Doctor of Philosophy, University of Akron, 2017, Polymer Engineering

Epoxides are widely used in the coatings industry as coating binders. Epoxide binders have several useful characteristics, which include the ability to react with polysulfide resin modifiers and thermosetting amide curatives. In order to improve the characteristics of epoxide coatings, various functional and non-functional additives and resins can be grafted or added to the epoxide binder. The first study involved the use of reacting polysulfides with epoxides and crosslinking with a polyamide to form films and coatings. While epoxide-polysulfides have heavily investigated in the literature for physical and fracture properties, a study investigating the fracture properties of epoxide-polysulfides at cold, ambient, and hot temperatures has not been attempted. The results indicated a toughening phenomenon at 5-10 wt. % polysulfides that led to enhancements in the fracture properties. Also, the addition of polysulfide content led to improvements in the flexibility and the impact resistance of the formulations. Self-assembled NAnoPhase (SNAP) particles are nano-scale functional sol-gels that were pioneered as corrosion-resistant surface preparations on aluminum substrates. No studies have investigated the use of SNAP particles as functional additives within epoxide-polyamide coating systems. SNAP sol-gel particles were formulated and added into epoxide-polyamide films and coatings. It was found that SNAP sol-gel particles were able to enhance the mechanical properties and corrosion resistance of the coatings. These studies are a novel discovery because the SNAP functional sol-gels are also able to act as a primer additive. In the last study, carbon nanotubes and magnesium were both added into epoxide-polyamide films and coatings systems, which were tested for mechanical and corrosion resistance properties, respectively. While existing studies have investigated the use of magnesium or carbon nanotubes as anti-corrosion additives in epoxide coatings, th (open full item for complete abstract)

Committee: Mark Soucek (Advisor); Evans Edward (Committee Member); Karim Alamgir (Committee Member); Cavicchi Kevin (Committee Member); Miyoshi Toshikazu (Committee Member) Subjects: Aerospace Materials; Engineering; Mechanical Engineering; Nanoscience; Nanotechnology; Polymer Chemistry; Polymers

Doctor of Philosophy (PhD), Wright State University, 2005, Engineering PhD

Pulikollu, Rajasekhar Venkata. Ph.D., Department of Mechanical and Materials Engineering, Wright State University, 2005. Nano-coatings on Carbon Structures for Interfacial Modification. Surface modification of materials is a rapidly growing field as structures become smaller, more integrated and complex. It opens up the possibility of combining the optimum bulk properties of a material with optimized surface properties such as enhanced bonding, corrosion resistance, reactivity, stress transfer, and thermal, optical or electrical behavior. Therefore, surface functionalization or modification can be an enabling step in a wide variety of modern applications. In this dissertation several surface modification approaches on carbon foam and carbon nano-fibers will be discussed. These are recently developed sp 2 graphitic carbon based structures that have significant potential in aerospace, automotive and thermal applications. Influence of surface modification on composite formation and properties have also been investigated. Two types of property changes have been investigated: one for enhancing the surface reactivity and another for surface inertness. Characterization techniques such as X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM), Contact Angle Measurement, Scanning Electron Microscope (SEM), Transmission Electron Microscope(TEM), and mechanical testing are used in this study to find out the influence of these coatings on surface composition, chemistry, and morphology. Mechanical testing has been performed on composites and stand-alone foam to study the influence of surface modification on physical and mechanical properties of the composite materials. The effectiveness of these coatings on metallic/graphite interface has also been investigated for metal-matrix composite related applications. Additionally, the influence of plasmacoatings on nucleation and growth of nanotubes on larger carbon structures (to produce multiscale, multifunctional mater (open full item for complete abstract)

Committee: Sharmila Mukhopadhyay (Advisor) Subjects: Engineering, Materials Science

