Chemistry Commons^™

Functionalized Materials From Atom Transfer Radical Processes, Sean Fischer

Electronic Theses and Dissertations

This work is focused on the synthesis, characterization, and application of functionalized materials prepared from atom transfer radical processes. Atom transfer radical processes encompass both atom transfer radical addition (ATRA) and polymerization (ATRP) reactions, both of which are catalyzed by ppm amounts of copper complexes. The synthetic efforts of ATRA include increasing adduct selectivity through optimization of reaction conditions to generate small molecules in high to moderate yields. ATRA provides retention of the halogen moiety, which is an attractive functional group that can be further modified with other transformations. Specifically, the copper-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) allows for the realization …

Atom Transfer Radical Processes: From Catalyst Design To Polymer Synthesis, Characterization, And Application, Michael Novak

Electronic Theses and Dissertations

Due to the toxicity of heavy metals and their prevalence in the environment there exists a need to develop highly active transition metal catalysts ultimately reducing the amount needed for chemical transformations. Additionally, there is interest in the scientific community for creating new materials that can remove these pollutants from industrial wastewater prior to its release into the environment. The work presented here focuses on the reduction and removal of heavy metals from industrial hazardous waste by designing novel highly active catalysts and developing polymeric adsorbents.

Highly active catalyst complexes consisting of novel hybrid ligands, 2-(dimethylamino)ethyl-bis-[2-(pyridylmethyl)amine] (M1-T2), and bis[2-(dimethylamino)ethyl]-2-(pyridylmethyl)amine (M2-T1), …

Control Of Corrosion On Ss316l Using Surface Initiated Polymers, Alexander Rupprecht

Electronic Theses and Dissertations

Pitting corrosion is arguably one of the most destructive and dangerous forms of corrosion, resulting in damage to structures, the environment, and public health. In addition, damage caused to structures such as bridges, pipelines, and boats, corrosion also has a profound effect on the biomedical community. Implanted metallic devices (i.e., vascular stents and artificial joints) are prone to pitting corrosion caused by aggressive ions present in extracellular fluid. To provide a corrosion-resistant surface on SS316L, films of poly(styrene), poly(methyl acrylate), and poly(methyl methacrylate) were formed using surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting hydrophobic polymer films had a fractional …

Practical Adhesion Measurements In Organic Coatings; Advancing Understanding And Mechanical Methods Development, Diana Gottschalk

Dissertations

“Adhesion” can be considered either a mechanical or chemical phenomenon. The mechanical interpretation describes the difficulty of separating surfaces and is useful for quantifying performance within applications that depend on bulk and interfacial properties. Chemical adhesion describes interfacial resistance to chemical attack and does not depend on bulk properties. Predicting chemical failure through mechanical measurement is confounded by the influence of bulk properties. However, the prospect is attractive because of the robust tolerance for sample geometries, allowing experiments to resemble an end-use system. The present work's primary goal was to elevate mechanical methods to provide a detailed interfacial characterization of …

One-Step Synthesis Of Soybean Oil-Based Polyol For Highly Flame-Retardant Rigid Polyurethane Foams, Tenzin Ingsel

Electronic Theses & Dissertations

The usage of petro-chemical based sources in polyurethane has raised environmental concerns in recent years. Bio-based polyurethanes are attractive alternatives for these conventional petrochemical-based polyurethanes. In this work, a soybean oil-based polyol was synthesized via thiol-ene reaction. Chromatography, wet chemistry methods, and spectroscopic evaluations were carried out to characterize the synthesized polyol. The polyol obtained was then used to produce flame-retardant rigid polyurethane foams with three different organophosphorus flame-retardants: dimethyl methyl phosphonate (DMMP), triethyl phosphate (TEP), and triphenyl phosphate (TPP). Incorporating flame-retardants in polyurethane foams provide them resistance to ignition where these foams are originally highly combustible. Physico-mechanical and flammability …

Structure And Dynamics Of Phospholipid Vesicles And The Dependence On Nanoscale Interactions With Molecules Of Varying Complexity, Lakshapathy Widanelage Judith Upeka De Mel

