Chemical Engineering Commons^™

Synthesis And Characterization Of Extractive Scintillating Resin For Ultra-Trace-Level Quantification Of Uranium In Aqueous Media, C Duval, V Bliznyuk, A Seliman, T Devol, S Husson

Graduate Research and Discovery Symposium (GRADS)

The detection and quantification of radionuclides in aqueous media is of interest to both the Environmental Protection Agency, for matters of public health, and international organizations like the Comprehensive Test Ban Treaty Organization, that use environmental samples to investigate claims of illicit nuclear activities. The current method of quantification involves batch style analytical techniques which utilize bulky instruments. Portable, flow cell detectors utilizing extractive scintillating resin with physically sorbed extractants and fluorophores have been developed; however, this resin shows poor long term stability as the active components leach from the resin over time. There is a need to develop chemically …

Roll-To-Roll Synthesis Of Vertically Aligned Carbon Nanotubes For Electrical Double Layer Capacitors, Margarita R. Arcila-Velez, Jingyi Zhu, Anthony Childress, Mehmet Karakaya, Ramakrishna Podila, Apparao M. Rao, Mark E. Roberts

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Effect Of Surface Parameters On Interfacial Water Film Behavior, Brittany Glatz, Luke Rhym, Sapna Sarupria

Graduate Research and Discovery Symposium (GRADS)

Vapor-to-liquid and liquid-to-solid transitions on mineral surfaces are the primary pathways for phase transitions in atmospheric water. These phase transitions affect the microphysics of clouds and have significant effects on the weather and climate. Our overall goal is to elucidate the mechanisms through which surfaces affect these transitions, and develop predictive abilities to correlate surface properties to the thermodynamics and kinetics of the phase transitions. In this work, we use molecular dynamics simulations to study the structure, and dynamics of water near kaolinite-like surfaces. Kaolinite is the most abundant mineral dust in the atmosphere. We specifically investigate the effect of …

Carbon Fibers Derived From Pan/Bio-Based Bicomponent Precursor, Jing Jin

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Optimization Of Pyrochlore Catalysts For Dry Reforming Of Methane, Felipe Polo-Garzon, Ming He, David A. Bruce

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Fabrication And Analysis Of Soy Flour Filled Polyethylene Fibers, Ozgun Ozdemir, Sam Lukubira, Amod Ogale, Paul Dawson

Graduate Research and Discovery Symposium (GRADS)

Fibers composed of soy flour (soy) and linear low density polyethylene (PE) were produced by melt spinning method. The mixing time of soy flour and PE was adjusted to get better dispersion of soy flour inside the matrix. The inclusion of soy decreased tensile modulus by 35% and tensile strength by 30% of the fibers compared with 950 MPa and 43 MPa, respectively, for PE fibers. Strain to failure for soy-PE fibers was 292% where PE fibers have strain to failure at 513%. Tensile properties of soy-PE fibers are comparable to those of pure PE. Even washing did not deteriorated …

2014 Chemical And Biomolecular Graduate Research Symposium Program, Clemson University

Chemical and Biomolecular Graduate Research Symposium

Program for the 2014 Graduate Research Symposium in Holmes Ballroom - Clemson House.

Sulfonated Perfluorocyclobutyl (Pfcb) Aryl Ether Polymers: Synthesis, Reactivity, And Characterization For Polymer Electrolyte Applications, Jiyoung Park

All Dissertations

Perfluorocyclobutyl (PFCB) aryl ether copolymers are excellent candidates for proton exchange membrane (PEM) component in PEM fuel cells. Sulfonated PFCB copolymer membranes exhibit not only high chemical/thermal/mechanical stability but also high proton conductivity. In this regard, PFCB aryl ether copolymers were synthesized via thermal step-growth [2 + 2] cyclopolymerization from aryl bis-(trifluorovinyl ether) (TFVE) monomers and oligomers. Experimental and computational studies confirmed that copolymerization of relatively electron-rich and electron-poor TFVE monomers gave selective-segmented copolymers in an one-pot polymerization. After sulfonation, the PFCB copolymers comprising hydrophilic and hydrophobic segments gave membranes with high proton conductivity. Cross-linked membranes of the sulfonated PFCB …