Doctor of Philosophy, University of Akron, 2016, Polymer Engineering

This dissertation focused on hybrid nanostructures of alkoxysilane modified epoxides via in situ or ex situ sol-gel reaction with nanoparticles. Related morphologies and physical properties were studied. Bisphenol A epoxy (BPA) is a common primer and the modification with alkoxysilanes is a one way to combine the pre-treatment on substrates to a primer as unicoat. Applying nanoparticles such as the pigments, silicate colloids makes the hybrid networks more complicated. During film formation, crosslinking in both organic and inorganic phases goes on and the distribution of nanoparticles can be varied in relation with condensation kinetics. Having nanophasic morphology of the hybrid materials with nanoparticles requires the understanding of the fundamentals on interactions at the interfaces. In the first part of the study, in situ sol-gel reaction of alkoxysilane modified epoxides was investigated. BPA was modified with organosilanes (amine functionalized silane, isocyanate functionalized silane) and the modified epoxides were applied with tetraethyl orthosilicate (TEOS) oligomers and the pigments, TiO2. Both modified epoxides formed the Si-O-Si and Ti-O-Si bonding shown by FT-IR and solid-state 29Si-NMR. Corrosion resistance was studied by using filiform test, salt spray test and EIS. Isocyanate silane modified epoxides showed the higher impedance at the initial stage but aminosilane modified epoxides maintained the impedance up to day 20 from low water uptake by fitting to equivalent electrical models. The corrosion rate was varied with incomplete condensation of isocyanate modified epoxides and homogenous distribution of smaller nanophases in aminosilane modified epoxides shown by AFM and SAXS results. In relation with morphologies, the fracture toughness was studied and there was increased fracture toughness with aminosilane modified epoxides. The formulations of both modified epoxides were optimized with mixture design by Design of Experiments. Aminosilane modi (open full item for complete abstract)

Committee: Mark Soucek (Advisor); Thein Kyu (Committee Chair); Kevin Cavicchi (Committee Member); Toshikazu Miyoshi (Committee Member); Chrys Wesdemiotis (Committee Member) Subjects: Polymer Chemistry; Polymers

Doctor of Philosophy, University of Akron, 2016, Mechanical Engineering

Novel high-temperature experiments were conducted in ordered to address some of the most critical life-limiting issues facing woven melt-infiltrated, silicon carbide (SiC) fiber-reinforced SiC ceramic matrix composites (CMCs) as well as protective thermal and environmental barrier coatings (T/EBC). Heating of specimens was achieved using laser-based approaches that simulate the high heat-flux thermal gradient environments that these materials will be subjected to in service. Specialized non-destructive evaluation (NDE) and inspection techniques were developed to investigate damage modes and material response. First, in order to examine the capabilities of utilizing the emerging technique of electrical resistance (ER) measurement for use in high temperature mechanical testing in SiC/SiC CMCs, the temperature dependent ER response of several systems was determined. A model was developed to establish the contribution to overall ER from the individual composite constituents and applied thermal gradient. Then, elevated temperature tensile tests were performed to characterize the damage of composite materials to localized stress concentrations. Further experiments were done to assess the differences in damage mechanisms and retained tensile strength properties of uncoated SiC/SiC CMCs and EBC-CMC systems after prolonged exposure to high pressure, high velocity water vapor containing environments. Differences in damage modes were described using ER monitoring and post-test inspection. Localized strain fields were measured using a novel digital image correlation (DIC) technique and stress-dependent matrix crack accumulation was monitored using in-situ modal acoustic emission (AE). Coupled AE and thermography measurements were also used to describe failure of protective ceramic coatings due to the life-limiting case of thermal cyclic loading. Due to the complex nature of T/EBC failure, the decrease in coating life and durability due to thermal stress concentrations and degra (open full item for complete abstract)

Committee: Gregory Morscher (Advisor); Manigandan Kannan (Committee Member); Kwek Tze Tan (Committee Member); Craig Menzemer (Committee Member); Alper Buldum (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2016, Materials Science and Engineering

