nmr Spectroscopy And X-Ray Crystallography, Rachel E. Freer
Analysis Of Mercury Coordination Environments Of Tridentate And Tetradentate Nitrogen Based Ligands By Nmr Spectroscopy And X-Ray Crystallography, Rachel E. Freer
Dissertations, Theses, and Masters Projects
No abstract provided.
The Promotion Of Poly(Methyl Methacrylate) Depolymerization By Metal-Based Initiators, Jason Andrew Macko
The Promotion Of Poly(Methyl Methacrylate) Depolymerization By Metal-Based Initiators, Jason Andrew Macko
Dissertations, Theses, and Masters Projects
No abstract provided.
The Synthesis, Characterization, And Molecular Modeling Of Cyclic Arylene Ether Oligomers, Sheeba Ahmed
The Synthesis, Characterization, And Molecular Modeling Of Cyclic Arylene Ether Oligomers, Sheeba Ahmed
Dissertations, Theses, and Masters Projects
Cyclophanes are a family of bridged cyclic aromatic compounds that have found extensive applications in host-guest chemistry, molecular recognition, biomimetics and most recently as precursors in ring-opening polymerizations.;This research presents the synthesis of several novel cyclic arylene ether oligomers, based on 1,3-bis(4-fluorobenzoyl) benzene and 3,3{dollar}\sp\prime{dollar}-methylene diphenol and 3,3{dollar}\sp\prime{dollar}-(ethylene dioxy) diphenol, and their characterization by LC-MS/MS, 1-D {dollar}\sp1{dollar}H-NMR and x-ray crystallography. Electrospray ionization (ES) along with MS/MS was used to characterize cyclic oligomers of molecular weight up to 1600 Da. The thermal properties of these cyclic oligomers were studied by differential scanning calorimetery (DSC) and thermal gravimetric analysis (TGA).;These cyclic oligomers …
The Influence Of Microstructure On The Thermal Degradation Behavior Of Poly(Vinyl Chloride), Hoang Vi Tran
The Influence Of Microstructure On The Thermal Degradation Behavior Of Poly(Vinyl Chloride), Hoang Vi Tran
Dissertations, Theses, and Masters Projects
No abstract provided.
The Synthesis Of 6a,6b-Dideoxy-6 A,6b-(9,10-Dicyanoanthracenyl-2,3-Dimethylene)-Beta-Cyclodextrin, Jonathan D. Tan
The Synthesis Of 6a,6b-Dideoxy-6 A,6b-(9,10-Dicyanoanthracenyl-2,3-Dimethylene)-Beta-Cyclodextrin, Jonathan D. Tan
Dissertations, Theses, and Masters Projects
No abstract provided.
The Synthesis Of Benzophenone-3,5-Diacid Chloride For The Double Capping Of Beta-Cyclodextrin, Clyde Wesley Eargle
The Synthesis Of Benzophenone-3,5-Diacid Chloride For The Double Capping Of Beta-Cyclodextrin, Clyde Wesley Eargle
Dissertations, Theses, and Masters Projects
No abstract provided.
Correlation Of Dynamic Dielectric Properties To Reaction Kinetics And Changing Mechanical Properties Of Epoxy Resins During Cure, Yunfei Wang
Dissertations, Theses, and Masters Projects
The principal objective of this paper is to describe how complex impedance, obtained from frequency dependent dielectric sensing technique, can be used as an effective diagnostic tool for in situ real-time investigation in the fabrication of thermoset structures.;Two epoxy systems (Pr500 from 3M and My720 from Ciba Geigy) with different functionality are characterized in terms of their dielectric, thermal, and rheological behavior. It is observed that there is a one to one relationship between Tg and conversion which is independent of cure temperature. The chemical kinetics of the reaction is satisfactorily described by an autocatalyzed reaction mechanism. The chemical rate …
Microstructural Characterization Of An Ultra-High-Performance Polyimide, April Heather Baugher
Microstructural Characterization Of An Ultra-High-Performance Polyimide, April Heather Baugher
Dissertations, Theses, and Masters Projects
The motivation for this study was to further characterize a relatively new high-temperature polymer for application as a matrix resin for carbon fiber composites. The two primary questions addressed in this study dealt with the structural and chemical changes occurring in these polymers on exposure to high temperature.;To investigate the structural changes in the heat-treated samples, a positron annihilation lifetime spectrometer was designed, built and optimized. Because the lifetime of a positron in a material reflects the electronic structure of the material in which it annihilates, measurements by positron annihilation lifetime spectroscopy can be used to investigate changes in a …
The Thermal Cure Of Phenylethynyl-Terminated Polyimides And Selected Model Compounds, Karen H. Wood
The Thermal Cure Of Phenylethynyl-Terminated Polyimides And Selected Model Compounds, Karen H. Wood
Dissertations, Theses, and Masters Projects
