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Synthesis And Electrochemical Characterization Of Pani/Ni And Pani/Au/Ni Composites, Morgan Emily Pacini 2017 University of Nevada, Las Vegas

Synthesis And Electrochemical Characterization Of Pani/Ni And Pani/Au/Ni Composites, Morgan Emily Pacini

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research is to show that the electrochemically controlled formation of monometallic and bimetallic catalysts in polyaniline (PANI) can directly influence the efficiency and reproducibility of the catalytic oxidation of methanol. PANI is a conductive polymer that provides a three-dimensional template for the metallic catalysts deposition at nitrogen sites. The controlled deposition of metallic species can be achieved using the normal oxidation/reduction cycles of PANI. The deposition of metallic species relies on anion precursors that are electrostatically bound by the polymer during the oxidation cycle. The precursor is reduced directly at the nitrogen sites in the ...


The Effect Of Plant Source On Lignin-Based Polyurethanes And The Interdiffusion Dynamics Of Semi-Rigid Polymers, Jason Michael Lang 2017 University of Tennessee, Knoxville

The Effect Of Plant Source On Lignin-Based Polyurethanes And The Interdiffusion Dynamics Of Semi-Rigid Polymers, Jason Michael Lang

Masters Theses

The work reported in this thesis increases our understanding of the effect of lignin plant source on the mechanical and morphological properties of lignin-based polyurethanes and the interdiffusion of glassy/liquid bilayer thin films. The interdiffusion of glassy/liquid polymer pairs has received much less attention than liquid/liquid bilayers, leading to conflicting results and unresolved discrepancies. Therefore, the reported study of interdiffusion between polysulfone glassy/liquid polymer layers provides insight into the dynamics of these systems.

This thesis first reports the correlation between the mechanical properties of lignin-based polyurethanes and the lignin plant source. Lignin is a molecule that ...


Barrier Properties Of Polymer Nanocomposites With Graphene Oxide And Its Derivatives: Mechanism And Applications In Anticorrosive Coatings, Yidan Guan 2017 University of Southern Mississippi

Barrier Properties Of Polymer Nanocomposites With Graphene Oxide And Its Derivatives: Mechanism And Applications In Anticorrosive Coatings, Yidan Guan

Dissertations

Metallic devices made from steel or aluminum are subjected to deterioration by environmental contaminants over time. As one of the corrosion control methods, organic coatings show many advantages due to their low cost, versatility, decoration aesthetics and effective protections. Corrosion protection theories and failure modes of organic coatings are still not fully understood due to complicated interactions in the coating-metal-environment system, however, it is widely agreed that the barrier nature of polymeric materials towards aggressive species, such as oxygen, water, electrolyte, plays a key role. Improved barrier property of polymer nanocomposites (PNCs) with two-dimensional (2D) carbon filler, graphene and graphene ...


Hybrid Polymer Electrolyte For Lithium-Oxygen Battery Application, Amir Chamaani 2017 Amir Chamaani

Hybrid Polymer Electrolyte For Lithium-Oxygen Battery Application, Amir Chamaani

FIU Electronic Theses and Dissertations

The transition from fossil fuels to renewable resources has created more demand for energy storage devices. Lithium-oxygen (Li-O2) batteries have attracted much attention due to their high theoretical energy densities. They, however, are still in their infancy and several fundamental challenges remain to be addressed. Advanced analytical techniques have revealed that all components of a Li-O2 battery undergo undesirable degradation during discharge/charge cycling, contributing to reduced cyclability. Despite many attempts to minimize the anode and cathode degradation, the electrolyte remains as the leading cause for rapid capacity fading and poor cyclability in Li-O2 batteries. In this ...


