MS, University of Cincinnati, 2022, Engineering and Applied Science: Materials Science

Conducting polymers have multiple applications, such as for corrosion protection and anti-static coatings. Studied across disciplines, conducting polymers continue to be an advantageous alternative to their metal counterparts given their flexibility, low density, and tunable electronic properties. Polyaniline (PANi) and polypyrrole (PPy) have good conductivity but can be difficult to use individually due to poor solubility, fusibility, and processability. Samples with four PANi to PPy ratios and dopants were characterized to determine if, when combined, the material is more soluble, fusible, and processable. Thermal degradation of the materials was measured using a thermogravimetric analyzer (TGA) and a differential scanning calorimeter (DSC). Activation energy for material changes, such as dopant loss and polymer degradation, was found by analyzing TGA results using the Kissinger method. The DSC data were used to determine degradation rate, glass transition temperature, and melting temperature. Chemical properties were determined using ultraviolet–visible (UV-Vis) spectroscopy and Fourier-Transform Infrared (FTIR) spectroscopy. Three Uv-Vis bands were observed in the PANi/PPy samples and the absorbance ratios of the materials were all around 0.04, indicating that they are alternating copolymers. FTIR spectroscopy was used to determine the chemical structure of the material, as well as conjugation length and degree of oxidation of PANi, using the benzenoid/ quinoid ratios. Based on the combination of 1250 cm-1 and 1100 cm-1 bands from FTIR spectra, it was determined that most of the samples were copolymers. The DSC cooling curves showed that all samples except the 40/60 PANi/PPy sample were amorphous copolymers. The strong crystallization peak around 100 oC suggests the 40/60 PANi/PPy sample was a semi-crystalline copolymer. All PANi/PPy samples show promise to improve processability and thermal stability.

Committee: Jude Iroh Ph.D. (Committee Member); Mark Schulz Ph.D. (Committee Member); Yoonjee Park Ph.D. (Committee Member) Subjects: Materials Science

Master of Sciences, Case Western Reserve University, 2021, EMC - Mechanical Engineering

At high temperatures, polymer separators in conventional Li-ion Batteries are prone to melt, fail to separate the electrodes, and cause internal short circuits. A PVDF-based hybrid electrolyte with Li1.3Al0.3Ti1.7(PO4)3 (LATP) and Al2O3 filler, prepared with NMP/glycerol dual solvents by slurry coating is reported in this thesis. The effects of fillers and glycerol on the ionic conductivity of the hybrid electrolyte membrane are studied. It was found that the use of glycerol and Al2O3 nanoparticles can increase the hybrid electrolyte's ionic conductivity. The dual-solvent prepared sample with a specific composition of PVDF/LATP/Al2O3=3/6/1 shows the highest ionic conductivity of 1.39 mS/cm, which is 30% higher than the sample without Al2O3. The membrane also exhibits better thermal stability compared to a Celgard 2325 commercial polymer separator. Li//Li symmetrical cell assembled using the prepared membrane shows excellent stability. In NMC half-cell cycling tests, capacity retention of 92.8% and 92.1 % are achieved on 50 cycles at 0.5 C and 1 C, respectively.

Committee: Chris Yuan (Advisor); Bo Li (Committee Member); Burcu Gurkan (Committee Member) Subjects: Engineering

