Chemistry Commons^™

Synthesis, Characterization, And Deuterium Labeling Of Polyamides Studied By Nuclear Magnetic Resonance Spectroscopy, Christopher Allen Lange

Dissertations

The synthesis, characterization, and deuterium labeling of polyamides have been investigated. In Chapter II, selective deuterium labeling of various polyamides was demonstrated via a facile method which does not require organic solvent or catalyst. Quantitative solution-state NMR analysis showed deuterium incorporation at the carbon alpha to the carbonyl ranged from 20-75%. Incorporation in ε-caprolactam increased with repeated treatments. Isotopic shift effects for the deuterated materials were additive for all sites within experimental error.

In Chapter III, the effect of stoichiometric imbalances on the polymerization of poly(dodecamethylene terephthalamide)was investigated. Molecular weight was varied by polymerizing the monomer salt with excess diaminododecane, …

Polyisobutylene Chain End Transformations: Block Copolymer Synthesis And Click Chemistry Functionalizations, Andrew Jackson David Magenau

Dissertations

The primary objectives of this research were twofold: (1) development of synthetic procedures for combining quasiliving carbocationic polymerization (QLCCP) of isobutylene (IB) and reversible addition fragmentation chain transfer (RAFT) polymerization for block copolymer synthesis; (2) utilization of efficient, robust, and modular chemistries for facile functionalization of polyisobutylene (PIB). Two site transformation strategies were employed to create block copolymers effectively linking PIB with either poly(methylmethacrylate) (PMMA), polystyrene (PS), and poly(Nisopropylacrylamide) (PNIPAM) block segments. Functionalization of PIB was accomplished by utilizing two click chemistries, the azide-alkyne 1,3-dipolar cyclo addition and the thiol-ene hydrothiolation reaction, and by efficient transformation of the thiol functional …

Structure-Property Relationships In The Formation Of Polyphenylsulfone Molecular Composites And Nanocomposites, Paul Joseph Jones

Dissertations

As the constituent phases in a polymer composite approach the molecular level, specific phenomena occur that can lead to significant changes in material properties when only minimal quantities of the additive are incorporated into the polymer matrix. Molecular composite and nanocomposites are state-of-the-art polymeric materials that contain nanostructured additives effectively dispersed within polymer matrices. The properties of molecular composites and nanocomposites are directly related to the interactions of the nanostructured additive and the polymer matrix. Subtle changes to the nanostructured additive can have profound effects on the ultimate properties of the composite material. Therefore, understanding the structure-property relationships in these …

Self-Assembly Of Architecturally Complex Block Copolymers, Juan Hinestrosa

All Dissertations

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 …

Determination Of Polymer Molecular Weight Distributions: Dosy, Maldi, Gpc, Nathan A. Meredith

Honors Capstone Projects and Theses

No abstract provided.

Preparation Of Styrene Acrylic Copolymer Toner Resin By Solution Polymerization., Neo Su Siang

Student Works (2010-2019)

This project has investigated solution polymerization to produce toner resins. There are three stages: (i) synthesis of low molecular weight styrene acrylic copolymer; (ii) synthesis of high molecular weight styrene acrylic copolymer; (iii) mixing high and low molecular weight copolymers. Gel Permeation Chromatography (GPC) was used to study molecular weight distributions, Melt Flow Index (MFI) Instrument to study the flowability of resin, Differential Scanning Calorimetry (DSC) to study the thermal properties of resin, and acid number to quantitate the amount of acidic group in the resin. A comparison of properties between the experimental samples, patent’s claims, and commercial resins had …

Synthesis Of Chemically Produced Toner (Cpt) By Emulsion Aggregation Process., Ng Wei Goon

Student Works (2010-2019)

This project studied the full process of producing Chemically Produced Toner (CPT) used in laser printer. Latex particles of 0.40 to 0.60 μm were prepared by semicontinuous emulsion polymerization process. A series of latexes was made from the copolymerization of styrene, butyl acrylate and acrylic acid monomers in the presence of surfactants Dowfax 2A1 (anionic) and Ipegal 897 (non-ionic) surfactants with potassium persulphate as the initiator. The addition of different percentage of chain transfer agent (CTA), 1-dodecanethiol was used to control the molecular weight distribution. As the percentage of CTA was increased, the molecular weight and glass transition temperature decreased …