Phase Behavior Of Binary And Polydisperse Suspensions Of Compressible Microgels Controlled By Selective Particle Deswelling, A. Scotti, U. Gasser, E. S. Herman, Jun Han, A. Menzel, L. Andrew Lyon, A. Fernandez-Nieves 2017 Paul Scherrer Institut

Phase Behavior Of Binary And Polydisperse Suspensions Of Compressible Microgels Controlled By Selective Particle Deswelling, A. Scotti, U. Gasser, E. S. Herman, Jun Han, A. Menzel, L. Andrew Lyon, A. Fernandez-Nieves

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We investigate the phase behavior of suspensions of poly(N-isopropylacrylamide) (pNIPAM) microgels with either bimodal or polydisperse size distribution. We observe a shift of the fluid-crystal transition to higher concentrations depending on the polydispersity or the fraction of large particles in suspension. Crystallization is observed up to polydispersities as high as 18.5%, and up to a number fraction of large particles of 29% in bidisperse suspensions. The crystal structure is random hexagonal close-packed as in monodisperse pNIPAM microgel suspensions.We explain our experimental results by considering the effect of bound counterions. Above a critical particle concentration, these cause deswelling ...


Thermal, Mechanical, And Conductive Properties Of Bisimidazolium Thiol-Ene Pil Networks, Sunny Kwan, Sunny Kwan 2017 Murray State University

Thermal, Mechanical, And Conductive Properties Of Bisimidazolium Thiol-Ene Pil Networks, Sunny Kwan, Sunny Kwan

Honors College Theses

Polymers made from thiol-ene reactions are versatile – they can be made from a variety of easily obtainable starting materials and show promise as biomedical materials, hydrogels, resins, and nanoparticles. Ionic liquids (ILs) have uniquely exploitable physical and chemical properties, and polymerization of ILs into polymeric ionic liquids (PILs) enhances or changes these properties, allowing an even wider range of potential applications of ILs in technologies such as fuel cells, solar cells, and even artificial muscles. Bisimidazolium thiol-ene PIL (BITPIL) networks are polymers with each monomer consisting of two moles of bis-imidazolium bridged together with either an alkyl or poly(ethylene ...


Poly(Ethyl Glyoxylate) Solid-Core Particles For Drug Delivery, Michael Thomas Gambles 2017 The University of Western Ontario

Poly(Ethyl Glyoxylate) Solid-Core Particles For Drug Delivery, Michael Thomas Gambles

Electronic Thesis and Dissertation Repository

The ability to trigger the degradation of polymeric nanoparticles (NPs) by a specific stimulus can provide a method of improved drug targeting and selective release capabilities in vivo. The challenge for most polymeric drug delivery systems remains the necessity for many stimuli events to trigger the release of cargo. Polymeric nanotechnology containing “self-immolative polymers” looks to alleviate the reliance on high concentrations of stimuli by undergoing complete end-to-end depolymerization via a single stimulus-mediated reaction of an end-cap. Herein, NPs were developed using poly(ethyl glyoxylate) (PEtG) blended with poly(d,l-lactic acid) (PLA) to encapsulate a hydrophobic cargo to be ...


Multi-Scale Assembly Methodologies Of Poly(3-Hexylthiophene) Derivative Systems For Enhanced Optoelectronic Anisotropy, David William Bilger 2017 California Polytechnic State University - San Luis Obispo

Multi-Scale Assembly Methodologies Of Poly(3-Hexylthiophene) Derivative Systems For Enhanced Optoelectronic Anisotropy, David William Bilger

Master's Theses and Project Reports

Conjugated polymers represent a class of semi-conducting materials with numerous applications in optoelectronic devices, including organic light-emitting diodes, field-effect transistors, and photovoltaics. Because of the numerous advantages of macromolecular systems, including solution processing and mechanical flexibility, conjugated polymers have become a burgeoning field of research with the hopes of producing cost-effective solution-based electronics. Importantly, optoelectronic device performance is heavily influenced by conjugated polymer backbone orientation and overall thin film morphology. As such, the processing conditions of these systems are important to the construction of high- performance optoelectronics. Polythiophenes are model conjugated polymers that have been studied extensively in halogenated organic ...


