Polymer Science Commons^™

Characterization Of Fine Powders And Development Of Processes For Powder Coatings, Jing Fu

Electronic Thesis and Dissertation Repository

Traditional powder coating provides poor coating appearance. Fine powder coating can overcome this drawback since the smaller powder particles lead to much smoother finish. Nevertheless, fine powder has been experienced to cause more application problems. This study investigated fine powder coatings from different aspects and it provided solutions to solve these application problems.

The investigation on fine powders conducted by this study concluded that the medium particle size and D₁₀ was not suitable for the flowability characterization of fine powder coatings. Instead, an index which represented the particle size distribution could correlate with the flowabilities of the fine powder …

Ptsa Doped Conducting Graphene/Polyaniline Nanocomposite Fibers: Thermoelectric Behavior And Electrode Analysis, Mohammad Mansoob Khan Dr, M. O. Ansari, S. A. Ansari, M. I. Amal, J Lee, M. H. Cho

Dr. Mohammad Mansoob Khan

Highly conducting graphene/polyaniline (GN@Pani) nanocomposite was prepared by the in-situ oxidative polymerization of aniline in the presence of GN and the surfactant, cetyltrimethylammonium bromide (CTAB). The micellar structure of CTAB assisted both, the formation of GN@Pani tubules and the dispersion of GN. Sheet-like GN was distributed uniformly in the Pani matrix, leading to high electrical conductivity because of the π-π interactions between Pani and GN. Studies of the thermoelectrical behavior using isothermal and cyclic aging techniques showed that GN@Pani possessed a high combination of electrical conductivity and thermal stability, even beyond 150°C. GN@Pani was used as cathode active material in …

Antibacterial Studies On Titania Polyurethane Nanocomposite Coatings, Koosha Azhie

Electronic Thesis and Dissertation Repository

While temporary disinfection of a surface is possible with the help of strong cleaners, tremendous interest exists for the control of microorganisms on surfaces by effective, durable antimicrobial coatings. There is a wide spectrum of potential applications for antibacterial coatings, spanning from industrial surface coatings to biomedical applications, where sterile conditions are crucial. This work examined the synthesis of the functionalized 2,2-Dimethylolpropionic acid - nanotitanium dioxide (DMPA-nTiO₂) monomer. Moreover, functionalized nanotitanium dioxide/polyurethane (nTiO₂/PU) composite coatings were prepared using the above mentioned functionalized monomer. The distribution of nTiO₂ in the polymer matrix was enhanced by monomer …

Effect Of Multiwall Carbon Nanotubes On The Phase Separation Of Concentrated Blends Of Poly[(Α-Methyl Styrene)-Co-Acrylonitrile] And Poly(Methyl Methacrylate) As Studied By.Pdf, Suryasarathi Bose, Ruth Cardinaels, Ceren Özdilek, Jan Leys, Jin Won Seo, Michael Wübbenhorst, Paula Moldenaers

Chongwen Huang

Enhanced Thermoelectric Performance And Ammonia Sensing Properties Of Sulfonated Polyaniline/Graphene Thin Films,, M. O. Ansari, Mohammad Mansoob Khan Dr, S. A. Ansari, J. Lee, M. I. Amal, M H. Cho

Dr. Mohammad Mansoob Khan

Highly conducting nanocomposite film of polyaniline (Pani) with graphene (GN) was prepared by incorporating GN nanoplatelets in Pani matrix, followed by sulfonating it with fuming sulfuric acid. Sheet-like GN nanoplatelets were distributed uniformly in a Pani matrix, leading to high electrical conductivity due to π-π interaction between sulfonated Pani (s-Pani) and GN. Studies of the thermoelectrical behavior and ammonia-sensing behavior on GN@s-Pani showed high DC electrical conductivity retention under ageing conditions as well as excellent reproducible sensing response towards ammonia vapor in contrast to acid-protonated Pani.

Generation Of Multicomponent Polymer Blend Microparticles Using Droplet Evaporation Technique And Modeling Evaporation Of Binary Droplet Containing Non-Volatile Solute, Venkat N. Rajagopalan

Theses and Dissertations--Chemical and Materials Engineering

Recently, considerable attention has been focused on the generation of nano- and micrometer scale multicomponent polymer particles with specifically tailored mechanical, electrical and optical properties. As only a few polymer-polymer pairs are miscible, the set of multicomponent polymer systems achievable by conventional methods, such as melt blending, is severely limited in property ranges. Therefore, researchers have been evaluating synthesis methods that can arbitrarily blend immiscible solvent pairs, thus expanding the range of properties that are practical. The generation of blended microparticles by evaporating a co-solvent from aerosol droplets containing two dissolved immiscible polymers in solution seems likely to exhibit a …

Sans Study Of Highly Resilient Poly(Ethylene Glycol) Hydrogels, Erika M. Saffer, Melissa A. Lackey, David M. Griffin, Suhasini Kishore, Gregory N. Tew, Surita R. Bhatia