LSU Doctoral Dissertations

In this dissertation, molecular interactions and changes imposed by nano-scale structures on phospholipid vesicles were investigated. 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) large unilamellar vesicles (LUVs) were used as the model system. Understanding changes of the bilayer structure, interfacial properties, lipid dynamics, and self-assembly, allows bridging relationships between biological cell membrane structure and dynamics to cellular functionalities. For example, membrane curvature changes are linked to membrane protein functions, although the exact mechanisms of control are not yet understood. Moreover, the knowledge gained from vesicle models allows exploring novel strategies for drug delivery applications. To achieve this, DOPC LUVs were synthesized and characterized by a …

Ethoxylation And Polymerization Of Cardanol Derived Bifunctional Monomers, James Mgaya

Journal of Humanities and Social Sciences

Cardanol and its derivative; 3-(non-8-enyl)phenol (obtained by ethenolysis reaction of cardanol) were ethoxylated via one-pot reaction with urea and ethylene glycol using Na2CO3/ZnO as co-catalysts. The ethoxylates were later methoxycarbonylated using a 1,2-bis(ditertbutylphosphinomethyl)benzene (DTBPMB) modified palladium catalyst to produce ethoxylated bifunctional monomers. Polymerization of these monomers by heating in the presence of a standard polymerization catalyst, Ti(OBu)4, formed oligomers that were plastic-like. Analysis of these oligomers by MALDI-TOF MS indicated the condensation of up to nine monomer units.

Soybean: Good Source For High-Performance Supercapacitors, Jonghyun Choi

Electronic Theses & Dissertations

In this era of rising energy consumption, people are demanding high-performance and environment friendly energy storage devices. To meet these needs, there are many efforts to develop high performance supercapacitor using biomass. In this study, soybean shell, leaf, and stem was used as a source of carbon via chemical activation with an KOH activating agent. The activating agent KOH was mixed in several proportions ranging from 1:0.125 to 1:1, and all samples exhibited the tendency to increase the surface area and porosity as the activating agent ratio increased. Samples mixed with KOH in a 1:1 ratio showed not only the …

Synthesis And Investigation Of Amphiphilic Polypeptoids For Environmental And Biological Applications, Tianyi Yu

LSU Doctoral Dissertations

Polypeptoids are an emerging class of peptidomimetic polymers featuring N-substituted polyglycine backbones. Polypeptoids are cyto-compatible and backbone degradable, making them appealing to many biological applications. When the highly polar polyamide backbone is coupled with non-polar aliphatic side chains, polypeptoids can be considered as facial amphiphiles. Without extensive hydrogen bonding along the backbone, the conformation of polypeptoid is largely controlled by the N-substituent structures. The hydrophobicity-lipophilicity balance of polypeptoids can be readily tuned with the N-substituent structures as well as the molar ratio between the hydrophilic and hydrophobic segments in their copolymers. In view of these combined attributes, …

Investigation Of The Evaporation Rate Of Water From Colloidal Unimolecular Polymer (Cup) Systems By Isothermal Tga, Peng Geng, Ashish Zore, Michael R. Van De Mark

Chemistry Faculty Research & Creative Works

Studies of the evaporation of aqueous nanoparticle solutions have been limited due to lack of homogeneity of the solution, difficulties in obtaining reproducible samples and stability of substrates, as well as the effect of other volatile components or contaminants such as surfactants. Colloidal unimolecular polymer (CUP) is a spheroidal nanoparticle with charged hydrophilic groups on the surface, and the particle size ranges from 3 to 9 nm. The large amount of surface water on the CUP surface provides the opportunity to evaluate the evaporation of surface water, which may contribute to the investigation the factors that affect the evaporation rate …

High-Temperature Resistant Water-Soluble Polymers Derived From Exotic Amino Acids, Sumant Dwivedi, Aniruddha Nag, Shigeki Sakamoto, Yasuyoshi Funahashi, Toyohiro Harimoto, Kenji Takada, Tatsuo Kaneko