Synthesis, Characterization, And Reactive Modification Of 2-Vinyl-4,4-Dimethyl Azlactone Polymers, Bethany Michelle Aden 2017 University of Tennessee, Knoxville

Synthesis, Characterization, And Reactive Modification Of 2-Vinyl-4,4-Dimethyl Azlactone Polymers, Bethany Michelle Aden

Doctoral Dissertations

Polymeric materials possessing specific functionality have been designed for use in applications such as membranes, biocompatible coatings, lubricants, and tissue engineering. Because the chemical nature of the repeat units set the properties offered by the polymer, the ability to reactively modify polymer chains to integrate specific functionality expands the range of potential applications. Thus, reactive modification of polymer thin films provides a useful route to confer new properties to the underlying material, with the range, strength and type of interaction across the interface dictated by the display of functional groups decorating the surface. To address the links between design, in ...


Cellulose Reinforced Thermoplastic Composites By In-Situ Ring-Opening Polymerization, Shahab Kashani Rahimi 2017 University of Southern Mississippi

Cellulose Reinforced Thermoplastic Composites By In-Situ Ring-Opening Polymerization, Shahab Kashani Rahimi

Dissertations

Over the past two decades, the increasing concern about the negative environmental impacts of synthetic materials has led to rising interests in utilizing renewable natural resources to develop polymer materials with comparable properties and performance to their synthetic counterparts. One of the major fields of interest is polymer composites where the replacement of synthetic fibers with bio renewable natural fibers is of great potential. However, the processing difficulties, in terms of fiber dispersion and thermal stability have limited the application of cellulosic fibers to polymers with low processing temperatures which are mostly hydrophobic polymers. As a result, the true reinforcing ...


Oligo(Ethylene Glycol)-Sidechain Microgels Prepared In Absence Of Cross-Linking Agent: Polymerization, Characterization And Variation Of Particle Deformability, Nicole Welsch, L. Andrew Lyon 2017 Georgia Institute of Technology

Oligo(Ethylene Glycol)-Sidechain Microgels Prepared In Absence Of Cross-Linking Agent: Polymerization, Characterization And Variation Of Particle Deformability, Nicole Welsch, L. Andrew Lyon

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We present a systematic study of self-cross-linked microgels formed by precipitation polymerization of oligo ethylene glycol methacrylates. The cross-linking density of these microgels and, thus, the network flexibility can be easily tuned through the modulation of the reaction temperature during polymerization. Microgels prepared in absence of any difunctional monomer, i.e. cross-linker, show enhanced deformability and particle spreading on solid surfaces as compared to microgels cross-linked with varying amounts of poly(ethylene glycol diacrylate) (PEG-DA) in addition to self-crosslinking. Particles prepared at low reaction temperatures exhibit the highest degree of spreading due to the lightly cross-linked and flexible polymer network ...


Photopolymerization Synthesis Of Magnetic Nanoparticle Embedded Nanogels For Targeted Biotherapeutic Delivery, Daniel Jonwal Denmark 2017 University of South Florida

Photopolymerization Synthesis Of Magnetic Nanoparticle Embedded Nanogels For Targeted Biotherapeutic Delivery, Daniel Jonwal Denmark

Graduate Theses and Dissertations

Conventional therapeutic techniques treat the patient by delivering a biotherapeutic to the entire body rather than the target tissue. In the case of chemotherapy, the biotherapeutic is a drug that kills healthy and diseased cells indiscriminately which can lead to undesirable side effects. With targeted delivery, biotherapeutics can be delivered directly to the diseased tissue significantly reducing exposure to otherwise healthy tissue. Typical composite delivery devices are minimally composed of a stimuli responsive polymer, such as poly(N-isopropylacrylamide), allowing for triggered release when heated beyond approximately 32 °C, and magnetic nanoparticles which enable targeting as well as provide a mechanism ...