Master of Science (M.S.), University of Dayton, 2020, Chemical Engineering

The use of cost-effective bio-based materials, such as lignin, offers the potential to replace commercially available, expensive synthetic petroleum materials which are currently used in the production of fibers and plastics. Many lignin-based nano-scale fibers have the potential to be used in a vast range of applications, ranging from automobiles to the electronics industry. These nanofibers can also be used in chemical separations and adsorption technologies. Unfortunately, lignin possesses a low molecular weight, and therefore polymer blends are used for the production of lignin-based nanofibers. Hence there is a need to optimize and understand polymer-polymer interactions of lignin and a carrier polymer to ultimately generate nanofibers with desired characteristics. In this study, two types of lignin, low sulfonate (LSL) and alkali, kraft lignin (AL) were investigated and combined with polyacrylonitrile-co-methyl acrylate (PAN-MA) for the fabrication of nanofibers using electrospinning techniques. The polymers were solubilized in N,N dimethylformamide (DMF) and prepared at different PAN-MA:lignin ratios ranging from 100:0 to 50:50 at varying total polymer concentrations ranging from 10 wt % to 20 wt %. Using solvent evaporation, PAN-MA/lignin films were obtained and the polymer arrangements, phase separation, and morphology were studied via polarized optical microscope (POM) and scanning electron microscopy (SEM). AL blends showed good miscibility with PAN-MA at higher concentrations wherein LSL blends found to have phase separation. Rheological characterization of LSL and AL in PAN-MA polymer solutions included flow sweep, frequency sweep, and amplitude sweep tests, which were used to gain insights into the effects of lignin type and ratios in the polymer solutions. Electrospinning of various PAN-MA/lignin solutions proceeded at an operating voltage of 15 kV with currents varying between 0-2 µA and at a 0.003 ml/min constant flow rate. Thermal and chem (open full item for complete abstract)

Committee: Erick Vasquez Dr. (Committee Chair); Donald Klosterman Dr. (Committee Member); Kenya Crosson Dr. (Committee Member) Subjects: Automotive Engineering; Chemical Engineering; Chemistry; Environmental Engineering; Materials Science; Nanotechnology; Polymers; Sustainability

Master of Science in Pharmaceutical Science (MSP), University of Toledo, 2019, Pharmaceutical Sciences (Industrial Pharmacy)

Solid state characterization is commonly performed to find a drug candidate with optimal properties for early development or to find a form with different properties to improve a formulation in later development. As a matter of fact, repurposing or reformulating older drugs may help bypass part of the copious cost and time needed for validation and authorization of new therapeutic compounds. Therefore, a variety of solid form screening can be performed to find or develop the right polymorph, salt, co-crystal, solvates/hydrates or amorphous dispersion of pharmaceutical drug candidate. Using a combination of analytical techniques, this study revised the physiochemical characterization of Kanamycin sulfate and its hydrated crystals. The methodology entailed primarily of diffraction techniques, vibrational spectroscopy and thermal analysis. The morphological study was carried out using Scanning Electron Microscopy (SEM).

Committee: Jerry Nesamony PhD (Advisor); Gabriella Baki PhD (Committee Member); Caren Steinmiller PhD (Committee Member) Subjects: Analytical Chemistry; Chemistry; Pharmaceuticals; Pharmacy Sciences

Master of Science (M.S.), University of Dayton, 2014, Chemical Engineering

Metal-decorated carbon substrates such as carbon nanotubes, graphene oxide (GO), and carbon nanoparticles have been of great interest to the scientific community for the last three decades due to numerous potential applications. Graphene oxide is an oxidized derivative of graphene and is obtained from the severe oxidation of graphite powder. This process introduces oxygen-containing functional groups to the surface of GO. Chemical species both organic and inorganic molecules can be attached to the surface of graphene oxide via these functional groups. Also, functional groups on its surface can serve as nucleation and growth sites for metalnanoparticles. Metal nanoparticles especially Ag, have exhibited remarkable optical, antibacterial, and imaging properties just to name a few, at the nanometer level. However, during synthesis, these nanoparticles tend to agglomerate resulting in loss of their nanoscale properties. Since GO high surface area can serve as nucleation sites for metal nanoparticles, it can be used as a substrate to deposit metal nanoparticles. This will reduce agglomeration of Ag nanoparticles, thus allowing the properties that Ag exhibit at the nano-level to be accessed. In addition, recent results show that Ag-GO has very good antibacterial results. GO traps bacteria while Ag kills bacteria. Therefore, we intend to obtain the optimum ratio of Ag to GO which can be used in future studies in antibacterial filters. In this work, synthesis and characterization of Ag-decorated GO was investigated using sonochemistry. The initial approach to control the loading of Ag nanoparticle on the surface of GO involved changing the weight ratio between silver acetate and GO. However, it failed to achieve the desired control of Ag loading on GO surface and has led to the second approach, in which 26 wt% Ag-GO sample (26 wt% Ag) was mixed with GO. TEM analysis showed the second approach offers a better control of silver loading on GO surface. 26 wt% Ag-GO sa (open full item for complete abstract)