Faculty Publications

© The Royal Society of Chemistry. High-performance water-soluble polymers have a wide range of applications from engineering materials to biomedical plastics. However, existing materials are either natural polymers that lack high thermostability or rigid synthetic polymers. Therefore, we design an amino acid-derived building block, 4,4′-diamino-α-truxillate dianion (4ATA²⁻), that induces water solubility in high-performance polymers. Polyimides containing 4ATA²⁻ units are intrinsically water-soluble and are processed into films cast from an aqueous solution. The resulting polyimide films exhibit exceptional transparency and extremely high thermal stability. In addition, the films can be made insoluble in water by simple post-treatment using …

Synthesis And Characterization Of Water-Soluble Polyaniline For Hydrazine Detection / Hazira Hussin, Hazira Hussin

Student Works (2020-2029)

In this study, polyaniline (PAni) was synthesized through the chemical oxidation method using aniline (Ani) as a monomer, hydrochloric acid (HCl) as a dopant, and ammonium persulphate (APS) as an initiator. PAni was rendered water soluble through treating with cellulose derivatives. Cellulose derivatives such as methylcellulose (MC), hydroxypropyl cellulose (HPC), and hydroxypropyl methylcellulose (HPMC) were used as a stabilizer to improve the solubility of PAni in an aqueous medium. The water-soluble PAni-cellulose derivative was applied as a chemical sensor for hydrazine detection. The chemical structures and electrical conducting behaviours of PAni-cellulose derivatives were investigated using Fourier transform infrared (FTIR) and …

Design And Synthesis Of Core–Shell Microgels With One‐Step Clickable Crosslinked Cores And Ultralow Crosslinked Shells, Molla R. Islam, Chelsea Nguy, Sanika Pandit, L. Andrew Lyon

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The present study is conducted to explore the engineering of core–shell microgels such that the core can be rapidly labeled with a variety of fluorophores, while the shell retains the softness needed in specific biomedical applications. Azide containing crosslinked core particles based on a crosslinked poly(N‐isopropylacrylamide) particle, using a one‐pot, multistep polymerization is synthesized. A core–shell microgel is then synthesized by growing a crosslinker‐free poly(N‐isopropylacrylamide)‐co‐acrylic acid (ULC10AAc) shell through a two‐step seed and feed polymerization. A simple “click” reaction between the azide present on the core and dibenzocyclooctyne containing fluorophores to make dyed core–shell …

Peo-Ppo-Peo Surfactant Mixtures As Templates For Silicas With Very Large Cylindrical Mesopores At Ambient Temperature And With Helical Mesopores At Sub-Ambient Temperature, Laurance Beaton

Dissertations, Theses, and Capstone Projects

The original research described herein concerns the synthesis of mesoporous silicas through a surfactant-templating method. The approach taken involved the use of a mixed surfactant system of two poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) surfactants, with one of the copolymers containing a much larger percentage of hydrophobic (PPO) blocks than the employed co-surfactant. Systematic adjustments of experimental parameters initially enabled the preparation of 2-D hexagonally ordered mesoporous silicas (SBA-15) of uncommonly large pore diameter at ambient temperature. Comparable silica was synthesized with and without temperature control. Additional adjustments to experimental parameters, including reduction of the relative amount of framework precursor used in …

Pressure Driven Desalination Utilizing Nanomaterials, Fangyou Xie

Master's Theses

Nanomaterials such as graphene oxide and carbon nanotubes, have demonstrated excellent properties for membrane desalination, including decrease of maintenance, increase of flux rate, simple solution casting, and impressive chemical inertness. Here, two projects are studied to investigate nanocarbon based membrane desalination. The first project is to prepare hybrid membranes with amyloid fibrils intercalated with graphene oxide sheets. The addition of protein amyloid fibrils expands the interlayer spacing between graphene oxide nanosheets and introduces additional functional groups in the diffusion pathways, resulting in increase of flux rate and rejection rate for the organic dyes. Amyloid fibrils also provide structural assistance to …