Molecular And Polymeric Materials Based On Asymmetrically Substituted Bf2 3-Cyanoformazanates, Samantha Novoa 2017 The University of Western Ontario

Molecular And Polymeric Materials Based On Asymmetrically Substituted Bf2 3-Cyanoformazanates, Samantha Novoa

Electronic Thesis and Dissertation Repository

This thesis outlines the synthesis and characterization of asymmetric and symmetric 3-cyanoformazanate BF2 complexes and their incorporation into polymers. CuAAC chemistry was used to synthesize two additional asymmetric BF2 complexes and a side product that was identified as a symmetric dimer. Spectroscopic and electrochemical properties of these compounds are described.

Incorporation of an asymmetric 3-cyanoformazante BF2 complex into polymers was done by ROMP. This reaction was used to make homo, block, and random copolymers, where the comonomer was an organic norbornene derivative. Spectroscopic studies of these polymers revealed that, as the mole fraction of BF2 (ƒ ...


Fabrication And Applications Of Multifunctional Superhydrophobic Surfaces Based On Surface Chemistry And Morphology, Yang Liu 2017 The Graduate Center, City University of New York

Fabrication And Applications Of Multifunctional Superhydrophobic Surfaces Based On Surface Chemistry And Morphology, Yang Liu

All Dissertations, Theses, and Capstone Projects

Superhydrophobic surfaces are gaining great interests in both fundamental researches and technological applications, because of their unique non-wetting and self-cleaning properties. By mimicking the hierarchical surface structure of the natural superhydrophobic surface, i.e. lotus leaf, numerous artificial surperhydrophobic surfaces were developed. However, the challenge is how to fabricate superhydrophobic surfaces by a scalable and economical method. To address this challenge, our group has developed methodologies that enable the fabrication of superhydrophobic surfaces in inexpensive and potentially scalable ways, such as lamination and 3-D printing. To expand on applications, we also combined other desired functionalities into the superhydrophobic surfaces.

The ...


A Comparison Study Of Two Synthesis Methods For Polymer Of Intrinsic Microporosity 1 (Pim-1), Conor S. Perry 2017 California Polytechnic State University, San Luis Obispo

A Comparison Study Of Two Synthesis Methods For Polymer Of Intrinsic Microporosity 1 (Pim-1), Conor S. Perry

Materials Engineering

Polymers of Intrinsic Microporosity (PIMs) are an emerging polymeric material class for molecular sieving applications. This study focuses on PIM-1, an alternating copolymer of 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethyl-1,1’-spirobisindane and tetrafluoroterephthalonitrile synthesized via nucleophilic aromatic substitution. PIM-1 been widely studied as a gas separating material and filtering membrane, but in this case, it is studied as a battery separator material. PIM-1’s microporous (pore diameters less than 2 nm) structure allows smaller favorable ions to transport while preventing larger ions and compounds from transporting. Two synthesis methods, round bottom flask synthesis and ball mill ...


Processing And Characterization Of Nanocomposites Prepared By High Torque Melt Mixing, Lionel W. Cross Jr 2017 Clark Atlanta University

Processing And Characterization Of Nanocomposites Prepared By High Torque Melt Mixing, Lionel W. Cross Jr

Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University

The rapid development of polymer nanocomposites has received extensive attention over the last few decades. The ability to alter functionalities of composites, dramatically improving properties and performance at low filler content creates flexibility in designing materials for advanced applications in various industrial fields. This work focuses on nanocomposites relevant to the packaging and aerospace industries.

This work evaluated the ability to homogeneously distribute nanomaterials into a polymer matrix, understand the effects on rheological properties, understand changes to microstructure and effects, and characterize properties of resulting nanocomposite. High torque melt mixing was used to disperse surface modified cellulose nanocrystals in a ...