Gregory N. Tew

Polymer networks are critically important for numerous applications including soft biomaterials, adhesives, coatings, elastomers, and gel-based materials for energy storage. One long-standing challenge these materials present lies in understanding the role of network defects, such as dangling ends and loops, developed during cross-linking. These defects can negatively impact the physical, mechanical, and transport properties of the gel. Here we report chemically cross-linked poly(ethylene glycol) (PEG) gels formed through a unique cross-linking scheme designed to minimize defects in the network. The highly resilient mechanical properties of these systems (discussed in a previous publication) [J. Cui, M. A. Lackey, A. E. Madkour, …

Toward Polymer Coating With Easy Ice Release, Chenyu Wang

Theses and Dissertations

Minimizing adhesion of ice has been the subject of extensive studies for applications such aircraft wings, wind turbine blades spacecraft, power transmission wires, while a growing interest concerns coatings for aerospace applications. The work described here describes progress for coatings and ice release test method development over the last few years. Major achievements include: (1) New Rigid Adherent-Resistant Elastomers (RARE), (2) A new Epoxied Cylinder (EC) adhesion test, (3) Validation of an ice release test, and (4) Study of ice adhesion strength on coating thickness for a PDMS elastomer. Rigid Adhesion-Resistance Elastomers (RARE) are comprised of 3F 1 terminated with …

Electrospinning Applications Air Filtration And Superhydrophobic Materials, Negar Ghochaghi, Adetoun Taiwo

Graduate Research Posters

Electrospinning is a widely applicable technique that generates non-woven fibers in the micro and nano range. In this project two of its applications are highlighted namely filtration media and enhancement of wettability. The first project demonstrates that electrospinning can be used to produce new fiber filtration media with controlled microstructure. The bimodal and unimodal orthogonal and random filters were made and characterized against their filtration efficiency and pressure drop. Figure of Merit (FOM) was also calculated and discussed. It is shown that the FOM increases when the electrospun fibers are arranged into alternating layers of aligned course and fine fibers. …

Development Of Cementitious Materials For Adhesion Type Applications Comprising Calcium Sulfoaluminate (Csa) Cement And Latex Polymer, Joshua V. Brien

Theses and Dissertations--Civil Engineering

The objective of this research was to develop high performing polymer modified calcium sulfoaluminate (CSA) cement materials for use in applications requiring superior adhesion characteristics. Little information is available describing interactions of CSA cement containing minor phase tri-calcium aluminate (C₃A) with commonly used admixtures. Given the scarcity of information, a basic approach for developing cementitious materials was followed. The basic approach consisted of four tasks: cement design, admixture design, polymer design and testing developed materials. The iterative, time consuming process is necessary for understanding the influence of specific constituent components on overall system behavior. Results from the cement …

Aging Of A Polymer Core Composite Conductor Under Combined Ozone And Temperature Conditions, James M. Middleton

Electronic Theses and Dissertations

The next generation High Temperature Low Sag Polymer Core Composite Conductors (HTLS PCCC) can experience harsh in-service environments including high temperature and highly concentrated ozone. In some extreme cases, it is possible that the conductors will experience temperatures of up to 180°C and ozone concentrations as high as 1% (10,000 ppm). Therefore, the primary goal of this research was to determine the most damaging aging conditions which could negatively affect the in-service life of the conductors. This included characterizing the aging in ozone and at high temperature of the HTLS PCCC hybrid composite rods and neat resin. It was found …

Plasma Processes And Polymers Special Issue On: Plasma And Cancer, Mounir Laroussi, Michael Keidar

Electrical & Computer Engineering Faculty Publications

During the last two decades, research efforts on the application of low temperature plasmas in biology and medicine have positioned nonequilibrium lowtemperature plasmas as a technology that has the potential of revolutionizing healthcare.[1,2] Low temperature plasmas can be applied in direct contact with living tissues to inactivate bacteria,[3] to disinfect wounds and accelerate wound healing,[4] and to induce damage in some cancer cells.[5–11]

Layer-By-Layer Assemblies For Membrane-Based Enzymatic Catalysis, Andrew R. Tomaino

Theses and Dissertations--Chemical and Materials Engineering

While considerable progress has been made towards understanding the effect that membrane-based layer-by-layer (LbL) immobilizations have on the activity and stability of enzymatic catalysis, detailed work is required in order to fundamentally quantify and optimize the functionalization and operating conditions that define these properties. This work aims to probe deeper into the nature of transport mechanisms by use of pressure-induced, flow-driven enzymatic catalysis of LbL-functionalized hydrophilized poly(vinyldiene) (PVDF)-poly(acrylic acid) (PAA)-poly(allylamine hydrochloride) (PAH)-glucose oxidase (GOx) membranes. These membranes were coupled in a sealed series following cellulose acetate (CA) membranes for the elimination of product accumulation within the feed-side solution during operation. …

One-Step Production Of Long-Chain Hydrocarbons From Waste-Biomass-Derived Chemicals Using Bi-Functional Heterogeneous Catalysts, Cun Wen, Elizabeth A. Barrow, Jason R. Hattrick-Simpers, Jochen A. Lauterbach