Rheological Studies Of Fully-Formulated Coatings Thickened With Heur: Effects Of Surfactants, Brandon M. Bonilla

Master's Theses

Rheology modifiers such as hydrophobically-modified ethoxylated urethane (HEUR)thickeners are included in waterborne latex coatings to optimize shear-rate dependent viscosity and other rheological properties. While these HEUR polymers are commonly used in industry, the complex chemical interactions that contribute to rheological properties are still not completely understood. Prior work in this area has focused on understanding latex-HEUR and latex-surfactant-HEUR interactions that affect rheological properties. Additionally, studies have been previously conducted to understand the relaxation mechanisms of complex interactions present in HEUR-thickened waterborne latex coatings under various dynamic conditions. The objective of this work is to extend the experimental work to fully-formulated …

Highly Swelling Ph-Responsive Microgels For Dual Mode Near Infra-Red Fluorescence Reporting And Imaging, Mingning Zhu, Dongdong Lu, Qing Lian, Shanglin Wu, Wenkai Wang, L. Andrew Lyon, Weiguang Wan, Paulo Bártolo, Mark Dickinson, Brian R. Saunders

Engineering Faculty Articles and Research

Near infra-red (NIR) fluorescence is a desirable property for probe particles because such deeply penetrating light enables remote reporting of the local environment in complex surroundings and imaging. Here, two NIR non-radiative energy transfer (NRET) fluorophores (Cy5 and Cy5.5) are coupled to preformed pH-responsive poly(ethylacrylate-methacrylic acid-divinylbenzene) microgel particles (PEA-MAA-5/5.5 MGs) to obtain new NIR fluorescent probes that are cytocompatible and swell strongly. NIR ratiometric photoluminescence (PL) intensity analysis enables reporting of pH-triggered PEA-MAA-5/5.5 MG particle swelling ratios over a very wide range (from 1–90). The dispersions have greatly improved colloidal stability compared to a reference temperature-responsive NIR MG based on …

(Pseudo)Phase Tuning In The Service Of Synthesis: Technologies For Sustainable Catalysis., Justin Douglas Smith

Electronic Theses and Dissertations

Strategies for manipulation of chemical phases were explored with emphasis on synthetic chemistry applications. Some strategies are fairly divergent from their origin, but all ultimately began from investigations of micellar media. Accordingly, Chapter 1 reviews the historical development of micellar catalytic processes. Chapters 2 and 3 detail development of synthetic methods in micellar solutions of designer surfactant PS-750-M. PS-750-M was designed to create benign micellar solutions which effectively mimic toxic organic solvents; it contains a proline-based linker between its hydrophobic and hydrophilic regions which imparts increased polarity to the micellar core. Chapter 2 details an interfacial nucleophilic substitution of perfluoroarenes …

Synthesis Of Polyaniline Modified With Palm Oil Based Alkyd As Counter Electrode In Solar Cell Application, Ramli Mariam Fadzlina

Student Works (2020-2029)

Presently, shortage of sustainable and environmental friendly energy resources has become an important global concern. Dye-sensitized solar cell (DSSC) has widely been used as a clean energy conversion device that can solve this problem. Platinum (Pt) has commonly been used as counter electrode (CE) in DSSC due to its good redox property. However, Pt is expensive and could be easily corroded in tri-iodide solution. Recently, polyaniline (PAni) has shown promising performance in DSSC, but PAni exhibit poor adhesion on fluorine-doped tin oxide (FTO) substrate. In this study, an environmental friendly CE was developed by modifying PAni using titanium dioxide (TiO2) …

Development Of Plasticized Methylcellulosepotato Starch Blend Based Polymer Electrolytes For Protonic Cell And Supercapacitor Applications, Hamsan Muhamad Hafiz

Student Works (2020-2029)

