Polymer and Organic Materials Commons^™

Polymer And Small Molecule Designs For Anion Conducting Membranes: Connected Ion-Channel Morphologies And Highly Alkaline Stable Ammonium Cations, Sedef P. Ertem

Doctoral Dissertations

Fuel cells are one of the oldest sustainable energy generation devices, converting chemical energy into electrical energy via reverse-electrolysis reactions. With the rapid development of polymer science, solid polymer electrolyte (SPE) membranes replaced the conventional liquid ion transport media, rendering low-temperature fuel cells more accessible for applications in portable electronics and transportation. However, SPE fuel cells are still far from commercialization due to high operation cost, and insufficient lifetime and performance limitations. Anion exchange membrane fuel cells (AEMFCs) are inexpensive alternatives to current proton exchange membrane fuel cell (PEMFC) technology, which relies on utilizing expensive noble-metal catalysts and perfluorinated SPE …

Creation And Evaluation Of Polymer/Multiwall Carbon Nanotube Films For Structural Vibration Control And Strain Sensing Properties, Weiwei Lin

FIU Electronic Theses and Dissertations

Multifunctional materials both with damping properties and strain sensing properties are very important. They promise to be more weight-efficient, and provide volume-efficient performance, flexibility and potentially, less maintenance than traditional multi-component brass-board systems.

The goal of this dissertation work was to design, synthesize, investigate and apply polyaniline/Multiwall carbon nanotube (PANI/MWCNT) and polyurethane (PU) /MWCNT composites films for structural vibration control and strain sensors using free layer damping methods and static and dynamic strain sensing test methods.

The PANI/MWCNT was made by in situ polymerization of PANI in the presence of MWCNT, then frit compression was used to make circular and …

Cold Gas Dynamic Spray – Characterization Of Polymeric Deposition, Trenton Bush

Masters Theses

When a solid, ductile particle impacts a substrate at sufficient velocity, the resulting heat, pressure, and plastic deformation can produce bonding at the interface. The use of a supersonic gas flow to accelerate such particles is known as Cold Spray deposition. The Cold Spray process has been commercialized for some metallic materials, but further research is required to unlock the exciting material properties possible with polymeric compounds. In this work, a combined computational and experimental study a) simulated and optimized the nozzle flow conditions necessary to produce bonding in a polyethylene particle, b) developed and fabricated an experimental device, and …

Molecular Tetrapods For Optoelectronic Applications, Jianzhong Yang

Chemistry and Chemical Biology ETDs

In this dissertation, several molecular tetrapods were synthesized for optoelectronic applications. In the first two sections, two tetrapodal breakwater-like small molecules: SO and SFBTD were synthesized and characterized. Absorption, X-ray scattering and differential scanning calorimetry experiments indicate crystalline nature of these compounds but slow crystallization kinetics. Solar cells employing SO or SFBTD and phenyl-C₆₁-butyric acid methyl ester (PCBM) were fabricated and evaluated. Relatively low performance was obtained mainly due to the lack of appropriate phase separation, which was caused by molecularly mixed blends with PCBM. The molecularly mixed blends is the result of slow crystallization …

Study On Mechanical Properties Of Silicone Rubber Materials Used As Gaskets In Pem Fuel Cell Environment, Guo Li

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Analysis Of Optimal Process Conditions And Mechanical Properties On Nanocomposites According To Structural Changes Of Halloysite Nanotubes, Yun-Hae Kim, Soo-Jeong Park, Antonio Norio Nakagaito

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Plasticized Polymer Coatings For Sh-Saw Sensors For High Sensitivity And Long-Term Monitoring Of Btex Analytes In Liquid Phase, Pintu Adhikari

Master's Theses (2009 -)

BTEX compounds (benzene, toluene, ethylbenzene, and xylene) are constituents of crude oil and hazardous to human health. Among them, benzene has the lowest maximum contaminant level for drinking water because of its carcinogenicity. Spills or leakage from underground storage tanks or hazardous waste sites can contaminate nearby groundwater with these volatile organic compounds. Therefore, it is very important to detect the presence of BTEX contamination as early as possible in order to start the remediation process and maintain a healthy environment. To develop an in-situ continuous monitoring sensor system, shear horizontal surface acoustic wave (SH-SAW) sensor devices are being investigated …

Fabrication Of Large Mechanically Flexible Multi-Layered Pdms Optical Devices, Robert S. Green