Uv-Assisted Stabilization Of Polyacrylonitrile-Based Carbon Fiber Precursors, Marlon Salvador Morales Sandoval

All Dissertations

Due to their high strength and stiffness coupled with low density, carbon fibers are the preferred reinforcing fibers used in high-performance polymer matrix composites. Consequently, the demand for carbon fibers is expected to grow from 40,000 metric tons to about 150,000 metric tons over the next decade. A large fraction of the increase is anticipated in the industrial sector that is cost-sensitive. Therefore, there is a need for the development of novel processes and precursors to reduce the carbon fiber production cost and expand the use of carbon fibers. This research focuses on the development of an alternative, rapid stabilization …

Pyrene Oligomers: Their Isolation, Molecular Characterization, And Phase Behavior, David Esguerra Taborda

All Dissertations

Carbonaceous pitches can serve as attractive precursors for advanced carbon materials such as high thermal conductivity fibers or carbon-carbon composites. Yet the effects of composition and molecular structure on the bulk properties (e.g., mesophase content and melting point) of these precursors remain only partly known, mainly because of the difficulties associated with the isolation, identification, and quantification of the large (i.e., molecular weight (mol wt) > 350-400 Da) polycyclic aromatic hydrocarbon (PAH) oligomers comprising these pitches. In this study, oligomeric fractions were isolated via supercritical extraction (SCE) from two representative pitches: a petroleum pitch (M-50) produced by the thermal polymerization of …

Effect Of Graphitic Carbon Nanomodifiers On The Electromagnetic Shielding Effectiveness Of Linear Low Density Polyethylene Nanocomposites, Byron Villacorta Hernandez

All Dissertations

Conductive polymer composites have become alternative materials for providing electromagnetic and electrostatic shielding where metals are not suitable. In this study, the effect of crystallinity, morphology, concentration and orientation of carbon nanomodifiers on shielding provided by their polyethylene-based composites has been investigated relative to their transport properties.

First, the electrical properties and EM SE of composites consisting of heat-treated carbon nanofibers (Pyrograf^® -III PR-19 CNF) in a linear low density polyethylene (LLDPE) matrix were assessed. Heat treatment (HT) of CNF at 2500°C significantly improved their graphitic crystallinity and intrinsic transport properties, thereby increasing the EM SE of the nanocomposites. …

A Localized Controlled Delivery System Utilizing A Block Copolymer To Improve The Current Paradigm Of Chemotherapy, Jason Olbrich

All Dissertations

The goal of the field of Bioengineering has always been to bring about a better standard of care for patients. As a field encompassing a broad array of researchers and talents, such improvements often are brought about through the integration of different fields. This work advances the integration of controlled delivery and chemotherapy. The use of cytotoxic chemotherapy has become and will continue to be a powerful tool for the treatment of solid malignancies. Conventional dose scheduling of cytotoxic agents and newer biological response modifiers are investigated under a clinical paradigm initially designed to identify a drug dose that elicits …

Perfluorocyclobutyl Polymer Thin-Film Composite Membrane Fabrication, Plasticization And Physical Aging, Jinxiang Zhou

All Dissertations

Membrane technologies have been used widely in industrial practices such as waste water treatment, sea water desalination, gas separations, pharmaceutical separations, and food and beverage processing to name a few. Among the features that make them attractive are that they are cost effective, highly efficient, scalable, and environmentally benign. The focus of this dissertation is to contribute to the understanding and use of polymeric membranes for carbon dioxide separations.
Currently, the largest carbon capture demand lies in the natural gas industry. However, since global warming has become a severe concern for human existence, flue gas cleaning is potentially another very …