Changes To Electrical Conductivity In Irradiated Carbon-Nickel Nanocomposites, David F. Coy

Theses and Dissertations

Pre and post irradiation resistivity and XAFS measurements have been conducted to examine the effects of 0.5 MeV electron irradiations on nickel-carbon composites. Results showed a decrease in surface resistivity in all sample types of 14-30% following irradiation with a total electron exposure of 4 x 10^-16 cm^-2. Results also showed a corresponding decrease in NiO content for the irradiated samples as compared to measurements of non-irradiated samples. Surface resistivity measurement capabilities were established and measurement techniques refined to produce repeatable results of sufficient precision to discern changes in resistivity for an exposure of 2 x 10 …

Dual-Action Hygienic Coatings: Benefits Of Hydrophobicity And Silver Ion Release And Surface Analysis, Niall Stobie, Brendan Duffy, John Colreavy, Patrick Mchale, Steven Hinder, Declan Mccormack

Articles

Coatings that demonstrate reduced attachment of crystalline precipitates and the medical device colonising Staphylococcus epidermidis were prepared by the immobilisation of silver doped perfluoropolyether–urethane siloxane thin films on glass substrates. The presence of stratified hydrophobic perfluoropolyether groups protects the coating surface from the attachment of crystalline hydrophilic species such as chlorides and phosphates, whilst silver ion release inhibited attachment of S. epidermidis and subsequent biofilm formation in vitro. The release of silver ions protects the perfluoro groups from the hydrophobic interactions of S. epidermidis cells, which can reduce the hydrophobicity of the protective coating. These coatings also exhibited significant antibacterial …

Synthesis And Uses Of Polycarbonate, Hai Bui

Natural Sciences Student Research Presentations

Polycarbonate is one of the most important polymers being used today. Polycarbonate has many important characteristics that prove to be useful in its applications. Some characteristics of polycarbonate are that it is clear, light weight, and durable. The optical properties and the specific weight index of polycarbonate make it ideal for lens material in eyeglasses. There are two main ways of commercially synthesizing polycarbonate from bisphenol A. It can be synthesized through the process of solvent interfacial polymerization or through melt transeterification. Both processes are different and each has its own benefits.

The Thermal Characteristic Of Imipenem Encapsulated In Low And High Molecular Weight Of Polyethylene Glycol., Abdul Aziz Ismail

Student Works (2010-2019)

Microencapsulation technique is widely used in pharmaceutical industries to control the release of a drug. Biodegradable polymer such as Polyethylene glycol (PEG) is frequently used as encapsulation material. This study has tried to produce microencapsulation product of Imipenem antibiotics in Polyethylene Glycol.Commercially available product called Tienam® was used as a major source of Imipenem. We used freeze-drying method to produce the microencapsulation products. The successful of producing of this product is confirmed by the yellowish appearance of the product whereby it shows the colour properties of Tienam® Thermal analysis using Differential Scanning Calorimeter (DSC) was used to characterize pure materials …

Synthesis Of Urethane Acrylate Macromer From Palm Oil-Based Polyol And Its Application As A Resin For Dental Composite., Fadhel A. A. Alsanabani

Student Works (2010-2019)

A slightly branched urethane acrylate macromer (UAM) was synthesized by reacting palm oil-based polyol with excess amounts of polymeric methylene diphenyl diisocyanate (MDI) to form urethane prepolymer, then reacted with 2-hydroxyethyl methacrylate (HEMA) and FT-IR spectroscopy confirmed the urethane and grafted acrylate groups. 0.2% by weight of camphoroquinone (CQ) and 0.8% by weight of ethyl-4-N,N-dimethylamino-benzoate (4EDMAB) by weight were added to render the experimental resins light-curable. Their viscosity, percentage of degree of conversion (%DC) and cross-linking density (CLD), percentage of volumetric polymerization shrinkage (%VPS), water sorption and solubility, flexural strength, modulus of elasticity and toughness were determined and compared to …

Synthesis Of Chromium-Based Ziegler-Natta Catalysts And Thier Application In Ethylene Polymerization And Copolymerization., Wong Jun Xuan

Student Works (2010-2019)