Electronic Thesis and Dissertation Repository

Mechanically flexible large area polydimethylsiloxane (PDMS) optical devices are fabricated using soft-lithography techniques based on replica moulding. These non-rigid optical devices can be designed as sheets to act as either light concentrators (collectors) or diffusers (illuminators) based on the position and geometry of micro-optical structures (MOSs) embedded within the sheet or imprinted on its surface. The active surface area of the device can range from less than a sq. cm to several sq. m. The performance of the large area optical device is a function of the location and geometry of micro-optical structures, thickness and shape of the flexible waveguide, …

Degradation Of Carbon Fiber Reinforced Polymer And Graphite By Laser Heating, Nicholas C. Herr

Theses and Dissertations

The availability of high power, diode pumped solid state and fiber lasers at powers 10 kW and shorter wavelengths (1.07 micrometer) has invigorated the development of tactical laser weapons. This shift to tactical missions greatly increases the variety of potential targets including carbon fiber reinforced polymers and related materials. The complexity of laser-material interactions has driven a historical reliance on live-fire testing and empirical models, but this becomes more difficult as the number of target materials grow. This dissertation combines thermal imagery and existing thermal models of the fire response of composite materials to develop a hybrid modeling approach of …

Weight-Bearing Adhesives With Adjustable Angles, Alfred J. Crosby, Daniel J. King, Michael D. Bartlett, Duncan J. Irschick

Michael Bartlett

A Comparison Of The Elastic Properties Of Graphene- And Fullerene-Reinforced Polymer Composites: The Role Of Filler Morphology And Size, Chang-Tsan Lu, Asanka Weerasinghe, Dimitrios Maroudas, Ashwin Ramasubramaniam

Ashwin Ramasubramaniam

No abstract provided.

Catalytic Conversion Of Fructose, Glucose And Industrial Grade Sugar Syrups To 5-Hydroxymethylfurfural, A Platform For Fuels And Chemicals, Sadra Souzanchi

Electronic Thesis and Dissertation Repository

5-hydroxymethylfurfural (HMF) as a versatile and polyfunctional compound derived from dehydration of biomass has attracted increasing attentions in research over the past decades. HMF is an important intermediate and platform chemical, which can be converted into different useful chemicals as well as the promising biofuels. It can be obtained from acid-catalyzed dehydration of different C₆-based carbohydrates such as glucose, fructose, sucrose and cellulose.

In this thesis, a cost-effective process for catalytic conversion of simple sugars (particularly glucose and fructose) and industrial grade sugar syrups to HMF was studied in a novel biphasic continuous-flow tubular reactor using inexpensive heterogeneous …

Silk As A Biomaterial Paste For Biomimetic Composite, Sang Hyun Park

McKelvey School of Engineering Theses & Dissertations

Silk is a highly promising biomaterial with unique bio-physicochemical properties, such as excellent mechanical and optical properties, biocompatibility and programmable biodegradability. Among many different types, silk from domesticated silkworm, bombyx mori has received wide attention owing to its availability in virtually unlimited quantities and ease of extraction. In this study, we investigated silkworm silk as a protein glue to realize nacre-like composites. We have employed spin assisted layer-by-layer technique to fabricate ultrathin free-standing biocomposite films. Two different composites have been studied: (i) graphene oxide (GO)/silk and (ii) chitin/silk. From our prior work, it is known that the adsorption of amphiphilic …

Characterization Of Superabsorbent Polymers In Aluminum Solutions, Nicholas D. Macke, Matthew J. Krafcik, Kendra A. Erk

The Summer Undergraduate Research Fellowship (SURF) Symposium

Over the past few decades, super absorbent polymers (SAPs) have been the topic of research projects all around the world due to their incredible ability to absorb water. They have applications in everything from disposable diapers to high performance concrete. In concrete, aqueous cations permeate the polymer network, reducing swelling and altering properties. One of these ions, aluminum, alters SAP properties by creating a stiff outer shell and greatly reducing absorbency, but these effects have not been well characterized. One method of characterizing the effects of aluminum on SAP hydrogels was performing gravimetric swelling tests to determine equilibrium water capacity …

Characterization Of Suspension Polymerized Polyacrylamide And Poly(Sodium Acrylate-Acrylamide) Copolymer And Their Size Influence On The Properties Of Concrete, Cole R. Davis, Kendra A. Erk, Stacey L. Kelly