In this dissertation, several novel corrosion inhibition strategies have been developed, including application of smart coatings with self-healing capabilities, utilization of organic/inorganic hybrid corrosion inhibitors, and employment of novel organic conversion coatings. In the first part of this dissertation, a one-step method is presented for encapsulating a corrosion inhibitor, sodium metavanadate (NaVO3), relevant to protection of AA2024-T3, into hollow microparticles. The surface morphologies and core-shell structure of as-fabricated microparticles were characterized by using scanning electron microscopy and confocal microscopy. A release study showed that the encapsulated NaVO3 was continuously released from the microparticles over time. Potentiodynamic polarization scans indicated that the released NaVO3 noticeably inhibited corrosion on an AA2024-T3 surface by discouraging the oxygen reduction reaction. A smart coating with self-healing capability was developed by dispersing these microparticles in a polyvinyl butyral (PVB) coating. The improvement of corrosion inhibition by the NaVO3 microencapsulation described herein was validated through electrochemical methods and salt spray/immersion tests. The results indicated that the direct introduction of NaVO3 in the PVB coating impaired the barrier properties of the coating. However, by entrapping NaVO3 inmicroparticles, the corrosion resistance of the embedded coating was remarkably improved. In separate work, a strong synergistic corrosion inhibition effect was observed when phytate and molybdate were combined and applied onto a AA2024-T3 substrate. At pH 5, it was found that the optimum condition as revealed by free corrosion tests in 3.5 % NaCl solution with 1 mM phytate and 10 mM molybdate. The inhibition mechanism was explored by electrochemical, microscopic, and surface analytical techniques. XPS, SEM-EDS, and Raman results show that both phytate and molybdate exist on the metal surface treated (open full item for complete abstract)

Committee: Rudolph Buchheit (Advisor); Gerald Frankel (Committee Member); Jenifer Locke (Committee Member) Subjects: Chemistry; Engineering; Materials Science

Doctor of Philosophy (Ph.D.), University of Dayton, 2015, Materials Engineering

This work details two specific research thrusts exploring the deposition and characterization of mixed valent oxide systems. The first of these thrusts investigated the effect of the oxygen content, during reactive sputter deposition, on the optical, chemical, and structural properties of oxides of molybdenum, germanium, and rhenium. Exploration of the Mo-O system was conducted using a technique known as modulated pulse power magnetron sputtering (MPPMS), while the Ge-O and Re-O systems were deposited via direct current magnetron sputtering (DCMS). Films deposited under poisoned mode conditions were shown to be highly transparent with refractive index (n) values of n550=1.60 for GeO2, and n550=1.97 for MoO3, similar to values reported for bulk constituents. The Re-O system, unlike Ge-O and Mo-O, displayed a significantly high sensitivity to ambient moisture. Chemical analysis via XPS indicated the presence of instability as a result of the moisture induced decomposition of Re2O7 into HReO4, and catalytic disproportionation of Re2O3 into Re and hydrous ReO2. The second research thrust within this project was focused on the deposition of three component mixed oxide systems with multiple valence states. This effort, which utilized the results from individual material depositions mentioned previously, required the use of stable and thermodynamically compatible material systems, namely Mo-O and Ge-O (ΔfHo(MoO2)= -588 kJ/mol and ΔfHo(GeO2)= -580 kJ/mol). Note that Re-O was not explored as part of the ternary deposition effort due to the aforementioned chemical instability. To achieve the goal of depositing mixed valent thin films with tailorable optical absorption, an industrially scalable co-deposition method was devised in order to deposit molybdenum cations within a dielectric GeO2 matrix. The high power densities associated with the MPPMS process were systematically varied in order to control the oxygen partial pressure via gettering, allowing for control over the (open full item for complete abstract)

Committee: P. Terrence Murray Ph.D. (Committee Chair); Dean R. Evans Ph.D. (Advisor); John T. Grant Ph.D. (Committee Member); Daniel P. Kramer Ph.D. (Committee Member); Andrew M. Sarangan Ph.D. (Committee Member) Subjects: Materials Science

