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Full-Text Articles in Engineering
In-Situ Frequency-Dependent Electromagnetic Sensing For Monitoring Physical And Chemical Attributes During Chemical Processing, Jeffrey David Rogozinski
In-Situ Frequency-Dependent Electromagnetic Sensing For Monitoring Physical And Chemical Attributes During Chemical Processing, Jeffrey David Rogozinski
Dissertations, Theses, and Masters Projects
The objective of this research was to develop an in-situ sensing technique that monitors the molecular-level response of ions and dipoles to an applied electric field in order to characterize the changes in state of a polymer resin during chemical processing. This technique needs to be capable of monitoring the reaction progress not only in the laboratory setting but also in-situ in the processing tool or reaction environment. Frequency Dependent Electromagnetic Sensing (FDEMS) was selected for this task.;This dissertation investigates the applicability of FDEMS to monitoring two types of processing methods: reactive and batch reactor. The reactive processing system examined …
A Study Of The Aging Of Polyamide-11 Based On Molecular Weight Measurements, Yao Lin
A Study Of The Aging Of Polyamide-11 Based On Molecular Weight Measurements, Yao Lin
Dissertations, Theses, and Masters Projects
No abstract provided.
The Dehydrochlorination Mechanism Of The Internal Allylic Chloride Structure In Poly(Vinyl Chloride), Lynda B. Payne
The Dehydrochlorination Mechanism Of The Internal Allylic Chloride Structure In Poly(Vinyl Chloride), Lynda B. Payne
Dissertations, Theses, and Masters Projects
No abstract provided.
Chemical Interaction Of "Declorane Plus" With Antimony Trioxide In Nylon 66, Yum Min Kang
Chemical Interaction Of "Declorane Plus" With Antimony Trioxide In Nylon 66, Yum Min Kang
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 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, …
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.
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.
Low-Valent Metal Complexes As Reductive Coupling Agents For Smoke Suppression In Poly(Vinyl Chloride), Panagiotis Ioannou Kourtesis
Low-Valent Metal Complexes As Reductive Coupling Agents For Smoke Suppression In Poly(Vinyl Chloride), Panagiotis Ioannou Kourtesis
Dissertations, Theses, and Masters Projects
No abstract provided.
Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow
Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow
Dissertations, Theses, and Masters Projects
The development of boron-containing polymeric materials for neutron shielding applications was undertaken. Three types of materials were characterized for physical and thermal properties: boron powder-filled epoxy composites, carborane polyamides having boron chemically bonded into the polymer, and boron-loaded polyimide thin films. Addition of amorphous submicron boron powder did not affect significantly the thermal performance of the epoxy. The 17% boron loading produced a 26% increase in compressive failure strength and a 68% increase in the compressive modulus. 0.125 inch thick specimens containing 17% boron absorbed 92% of incident neutrons from a 5-Curie Pu/Be source compared with {dollar}<{dollar}1% for the neat epoxy. Dispersion of the boron in the epoxy was improved with the addition of larger size crystalline boron powders. Carborane polyamides containing up to 35% boron were thermally stable up to 400{dollar}\sp\circ{dollar}C in air. The polymers had hydrogen/boron ratios from 2.0 to 3.8 and were soluble in several organic solvents. Polymer solutions were processed into clear, colored thin films. Boron-filled polyamic acid solutions of a PMDA-ODA polyimide containing up to 10% boron were processed into thin films. Neutron absorption of the opaque films measured in a 5-Curie Pu/Be neutron source was linear with boron concentration and film thickness. The fraction of neutrons absorbed varied linearly with boron concentration and film thickness. The applicability of boron-containing materials to the aerospace, nuclear power and accelerator industries was investigated.
Fabrication Of Thermoplastic Polymer Composite Ribbon, Donald Allan Sandusky
Fabrication Of Thermoplastic Polymer Composite Ribbon, Donald Allan Sandusky
Dissertations, Theses, and Masters Projects
The goal of this research was to develop a controllable process to convert a thermoplastic powder-coated carbon-fiber towpreg into uniform and consolidated ribbon. The approach comprised four primary activities. (1) The patent and processing literature was studied to evaluate the state of the art. (2) A functional ribbon fabrication technique was developed by scaling-up, in a novel configuration, hardware components found in the literature. (3) The ex parte ribbonizing process was characterized by calibrating equipment, determining steady state and studying cause and effect between process parameters and ribbon quality. (4) Process design and control methods were derived from heat transfer …
Characterization Of Pr500 For Use In Resin Transfer Molding, Rhonda Michelle Barksdale
Characterization Of Pr500 For Use In Resin Transfer Molding, Rhonda Michelle Barksdale
Dissertations, Theses, and Masters Projects
No abstract provided.