Four chromium-based oxo-trinuclear carboxylate complexes were prepared by reacting Cr(NO3).9H2O with acetic acid and substituted carboxylic acids to produce [Cr3O(CH3COO)6.3H2O]NO3.7H2O,[Cr3O(ClCH2COO)6.3H2O]NO3.3H2O, [Cr3O(Cl2CHCOO)6.3H2O]NO3.H2O and [Cr3O(Cl3CCOO)6.3H2O]NO3.2H2O, which alysis (TGA).Chromium content in each complex was determined by titrimetry method and the result was in good agreement with that from TGA. Chromium(III)monochloroacetate complex[Cr3O(ClCH2COO)6.3H2O]NO3.3H2O in combination with diethylaluminium chloride formed heterogeneous catalyst system for ethylene polymerization and ethylene-propylene copolymerization. Both Al/Cr ratio and temperature influenced the catalytic activity. The maximum activity of ethylene polymerization was 1768 gPE/gCr/hr/atm, achieved by polymerizing ethylene at 29°C with Al/Cr ratio 30.8. Effect of chloro-substituent groups on carboxylic ligand was studied …

Synthesis Of Urethane Acrylate Macromer From Palm Oil-Based Polyol And Its Application As A Resin For Dental Composite., Fadheel A. A. Alsanabani

Student Works (2010-2019)

A slightly branched urethane acrylate macromer (UAM) was synthesized by reacting palm oil-based polyol with excess amounts of polymeric methylene diphenyl diisocyanate (MDI) to form urethane prepolymer, then reacted with 2-hydroxyethyl methacrylate (HEMA) and FT-IR spectroscopy confirmed the urethane and grafted acrylate groups. 0.2% by weight of camphoroquinone (CQ) and 0.8% by weight of ethyl-4-N,N-dimethylamino-benzoate (4EDMAB) by weight were added to render the experimental resins light-curable. Their viscosity, percentage of degree of conversion (%DC) and cross-linking density (CLD), percentage of volumetric polymerization shrinkage (%VPS), water sorption and solubility, flexural strength, modulus of elasticity and toughness were determined and compared to …

Characteristics Of Proton Conducting Pva-Chitosan Polymer Blend Electrolytes., Mohd Fakhrul Zamani Abdul Kadir

Student Works (2010-2019)

The main focus of this present work is to build a good conducting solid polymer electrolyte (SPE) based on chitosan and poly(vinyl alcohol)(PVA) blend. Solution cast technique has been employed to produce sample films in this work. From the scanning electron micrographs (SEM) the surface morphology of the blend containing 40 wt.% chitosan and 60 wt.% PVA (C4P6) is homogenous and miscible in one and another. The C4P6 film is the most amorphous and is the best candidate for the polymer host in the electrolyte systems studied in the present work. Ammonium Nitrate (NH4NO3) is the doping salt that provides …

Microporous Organic Polymers: Synthesis And Post Synthetic Modifications, Phillip Andrew Kerneghan

Theses and Dissertations (Comprehensive)

Microporous solids are an important class of materials that have been studied extensively. Newer to this field are Microporous Organic Polymers (MOPs) which are networks constructed from smaller organic building blocks and exhibit large surface areas, small pore sizes and low densities. It is due to these characteristics that MOPs have attracted attention because of their potential use in applications such as catalysis, chemical separations and gas storage.

In this thesis is described the synthesis of two novel MOPs, the first of which being a network based on benzenediboronic acid and triptycene building blocks linked together by boronate esters. This …

Electrical And Structural Studies Of Polyacrylonitrile (Pan) Complexed With Inorganic Salts., Khairul Bahiyah Md Isa

Student Works (2010-2019)

In the present study, polymer electrolyte films composed of polyacrylonitrile (PAN) as a host polymer, ethylene carbonate (EC) as the plasticizer and lithium triflate (LiCF3SO3) and sodium triflate (NaCF3SO3) as dopant salts were prepared by the solution cast technique. Five systems of polymer electrolytes films have been prepared; these systems are the plasticized-PAN system i.e. PAN-EC system, two salted-PAN systems i.e. PAN-LiCF3SO3 and PAN-NaCF3SO3, and two plasticized-salted PAN systems i.e. PAN-EC-LiCF3SO3 and PAN-EC-NaCF3SO3. The pure PAN film was prepared as a reference. The ionic conductivity for each system is characterized using impedance spectroscopy. The room temperature conductivity of the pure …

Investigation Of Network Architecture Development And Properties In Thermoset Matrices, Jeremy Owen Swanson

Dissertations

Matrices employed in composite materials directly influence overall composite properties. In all thermoset materials, molecular level interactions and transformations during cure result in heterogeneous architecture. Variability in connectivity results from the often dramatic spatial and topological changes that occur during the crosslinking process. Compatibility (fillers, pigments, additives), temperature gradients and reactivity differences in the precursors only serve to increase the complexity of network formation. The objective of the research herein is to characterize and understand the relationships between cure conditions, conversion, connectivity, network architecture and properties in glassy thermosetting matrix resins.