MS, University of Cincinnati, 2006, Engineering : Materials Science

Epoxy/layered silicate based nanocomposite coatings have been processed and characterized for corrosion protection of Aluminum Alloy. The nanocomposite coatings were processed in N-Methyl-Pyrrolidinone (NMP) and water, forming self assembled nanoscale composite. The layered silicate used in the NMP Coating System was PolyAniline coated Cloisite 20 A. Pristine montmorillonite clay, Cloisite Na+ was used in the Water Based Coatings. The structure and composition of the nanocomposite coatings was determined using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction Spectrometry (XRD). Curing kinetics was tracked using FTIR and a semi-quantitative equation was developed. Viscosity studies were performed to understand the rheology of the clay/epoxy suspensions. XRD results indicated the formation of an exfoliated nanocomposite in the NMP System. The PACN powder was exfoliated, as determined by the disappearance of clay peak. Corrosion performance was determined using DC Polarization and Electrochemical Impedance Spectroscopy (EIS). The DCP results were used to determine the optimal filler % of the nanocomposite and in both the systems. The corrosion current and hence the corrosion rate for the NMP system decreased with increasing weight % of PolyAniline coated Clay. Water system coatings also exhibited a decrease in the corrosion current with the addition of pristine clay. EIS results show that the NMP System has higher impedance than the Water system coatings. The impedance was in the order of E+6 Ohms, which remained consistent over 8 weeks of testing, and in the order of E+5 Ohms for the water system.

Committee: Dr. Jude Iroh (Advisor) Subjects: Engineering, Materials Science

Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2024, Food Science and Technology

Two polymer coatings derived from spent coffee grounds were explored as a bio-sourced biodegradable alternative to traditional petroleum-based non-biodegradable plastic coatings used commonly in food packaging. The aim of this research is to formulate a bioplastic coating derived from spent coffee grounds that can serve as a viable alternative to current petroleum-based wax films used in the food packaging industry. Water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) tests were conducted to assess the coatings' barrier properties. Results indicated inferior water vapor resistance compared to the control, yet an enhanced water barrier of the cardboard alone. The coffee oil coating demonstrated superior OTR performance compared to the other samples. Biodegradability experiments conducted over 73 days revealed partial degradation of the coffee oil coated cardboard, showing potential as a bio-sourced biodegradable alternative. However, challenges encountered in biodegradability testing methodology require further investigation. Crystallization and thermal analysis revealed differences between cured and uncured samples, indicating structural changes during curing. Rheological analysis demonstrated Newtonian behavior in uncured samples and shear thinning in cured samples, providing insights into material behavior under increased deformation rates. Adhesion tests confirmed polymer adhesion to cardboard, with no observed odor or microbial growth. Overall, the coffee oil coating presents a promising option for sustainable food packaging, but further research is necessary to optimize properties.

Committee: Yael Vodovotz (Advisor); Emmanuel Hatzakis (Committee Member); Katrina Cornish (Committee Member) Subjects: Food Science; Packaging; Plastics; Sustainability

Master of Science (M.S.), University of Dayton, 2024, Materials Engineering

If gone undetected, volcanic ash in the atmosphere can have significant negative effects on the performance of air-breathing gas turbine engines. When ingested into the front of the engine, abrasion and erosion of key mechanical components can occur, accompanied by degradation of the materials located in the late-stages of the engine by ash that has become molten due to the high-temperature environment. These phenomena can lead to significant damage and premature failure in a fielded gas-turbine engine, thus the need to evaluate engine materials prior to their implementation arises. While volcanic ashes and turbine engine materials have been studied extensively in the literature, they have largely been studied independently, therefore no standardized volcanic ash media to be used in materials testing has been developed. In this work, a group of natural volcanic ash samples were evaluated using a variety of techniques to understand their chemical, physical, and thermal behavior. The information gathered in the characterization of the group of natural ash samples was then used to develop a synthetic volcanic ash media that has similar chemistry to and behaves like a natural ash when exposed to an environment like that in a late-stage gas turbine engine. The new synthetic ash media was compared to a natural ash, from Mt. Mazama in Oregon, USA. Specifically, its ability to melt and infiltrate the microstructural features of 7% yttria-stabilized zirconia thermal barrier coatings deposited on superalloy coupons was examined. It was shown via SEM analysis that when heated to 1200 °C, the synthetic ash melts and infiltrates the thermal barrier coating within a comparable time (<30 minutes) as Mt. Mazama ash, leading to the conclusion that it can be deemed an effective replacement for natural volcanic ash in materials testing. The development of this synthetic ash test media is meant to provide a solid starting point for future development of medias used (open full item for complete abstract)