Committee: Shiral Fernando PhD (Advisor); Guliants Elena PhD (Advisor); Amy Ciric PhD (Committee Chair); Alexander Morgan PhD (Committee Chair) Subjects: Aerospace Engineering; Aerospace Materials; Aesthetics; Biology; Chemical Engineering; Chemistry; Engineering; Morphology; Nanoscience; Nanotechnology; Organic Chemistry

Doctor of Philosophy, University of Akron, 2013, Chemical Engineering

This dissertation encompasses the doctoral work of the author, which focused on the ideation and materials synthesis of novel sensor technologies for biomedical and environmental applications. The purpose of this work is to identify and exploit the nanostructured properties of certain materials to produce advanced sensing platforms, utilizing the advances made by nanotechnology. Herein, a number of developed sensors are described using electrochemical and colorimetric transduction techniques. A number of background chapters providing an introduction to nanomaterials, typical sensor fabrication routes, and sensor technologies are provided, followed by experimental studies of the developed sensors. The author describes a polymer/multi-walled carbon nanotube sensing platform, which has been found to be both selective and sensitive to sodium ions at normal physiological range. Two chapters describing experimental work related to both a colorimetric water contaminant preconcentration/detection system—able to detect contaminants at the United States Environmental Protection Agency maximum contaminant level—and an electrochemical water contaminant detection system are discussed. A chapter describing the theoretical and optimization modeling of the polymer/multi-walled carbon nanotube sensing platform is also enclosed. Through this work, the author has developed a number of novel sensing technologies for both biomedical and environmental applications.

Committee: Chelsea Monty Dr. (Advisor); Lu-Kwang Ju Dr. (Committee Member); George Chase Dr. (Committee Member); Gang Cheng Dr. (Committee Member); Marnie Saunders Dr. (Committee Member); Wiley Youngs Dr. (Committee Member) Subjects: Analytical Chemistry; Biomedical Engineering; Chemical Engineering; Environmental Engineering

Master of Science (MS), Wright State University, 2008, Chemistry

A series of 1,3-di-substituted-imidazolium lithium phthalocyanines, in which the substituents on the imidazolium nitrogens were combinations of methyl, ethyl, pentyl, hexyl, isopropyl, adamantyl or 2,4,6-trimethylphenyl groups, was synthesized. The cation exchange of a single lithium ion of dilithium phthalocyanine for a 1,3-disubstituted-imidazolium ion was performed by mixing their salts in common organic solvents under ambient conditions. This afforded a number of imidazolium lithium phthalocyanines in moderate yields. They exhibited poor solubility in most solvents. Their composition and purity were initially verified by 1H and 13C-NMR and elemental analysis. The 1H-NMR spectra also indicated that the imidazolium and lithium phthalocyanine ions are present in a 1:1 ratio. Infrared spectra confirmed the C-C and C-N stretching modes that are characteristic of phthalocyanine and imidazolium aromatic structures. UV-Vis spectra for each compound showed essentially no change in absorption from that of dilithium phthalocyanine, which suggests a lack of influence of the imidazolium ions. Thermal properties of the title compounds were determined through melting points and TGA, in which high melting temperatures (330-370°C) were seen for several complexes and lowered thermal stability was seen for all. The crystal structure of the bis(adamantyl)imidazolium derivative was determined through X-ray diffraction. It was found that water molecules are associated to imidazolium and lithium phthalocyanine ions through hydrogen-bonding, which is possibly the basis for crystallization in imidazolium-lithium-phthalocyanines.