A Computational Approach For The Rational Design Of Bimetallic Clusters For Ethanol Formation From Syn-Gas, Ming He

All Dissertations

There is currently a growing interest in the catalytic synthesis of ethanol from syn-gas (2CO + 4H2 --> C2H5OH + H2O). A major challenge associated with this direct route is an inability to find a low-cost catalyst that promotes the proper combination of CO dissociation and CO insertion steps, so as to yield ethanol as the primary reaction product. Bimetallic catalysts, in which one metal promotes hydrocarbon production and the other oxygenate production, may exhibit a synergistic effect that can facilitate the formation of ethanol. Given the complexity of this reaction system, a simple trial-and-error approach to catalyst design is …

Advanced Biomaterials From Renewable Resources: An Investigation On Cellulose Nanocrystal Composites And Co2 Extraction Of Rendered Materials, Jose Orellana

All Dissertations

The annual global consumption of petroleum-based plastics is approximately 280 million tons and is impacting the sustainability of our planet and prosperity of future generations. One solution is the development of bio-based polymer materials with advanced properties for commercial applications. Therefore, the ultimate goal of this dissertation is to investigate the properties of new bio-based materials for broader applications. This dissertation includes two research areas: cellulose nanocomposites, and CO₂ extractions of rendered fat. In the first half, cellulose nanocrystals (CNCs), which exhibit excellent mechanical and optical properties, were investigated for the reinforcement of a biodegradable polymer. The properties of …

Novel Ceria-Zirconia-Yttria Mesostructures: Synthesis, Characterization, Diffusional Studies And The Effects Of Morphology On Their Properties, Alma Cordova Morales

All Dissertations

Ceria-zirconia-yttria (CZY) mixed oxides are used as catalyst supports for three-way catalysts for automotive exhaust emission control and in solid oxide fuel cells. By improving the morphology of CZY mesopores it is possible to reduce the sintering of supported noble metals and enhance overall catalyst lifetime and performance. However, limited studies have been published on the synthetic control of the morphology of CZY materials and the effects that CZY pore geometry has on catalyst operation.
To create optimized CZY catalyst supports, novel mesoporous CZY oxides were synthesized via classical sol-gel and evaporation induced self-assembly (EISA) methods, obtaining mesostructures that exhibited …

Aqueous Suspensions Of Polymer Coated Magnetite Nanoparticles: Colloidal Stability, Specific Absorption Rate, And Transverse Relaxivity, Steven Saville

All Dissertations

The design, functionalization, characterization, and applications of magnetic nanoparticles have garnered significant interest over the past several decades. While this area has garnered increasing attention, several questions remain unanswered about the stability of these systems and it's influence on their biomedical applications. To help answer these questions about the stability of these, a novel tri(nitroDOPA) terminated polymer based ligand has been developed for the stabilization of magnetite nanoparticles. The synthesis involves a process in which ethylene oxide is polymerized using a trivinyl initiator, modified with carboxylic acid using a free radical addition of mercaptoundecanoic acid, and then functionalized with nitroDOPA …

Application Of Carbon Dioxide Towards The Development Of Smart Materials, Green Reaction Schemes And Metallic Nanoparticle Synthesis, Fiaz Mohammed

All Dissertations

Global carbon dioxide (CO₂) emissions have steadily risen over the last 50 years, with 34 billion tons of CO₂ released in 2009 alone. Its potential as a greenhouse gas has negatively affected of our lives and environment by the resulting ocean acidification and climate change. To mitigate atmospheric CO₂, various strategies have been implemented for CO₂ separation, capture, storage and use as a chemical feedstock. The use of CO₂ in various chemical industries is attractive as its non-flammable, non-toxic, and relatively inert properties have made it an inherently safer alternative to traditional organic …