Committee: Li Cao Ph.D. (Committee Chair); Matthew Hartshorne Ph.D. (Advisor); Donald Klosterman Ph.D. (Committee Member) Subjects: Aerospace Materials; Chemistry; Earth; Engineering; Geology; High Temperature Physics; Materials Science; Mineralogy

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2024, Chemistry

The development of hybrid organosilicon materials as both rapid curing coatings and photo-responsive sponges has been conducted utilizing silsesquioxane (SQ) based chemistries for the robustness they provide in the final materials. Additional research was conducted on the formation of sulfur-based SQ analogs. Chapter I will provide background about the synthesis of silsesquioxanes, their properties, and the favorability for three-dimensional material formation using these molecules. Additional information will include challenges and histories of siloxane based protective coatings and the use of both photo-radical and photo-acid-generating initiators in them, along with a brief explanation of photo-switches, specifically azobenzene and its derivatives and their use in sol-gels. Chapter II will discuss protective coatings for monuments and the specific needs associated with these materials. A history of the types of materials used and their faults will detail the desire for new materials aimed at this application. The development of a coating with three distinct curing methods (including photo-radical and photo-acid generating processes) which forms a protective layer with a mixture of partially formed polisilsesquioxane and oligosilsesquioxane structures as the backbone of the network. Findings and properties of the resulting coating formulations, modifiability, and alternative functionalities will be discussed in detail. Chapter III will discuss the use of photo-switches as crosslinkers in silicon-based networks. Previous work utilized Q-type silsesquioxanes (Q8M8H) and 4,4'-diallyloxyazobenzene (DAA) to develop photodynamic sponges. The modification process of these sponge materials, through both in-situ and post-polymerization functionalization, will be described. The effects on solvent preference resulting from the modifications will describe “sponge” uptake and swell-ability in various environmental pollutants. Chapter IV discusses the synthesis, characterizatio (open full item for complete abstract)

Committee: Joseph Furgal Ph.D. (Committee Chair); Pavel Anzenbacher Ph.D. (Committee Member); Alexey Zayak Ph.D. (Committee Member); Sri Kolla Ph.D. (Other) Subjects: Chemistry; Materials Science; Physical Chemistry

PhD, University of Cincinnati, 2023, Arts and Sciences: Chemistry

Implantable biosensors and neural electrodes serve as essential tools for exploring the brain function, the pathology of brain related disorders, and the development of therapeutic tools like deep brain stimulators (DBS) for conditions like Parkinson's disease, Alzimer's disease and epilepsy. Given that these conditions often persist throughout a person's lifetime, the consistent performance of these devices is critical. To gain insights into the complex nature of these diseases, biosensors and recording electrodes are implanted for extended durations, spanning from days to months. Therefore, these recording devices must ensure the delivery of accurate information over the entire study period. In recent decades, scientists have dedicated substantial efforts to the development of implantable devices, aiming to improve their performance for chronic applications. DBS represents one of the successful outcomes of these efforts. However, developing an ideal neural device is an ongoing challenge due to undesirable interactions with the biological environment upon implantation. The work presented in this thesis seeks to address the enduring challenges in this field and explore the potential of carbon nanotubes (CNTs) in development of neural electrodes, with the goal of improving their performance. This thesis comprises the work of three projects. The first project provides a comprehensive in vitro analysis of an anti-fouling interface based on zwitterionic molecules and CNTs. In this project, we developed an antifouling interface combining zwitterionic molecules and CNTs to reduce the effect of initial inflammatory responses. The developed interface was assessed in vitro using various methods, including spectroscopy, electrochemistry, morphology, and biological testing. Accelerated aging tests were also conducted to assess the stability of the developed interface. The second project describes a continuous dip coating (CDC) technique for developing fl (open full item for complete abstract)

Committee: Noe Alvarez Ph.D. (Committee Chair); Ashley Ross Ph.D. (Committee Member); Elke Buschbeck Ph.D. (Committee Member) Subjects: Analytical Chemistry