In this research, epoxy and vinyl ester resins (VERs) …

Synthesis And Manufacture Of Photocrosslinkable Poly(Caprolactone)-Based 3d Scaffolds For Tissue Engineering Applications, Nathan Jonathan Castro

Open Access Theses & Dissertations

It is known that the body can efficiently repair hard tissue (bone) micro fractures by suturing the defect through the deposition of minerals resulting in an area that is stronger post-injury. Larger defects, however, generally cause more trouble since the body is incapable of repairing them. Bone defects can occur as a result of congenital abnormalities, trauma, or disease. Traditional methods for addressing these defects have involved the use of acellular cadaverous bone or autologous bone. Both contain innate problems associated with them; the former method can result in disease transmission, as well as very low integration with the host …

Investigation Of Novel Thiol "Click" Reactions, Justin William Chan

Dissertations

The thio-Michael addition reaction is traditionally considered a base catalyzed reaction which involves high catalyst concentrations and long reaction times. This reaction utilizes potent, simple nucleophiles to catalyze the reaction, decreases the catalyst concentration and greatly increases the reaction times. The free radical mediated thiol-ene click reaction uses light or heat and an initiator to catalyze the rapid and quantitative addition of thiols to most electron rich enes without the formation of side products and in the absence of solvent. Recently, the thiol-ene click reaction has been exploited for these reasons in materials science and organic synthesis. The research herein …

Investigation Of The Relationship Between Polymer Structures And Thermal, Mechanical, Viscoelastic Properties, Ethem Kaya

Dissertations

The research presented in this dissertation involves four distinct areas: physical crosslinking systems, UV curable coatings for enhanced oxygen and carbon dioxide barrier properties, synthesis, and investigation of melting behavior/crystallinity relations of linear polyamides with long alkyl chains, and synthesis and characterization of cyclic diamides as precursors to linear polyamides 6 4.

The physical crosslinking section involves synthesis of monomers and polymers bearing cyclodextrin and adamantane pendent groups, and investigation of non-covalent interactions between these polymers (Chapter II). Two methacrylate monomers bearing cyclodextrin and adamantane were synthesized, and copolymerized with poly(ethylene glycol) methyl ether methacrylate. The specific interaction between copolymers …

Random And Block Copolymers Of Poly(Dodecamethyleneterephthalamide), Theodore Frank Novitsky Jr.

Dissertations

The following dissertation focuses on the synthesis and characterization of poly(dodecamethylene terephthalamide) (PA-12,T) and novel copolymers. Chapter I details the synthesis of PA-12,T homopolymer by melt condensation polymerization. A series of homopolymers with different molecular weights were obtained by adjusting the stoichiometry of the polymerization using 1,12-diaminododecane, terephthalic acid and benzoic acid. End group 13C NMR spectroscopy resonances were obtained by correlating peak intensities with intrinsic viscosity values. From the NMR data, total end group concentrations and molecular weights were determined for each sample. The data exhibited a linear trend when plotting log (IV) versus log (Mn), and previously unknown …

Preparation And Characterization Of Thiol Based Polymeric Materials, Junghwan Shin

Dissertations

The thiol click-type reaction is one of the most efficient chemical processes that can undergo at room temperature in the benign organic solvent providing excellent opportunity in the fabrication of new materials as well as development of new manufacturing processes. Moreover, the versatility of thiol click-type reactions with many different functional groups such as ene, yne, epoxy, isocyanate, and alkyl halide is the important aspect that should be differentiated from the classic azide-alkyne click chemistry. Although, there are tremendous studies on many areas using thiol click-type reactions, the efficiency and utilities for the material applications have been barely explored. Especially, …

Off-Metal Synthesis Of Some Aryl Substituted Rhenium N5-Cyclopenta [C] Pyridazyl Complexes, James Leif Neathery

