Polymer Chemistry Commons^™

Biodegradable Poly(Ester Urea's) Scaffold Sponges Containing Platelet-Rich Plasma For Targeted Tendon-Bone Fixation, Alex B. Ellenberger Mr.

Williams Honors College, Honors Research Projects

In this report the synthesis and characterization of L-valine and L-isoleucine poly(ester ureas) (PEUs) for future use in the synthesis of biodegradable PEUs sponges will be discussed. The method of monomer and polymer synthesis will be explained along with the characterization of the monomer and polymer products. This characterization will be done by the use of Nuclear Magnetic Resonance (NMR) and Size Exclusion Chromatography (SEC). NMR is a quick and convenient method for determining structure and purity of the monomer and polymer products. SEC gives the number average molecular weight, which is the statistical average molecular weight of all the …

Humidity And Rest Period Effects On Viscid Silk Recovery, Catherine Donley

Williams Honors College, Honors Research Projects

Spider silk applications, and applications of composite materials generally, are limited due to lack of recovery once damaged. Viscid silk, however, is known to have self-healing capabilities which restore, at least partially, its initial properties. If maximized, this ability could potentially increase viscid silk’s practicality and ultimately, provide insight into a self-healing system of use in synthetics. To that end, samples of viscid silk spun by female Larinioides cornutus spiders were tested via cyclical loading at 3 different relative humidities, with 3 different rest period lengths between complete cycles. Data from previously-performed tensile tests conducted at the same 3 humidities …

The Effects Of Substrate Roughness In Air And Water On The Gecko Adhesive System, Amanda Palecek

Williams Honors College, Honors Research Projects

In an effort to better understand the fascinating gecko adhesive system, scientists have long tested the abilities of the gecko in controlled conditions that mimic the gecko’s native environment. The effects of humidity, environmental temperature, and exposure to water have all been tested. Roughness, however has not been studied in great detail. Surfaces of varying roughnesses are all over the gecko’s natural environment. We tested geckos on hydrophilic silicon carbide sandpapers of varying roughnesses in both air and water to attempt to better study the effects of roughness on gecko adhesion. When tested on the rougher (1 µm) surface, the …

Multi-Mode And Single Mode Polymer Waveguides And Structures For Short-Haul Optical Interconnects, Kevin L. Kruse

Dissertations, Master's Theses and Master's Reports - Open

Single mode and multi-mode polymer optical waveguides are a viable solution for replacing copper interconnects as high speed and large bandwidth short-haul optical interconnects in next-generation supercomputers and data servers. A precision laser direct writing method is implemented for producing various single mode and multi-mode polymer waveguide structures and their performance is evaluated experimentally showing agreement with theoretically developed models. The laser direct writing method is the optimal solution for low-rate cost-effective prototyping and large area panel production.

A single mode polymer waveguide bridge module for silicon to glass optical fibers is designed, modeled, fabricated, and measured. The bridge module …

Biological Materials: Part A. Temperature-Responsive Polymers And Drug Delivery And Part B. Polymer Modification Of Fish Scale And Their Nano-Mechanical Properties, Xu Xiang

Dissertations, Master's Theses and Master's Reports - Open

This research has three parts. Two parts deal with novel nanoparticle assemblies for drug delivery, and are described in Part A, while the third part looks at properties of fish scales, an abundant and little-used waste resource, that can be modified to have value in medical and other areas.

Part A describes fundamental research into the affects of block sequence of amphiphilic block copolymers prepared from on a new and versatile class of monomers, oligo(ethylene glycol) methyl ether acrylate (OEGA) and the more hydrophobic di(ethylene glycol) methyl ether methacrylate (DEGMA). Polymers from these monomers are biologically safe and give polymers …

Characterization Of Noncovalent Complexes Of Polyelectrolytes By Mass Spectrometry, Anthony J. Marino

Williams Honors College, Honors Research Projects

Various ions of poly-L-lysine and polystyrene sulfonic acid were successfully observed first within a matrix-assisted laser desorption/ionization mass spectrometer and subsequently in an electrospray ionization mass spectrometer. The successful ionization of these polymers allowed for studies to be performed on the noncovalent interactions between the two. Noncovalent interactions were effectively studied on both instruments, but further quantified using tandem mass spectrometry found within the MALDI system and ion-mobility mass spectrometry found within the electrospray ionization system. As a result of employing the use of ion-mobility, various different stoichiometries and charges of polyelectrolyte complexes could be distinguished.

Gene Expression Of Tissue-Engineered Distal Phalanx Models Utilizing Polymer Scaffolds With Hydroxyapatite And Beta-Tricalcium Phosphate, Kristrun H. Kristinsdottir, William J. Landis Ph.D., Robin Jacquet M.S.