Faculty Publications

n this study, we demonstrate the production of long-chain hydrocarbons (C₈₊) from 2-methylfuran (2MF) and butanal in a single step reactive process by utilizing a bi-functional catalyst with both acid and metallic sites. Our approach utilizes a solid acid for the hydroalkylation function and as a support as well as a transition metal as hydrodeoxygenation catalyst. A series of solid acids was screened, among which MCM-41 demonstrated the best combination of activity and stability. Platinum nanoparticles were then incorporated into the MCM-41. The Pt/MCM-41 catalyst showed 96% yield for C₈₊ hydrocarbons and the catalytic performance was stable …

Rheological Signatures In Limit Cycle Behaviour Of Dilute, Active, Polar Liquid Crystalline Polymers In Steady Shear, M. Gregory Forest, Panon Phuworawong, Qi Wang, Ruhai Zhou

Mathematics & Statistics Faculty Publications

We consider the dilute regime of active suspensions of liquid crystalline polymers (LCPs), addressing issues motivated by our kinetic model and simulations in Forest et al. (Forest et al. 2013 Soft Matter 9, 5207-5222 (doi:10.1039/c3sm27736d)). In particular, we report unsteady two-dimensional heterogeneous flow-orientation attractors for pusher nanorod swimmers at dilute concentrations where passive LCP equilibria are isotropic. These numerical limit cycles are analogous to longwave (homogeneous) tumbling and kayaking limit cycles and two-dimensional heterogeneous unsteady attractors of passive LCPs in weak imposed shear, yet these states arise exclusively at semi-dilute concentrations where stable equilibria are nematic. The results in Forest …

Production Of Lignin-Based Phenolic Resins Using De-Polymerized Kraft Lignin And Process Optimization, Homaira Siddiqui

Electronic Thesis and Dissertation Repository

Commercialization of Lignin-based phenol formaldehyde resins (LPF) has been limited due to the increase in curing temperatures and decrease in adhesive strength of LPF compared to conventional phenolic resins. Lignin depolymerization can increase the reactivity of lignin; however, the effect of lignin molecular weight on curing performance of LPF resins has yet to be investigated. This research work examined the optimization of synthesis parameters including percent substitution of phenol with lignin, formaldehyde- to-phenol ratio (F/P), and Mw of lignin to reduce the curing temperature and increase the adhesive strength of LPF. DSC analysis indicated that lignin with Mw ~1200g/mol resulted …

Effects Of Biodiesel Concentration On Microbial Deterioration Of Polyethylene In A Simulated Fuel Storage Tank, Juan Manuel Restrepo-Florez

Electronic Thesis and Dissertation Repository

In this study a simulated fuel storage tank was used to investigate the effect of biodiesel concentration on biodegradation of polyethylene. This research is relevant in the field of fuel storage. The simulated storage system consisted of a number of identical conical flasks. Each flask was comprised of two layers, an upper one consisting of a fuel blend of diesel with biodiesel in concentrations ranging from 0 to 100% of biodiesel and the bottom layer containing an aqueous mineral media inoculated with a community obtained from a real fuel storage facility. Polyethylene slabs cut to a specific size were immersed …

Membrane And Performance Study In Polymer Electrolyte Membrane Fuel Cells And Hydrogen Bromine Redox Flow Batteries, Yujia Bai

Doctoral Dissertations

This dissertation represents the consideration of the problems of polymer electrolyte membrane fuel cells (PEMFC) and hydrogen-bromine redox flow batteries (RFB). Due to the importance of water management in PEMFCs, all the experiments were strictly controlled at different water hydration conditions. Water uptake and densities were measured for Nafion^® and a series of 3M ionomer membranes. The thermodynamics of water and polymer was analyzed based on water uptake experiment and calorimetry. Furthermore, partial molar volumes (PMV) of water/membrane system was defined for the first time and used to analyze the interaction between water and polymers. Three states of water …

Structure And Energetics Of Nanoparticles And Ionomer Films In Fuel Cell Catalyst Layers, Qianping He

Doctoral Dissertations

Improving the durability and utilization efficiency of the platinum-on-carbon (Pt/C) catalyst is of vital importance to the commercialization of the polymer electrolyte membrane fuel cell (PEMFC). This body of work provides molecular level insights to aid the fulfillment of this goal. Chapter 1 describes the use of molecular dynamics (MD) simulation in an effort to understand the Pt/C degradation issue from the nano-adhesion point of view. The roles of catalyst nanoparticle size, shape, Pt/C surface oxidation and the extent of ionomer film hydration are investigated to study their effects on nano-particle adhesion. It is found that the adhesion force strengthens …

Characterization Techniques And Electrolyte Separator Performance Investigation For All Vanadium Redox Flow Battery, Zhijiang Tang

Doctoral Dissertations

The all-vanadium redox flow battery (VRFB) is an excellent prospect for large scale energy storage in an electricity grid level application. High battery performance has lately been achieved by using a novel cell configuration with advanced materials. However, more work is still required to better understand the reaction kinetics and transport behaviors in the battery to guide battery system optimization and new battery material development. The first part of my work is the characterization of the battery systems with flow-through or flow-by cell configurations. The configuration difference between two cell structures exhibit significantly different polarization behavior. The battery output can …