In the current work, the preparation of the polymer electrolyte (PE) systems consists of methylcellulose-potato starch polymer matrix, ammonium nitrate (NH4NO3) as ionic source and glycerol as plasticizer are done by solution cast technique. X-ray diffraction (XRD) has shown that blend with 60 wt.% methylcellulose and 40 wt.% potato starch possesses the lowest degree of crystallinity. The possible interactions within the PE are verified using Fourier transform infrared (FTIR) spectroscopy. As the concentration of NH4NO3 is at 30 wt.%, the conductivity is optimized up to (4.37 ± 0.16) × 10-5 S cm-1 and then maximized to (1.26 ± 0.1) × …

Antibacterial Coatings Derived From Novel Chemically Responsive Vesicles, Emily B. Mobley

Master's Theses

In order for a drug, or any material used for the purpose of eliciting a change in an organisms’ physical or chemical state, to be effective it must reach the intended target intact and for a sustained rate over time. Drug delivery systems encapsulate a drug to protect it from degradation, prevent side reactions, increase solubility, improve accumulation rates at target sites, and release drugs at a controlled rate. Controlled and sustained release of drugs is achieved by degradation of the carrier triggered by breaking dynamic chemical bonds caused by changes in the chemical environment such as pH or redox …

Visualization Without Vision – How Blind And Visually Impaired Students And Researchers Engage With Molecular Structures, Croix J. Laconsay, Henry B. Wedler, Dean J. Tantillo

Journal of Science Education for Students with Disabilities

This article examines the tools and techniques currently available that enable blind and visually impaired (BVI) individuals to visualize three-dimensional objects used in learning chemistry concepts. How BVI individuals engage with and visualize molecular structure is discussed and recent tactile (or haptic) and auditory methods for visualization of various chemistry concepts are summarized. Remaining challenges for chemistry education researchers are described with the aim of highlighting the potential value of educational research in further enabling BVI students to pursue careers in science, technology, engineering, and mathematics (STEM) fields.

Thiophene Derivative Monomers Co-Electropolymerized On Microelectrodes Within Arrays For Tailored Surface Chemistry And Electrochemical Properties, Benjamin J. Jones

Graduate Theses and Dissertations

Potentiodynamic co-electropolymerization of two thiophene derivatives, (2,3-dihydrothieno[3,4-b]dioxin-2-yl)methanol (1) and 4-((2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)-methoxy)-4-oxobutanoic acid (2), in aqueous solutions (0.02 M total monomer, 0.05 M sodium dodecyl sulfate (SDS) and 0.1 M LiClO4) on gold microband electrodes in an array was investigated. A modified Steglich esterification reaction between monomer 1 and succinic anhydride produced monomer 2 at 93.6% yield. Seven deposition solutions of the two monomers, defined by mol% of monomer 2 (0, 25, 34, 50, 66, 75, 100) generated seven sets of polymer films by cyclic voltammetry in a specially designed cell to conserve monomer. The onset potential for monomer oxidation and total …

Thermodynamic Characterization Of Free And Surface Water Of Colloidal Unimolecular Polymer (Cup) Particles Utilizing Dsc, Peng Geng, Ashish Zore, Michael R. Van De Mark

Chemistry Faculty Research & Creative Works

Colloidal Unimolecular Polymer (CUP) particles are spheroidal, 3-9 nm with charged groups on the surface and a hydrophobic core, which offer a larger surface water fraction to improve the analysis of its characteristics. Differential scanning calorimetry (DSC) was performed to determine the characteristics of surface water. These properties include the amount of surface water, the layer thickness, density, specific heat of the surface water above and below the freezing point of water, melting point depression of free water, effect of charge density and particle size. The charge density on the CUP surface was varied as well as the molecular weight …

Altering An Epoxy-Amine Thermoset's Performance Through Varying Mix Ratios, Kiersten M. Smith

Master's Theses

Epoxy resins are used in a number of different industries and therefore have application-specific material requirements, from satellites that require materials that operate in space, to paints and coatings that require high scratch resistance and mechanical durability, to medical devices, designed to be in continuous contact with biological fluids. Commercial epoxy products come with manufacturer’s information explaining the epoxy properties and recommended preparation processing conditions, which may include epoxy resin to curing agent mix ratio (Part A : Part B), cure time, and cure temperature, for example. Due to proprietary reasons, it can be difficult to understand why these values …