Enzyme Actuated Bioresponsive Hydrogels, Andrew Wilson

All Theses

Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, …

Microstructural And Mechanical Characterization Of Soy-Based Polyethylene Fibers, Ozgun Ozdemir

All Theses

Bio-composite fibers have attracted increasing attention from environmentally-conscious consumers because of their low cost and biodegradability. Soy protein isolates and other purified forms have been proposed as bio-based substitutes for pure synthetic polymers for use in textiles. However, fibers from pure soy proteins do not possess adequate properties for use as textile fibers. Therefore, this research aimed to investigate composite fibers consisting of soy and polyethylene for their microstructure and mechanical properties. Changes in properties with increasing filler content and long-term properties of fibers were systematically examined.
First, the microstructure of the fibers was investigated by optical analysis. Six different …

Design Of Advanced Fouling-Resistant And Self-Cleaning Membranes For Treatment Of Oily And Impaired Waters, Daniel Wandera

All Dissertations

The overall goal of my Doctor of Philosophy (PhD) research was to design and develop advanced anti-fouling and self-cleaning membranes for treating impaired waters. Initial work focused on the development of membranes to treat produced water, which is oily wastewater that is co-produced during oil and gas exploration. Economical, environmentally sustainable treatment of the large volumes of produced water is a grand challenge for oil and gas companies. While membranes offer many advantages over more conventional treatment methods, membrane-based treatment processes for oily waters often fail due to membrane fouling. Therefore, the primary objective of my doctoral research was to …

Chlorine Absorption Utilizing Caustic Sodium Sulfite, Henry Mcdonald

All Theses

A scrubber was required to abate a waste stream containing chlorine gas created in the electrolytic dissolution step of the aqueous polishing process at the Mixed Oxides Fuel Fabrication Facility at Savannah River Site, South Carolina. A method of absorption that utilized caustic sodium sulfite as the scrubbing agent was studied for implementation in the process. This method was found to be highly efficient with respect to process requirements, and it was also found to provide enhanced performance over the more conventional method of chlorine scrubbing which uses only aqueous sodium hydroxide as a reagent. Sulfite provides an additional advantage …

Light-Emitting Nanocomposites And Novel Amorphous Polymers For Optical Applications, Kyle Gipson

All Dissertations

Polymeric optical materials generally are comprised of amorphous polymers that are transparent in at visible wavelengths but exhibit strong absorption bands in the near-infrared making them less useful for many optical applications. Attenuation, which is the absorption per unit length, largely results from the high vibrational energy associated with carbon-hydrogen bonds contained in the polymer backbone. Attenuation can be mitigated by optical amplification utilizing light emitting additives. Investigated in this dissertation are synthesis techniques for the fabrication of light-emitting polymer nanocomposites and their resultant thermal and rheological characteristics for potential use as polymer optical fibers or films.
Inorganic nanocrystals doped …

Quantitative Analysis And Structural Characterization Of Carbonaceous Pitches, Sourabh Kulkarni

All Dissertations

Both petroleum pitches and pitches derived from pure polycyclic aromatic hydrocarbons (PAHs) are oligomeric materials that can serve as precursors for a wide variety of advanced carbon materials. The goal of this study was the structural characterization and quantitative analysis of the dominant constituent oligomers and species present in these pitches.
A key requirement for such work is the ability to fractionate these complex mixtures into samples of narrow molecular weight distribution (mol wt; MWD) that can be used as standards. To this end, semicontinuous (or semibatch) dense-gas/supercritical extraction (DGE/SCE) was used to produce monomer, dimer, and trimer fractions of …

Modeling And Synthesis Of Functionalized Meta-Poly(Phenylene Ethynylene) Helical Structures, Ha Nguyen