Doctor of Philosophy, University of Akron, 0, Polymer Science

UV-curable powder coatings offer significant advantages over thermally cured powder coatings. In particular, the use of UV-light, rather than heat, provides three distinct advantages over traditional powder coating systems: 1) The ability to separate the film formation and curing processes from one another; 2) lower curing temperatures; and 3) rapid cure speeds. However, despite the potential of UV-curable powder coatings, these systems generally provide inferior mechanical properties, mediocre film formation, and only a modest improvement in low temperature cure capability. The present work addresses some of the issues associated with UV-curable powder coatings. The first part of this research developed structure-property-performance relationships for UV-curable polyester powder coatings. In Chapter III, UV-curable semi-crystalline resins were blended with a conventional UV-curable amorphous base resin. When used judiciously, the semi-crystalline resins, due to their low melt viscosities, dramatically improved the film formation properties of the coating without tremendous sacrifices to thermal or mechanical performance. In Chapters IV-V, crystalline urethane methacrylates were synthesized and used as reactive diluents for UV-curable polyester powder coatings. This novel approach demonstrated that crystalline small molecules could be used to reduce the melt viscosity of the amorphous resin, improve the thermo-mechanical properties of crosslinked films, and increase the photopolymerization rates and conversions. Studies were also conducted to understand how these reactive small molecules affected the crosslinked network structure. In Chapter VI, a systematic investigation on the extent of branching in UV-curable polyester powder coating resins was conducted. Branching altered the rheological and thermal properties of the resin, the thermo-mechanical properties of the crosslinked films, and the crosslinked network structures that were created. The second part (open full item for complete abstract)

Committee: Mark Soucek (Advisor); Chrys Wesdemiotis (Committee Member); Yu Zhu (Committee Member); Li Jia (Committee Member); Coleen Pugh (Committee Chair) Subjects: Materials Science; Polymer Chemistry; Polymers

Doctor of Philosophy, University of Akron, 2021, Polymer Engineering

This work studies pigment dispersion in thermoset polyester powder coatings processed in an ultrasonic twin screw extruder (UTSE) and the real-time film formation process of methyl methacrylate (MMA) maintenance coatings. First, pigment dispersion of thermoset polyester powder coatings processed in an ultrasonic twin screw extruder (UTSE) was analyzed. A high Tg carboxylic functionalized polyester coating was extruded at several barrel temperatures and ultrasonic amplitudes. Two different crosslinkers, Triglycidylisocyanurate (TGIC) and β-hydroxyalkylamide (HAA), and pigments, TiO2 (PW6) and Phthalocyanine Blue (PB15:3), were studied. The extrudate was analyzed to quantify the amount of premature curing that occurred during extrusion via DSC. Powder coatings were created and applied to aluminum panels to study dispersion through gloss and color. It was determined that TGIC coatings had a higher risk of premature crosslinking when processed at temperatures above the crosslinker's melting point. Ultrasonic treatment was shown to improve the hue (h) of PB15 pigmented coatings and improve the lightness (L*) of TiO2 pigmented coatings. Processing was improved by ultrasonic treatment, evident by a significant decrease in torque. Next, a low Tg polyester resin was extruded in the UTSE. The combination of using a lower Tg resin and a smaller die enabled higher ultrasonic amplitudes to be studied. HAA formulations processed at 100 and 130°C, with and without a dispersion agent, were compared to each other. Scanning electron microscopy (SEM) and particle image analysis was used in addition to gloss and color change to visualize and quantify pigment dispersion. Ultrasound was shown to decrease UTSE torque, improve the hue of PB15 pigmented coatings, and improve the lightness (L*) of TiO2 pigmented coatings. SEM particle analysis revealed that ultrasound aided dispersion. Also, a model formulation of a methyl methacrylate (MMA) thermoset acrylic maintenance coating was devel (open full item for complete abstract)

Committee: Mark Soucek (Advisor); Kevin Cavicchi (Committee Chair); Fardin Khabaz (Committee Member); James Eagan (Committee Member); Sasa Dordevic (Committee Member) Subjects: Plastics; Polymer Chemistry; Polymers

Doctor of Philosophy, The Ohio State University, 2021, Materials Science and Engineering