Committee: William Feld PhD (Advisor); David Grossie PhD (Committee Member); David Dolson PhD (Committee Member); Kenneth Turnbull PhD (Other); Joseph F. Thomas, Jr. PhD (Other) Subjects: Chemistry

PhD, University of Cincinnati, 2012, Engineering and Applied Science: Environmental Engineering

Biodiesel continues to enjoy increasing popularity. However, recent studies on carbonyl compounds emissions from biodiesel fuel are inconclusive. Emissions of carbonyl compounds from petroleum diesel fuels were compared to emissions from pure biodiesel fuels and petroleum-biodiesel blends used in a non-road diesel generator. The concentration of total carbonyl compounds was the highest when the engine was idling. The carbonyl emissions, as well as ozone formation potential, from biodiesel fuel blends were higher than those emitted from petroleum diesel fuel. The sulfur content of diesel fuel and the source of biodiesel fuel were not found to have a significant impact on emissions of carbonyl compounds. Mechanism parameters of the thermal decomposition of biodiesel-range methyl esters were obtained from the results of thermal gravimetric analysis (TGA). The overall reaction orders are between 0.49 and 0.71 and the energies of activation are between 59.9 and 101.3 kJ/mole. Methyl esters in air have lower activation energies than those in nitrogen. Methyl linoleate has the lowest activation energy, followed by methyl oleate, and methyl stearate. The pyrolysis and oxidation of the three methyl esters were investigated using a semi-isothermal tubular flow reactor. The profiles of major products versus reaction temperature are presented. In the pyrolysis of methyl stearate, the primary reaction pathway is the decarboxylic reaction at the methyl ester functional group. Methyl oleate's products indicate more reactions on its carbon-carbon double bond. Methyl linoleate shows highest reactivity among the three methyl esters, and 87 products were detected. The oxidation of three methyl esters resulted in more products in all compound classes, and 55, 114, and 127 products were detected, respectively. The oxidation of methyl esters includes decarboxylation on ester group. The methyl ester's carbon chain could be oxidized as a hydrocarbon compound and form oxidized esters and un (open full item for complete abstract)

Committee: Mingming Lu PhD (Committee Chair); Eileen Birch PhD (Committee Member); San-Mou Jeng PhD (Committee Member); Timothy Keener PhD (Committee Member) Subjects: Environmental Engineering

MS, University of Cincinnati, 2010, Engineering and Applied Science: Environmental Engineering

This research deals with the carbonation phenomena in concrete for the first 28 days of the concrete curing period. The reactions known as carbonation are those which take place with the hydrated and un-hydrated components of the cement paste in the concrete mixture and the atmospheric carbon dioxide (CO2). A literature review of the chemistry of cement and concrete as well as the physical phenomena of carbonation governed by Fick's first law and the influential factors in the carbonation reaction has been summarized. Moreover, information of different studies done at several conditions to measure carbonation rates, have been gathered and compared with the experimental results obtained in this research. Also, information regarding CO2 emissions from the calcination reaction in the cement process was brought together in order to find out how much of the CO2 emitted can be absorbed by concrete the first 28 days of the curing period. In order to study how is the process of concrete carbonation for the period of time specified, concrete specimens right after being poured in cylindrical molds, were exposed to accelerated carbonation conditions during 28 days, with controlled atmosphere of 5% CO2 vol., 30°C and 65%RH. Products of the carbonation reaction in the concrete were measured versus time, with techniques such as Carbonation depth by phenolphthalein stain and Carbon Dioxide content by Thermo Gravimetrical Analyses and Mass Spectrometry. Calculations of carbonation rate with phenolphthalein data and CO2 absorption rates with TGA-MS data were done with the information collected. When phenolphthalein test and CO2 content by TGA and TGA-MS techniques were used, the same tendency in the results was found; which coincides at the same time with formulations done by Fick's first law. The higher values of CO2 content achieved by the concrete were consistent with the maximum availability of components to react within the concrete matrix. Similar results were found between th (open full item for complete abstract)

