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Articles 1 - 15 of 15
Full-Text Articles in Polymer Chemistry
Atom Economical Reactions Of Terpenoids And Post-Consumer Plastics With Sulfur, Charini Maladeniya
Atom Economical Reactions Of Terpenoids And Post-Consumer Plastics With Sulfur, Charini Maladeniya
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The production of Ordinary Portland Cement (OPC) and its uses have a complicated environmental impact, which is influenced by infrastructure development and building operations as well as CO2 emissions, which account for 7% of all worldwide CO2 emissions. Due to the increasing population, production is still ongoing. The search for cement and construction materials produced with zero to low CO2 emissions is therefore continuous. Finding recyclable, CO2 gas-free biocomposites with high sulfur content that can rival the mechanical properties of popular building supplies like Portland cement is the primary objective of the research discussed in this …
Composite And Polymer Formulation Employing Sulfur And Bio-Olefin Feedstocks, Claudia V. Lopez
Composite And Polymer Formulation Employing Sulfur And Bio-Olefin Feedstocks, Claudia V. Lopez
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Environmental sustainability represents a challenge for society since industrial growth has a direct impact on natural resources and waste production. New technologies that effectively incorporate waste into renewable resources are critical to the development of a sustainable and circular economy. The manufacturing of structural materials like Portland cement (OPC) is responsible for >8% of the global anthropogenic emissions of carbon dioxide, with ~ 1 kg of CO2 released to the atmosphere for every kilogram of OPC produced. For instance, the development of sustainable structural materials is a key factor to reduce the greenhouse emissions and to attenuate the climate …
Synthesis Of Fluorinated Monomers And Polymers For Various Applications, Cassandra J. Hager
Synthesis Of Fluorinated Monomers And Polymers For Various Applications, Cassandra J. Hager
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The world of industry utilizes a variety of polymers for various applications in many prominent fields. From electronics to food storage, the versatility of this class of chemistry has been widely proven. The Thrasher research group undertook a program dedicated towards the development of a library of fluorinated materials that focused on the synthesis and characterization of perfluoroalkoxy (PFA) copolymers of tetrafluoroethylene (TFE) and perfluoroalkyl trifluorovinyl ethers. One aim of the project was to improve upon the mechanical strength and wearability of commercial PFA resins by incorporating bulkier perfluoroalkoxy trifluorovinyl ether monomers into these copolymers. In addition to focusing on …
Extractive Membranes For The Detection And Screening Of Waterborne Plutonium, James Foster
Extractive Membranes For The Detection And Screening Of Waterborne Plutonium, James Foster
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The development of rapid screening tools for special nuclear materials remains a crucial focus for nonproliferation efforts. Traditional approaches for the analysis of trace-level Pu isotopes in water requires tedious and time-consuming sample preparation steps that do not lend well to expeditious screening. Therefore, a novel analytical method that combines both Pu concentration and source preparation into a single detection system would make for an invaluable tool for nuclear security applications. Extractive membranes absorbers can help to fulfill this role as they are capable of concentrating Pu to detectable limits while subsequently serving as alpha spectrometry sample sources. In Chapter …
Synthesis And Molecular Processes Governing Self-Healing Polymeric Materials, Siyang Wang
Synthesis And Molecular Processes Governing Self-Healing Polymeric Materials, Siyang Wang
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Self-healing polymers capable of recovering from physical damages are promising materials for advanced technologies. In these studies, we developed routes to achieve self-healable properties in acrylic-based copolymers that rely on non-covalent dipolar interactions present in essentially all polymeric materials. Using a combination of spectroscopic tools, thermo-mechanical analysis, and molecular dynamic (MD) simulations, these studies have shown that dipolar interactions lead to conformational changes of macromolecular segments which, in turn, result in self-healing without external intervention. This dissertation also describes the development of novel self-healable acrylic-based covalent adaptable networks (CANs) that combine reprocessing and self-healing properties. The utilization of dipolar interactions …
Valorization Of Biopolymers And Biomass To Produce Materials For A More Circular Economy, Moira Lauer
Valorization Of Biopolymers And Biomass To Produce Materials For A More Circular Economy, Moira Lauer