Masters Theses & Specialist Projects

Heterocyclic organic and organometallic compounds (e.g. polypyrrole), and their derivatives, have been of great interest for conductive polymers due to their novel properties and environmental stability as compared to non-aromatic analogs (e.g. polyacetylene). Our current interests focus upon the potential role of pyridazines in next generation electronic devices that utilize organics as the semiconducting material. Pyridazines, 6-membered aromatic rings with two adjacent nitrogens, are promising candidates for a variety of materials and commercial applications. These molecular electronic materials posses several advantages over traditional inorganic semiconducting materials including lower cost of production, higher processibility, and the ability to function on flexible …

A Characterization Of Caffeine Imprinted Polypyrrole Electrode, Deepika Mandadi

Masters Theses & Specialist Projects

Nanotechnology holds great potential for improving our lives by creating many new materials and devices in medical sciences, electronics and also in energy production. Molecularly imprinted polymers (MIPs) are highly stable synthetic polymers that possess molecular recognition properties due to cavities created in the polymer matrix that are complementary to an analyte both in shape and in positioning of functional groups. These MIPs have been widely employed for diverse applications (e.g., in chromatographic separation, drug screening, chemosensors, catalysis, immunoassays etc) due to their specificity towards the target molecules and high stability against physicochemical perturbations. Conductive polymers, (CPs) such as polypyrrole, …

Study Of Thermal Frontal Polymerization Utilizing Reactive And Non-Reactive Additives, Veronika Grace Viner

Dissertations

Thermal frontal polymerization is a process that involves a propagating front travelling through a monomer/initiator solution and converting monomer into polymer. The effects of different reactive and non-reactive additives on front temperature, front velocity, and pot life were studied in a thermal frontal polymerization system of multifunctional acrylates. One issue with thermal frontal polymerization of acrylate monomers is the amount of smoke and fumes produced due to high front temperatures. The effect of thermally-expandable microspheres was studied utilizing a variety of monomers. Solid additives including fillers, inert phase changer materials, and high thermal conductive fillers were investigated. The addition of …

Interface Slippage Study Between Polyamide 12 And Ethylene Butene Copolymer Melt In Capillary Extrusion, Jinhai Yang, James L. White

Faculty Publications

Extrusion of a polyamide 12 (PA12) material through a capillary die coated with an ethylene butene copolymer (EBM) was studied. The EBM coated die significantly increased the flow rates of the PA12 melt compared to a clean die at the same extrusion pressure. Introducing a maleic anhydride grafted ethylene-octene copolymer (EOM-g-MAH) into the EBM suppressed the effect. This behavior seems only explained by significant interface slippage between PA12 and EBM melts, which could be eliminated by introducing covalent chemical bonds across the interface. A mathematical analysis was carried out to calculate the interface slippage. The shear stress where slippage began …

Synthesis And Characterization Of Some Rhenium Complexes, Joseph Brian Scott

Masters Theses & Specialist Projects

Plastics or polymers are thought to behave oppositely from metals. Ideally, polymers behave as insulators while metals conduct electricity. Shirakawa and coworkers discovered conductive polymers in 1977.1 These conductor polymers have been extensively studied, discovering that charge transfer oxidative doping of polyacteylene could increase its conductivity by 12 orders of magnitude. Polyacetylene, although showing promise as an organic conductor, because it is highly air-sensitive and oxidizes when exposed to molecular oxygen, therefore making this an unattractive use for commercial products. Attention has been focused on heterocylic aromatic polymers such as polythiophene and polypyrrole, in efforts to produce conductive polymers that …

Synthesis Of Polymers Featuring Novel Diphosphines, Eleanor Tennyson

All Theses

This report details the synthesis of functionalized platinum-based metallopolymers featuring m-terphenyl-scaffolded and light-harvesting phosphine ligands. Substituents placed on both the phosphine and pendant alkynyl units can enhance the optical activity of the metallopolymers depending on their inherent properties. The presence of the platinum metal atom can be exploited to increase conductivity of the molecule and promises to be a unique and valuable modification for polymers to be used in light emitting diodes and photovoltaics. Light-harvesting phosphines prepared in the course of the metallopolymer development have also been used to prepare luminescent polyelectrolytes that prove valuable for well-defined composite film formation …

Development Of Improved Torsional Potentials In Classical Force Field Models Of Poly (Lactic Acid), James Mcaliley

All Dissertations

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 …