All Dissertations

The ability of meta-poly(phenylene ethynylene) (mPPE) materials to undergo random coil to helix conformational changes under select conditions affords many opportunities for their use in sensor, separation, catalysis, and bio-related applications. Thus, to advance the development of these materials, a modeling procedure based on replica exchange molecular dynamics (REMD) simulation was developed to reliably assess factors affecting the folding behaviors of functionalized mPPE variants in solution. A combinational modeling study of 20 functionalized mPPEs in five solvent conditions provided insight into how mPPE secondary structure is impacted by the complex relationship between mPPE functional groups and solvent moieties. Further, these …

Pitch-Based Activated Carbon Fibers: The Effect Of Precursor Composition On Pore Structure, Halil Tekinalp

All Dissertations

Although researchers have previously investigated the effect of precursor differences on the final properties of activated carbon fibers (ACFs), those precursors were not well-characterized. In particular, detailed information about their molecular composition and anisotropy was not available.
In this study, seven oligomeric fractions, each of well-defined composition and molecular weight (mol wt) distribution, were isolated from a commercially produced isotropic petroleum pitch (i.e., Marathon M–50) and used for the production of ACFs. Four of these precursors of varying oligomeric composition were fully isotropic and three contained different levels of mesophase, so that the effects of molecular composition and molecular order …

Oxygenate Synthesis During Co Hydrogenation On Cocuzno- Based Catalysts, Yu-Tung Tsai

All Dissertations

The research of catalytic synthesis of methanol and other higher alcohols from CO hydrogenation has received great attention since 1980s. The focus of this research is to establish a better fundamental insight into heterogeneous metal catalysts for oxygenate (especially alcohol) synthesis by CO hydrogenation.
Co-based catalysts have been reported widely as the high-performance Fischer-Tropsch Synthesis (FTS) catalysts. The solid base, hydrotalcite (HT), using as a support for Co catalysts resulted in higher activity for CO hydrogenation comparing to other supports (pre-calcined hydrotalcite, MgO and Al₂O₃). The activities of Co/HT reduced at different reduction temperatures (300-600oC) were …

Effects On Hydrogen Adsorption And Activation On Platinum In A Fuel Cell Catalyst, Jack Zhang

All Dissertations

Proton exchange membrane fuel cells are a highly efficient source of power generation that is needed to sustain the energy demands of today's more environmentally conscience society. However, the presence of impurities in the hydrogen fuel stream, such as CO, H₂S, and NH₃ from the steam reforming/partial oxidation of hydrocarbons/methanol, can severely poison the Pt electrocatalyst present in the fuel cell electrode causing degradation in the fuel cell performance. To counter these poisoning effects, fuel cell manufacturers are forced to use higher Pt loadings, which dramatically increases material costs and prevents the successful commercialization of the technology. …

Cellulose Nanocrystals Properties And Applications In Renewable Nanocomposites, Esteban Urena Benavides

All Dissertations

Development of novel bio-based nanocomposites is fundamental to reduce the dependence on fossil resources and provide a sustainable future. In light of this global problem, cellulose nanocrystals (CNCs) have raised interest due to their remarkable mechanical properties. Adequate design of nanocomposites requires a fundamental understanding of how the structure affects the mechanical properties of the material. However, contradictory results in the literature have revealed a lack of comprehension of this relationship for CNC based composites. Consequently, this work provides an explanation to unusual results for CNC nanocomposites presented in the literature and demonstrates the ability to achieve property enhancements in …

Process Development For The Fractionation And Isolation Of Corn Fiber Hemicellulose, Justin Montanti

All Theses

Corn fiber is a co-product of the corn wet-milling process that holds potential to become a value-added product. A process was developed to fractionate and isolate the hemicellulose B component of corn fiber generated by corn wet milling. The process consisted of pretreatment by soaking in aqueous ammonia (SAA) of starch-free corn fiber followed by enzymatic cellulose hydrolysis, during which the hemicellulose B was solubilized by cleavage into xylo-oligosaccharides. The hemicellulose A and B fractions were separated by adjustment of pH, and the hemicellulose B recovered by precipitation with ethanol.
The pretreatment step resulted in a high retention of major …