Effect Of Polymer Design And Coating Formulation On The Water Uptake And Sensitivity Of Acrylic Water-Borne Films, William Z. Thompson

Master's Theses

Water-borne latex coatings represent a safer, more user-friendly, and environmentally responsible alternative to solvent-borne coatings, and are growing in popularity each year. However, these coatings often exhibit unfavorable performance when exposed to water for extended periods of time. This prolonged exposure often results in water uptake, which may give rise to other detrimental effects such as a decrease in modulus, blushing or water-whitening, reduced serviceable life, and softening of the film. In this study, various polymer composition latex design spaces are studied to develop an understanding of how water uptake can be modulated and minimized using common synthetic approaches. Factors …

Effect Of Different Phosphate Glass Compositions On The Process-Induced Macromolecular Dynamic Of Polyamide 66, Imane Belyami, Mohammad K. Hassan

Faculty Publications

The present study provides a fundamental understanding of the mechanism of action of special new phosphate glass (P-glass) systems, having different glass transition temperatures (T_g), in polyamide 66 (PA66). Dynamic mechanical analysis (DMA) revealed that the T_g of PA66/low T_g P-glass (ILT-1) was significantly shifted to a lower T_g (65 °C), and another transition appeared at high temperature (166 °C). This was supported by a drop in the melting point and the crystallinity of the PA66/ILT-1 hybrid material as detected by differential scanning calorimetry (DSC). The dielectric spectroscopic investigation on the networks’ molecular level structural …

I. Non-Degradable Polysiloxane Networks For Controlled Release Applications, And Ii. Additive Free, Degradable Silyl-Ether Furyl-Maleimide Networks, Caleb M. Bunton

Chemistry Theses and Dissertations

I. Two different series of non–degradable polysiloxane networks were prepared for the encapsulation and controlled release of a small molecule agent. For the first series, hydrosilylation was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and silylhydride functional poly(dimethyl)siloxanes. For the second series, the thiol-ene reaction was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and mercaptopropyl functional poly(dimethyl)siloxanes. Nile red dye was used as an encapsulated agent and dye release from each series of networks was measured using UV–vis spectroscopy to determine controllability …

Effect Of Post-Consumer Content And Bioplastic Incorporation On Polymeric Resin In Consumer Applications, Shelby Bicknell

Electronic Theses & Dissertations

Controversy surrounds the use of plastic products, primarily due to their potentially negative impact on the environment at the end of their lifecycle. The most widely used plastics are manufactured from petrochemicals such as petroleum, coal or natural gas. Petrochemical plastics are not able to readily breakdown in the environment, which aggravates the existing pollution problems. Fortunately, there are eco-friendly alternatives to petrochemical-based plastics. Bioplastics may be derived from renewable sources, biodegradable, or both. Bio-based plastics are plastics that may be derived from renewable biomass sources including, but not limited to, vegetable oils, cornstarch, straw, woodchips, and food waste. They …

Fabrication Of Polymer Monoliths Within The Confines Of Non-Transparent 3d-Printed Polymer Housings, Noor Abdulhussain, Suhas H. Nawada, Sinéad Currivan, Marta Passamonti, Peter J. Schoenmakers

Articles

In the last decade, 3D-printing has emerged as a promising enabling technology in the field of analytical chemistry. Fused-deposition modelling (FDM) is a popular, low-cost and widely accessible technique. In this study, RPLC separations are achieved by in-situ fabrication of porous polymer monoliths, directly within the 3D-printed channels. Thermal polymerization was employed for the fabrication of monolithic columns in optically non-transparent column housings, 3D-printed using two different polypropylene materials. Both acrylate-based and polystyrene-based monoliths were created. Two approaches were used for monolith fabrication, viz. (i) in standard polypropylene (PP) a two-step process was developed, with a radical initiated wall-modification step …