Committee: Timothy Keener PhD (Committee Chair); Mingming Lu PhD (Committee Member); Joo Youp Lee PhD (Committee Member) Subjects: Environmental Engineering

MS, University of Cincinnati, 2010, Engineering and Applied Science: Environmental Engineering

Petroleum-contaminated sediment and coal refuse have been considered for beneficial use in this research. Sediment, which is contaminated with petroleum wastes, is harmful to animals and environment, and needs to be treated. On the other hand, coal refuse is not considered as hazardous, but its abundance, attracts people to gain some benefit from it. Both types of waste are considered to be beneficially useful. Therefore, this research focuses on their potential uses and the emissions that result from their applications. The western portion of the Lake George Branch of the Indiana Harbor Canal (IHC) is considered an important habitat for many animal species; however, the lake contains a huge amount of petroleum-contaminated sediment that need to be treated. One of the restoration options of the IHC is dredging up the sediment from the canal, and then some forms of sediment management (disposal or treatment) are required. Consequently, both the public and regulatory authorities will benefit if the dredged material can be used in a beneficial way, such as recovering energy from the petroleum portion or applying it as supplemental construction material. Therefore, the characteristics of sediment are studied in order to determine their possible applications. The experiment examines heat content, elemental, thermal characteristics, and potential emissions analysis. Although the results show that the sediment has various petroleum-like compounds, it contains a low heating value and a high amount of ash, which is considered inappropriate for use as supplemental fuel. Accordingly, sediment is considered to be used as an asphalt binder in hot mix asphalt plants, where in all critical pollutants in the sediment are examined, and the sediment is deemed to be safe for applying as asphalt supplemental material. The coal refuse from the private coal company is analyzed to reduce the emissions of NOx and SO2 from the combustion process while obtaining a high energy value. Therefo (open full item for complete abstract)

Committee: Timothy Keener PhD (Committee Chair); Joo Youp Lee PhD (Committee Member); Margaret Kupferle PhD, PE (Committee Member) Subjects: Environmental Engineering

PhD, University of Cincinnati, 2008, Arts and Sciences : Chemistry

We used o-azidoaniline, 4, 4'-diazidobiphenyl and 4, 4'-diazidooctafluorobiphenyl to crosslink polyaniline. o-Azidoaniline was copolymerized with aniline to form poly(aniline-co-azidoaniline), which was crosslinked via thermal activation of the azido groups. . Thermal analysis of the copolymer, poly(aniline-co-azidoaniline) indicated that their thermal stability improved upon crosslinking . 4,4'-diazidobiphenyl and 4,4'-diazidooctafluorobiphenyl were used as post polymerization crosslinking agents. The thermal crosslinking of the polyaniline with these aryl azides was demonstrated with the help of Differential Scanning Calorimetry, Thermogravimetric Analysis and FT-IR spectroscopy. Crosslinked polyaniline films showed a better thermal stability than the plain polyaniline films. The electrical conductivities of the crosslinked polyaniline films were measured with a 4 point probe, which demonstrated that the conductivities were conserved upon crosslinking. The mechanical properties of the crosslinked polyaniline films are tested by Dynamic Mechanical Analysis and the crosslinked polyaniline films show an improvement in tensile strength. Mechanistic studies of these biphenyl azides revealed that the mechanism of crosslinking depends on the environment. Photolysis of 4-azido, 3-methyl, 1-phenyl-buten-1-one in argon matrices yields formation of benzoyl and allyl imine radicals. Computational studies of stationary points on the triplet energy surface of 4-azido, 3-methyl, 1-phenyl-buten-1-one indicate the formation of above radicals goes through a hot triplet vinyl nitrene intermediate. TD-DFT calculations support the first excited triplet ketone and the second excited triplet ketone in 3-azido-1,3-diphenyl-propan-1-one 3-azido-2, 2-dimethyl-1, 3-diphenyl-propan-1-one are almost degenerate. Calculations support that the triplet excited state with an (n,π*) configuration will cleave to form azido radical and the corresponding benzyl radical whereas the triplet ketone with (open full item for complete abstract)