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With a globally increasing population and largely unchecked consumption of raw materials, human society is on track for devastating consequences. Two industries responsible for utilizing massive amounts of raw materials and generating equally gargantuan quantities of waste are the packaging and infrastructure sectors. In 2017 in Europe, for example, packaging reached a record 173 kg of packaging waste per capita. One of the largest packaging consumers is the food industry, in which 40% of packaging is made of petroleum-derived single-use plastic, leading to a massive carbon imbalance. “The Built Environment,” on the other hand, is responsible for about 50% of …
Production And Characterization Of Cut Resistant Acrylic/Copolyaramid Fibers Via Bicomponent Wet Spinning, Stephen Hipp
Production And Characterization Of Cut Resistant Acrylic/Copolyaramid Fibers Via Bicomponent Wet Spinning, Stephen Hipp
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A composite fiber system consisting of a sheath core bicomponent polymer fiber loaded with hard ceramic particles was developed and characterized for use in cut protective clothing. The core component was comprised of a copolyaramid in order to provide high base cut resistance. An acrylic-copolyaramid polymer blend was used for the sheath component to improve processability and provide potential benefits such as dyeability. Lastly, aluminum oxide particles were incorporated into the fiber core to deflect and deform the cutting edge, further improving cut resistance. A series of designed experiments was used to explore the effects of the wet spinning and …
Novel Π-Conjugated Materials Plus Their Characterizations And Applications, Xiuxian He
Novel Π-Conjugated Materials Plus Their Characterizations And Applications, Xiuxian He
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The theme of this dissertation will focus on the syntheses and characterization of bipyridine (bipy) containing π-conjugated polymers (CPs). Specifically, poly(p-phenylene ethynylene), polyfluorene and poly(p-phenylene vinylene) derivatives have been prepared via Sonogashira coupling, Suzuki coupling and Heck coupling, respectively. Derivatives of poly(p-phenylene ethynylene), polyfluorene and poly(p-phenylene vinylene) are known to have applications in optical and electronic devices. Through this study, polymers condensed with bulky bipy-containing TAB as one of the copolymer units have shown increased solubility and diminished intrachain/interchain aggregation in solution and in film due to the effectiveness of TAB in controlling the relative orientations of individual polymer chains. …
Self-Assembly Of Architecturally Complex Block Copolymers, Juan Hinestrosa
Self-Assembly Of Architecturally Complex Block Copolymers, Juan Hinestrosa
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The term self-assembly denotes the formation of complex structures from simpler building blocks, resembling the manner in which Nature generates functional systems. In this pursuit, block copolymers present a great opportunity to study the interactions, dynamics and self-assembly of soft matter. Block copolymers have the ability to self-assemble into thermodynamically stable microphase segregated domains of precise shape and size, which are controlled by the chemistry of the constituent blocks, their size and connectivity, temperature and solvent conditions. Specifically, in this body of work two different types of branched copolymers with polystyrene (PS) and polyisoprene (PI) constituents are studied. The complex …
Development Of Improved Torsional Potentials In Classical Force Field Models Of Poly (Lactic Acid), James Mcaliley
Development Of Improved Torsional Potentials In Classical Force Field Models Of Poly (Lactic Acid), James Mcaliley
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In this work, existing force field descriptions of poly (lactic acid), or PLA, were improved by modifying the torsional potential energy terms to more accurately model the bond rotational behavior of PLA. Extensive calculations were carried out using density functional theory (DFT), for small PLA molecules in vacuo, and also using DFT with a continuum model to approximate the electronic structure of PLA in its condensed phase. From these results, improved force field parameters were developed using a combination of the OPLS and CHARMM force fields. The new force field, PLAFF2, is an update to the previously developed PLAFF model …
Synthesis And Characterization Of Biodegradable Polyurethanes For Biomedical Application, Changhong Zhang
Synthesis And Characterization Of Biodegradable Polyurethanes For Biomedical Application, Changhong Zhang
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This dissertation constitutes the studies about the biomedical materials research of novel polyurethanes. These elastic and degradable polyurethanes exhibited the potential for drug delivery, scaffold fabrication by novel ink-jet printing technology or other biomedical applications. This dissertation includes two parts about two different types of polyurethanes.