Mechanisms Of Poly(Vinyl Chloride) Pyrolysis In The Presence Of Transition Metals, William Stephen Bryant
Mechanisms Of Poly(Vinyl Chloride) Pyrolysis In The Presence Of Transition Metals, William Stephen Bryant
Dissertations, Theses, and Masters Projects
No abstract provided.
Characterization Of Nylon-11 Degradation, Leslie Christian Mccullough
Characterization Of Nylon-11 Degradation, Leslie Christian Mccullough
Dissertations, Theses, and Masters Projects
No abstract provided.
Characterization And Modeling Of Amino Epoxide Resins, Maria Anastasia Argiriadi
Characterization And Modeling Of Amino Epoxide Resins, Maria Anastasia Argiriadi
Dissertations, Theses, and Masters Projects
No abstract provided.
Physical And Mechanical Behavior Of Amorphous Poly(Arylene Ether-Co-Imidazole)S And Poly(Arylene Ether-Co-Imidazole) Modified Epoxies, Patricia D. Roberts-Mcdaniel
Physical And Mechanical Behavior Of Amorphous Poly(Arylene Ether-Co-Imidazole)S And Poly(Arylene Ether-Co-Imidazole) Modified Epoxies, Patricia D. Roberts-Mcdaniel
Dissertations, Theses, and Masters Projects
Due to the high crosslink density of cured epoxy resins they generally lack damage tolerance. A significant amount of research has been expended to improve the toughness of epoxies. Research into the area of thermoplastic epoxy modifiers has begun to overcome some of the limitations of early methods of epoxy toughening (i.e. lower modulus and thermal stability).;This study examines the physical and mechanical properties of random poly(arylene ether-co-imidazole) (PAE-co-Is) and the characterization of epoxies modified with poly(arylene ether-co-imidazole)s.;Poly(arylene ether-co-imidazole)s exhibited the highest solubility in N,N,N{dollar}\rm\sp\prime,N\sp\prime,{dollar}-tetraglycidyl- 4,4{dollar}\sp\prime{dollar} diaminodiphenyl methane (TGMDA) based resins. The high molecular weight polymers caused significant decreases in …
Characterization Of Epoxy Resins For Use In The Resin Transfer Molding Process, Christina Kaye Short
Characterization Of Epoxy Resins For Use In The Resin Transfer Molding Process, Christina Kaye Short
Dissertations, Theses, and Masters Projects
No abstract provided.
Cross-Linking Additives As Smoke Suppressants For Poly(Vinyl Chloride), Steven Alfred Terranova
Cross-Linking Additives As Smoke Suppressants For Poly(Vinyl Chloride), Steven Alfred Terranova
Dissertations, Theses, and Masters Projects
No abstract provided.
Dielectric Sensor In-Situ Control Of The Rtm Composite Fabrication Process, Alex Stewart Williamson
Dielectric Sensor In-Situ Control Of The Rtm Composite Fabrication Process, Alex Stewart Williamson
Dissertations, Theses, and Masters Projects
No abstract provided.
Dielectric And Kinetic Analysis Of Thermosetting Polyester Resin, Patricia Haverty Tully
Dielectric And Kinetic Analysis Of Thermosetting Polyester Resin, Patricia Haverty Tully
Dissertations, Theses, and Masters Projects
No abstract provided.
Nonlinearity Parameters Of Polymers, Meng-Chou Wu
Nonlinearity Parameters Of Polymers, Meng-Chou Wu
Dissertations, Theses, and Masters Projects
Three types of acoustic nonlinearity parameters for solids are discussed. The results of measurements of these parameters for three polymers--polymethyl methacrylate, Polystyrene, and polysulfone--are presented.;The author has developed a new technique, using piezoelectric transducers directly bonded to the specimens, which allows the measurements of fundamental and second harmonics generated in the solids, and thereby the determination of nonlinearity parameter {dollar}\beta\sb3{dollar}, which is the ratio of a linear combination of second- and third-order elastic coefficients to the second-order elastic coefficient.;The second nonlinearity parameter, B/A can be determined from the temperature and pressure derivatives of the sound velocity. We derive its exact …