Committee: Anna Gudmundsdottir (Committee Chair); Bruce Ault (Committee Member); Carl Seliskar (Committee Member) Subjects: Chemistry

Master of Science in Engineering, University of Toledo, 2012, Bioengineering

In this research, a series of experiments were conducted to study the mechanical and thermo-degradation properties of PLA and PLA composite films and to find a methodology that increases the degradation rate of PLA or PLA composites based on the data and results. PLA and PLA composite films were fabricated by dissolving PLA particles into organic solvent. The solution was then poured in petri-dish and dried to form films. Three types of mixtures were added to PLA respectively to make the PLA composite films. They were starch, cellulose and methyl cellulose. Different percentages of the additions were mixed with PLA ranging from 10% to 60%. PLA and PLA composite films were stored in an incubator with controlled temperature and relative humidity for the purpose of accelerating degradation process and shorten the experimental period. The mechanical properties as an indication of degradation rate were measured via tensile tests. 3-D images were obtained using Scanning Electron Microscope (SEM) for microstructure study. The thermo-degradation properties were measured by Thermo Gravimetric Analysis (TGA) for the study of possible chemical reaction.

Committee: Arunan Nadarajah (Committee Chair); Sarit Bhaduri (Committee Chair); Joseph Lawrence (Committee Member) Subjects: Agricultural Engineering; Biomechanics

Master of Science, The Ohio State University, 2010, Food Science and Nutrition

Poly (hydroxybutyrate) (PHB) is biodegradable aliphatic polyester that is produced by a wide range of microorganisms. Basic PHB has relatively high glass transition and melting temperatures. To improve flexibility for potential food packaging applications, syntheses of PHB with various co-polymers such as Poly-(3-hydroxyvalerate) (HV) decreases the glass and melting temperatures as well as broadens the processing window since there is improved melt stability at lower processing temperatures. In this study, PHB was synthesized with different valerate contents (5, 12, and 20%) and molecular weights ranging from 150 to 600 kDa. This study focused on characterizing the thermal, mechanical, rheological, and barrier properties of PHB synthesized with different valerate contents, and second to compare these properties in PHBV with similar hydroxyvalerate content but different molecular weight. All PHBV materials displayed a glass transition between -10 to 20°C. The two melting transitions found for Aldrich 5%, 12%, and Tianan 20%, resulted from crystals formed during cooling of the samples. The melt rheology suggested thermal instability of samples as the complex viscosity decreased with increasing temperature due to a decrease in molecular weights of the materials. These results suggest that processing the copolymer below 160°C would be beneficial with low screw speed. The mechanical results indicate all PHBV materials had high elastic modulus and flexural strength with low tensile strength and elongation at break. The WVTR results indicated the polymer to be very hydrophilic resulting in higher transmission rates. Individually PHBV and PLA polymers have serious disadvantages when compared to thermoplastics that are currently used. To address high costs and thermal instability, blends of PHBV with PLA were explored as an alternative way of acquiring novel materials with desired properties. At the start of this work, three grades of PLAs were commercially available for pu (open full item for complete abstract)

Committee: Yael Vodovotz Phd (Advisor); Kurt Koelling PhD (Committee Member); Sudhir Sastry PhD (Committee Member) Subjects: Polymers