The ability to process high performance polymers into useful adhesives and high quality composites has been significantly advanced by synthetic techniques in which oligomers terminated with reactive groups cure or crosslink at elevated temperature after the article has been fabricated. Several matrix resin systems of considerable interest to the aerospace community utilize phenylethynyl terminated imide (PETI) technology developed at the Langley Research Center to achieve this advantage. This work addresses the cure chemistry of PETI oligomers.;The thermal cure of selected oligomers and model compounds was studied using a variety of analytical techniques including differential scanning calorimetry, high pressure liquid chromatography, …
The Synthesis Of Reflective And Electrically Conductive Polyimide Films Via An In Situ Self-Metallization Procedure Using Silver(I) Complexes, Robin Elaine Southward
The Synthesis Of Reflective And Electrically Conductive Polyimide Films Via An In Situ Self-Metallization Procedure Using Silver(I) Complexes, Robin Elaine Southward
Dissertations, Theses, and Masters Projects
Optically reflective polyimide films have been prepared by the incorporation of silver(I) acetate and a {dollar}\beta{dollar}-diketone solubilizing agent, hexafluoroacetylacetone (HFAH), into a dimethylacetamide solution of the poly(amic acid) formed from {dollar}3,3\sp\prime,4,4\sp\prime{dollar}-benzophenonetetracarboxylic acid dianhydride (BTDA) and {dollar}4,4\sp\prime{dollar}-oxydianiline {dollar}(4,4\sp\prime{dollar}-ODA). Optically reflective and conductive polyimide films have been prepared by replacing the {dollar}\beta{dollar}-diketone (HFAH), with the less substituted {dollar}\beta{dollar}-diketone, trifluoroacetylacetone (TFAH). The former system has been both cast directly from the poly(amic acid) resin and cast from the poly(amic acid) resin onto a fully imidized {dollar}\rm BTDA/4,4\sp\prime{dollar}-ODA base (forming a metallized topcoat). Thermal curing of the silver(I)-containing poly(amic acid) leads to imidization with …
Microstructures Of Poly(Vinyl Acetate) Studied By Nuclear Magnetic Resonance Spectroscopy, Hongyang Yao
Microstructures Of Poly(Vinyl Acetate) Studied By Nuclear Magnetic Resonance Spectroscopy, Hongyang Yao
Dissertations, Theses, and Masters Projects
Carbon-13 NMR spectroscopy was used to investigate the microstructures of poly(vinyl acetate) prepared by solution polymerization in benzene. A series of aromatic compounds was synthesized in order to model the structures formed via chain transfer to solvent. The peaks near 126.5 and 128.5 ppm in the spectra of the polymer samples were assigned to a 1-phenyl-(2n + 1)-multi-acetoxyalkane (where n = 1, 2, 3, etc.) microstructure. The concentration of that structure obtained from NMR spectra was correlated with the concentration calculated from reported kinetic data.;Chain transfer to benzene was shown to occur by addition of the macroradical to benzene, followed …
A Study Of Poly(Vinyl Chloride) Microstructure, Vadim Guennadievich Zaikov
A Study Of Poly(Vinyl Chloride) Microstructure, Vadim Guennadievich Zaikov
Dissertations, Theses, and Masters Projects
High-field {dollar}\sp{lcub}13{rcub}{dollar}C and {dollar}\sp1{dollar}H NMR spectroscopies were used to investigate some unusual features of the molecular microstructure of poly(vinyl chloride) (PVC).;Several model monochloroalkenes were synthesized in order to determine {dollar}\sp{lcub}13{rcub}{dollar}C shift increments for the replacement of H by Cl at positions that are near an isolated internal double bond. These increments then were used to predict the {dollar}\sp{lcub}13{rcub}{dollar}C shifts of the internal allylic chloride structure in PVC. The predictions were not satisfactory, because, as expected, the increments were not additive.;It was shown that during conventional VC polymerization, the chloroallylic chain end (-CH{dollar}\sb2{dollar}CH=CHCH{dollar}\sb2{dollar}Cl) does not copolymerize with the monomer and is …
Characterization Of Epoxy-Amine Systems And Nylon-11 And Pvdf Degradation, Wendy Raquel Mahler
Characterization Of Epoxy-Amine Systems And Nylon-11 And Pvdf Degradation, Wendy Raquel Mahler
Dissertations, Theses, and Masters Projects
No abstract provided.
Development Of Supercritical Fluid Extraction (Sfe) For The Determination Of Polychlorinated Biphenyls In Tissues Of Aquatic Biota, Michael O. Gaylor
Development Of Supercritical Fluid Extraction (Sfe) For The Determination Of Polychlorinated Biphenyls In Tissues Of Aquatic Biota, Michael O. Gaylor
Dissertations, Theses, and Masters Projects
No abstract provided.