Microwave-Assisted Topochemical Manipulation Of Layered Oxide Perovskites: From Inorganic Layered Oxides To Inorganic-Organic Hybrid Perovskites And Functionalized Metal-Oxide Nanosheets, Sara Akbarian-Tefaghi 2017 University of New Orleans

Microwave-Assisted Topochemical Manipulation Of Layered Oxide Perovskites: From Inorganic Layered Oxides To Inorganic-Organic Hybrid Perovskites And Functionalized Metal-Oxide Nanosheets, Sara Akbarian-Tefaghi

University of New Orleans Theses and Dissertations

Developing new materials with desired properties is a vital component of emerging technologies. Functional hybrid compounds make an important class of advanced materials that let us synergistically utilize the key features of the organic and inorganic counterparts in a single composite, providing a very strong tool to develop new materials with ”engineered” properties. The research presented here, summarizes efforts in the development of facile and efficient methods for the fabrication of three- and two-dimensional inorganic-organic hybrids based on layered oxide perovskites. Microwave radiation was exploited to rapidly fabricate and modify new and known materials. Despite the extensive utilization of microwaves ...


Regioselective Baeyer–Villiger Oxidation Of Lignin Model Compounds With Tin Beta Zeolite Catalyst And Hydrogen Peroxide, John Adam Jennings, Sean R. Parkin, Eric Munson, Sean Delaney, Julie L. Calahan, Mark Isaacs, Kunlun Hong, Mark Crocker 2017 University of Kentucky

Regioselective Baeyer–Villiger Oxidation Of Lignin Model Compounds With Tin Beta Zeolite Catalyst And Hydrogen Peroxide, John Adam Jennings, Sean R. Parkin, Eric Munson, Sean Delaney, Julie L. Calahan, Mark Isaacs, Kunlun Hong, Mark Crocker

Chemistry Faculty Publications

Lignin depolymerization represents a promising approach to the sustainable production of aromatic molecules. One potential approach to the stepwise depolymerization of lignin involves oxidation of the benzylic alcohol group in β-O-4 and β-1 linkages, followed by Baeyer–Villiger oxidation (BVO) of the resulting ketones and subsequent ester hydrolysis. Towards this goal, BVO reactions were performed on 2-adamantanone, a series of acetophenone derivatives, and lignin model compounds using a tin beta zeolite/hydrogen peroxide biphasic system. XRD, 119Sn MAS NMR spectroscopy, DRUVS and XPS were used to determine tin speciation in the catalyst, the presence of both framework Sn and ...


Disordered Proteins: Connecting Sequences To Emergent Properties, Tyler Scott Harmon 2017 Washington University in St. Louis

Disordered Proteins: Connecting Sequences To Emergent Properties, Tyler Scott Harmon

Arts & Sciences Electronic Theses and Dissertations

Many IDPs participate in coupled folding and binding reactions and form alpha helical structures in their bound complexes. Alanine, glycine, or proline scanning mutagenesis approaches are often used to dissect the contributions of intrinsic helicities to coupled folding and binding. These experiments can yield confounding results because the mutagenesis strategy changes the amino acid compositions of IDPs. Therefore, an important next step in mutagenesis-based approaches to mechanistic studies of coupled folding and binding is the design of sequences that satisfy three major constraints. These are (i) achieving a target intrinsic alpha helicity profile; (ii) fixing the positions of residues corresponding ...


Use Of Decahydrodecaborate As Flame Retardants In Polyurethanes, Austin W. Bailey 2017 Pittsburg State University

Use Of Decahydrodecaborate As Flame Retardants In Polyurethanes, Austin W. Bailey

Electronic Thesis Collection

There is a growing need for non-halogenated flame retardants due to the toxicity and environmental impacts that are exhibited by current ones. The polyurethane industry is one that has expressed a need for flame retardants in many of its industrial and commercial applications. For these reasons, two different decaborate compounds, tetramethyl and tetrabutyl ammonium decahydrodecaborate, were synthesized and incorporated into polyurethane films for testing. The compounds were characterized using Fourier Transform Infrared (FT-IR) spectroscopy, Proton-Nuclear Magnetic Resonance (1H-NMR) spectroscopy, Carbon-Nuclear Magnetic Resonance (13C-NMR) spectroscopy, and Boron-Nuclear Magnetic Resonance (11B-NMR) spectroscopy. The compounds were incorporated into a polyol ...


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