Master of Science, The Ohio State University, 2009, Food Science and Nutrition

Corn is the main component of tortilla chips and must undergo several steps of modification to produce masa dough. Different varieties of corn and the interaction of environmental conditions with post-harvest handling can produce variability in the kernel structure and composition, affecting its functionality in the masa-making process. This study sought to understand how corn composition with processing contributed to the texture of acceptable masa using various rheological and thermal analysis techniques. TGA analysis illustrated the unique water populations in pericarp, soft endosperm, hard endosperm, and germ during the processing of nixtamalization. Alkaline cooking was the most critical step for increasing the water uptake in all fractions and water became more associated in the pericarp and endosperms. Although germ imbibed water, no increase in water entrapment was displayed following cook. Increase in “freezable water” as observed with DSC also confirmed an increase in bulk water for the four fractions. Soaking only modified the soft endosperm water component to an appreciable degree. Possible thermal shifts between unacceptable and acceptable pericarp and hard endosperm fractions were observed and warranted additional analysis to verify these differences. Findings from this study narrowed the research focus to the hard endosperm and pericarp fractions in the raw and cook state. Further thermal and rheological analysis was combined with additional testing to characterize the basic composition and material behavior of unacceptable and acceptable corn. Masa adhesion as measured by the TAX.T2 Texture Analyzer, masa moisture quantitated with the Moisture Analyzer, macromolecular composition using near-infrared spectroscopy (NIR), and chemical quantitation of unextractable extensin protein were evaluated. One-way ANOVA (p < 0.05) established statistical differences between unacceptable and acceptable corn categories while Soft Independent Modeling of Class An (open full item for complete abstract)

Committee: Yael Vodovotz PhD (Advisor); Luis Rodriguez-Saona PhD (Committee Member); Peter Thomison PhD (Committee Member) Subjects: Food Science

Master of Science in Chemistry, Cleveland State University, 2010, College of Sciences and Health Professions

This Master of Science thesis encompasses two projects in chemical pharmaceuticals. The first is a study of excipients and the added new information collected beyond Thermal Gravimetric Analysis and Differential Scanning Calorimetry from Dielectric Analysis. These new properties enhance our global knowledge of excipients by thermal analytical methods. Excipients, the inactive ingredients in formulated drugs, aid different functions of the active pharmacy ingredient, the drugs. Low temperature transitions, by DEA including melting of frozen solvents, e.g. water, are more definitive than observed by low temperature DSC. Millions of dollars are expended annually on pharmaceutical testing to qualify excipients for fully formulated drugs, medicines and active ingredients. To understand the action of the excipients in the human body at body temperature of 37°C, the study of their individual and interactive properties are desirable. DEA DSC and Thermal Gravimetric analysis (TGA) methods are employed to screen the most widely used drug excipients. In this study the following excipients were examined by DEA: cotton seed oil, mannitol, peanut oil, polyethylene glycol, sugar, sodium lauryl sulfate, sodium starch glycolate, sodium stearate, canola oil, and anhydrous lactose, benzoic acid and vanillin. The comparison of DSC and DEA thermal curves for each excipient indicates that major endothermic events have occurred e.g., volatilization or melting of the excipient are viewed as fundamental DEA properties. These properties are the rise in permittivity and dielectric loss factor. The focus of this project was to learn to prepare, examine and interpret the resulting variations. The electrical conductivity (e” * frequency* constant), permittivity (e') and tan delta value (e”/e') are used to enhance the characterization of the excipient. The second, and major project for this thesis, is to evaluate bipolar disorder drug transport with and without an applied electric field of (open full item for complete abstract)

Committee: Bin Su PhD (Committee Chair); Alan Riga PhD (Committee Co-Chair); Stan Duraj PhD (Committee Member); Tobili Sam-Yellowe PhD (Committee Member) Subjects: Analytical Chemistry; Chemistry

Doctor of Philosophy, Case Western Reserve University, 2007, Macromolecular Science