The corrosion phenomena in coated tinplate food cans have not been fully understood but are known to cause different failures of cans from slight discoloring to severe can perforation and leaking. The corrosion in tinplate cans for food storage is of significant importance because it can directly affect human health. Coatings containing bisphenol A (BPA) have been commonly used in the coating of metal cans for the past few decades. Due to recent health concerns about BPA, coatings with no intentional addition of BPA (BPA-NI coatings) are currently being considered. However, it is challenging to find other coatings without BPA due to the low price, and good thermal and mechanical properties of BPA. It is desirable to develop and test BPA-NI coatings that provide good corrosion resistance and performance similar to BPA-containing coatings. During the food sterilization process, the canned food is heated to an elevated temperature, and heat is known to lead to degradation of the polymer coating. Degradation of the coating can also occur slowly with immersion exposure time on the shelf. Additionally, headspace blackening, which is sometimes found in packaged protein-containing foods, is notorious for the concern it raises with customers. Volatile chemicals produced by the sterilization process and long-term storage might cause the headspace blackening. Some studies have shown that headspace blackening is related to attack by sulfur-containing chemicals. For example, the black corrosion products observed in the headspace of cans with seafood were found to contain iron sulfide. In this study, the corrosion of tinplate cans exposed to different solutions was studied through electrochemical impedance spectroscopy (EIS), X-Ray diffraction (XRD), scanning electron microscopy (SEM), and Raman Spectroscopy. To accelerate the corrosion process, cans were stored at 49 °C for varying storage times prior to testing in various solutions. EIS in the storage environment solution (open full item for complete abstract)

Committee: Gerald Frankel (Advisor); Narasi Sridhar (Committee Member); Jenifer Locke (Committee Member); Malvin Pascall (Committee Member); Stuart Mangel (Committee Member) Subjects: Materials Science

Doctor of Philosophy, The Ohio State University, 2021, Industrial and Systems Engineering

Polymer Composites (PC) nowadays have many applications due to their lightweight to strength and stiffness ratio, corrosion resistance, part integration, etc. When utilized for exterior body panels in the automotive or trucking industry and in most cases when surface quality is critical, they will need to be painted or coated. The most effective and also higher quality method for painting involves the electrostatic painting (EP) application, which provides an improved paint transfer efficiency (PTE) as well as a more uniform paint film. Another important application of PCs is for electromagnetic interference (EMI) shielding. Because most polymers are nonconductive, conductive fillers need to be incorporated to provide conductive pathways through polymer matrices. PCs should have a conductivity of 10-4 S/m for electrostatic painting (EP). and have a conductivity of 10 S/m for electromagnetic interference (EMI) shielding. Because most polymers are non-conductive, conductive fillers need to be incorporated to provide conductive pathways through polymer matrices. A more efficient method than mixing conductive fillers with the composite part is to apply a conductive thin film. For the conductivities required for EP applying a liquid coating on the surface of the parts is an excellent alternative. Industry currently utilizes the process called in-mold coating (IMC) for applying a conductive film to sheet molding compound (SMC) compression molded parts that need to be painted. And is evaluating its use to injection molded parts. The current commercial IMC material (standard IMC) contains 2.8 wt. % of CB. The CB used in the IMC, however, is a distinctive micro-particle CB, which needs special treatments and, in some cases, limits the part coverage due to the high viscosity of the coating. The standard IMC is formulated with the required conductivity to achieve maximum paint transfer efficiency (PTE). To address this issue, we developed improved alternative conductive coat (open full item for complete abstract)

Committee: Jose Castro (Advisor); Allen Yi (Committee Member); Michael Groeber (Committee Member) Subjects: Chemical Engineering; Industrial Engineering

Doctor of Philosophy, Case Western Reserve University, 2021, Macromolecular Science and Engineering