The Summer Undergraduate Research Fellowship (SURF) Symposium

Shrinkage leading to cracking and mechanical instability is a major problem for concrete due to the loss of water during the curing process. However, through the addition of Superabsorbent Polymer (SAP) hydrogels, shrinkage can be prevented, increasing the strength of concrete. Characterization of suspension polymerized polyacrylamide (PAM) poly(sodium acrylate-polyacrylamide) (PANa-PAM) copolymer microsphere sizes, morphology and swelling behavior was conducted before adding them to concrete. Size was determined using microscopy paired with ImageJ analysis. Coulter Counter size characterization was also used to determine the particle size distribution. Swelling behavior was determined using the tea bag method as well as size analysis …

Study Of Oxidative-Crosslink Reaction In Polyphenyl Sulfide (Pps) / Carbon Fiber And Its Influence In Additive Manufacturing, Dong Hee Kim, Eduardo Barocio, Bastian Brenken, Anthony Favaloro, Byron Pipes

The Summer Undergraduate Research Fellowship (SURF) Symposium

Ever since its development in 1980s, Fused Filament Fabrication (FFF) has been an attractive additive manufacturing technology due to its flexibility to create intricate shapes at lower costs and faster manufacturing process than subtractive techniques. These advantages make FFF suitable for printing molds for use in traditional composites manufacturing processes. Combining FFF with high-temperature thermoplastic composites enables producing molds that not only sustain autoclave conditions but also have low coefficient of thermal expansion (CTE). A semi-crystalline polymer, Poly-phenylene Sulfide (PPS), with 50% by weight of carbon fiber is used as feedstock material for FFF. Nonetheless, PPS is sensitive to undergo …

Development Of Eco-Friendly Composite Foam Boards For Thermal Insulation And Packaging Purposes Using Cellulose Nanofibrils (Cnf), Nadir Yildirim

Electronic Theses and Dissertations

Reducing energy consumption is a high priority in the United States and throughout the world. Energy used to heat and cool occupied constructed facilities is of particular concern, and one of the most effective strategies is insulating the building envelope. Historically, builders used whatever material was available to fill the void between interior and exterior walls, including wool fibers, paper, and even corn cobs. Today, homes are built using foam insulation that harden when applied, blown-in loose insulation, fiberglass mats or rigid foam boards usually composed of polystyrene. Rigid foam boards are used in a variety of applications despite the …

Studies On Nanocomposite Coating Produced By Laser-Assisted Process To Prevent Silicone Hydrogels From Bio-Fouling, Vishnuvardhana Wuppaladhodi

Electronic Thesis and Dissertation Repository

In this thesis, silver nanoparticles incorporated into polyvinylpyrrolidone (PVP) were deposited on silicone hydrogel to improve the hydrophilicity of the silicone hydrogel and prevent the growth of bacteria. Two different processes were employed to produce Ag nanoparticles: (1) Process-A is a photochemical reduction; (2) Process-B is laser ablation in liquid. Following that, MAPLE process was employed to deposit the Ag-PVP nanocomposites on the surface of silicone hydrogel. A solid-state pulsed laser (Nd:YAG) with a wavelength of 532 nm at a fluence of 50.4 mJ/cm² was used in the MAPLE system to deposit Ag-PVP nanocomposite coating. Our results indicate that …

Interaction Between Charge-Transfer States Studied By Magnetic Field Effects, Mingxing Li

Doctoral Dissertations

Organic semiconducting materials, consisting mostly of carbon and hydrogen atoms, provide remarkable promise for electronic applications due to their easy processing, chemical tenability, low costs and environmental-friendly characteristics. For realizing electronic applications such as light emitting diodes and photovoltaic cells, charge-transfer states act as an important intermediate state for recombination and dissociation. Interestingly, magnetic field effects on semiconducting materials have been realized based on the suppression of spin mixing in the charge-transfer states. Although lots of studies have been carried out on investigating the properties of charge-transfer states, little has been done to consider the interaction between them. This thesis …

Exploring Thermoelectric Effect Based On Multi-Layer Conductor/Organic/Conductor Devices, Qing Liu

Doctoral Dissertations

Thermoelectric phenomena involve the simultaneous presence of both electrical and thermal currents. The entropy has been heavily used as the driving force to diffuse charge carriers between high and low temperature surfaces towards the development of Seebeck effects in thermoelectric devices. However, this driving force from entropy difference can cause an inverse relationship between Seebeck coefficient and electrical conductivity in the thermoelectric developments. Increasing the charge density can decrease the entropy difference to diffuse the charge carriers at a given temperature difference and lead to a decrease on the Seebeck coefficient developed by the entropy difference. Therefore, it is necessary …