Williams Honors College, Honors Research Projects

Tissue engineering is a scientific methodology that provides the means for fabrication of vital tissues in a laboratory with the ultimate goal of translating the tissue to a patient in a clinic. It is a desirable technique in clinical medicine because it eliminates the need for patient tissue grafts and transplants, which have the potential for donor site morbidity and rejection. In tissue engineering, the scaffolding material, typically a polymer upon which tissue is grown, is important. The goal of this research is to investigate optimization of tissue-engineered polymer scaffold constructs for cell proliferation and gene expression. This work includes …

Diazaborole Linked Porous Polymers: Design, Synthesis, And Application To Gas Storage And Separation, Zafer Kahveci

Theses and Dissertations

The synthesis of highly porous organic polymers with predefined porosity has attracted considerable attention due to their potential in a wide range of applications. Porous organic polymers (POPs) offer novel properties such as permanent porosity, adjustable chemical nature, and noteworthy thermal and chemical stability. These remarkable properties of the POPs make them promising candidates for use in gas separation and storage. The emission of carbon dioxide (CO₂) from fossil fuel combustion is a major cause of global warming. Finding an efficient separation and/or storage material is essential for creating a cleaner environment. Therefore, the importance of the POPs …

Fabrication Of Tissue Precursors Induced By Shape-Changing Hydrogels, Olukemi O. Akintewe

USF Tampa Graduate Theses and Dissertations

Scaffold based tissue reconstruction inherently limits regenerative capacity due to inflammatory response and limited cell migration. In contrast, scaffold-free methods promise formation of functional tissues with both reduced adverse host reactions and enhanced integration. Cell-sheet engineering is a well-known bottom-up tissue engineering approach that allows the release of intact cell sheet from a temperature responsive polymer such as poly-N-isopropylacrylamide (pNIPAAm). pNIPAAm is an ideal template for culturing cell sheets because it undergoes a sharp volume-phase transition owing to the hydrophilic and hydrophobic interaction around its lower critical solution temperature (LCST) of 32°C, a temperature close to physiological temperature. Compared to …

Synthesis, Characterization And Application Of Acrylic Colloidal Unimolecular Polymer (Cup), Ameya Manohar Natu

Doctoral Dissertations

"Colloidal Unimolecular Polymer (CUP) particles were prepared by the process of water reduction on amphiphilic acrylic copolymers prepared via free radical polymerization technique. The formation of CUP particles was driven by the polymer-polymer interaction being greater than the polymer-solvent interaction and entropically favored by release of the water. It was demonstrated by Dynamic Light Scattering technique that CUP particles based on copolymers below 13,000 MW were unstable and the particles aggregated to a higher particle size. For the polymers with molecular weight (MW) above 13,000, a good correlation between the theoretical and experimental CUP particle size was observed. The rheology …

Application Of Colloidal Unimolecular Polymer (Cup) Particles In Coatings, Sagar Vijay Gade

Doctoral Dissertations

"Colloidal unimolecular polymer (CUP) particles were prepared by the process of water reduction on copolymers containing hydrophobic and hydrophilic monomers at definite ratio using free radical polymerization. The CUPs are formed by the effect of hydrophilic /hydrophobic interactions of the polymer with a change in the solvent environment around them. Once formed these colloidal particles are thermodynamically stable with collapsed hydrophobic groups forming a spheroidal core and hydrophilic charges on the surface stabilizing the particle by the charge repulsion. CUPs contain only the charged CUP particles, water and counterions with all the functionality on the surface for further chemistry. CUP …

Development Of Platinum-Based Catalysts On Polyimide Films For Alcohol Electro-Oxidation, Rungnahpa Ruangsariyanon

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research studied the preparation of highly dispersed platinum nanoparticles on polyimide films or Pt/PI by surface modification method. Firstly, polyimide film was hydrolyzed in basic solution, followed by being immersed in platinum-ion solution to allow ion exchange process. Platinum ions on the film were subsequently reduced using proper reducing agent to give Pt/PI. After that, morphological and other information of the Pt/PI was investigated by X-ray diffraction analysis, scanning electron microscopy-energy dispersive X-ray spectroscopy, transmission electron microscopy, and inductively coupled plasma-optical emission spectroscopy. Electrochemical performance of the Pt/PI for the electro-oxidation of alcohols was investigated by means of cyclic …

The Use Of Polystyrene-Tethered Fullerenes As Stabilizers In Bulk Heterojunctions, Joshua A. Moore

Theses and Dissertations

Self-assembly of nanoparticles can potentially provide improvements for many current applications and could influence the design of future technologies. The assembly of nanoparticles, which can be controlled through external forces or through molecular interactions, can affect the properties of a material. Nanoparticles can be chemically modified by attaching molecules such as polymers to their surface. The nature and placement of these tethers affects the arrangement of the nanoparticles leading to materials with novel chemical, electrical, and physical properties. In this research, the assembly of the fullerene (C60) based nanoparticles was modified using polystyrene-tethered fullerenes (PTFs) as additives. Polystyrene (PS) was …

Template-Assisted Fabrication Of Ferromagnetic Nanomaterials, Jagnyaseni Tripathy

LSU New Orleans Theses and Dissertations

Abstract

Template assisted deposition was used to produce various nanomaterials including simple nanowires, nanorods, multi-segmented metal nanowires, core-shell nanowires, alloy and polymer wires and tubes. Anodized aluminum oxide (AAO) membranes were used as templates for the growth of the various structures using an electrochemical deposition method and also by wetting the porous templates. In the electrochemical deposition method, the pore size of the templates affects the rate of synthesis and the structures of the nanomaterials while in the wetting method, the viscosity and reaction time in the polymer solution influence the structures of the nanomaterials.

