Humidity And Rest Period Effects On Viscid Silk Recovery, 2015 University of Akron Main Campus
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 …
Initiated Chemical Vapor Deposition (Icvd) Polymer Thin Films : Structure-Property Effects On Thermal Degradation And Adhesion, 2015 University at Albany, State University of New York
Initiated Chemical Vapor Deposition (Icvd) Polymer Thin Films : Structure-Property Effects On Thermal Degradation And Adhesion, Vijay Jain Bharamaiah Jeevendrakumar
Legacy Theses & Dissertations (2009 - 2024)
Opportunities and challenges for chemical vapor deposition (CVD) of polymer thin films stems from their applications in electronics, sensors, and adhesives with demands for control over film composition, conformity and stability. Initiated chemical vapor deposition (iCVD) is a subset of the CVD technique that conjoins bulk free-radical polymerization chemistry with gas-phase processing. The novelty of iCVD technique stems from the use of an initiator that can be activated at low energies (150 – 300 °C) to react with surface adsorbed monomer to form a polymer film. This reduces risk for potential unwarranted side-reactions.
Synthesis, Characterization And Application Of Acrylic Colloidal Unimolecular Polymer (Cup), 2015 Missouri University of Science and Technology
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 …
Burst Pressure Properties And Ex Vivo Analysis Of Alginate-Based Hydrogels For Tissue Sealant Applications, 2015 University of Vermont
Burst Pressure Properties And Ex Vivo Analysis Of Alginate-Based Hydrogels For Tissue Sealant Applications, Patrick Nelson Charron
Graduate College Dissertations and Theses
Lung diseases, cancers, and trauma can result in injury to the connective tissue lining the lung, i.e., the pleura. Pleural injuries lead to pneumothoraxes or pleural effusions, i.e., air or fluid leaking out of the lung respectively, and potential lung collapse - an immediately life threatening condition. While several bioengineered soft tissue sealants exist on the market, there is only one sealant FDA-approved for use in pulmonary surgery. In addition, very limited techniques are presented in the literature for characterizing the burst properties of hydrogel tissue sealants. For my thesis, I proposed to develop a protocol for characterizing the burst …
Template-Assisted Fabrication Of Ferromagnetic Nanomaterials, 2014 University of New Orleans
Template-Assisted Fabrication Of Ferromagnetic Nanomaterials, Jagnyaseni Tripathy
University of 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 …
Production And Applications Of Formaldehyde-Free Phenolic Resins Using 5-Hydroxymethylfurfural Derived From Glucose In-Situ, 2014 The University of Western Ontario
Production And Applications Of Formaldehyde-Free Phenolic Resins Using 5-Hydroxymethylfurfural Derived From Glucose In-Situ, Yongsheng Zhang
Electronic Thesis and Dissertation Repository
The phenol-formaldehyde (PF) resin manufacturing industry is facing a growing challenge with respect to concerns over human health, due to the use of carcinogenic formaldehyde and sustainability due to the use of petroleum-based phenol in PF resin manufacture. Glucose and its derivative, 5-hydroxymethylfurfural (5-HMF), have proven to be potential substitutes for formaldehyde in the synthesis of phenolic novolac resins.
This thesis investigated a number of glucose and 5-HMF resin systems including the curing of phenol-glucose novolac resin (PG) with a bis-phenol-A type epoxy. The curing process was modeled according to the Sestak-Berggren equation (S, B) using Málek methods. This was …
Polyglyoxylates: A New Class Of Triggerable Self-Immolative Polymers, 2014 The University of Western Ontario
Polyglyoxylates: A New Class Of Triggerable Self-Immolative Polymers, Bo Fan
Electronic Thesis and Dissertation Repository
Self-immolative polymers, which degrade by an end-to-end depolymerization mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus, are of increasing interest for a wide variety of applications ranging from sensors to controlled release. However, the preparation of these materials often requires expensive, multi-step monomer syntheses and the degradation products such as quinone methides or phthalaldehydes are potentially toxic to humans and the environment. We demonstrate here that polyglyxoylates can serve as a new and versatile class of self-immolative polymers. Polymerization of the commercially available monomer ethyl glyoxylate, followed by end-capping with a 6-nitroveratryl carbonate provides …
Poly(Ester Amide) And Poly(Ethyl Glyoxylate) Nanoparticles For Controlled Drug Release, 2014 The University of Western Ontario
Poly(Ester Amide) And Poly(Ethyl Glyoxylate) Nanoparticles For Controlled Drug Release, Amira Mohamed Moustafa
Electronic Thesis and Dissertation Repository
The objective of this research was to develop polymeric nanoparticles (NPs) having improved drug release properties for drug delivery. Poly(ester amide)s (PEAs) are promising biodegradable polymers. PEA NPs were prepared via emulsification-evaporation and salting-out methods and optimized through by varying different processing parameters. Polymer-model drug conjugates based on PEAs containing L-aspartic acid and rhodamine B were synthesized and used for NP preparation. Release behavior was studied and compared to a control system with physically encapsulated rhodamine B. It was shown that the release of rhodamine B from the covalent system did not show the burst effect and exhibited a slower …
Molecular Dynamics Study Of The Opening Mechanism For Dna Polymerase I, 2014 University of Richmond
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 …
Continuous Polymer Reactor Design, 2014 University of Southern Mississippi
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 …
Utilization Of Aqueous Raft Prepared Copolymers To Improve Anticancer Drug Efficacy, 2014 University of Southern Mississippi
Utilization Of Aqueous Raft Prepared Copolymers To Improve Anticancer Drug Efficacy, Andrew Christopher Holley
Dissertations
The advent of controlled radical polymerization (CRP) techniques, along with advancements in facile conjugation chemistry, now allow synthetic tailoring of precise, polymeric architectures necessary for drug/gene delivery. Reversible addition- fragmentation chain transfer (RAFT) polymerization and its aqueous counterpart (aRAFT) afford quantitative control over key synthetic parameters including block length, microstructure, and placement of structo-pendent and structo-terminal functionality for conjugation of active agents and targeting moieties. The relevance of water-soluble and amphiphilic (co)polymers synthesized by RAFT for in vitro delivery of therapeutics in biological fluids is an especially attractive feature. In many cases, polymerization, binding, conjugation, …
Investigation Of Glassy State Molecular Motions In Thermoset Polymers, 2014 University of Southern Mississippi
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 …
Computational And Experimental Investigation Into Yield Behavior And Cure Rate Dependence Of Thermoset Polymers, 2014 University of Southern Mississippi
Computational And Experimental Investigation Into Yield Behavior And Cure Rate Dependence Of Thermoset Polymers, Christopher Harold Childers
Dissertations
This dissertation is broken down into two primary sections: firstly, the development and improvement of molecular dynamics simulations of thermoset matrix polymers including their use in understanding molecular response to applied strain deformation and secondly, the discernment of a cure heating ramp rate dependence of the final molecular and macro-molecular properties of thermoset matrix polymer.