In the first part of this dissertation, we studied a polyurethane that was synthesized from methylene di-p-phenyl-diisocyanate (MDI), polycaprolactone diol (PCL-diol) and N, N-bis (2-hydorxyethyl)-2-aminoethane-sulfonic acid (BES). MDI, PCL-diol and BES were polymerized into polyurethane and served as the hard segment, soft segment and chain extender respectively. The effects of the chain extender BES …
Electrochemical Synthesis And Characterization Of Polymers From Bis(3,4-Ethylenedioxythiophene)-Thiophenes (Bedot-Ts) And Bis(3,4-Ethylenedioxythiophene)-Benzenes (Bedot-Bs) As Optoelectronic Materials, Kalya Eaiprasertsak
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ABSTRACT
A series of bis(3,4-ethylenedioxythiophene)-thiophene derivatives (BEDOT-Ts) and bis(3,4-ethylenedioxythiophene)-benzene derivatives (BEDOT-Bs) monomers were electrochemically polymerized onto glassy carbon or ITO-coated glass electrodes. Cyclic voltammetry (CV), infrared (IR), UV-vis-NIR and photoluminescence (PL) spectroscopy were employed to investigate and characterize properties of resulting polymers. dc-conductivities of these polymers were measured by the four-point probe method.
Cyclic voltammetry studies show that the redox half potentials of PBEDOT-3BT, PBEDOT-3OT, PBEDOT-3TBS and PBEDOT-3MPT are -290, -297, -325 and -284 mV versus Ag/Ag+, respectively. The redox half potentials of PBEDOT-TOL, PBEDOT-BOB and PBEDOT-FB are -130, -147 and -327 mV vs. Ag/Ag+, respectively, and a bit higher …
Semifluorinated Polymers Via Cycloaddition And Nucleophilic Addition Reactions Of Aromatic Trifluorovinylethers, Scott Iacono
Semifluorinated Polymers Via Cycloaddition And Nucleophilic Addition Reactions Of Aromatic Trifluorovinylethers, Scott Iacono
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This dissertation encompasses the synthesis, characterization, and properties of semifluorinated polymers derived from thermal polymerization of aryl trifluorovinyl ether (TFVE) monomers. This work is divided into two parts based on the methodology of thermal polymerization using aryl TFVE monomers. The first part of this work involves the thermal [2 + 2]cyclodimerization of aryl TFVE monomers affording perfluorocyclobutyl (PFCB) aryl ether polymers. Chapter 1 provides an overview of PFCB aryl ether polymers as a next-generation class of high performance fluoropolymers that have been successfully employed for a myriad of technologies. PFCB aryl ether polymers are highly desired because of their high …
Carbon Nanotubes And Nanocomposites For Thermal And Electrical Applications, Wei Wang
Carbon Nanotubes And Nanocomposites For Thermal And Electrical Applications, Wei Wang
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The known electrical and thermal properties of carbon nanotubes have prompted many predictions on their extraordinary potentials for ultimately performing polymeric nanocomposites. In this dissertation, chemical modification and functionalization of carbon nanotubes have been demonstrated as being effective for high-quality polymeric carbon nanotube composites, especially with our approach of using polymers that are structurally identical or maximally similar to the matrix polymers in the nanotube functionalization. For example, a poly(N-vinyl carbazole) (PVK) copolymer containing pendant hydroxyl groups was synthesized for the functionalization of single-walled carbon nanotubes (SWNTs). The shared solubility of the functionalized nanotube samples with PVK matrix polymer enabled …
Synthesis, Reactions, And Applications Of Bis-Ortho-Diynyl Arene (Boda) Monomers, Polymers, And Derivatives, Mark Perpall
Synthesis, Reactions, And Applications Of Bis-Ortho-Diynyl Arene (Boda) Monomers, Polymers, And Derivatives, Mark Perpall
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Bis-ortho-diynyl arenes (BODA) monomers contain two arenediyne functional groups with variable functionality at both the linker group, X, and the alkyne terminal group, R. These arenediyne moieties undergo thermal Bergman reactions to cycloaromatize to naphthyl diradical species. The inclusion of two of these arenediyne functionalities allows the polymer to grow without losing processability and solubility as most aromatic polymers do. The second functionality acts as a solubilizing group until all functionalities are consumed in the fully cured network polymer.
When heated above 800 °C, BODA polymer converts to a high-yield glassy carbon material. This work has been extended …