Poly(vinyl chloride), or PVC, has various defects which limit its processing temperature by lowering thermal stability. Possible structural defects in PVC are short and long chain branches, chloroallyl groups, end groups and head-to-head structures. Some structural defects connect with an active chloride, which easily loses HCl at elevated temperatures. In this thesis, a comprehensive study was performed on the vinyl chloride polymerization in the presence of small amount of organic additives. These additives were weakly basic compounds, high dipole carbonyl compounds, ether compounds and some heteroraromatics. The initial polymerization rates and the molecular weights of the resulting polymers increased in the presence of weakly ‘basic' compounds such as dimethyl terephthalate (DMT), ethylene carbonate (EC), γ-butyrolactone (GBL), tributylphosphine oxide (TBPO) and trimethyl-1,3,5-benzene tricarboxylate (TMB). A kinetic model was developed for vinyl chloride polymerization in the presence of these weakly basic additives, using the hypothesis that a hydrogen-bond complex formed between an additive and the terminal hydrogen of the propagating radical, and that the major termination reaction was between a small radical (possibly Cl• or combined Cl•) and the propagating radical. The kinetic model successfully explained the increase of the polymerization rate and the resulting polymer molecular weights. An optimal additive concentration exists to get maximum molecular weight increase and possibly reducing structural defects of the resulting polymers. Various methods were applied to evaluate the additive effects on the resulting polymer structures. Differential Scanning Calorimetry (DSC) was used to study the crystallization behavior of the resulting polymers. The thermal stability of the resulting polymers was evaluated by dynamic Thermogravimetric Analysis (TGA) and dehydrochlorination. A 2-parameter model was developed to describe the initial dehydrochlorination of th (open full item for complete abstract)

Committee: Morton Litt (Advisor) Subjects:

Doctor of Philosophy, University of Akron, 2011, Polymer Science

A variety of methods were used to make polymers with different architecture and functionalities. The linking chemistry of vinyldimethylchlorosilane (VDMCS) with poly(styryl)lithium (Mn = 1,700-3,000 g/mol) was studied. The average degree of branching varied from 7.5 to 9.4 with an increase in concentration of VDMCS (1.2 to 5.2 eq). The intrinsic viscosities and melt viscosities (at 160 °C) of the star polymers were found to be less than half of that of the corresponding linear polystyrenes. α-Pyrrolidine-functionalized polystyrene (Mn = 2,700 g/mol, Mw/Mn = 1.03, 92.5%) was successfully synthesized from α-chloromethyldimethylsilane-functionalized polystyrene(Mn = 2,600 g/mol, Mw/Mn = 1.02) based on NMR spectroscopy, MALDI-TOF and ESI mass spectrometry. The stability of silyl hydride groups under atom transfer radical polymerization conditions was proven by copolymerizing methyl methacrylate and (4-vinylphenyl)dimethylsilane (VPDS). Tapered block copolymers of isoprene, VPDS, and styrene with narrow molecular weight distributions (1.04 and 1.05) were synthesized via anionic polymerization. Evidence regarding the topology of cyclic polybutadienes was obtained by Atomic Force Microscopy of grafted polymers obtained by grafting an excess of silyl hydride functionalized polystyrene (Mn = 8,300 g/mol, Mw/Mn =1.01) onto cyclic polybutadiene(Mn=88,000 g/mol, Mw/Mn = 2.0). The reactivity of polyisobutylene carbocations was compared with respect to competitive electrophilic addition to a vinyl group versus silyl hydride transfer by investigating the reaction with VPDS. Based on GPC results, and 1H and 13C NMR spectroscopy, no evidence for any vinyl group addition was observed. A successful attempt was made to prepare electrospun fibers from fluorofunctionalized styrene-butadiene elastomers. The water contact angle of these surfaces was found to be 162.8o ± 3.8o for the fibrous mat of the fluorinated polymers as compared to 151.2o ± 2.4o for the analogous fibrous (open full item for complete abstract)

Committee: Roderic Quirk Dr. (Advisor); Mark Foster Dr. (Committee Chair); Judit Puskas Dr. (Committee Member); Chrys Wesdemiotis Dr. (Committee Member); Kevin Cavicchi Dr. (Committee Member) Subjects: Polymers