A conventional two-step anodization procedure …

Thermomechanical Performance Assessment Of Bio-Based Pu Adhesives Derived From Castor Oil, Anand Patel

Electronic Theses & Dissertations

Thermomechanical Performance Assessment of Bio-based PU Adhesives Derived from Castor Oil

An Abstract of the Thesis by

Anand V. Patel

Adhesives play a critical role in binding diverse materials, thereby promoting structural integrity and functional versatility across numerous daily applications. A significant challenge remains in developing polyurethane adhesives that exhibit exceptional bonding strength, as many are derived from petroleum products. To reduce dependence on non-renewable resources and offer sustainable and affordable alternatives, vegetable oils are being utilized to create a range of polyurethane adhesives. These oils are preferred due to their low toxicity, cost-effectiveness, and reduced environmental impact. This research …

Molecular Dynamics Study Of The Opening Mechanism For Dna Polymerase I, Carol A. Parish, Bill R. Miller Iii, Eugene Y. Wu

Chemistry Faculty Publications

During DNA replication, DNA polymerases follow an induced fit mechanism in order to rapidly distinguish between correct and incorrect dNTP substrates. The dynamics of this process are crucial to the overall effectiveness of catalysis. Although Xray crystal structures of DNA polymerase I with substrate dNTPs have revealed key structural states along the catalytic pathway, solution fluorescence studies indicate that those key states are populated in the absence of substrate. Herein, we report the first atomistic simulations showing the conformational changes between the closed, open, and ajar conformations of DNA polymerase I in the binary (enzyme:DNA) state to better understand its …

Designing Magnetically Responsive Ultrafiltration Membranes, Robert William Dong

Graduate Theses and Dissertations

Ultrafiltration (UF) membranes developed out of a need for protein separation processes. Currently, they are used in a variety of industries ranging from food manufacturing to pharmaceuticals for two main purposes: concentration, separation, and buffer exchange. UF membrane processes in product streams undergo frequent use and like all membrane processes experience a gradual decline in performance due to fouling phenomena both irreversible and reversible. Ultimately, performance declines to a point where the UF membrane needs to be replaced. Frequent replacement of UF membranes is detrimental to major industries that require high product throughput using UF processes. Thus, it is important …

Tuning Responsiveness Of Polypeptide Based Block Copolymers For Drug Delivery, Ashley J. Johnson

Dissertations

The goal of this dissertation was to tune the pH response and self-assembled morphologies of amphiphilic polypeptide block copolymers for use as drug delivery vehicles. Poly(L-lysine) and poly(L-glutamtic acid) are responsive, ionizable polypeptides that undergo secondary structure transitions, from α-helix to random coil, whereby the change in conformation of the peptide chain results in changes to the global morphology of a self-assembled system. The main focus of this work was to understand how changes in the polymer composition and the local environment can lead to control over the behavior of the overall system. First, the responsive behavior of poly(L-lysine) block …

Continuous Polymer Reactor Design, David Sujay Kingsley

Dissertations

Twin screw extruders can be used as continuous polymer reactors to process polymers, which are conventionally made through batch reactors. Batch processes have certain undesirable qualities such as improper mixing and the inability to precisely control the reaction, which leads to variation between batches and potential exotherms. The work presented in this dissertation investigates the use of continuous polymer reactor designs to efficiently process renewable sourced thermoplastic polyurethanes (TPU), and prepreg epoxy matrix prepolymers.

The overall goal of this research is to highlight the modularity of twin screw extruders as continuous polymer reactors to synthesize the relevant polymers. Chapter I …

Investigation Of Glassy State Molecular Motions In Thermoset Polymers, Jianwei Tu

Dissertations

This dissertation presents the investigation of the glassy state molecular motions in isomeric thermoset epoxies by means of solid-state deuterium (²H) NMR spectroscopy technique. The network structure of crosslinked epoxies was altered through monomer isomerism; specifically, diglycidyl ether of bisphenol A (DGEBA) was cured with isomeric amine curatives, i.e., the meta-substituted diaminodiphenylsulfone (33DDS) and para-substituted diaminodiphenylsulfone (44DDS). The use of structural isomerism provided a path way for altering macroscopic material properties while maintaining identical chemical composition within the crosslinked networks.

The effects of structural isomerism on the glassy state molecular motions were studied using solid-state ²H …