The molecular dynamics section will discuss the development of molecular dynamics simulations of thermoset epoxy/amine matrix polymers, and the implementation of this work to determine the underlying molecular level events that cause thermoset matrix polymer yield. It will report a novel method for the determination …
Tuning Responsiveness Of Polypeptide Based Block Copolymers For Drug Delivery, 2014 University of Southern Mississippi
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 …
Designing Magnetically Responsive Ultrafiltration Membranes, 2014 University of Arkansas, Fayetteville
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 …
Speciation Of Pentavalent Technetium Complexes With Aniline And Thiobenzene Derivatives, 2014 University of Nevada, Las Vegas
Speciation Of Pentavalent Technetium Complexes With Aniline And Thiobenzene Derivatives, Kyle E. Childs
UNLV Theses, Dissertations, Professional Papers, and Capstones
The reaction of bidentate aniline oligomers with pentavalent technetium has been investigated previously through the reaction of (n-Bu4N)TcOCl4 with o-phenylenediamine (PDA). The initial studies found that PDA reacted in a 1 to 2 molar ratio with pentavalent technetium in in ethanol. This study was expanded by the examination of a second aniline derivatives, 2-aminophenol (AMP)) and two thiobenzene derivatives (2-mercaptophenol (MP) and thiosalicylic acid (TSA)) to evaluate the kinetic formation of these complexes with pentavalent technetium. The pentavalent technetium complexes all showed reactivity with technetium having a coordination numbers of 5 with all ligands reacting in a 1 to 2 …
Self-Assembly And Ring-Opening Metathesis Polymerization Of A Bifunctional Carbonate–Stilbene Macrocycle, 2014 University of South Carolina - Columbia
Self-Assembly And Ring-Opening Metathesis Polymerization Of A Bifunctional Carbonate–Stilbene Macrocycle, Yuewen Xu, Weiwei L. Xu, Mark D. Smith, Linda S. Shimizu
Faculty Publications
No abstract provided.
Patterning And Mechanical Analysis Of Fiber-Based Materials, 2014 University of Massachusetts Amherst
Patterning And Mechanical Analysis Of Fiber-Based Materials, Samuel A. Pendergraph
Doctoral Dissertations
The ability to define and control the topography of a surface has been studied extensively due to its importance in a wide variety of applications. The control of a non-planar topography would be very valuable since a number of structures that are pervasive in artificial applications (e.g. fibers, lenses) are curved interfaces. This potential of enabling applications that incorporate non-planar geometries was the motivation for this thesis. The first study of this thesis comprises the study of patterning the circumference of micrometer sized fibers. Specifically, a unique technique was described to pattern the fiber with a periodic array of colloids. …
Guanidinium-Rich Romp Polymers Drive Phase, Charge, And Curvature-Specific Interactions With Phospholipid Membranes, 2014 University of Massachusetts Amherst
Guanidinium-Rich Romp Polymers Drive Phase, Charge, And Curvature-Specific Interactions With Phospholipid Membranes, Michael T W Lis
Doctoral Dissertations
Protein transduction domains (PTDs) and their and their synthetic mimics are short sequences capable of unusually high uptake in cells. Several varieties of these molecules, including the arginine-rich Tat peptide from HIV, have been extensively used as vectors for protein, DNA, and siRNA delivery into cells. Despite the wide-ranging utility of PTDs and their mimics, their uptake mechanism is still under considerable debate. How the molecules are able to cross phospholipid membranes, and what structural components are necessary for optimal activity are poorly understood. This thesis explores how PTDMs interact with phospholipid membrane phase, anionic lipid content and negative Gaussian …
Functional Nanoparticles At Interfaces: Emulsion Stabilization And Triggered Inversion, 2014 University of Massachusetts Amherst
Functional Nanoparticles At Interfaces: Emulsion Stabilization And Triggered Inversion, Caroline Laure Marie Miesch
Doctoral Dissertations
Encapsulation of materials can be performed through the stabilization of fluid-fluid interfaces and the formation of emulsion droplets, which is commonly achieved with surfactants, including small molecules and polymers, as well as particles that are, typically, micron-scale in diameter. The worked contained in this dissertation centered on droplets that are stabilized by nanoparticles, including metallic nanoparticles and semiconductor quantum dots, which bring the conductive and fluorescent properties inherent to such nanoparticles into the droplet construction. Double emulsion droplets, both oil-in-water-in-oil (o/w/o) and water-in-oil-in-water (w/o/w) were formed using nanoparticles as the only surfactant in solution. Different types of nanoparticles were found …