With flourishing technological advancements, recent human activities present difficult technological conditions and extreme environmental situations that have never been seen before. Therefore, to ensure the safety of humans themselves and the related technological gadgets, developing innovative and high-performing materials are essential to operate at high temperatures, ultra-high strain rates, fire-conditions, corrosive environments, and more. Polymers are a common part of such high performance materials, and are often mixed with other ingredients to create composites to provide the desired functionality. The composites discussed in this dissertation are separated into two vignettes: flame-retardant intumescent coatings and thermoplastics for ballistic protection. The first flame-retardant section (Chapter 2) presents an alternative to the reprotoxin boric acid in intumescent coatings. Defined as coatings that expand upon heating to create thick, insulative char, intumescent coatings are commonly applied to load-bearing steel beams, such as those in parking structures. Boric acid is a popular and effective additive in intumescent composites, but was recently listed as a `substance of very high concern' by the European Chemical Agency due to its reprotoxic nature. This section highlights company-sponsored work that substituted boric acid with poly(acrylic acid) to create more biologically-conscious composites with thermal performance similar to that of boric acid-containing systems. The second flame retardant section (Chapter 3) discusses highly-expansive intumescent composite coatings formulated for use in package protection, with attention to suppress lithium-ion battery fires. The increased presence of battery packs in most consumer products creates a dangerous situation in which improper standards exist to properly handle and transport said products. With interest from Underwriters Laboratories, highly-expansive intumescent formulations were developed and (open full item for complete abstract)

Committee: Gary Wnek Ph.D. (Advisor); Andrew Olah Ph.D. (Committee Member); Ya-Ting Liao Ph.D. (Committee Member); Eric Baer Ph.D. (Committee Member); David Schiraldi Ph.D. (Committee Member) Subjects: Engineering; Materials Science; Polymers

Doctor of Philosophy, Case Western Reserve University, 2021, Macromolecular Science and Engineering

Oil and gas have been the two most consumed energy sources in the world for many decades, and despite the recent growth of the renewable energies, estimates show that oil and gas will remain on top by 2045. The increasing demand for drilling, production, transportation and storage of oil and its derivatives have led to catastrophic oil spills, with severe economic, environmental and social effects. In this work, two fluorine-free, superhydrophobic/superoleophilic polymeric coatings were developed, characterized, and successfully used for oil/water separation, besides exhibiting excellent adhesion properties, and high thermal stability. Also, in order to encourage the circular economy within the oil and gas industry, and to promote the valorization of an agro waste, Miscanthus x. Giganteous was first used as a filtrate reducer for water-based drilling fluids, and its filtration properties were comparable or superior than other synthetic additives obtained by more complex, expensive and time-consuming processes.

Committee: Gary Wnek (Committee Chair); Rigoberto Advincula (Committee Co-Chair); David Schiraldi (Committee Member); Elizabete Lucas (Committee Member); Veronica Calado (Committee Member); Marcio Nele (Committee Member); Xiong (Bill) Yu (Committee Member) Subjects: Environmental Studies; Petroleum Engineering; Polymer Chemistry

Doctor of Philosophy, University of Akron, 2020, Polymer Engineering

Colors are ubiquitously present in nature and are used in several day-to-day applications such as paints, textiles, cosmetics and displays. Most of these colors are pigment-based and suffer from non-environment friendliness, toxicity and non-tunability. Structural colors have received significant attention as alternatives to degradation-prone pigment-based colors. Many non-iridescent (angle-independent) structural colors in nature are produced from porous bio-polymer nanostructures with multi-functional properties such as UV-protection and hydrophobicity. However, most bioinspired synthetic non-iridescent structural colors have been attained via self-assembly of colloids and 3D printing, but they suffer from poor adhesion and robustness. Non-iridescent structural colors in nature, on the other hand, are produced from quasi-ordered porous nanostructures and are thought to form by polymeric phase separation but have not yet been achieved artificially despite their advantages including scalability. The objective of this dissertation is to develop a polymeric phase-separation process that results in non-iridescent structural coloration. Here, we report, for the first time, fabrication of non-iridescent structural colors from porous polymers via temperature-induced phase-separation of compatibilized polymer blend films. By simply tuning the molecular parameters such as composition of the polymer blend (ϕ), the color of the films can be tuned from white to blue to transparent with underlying morphological transitions from a disordered to a quasi-ordered state. Control on brightness and color saturation can be achieved by tuning optical interfaces and structural order respectively at a molecular level without using any additives by tuning molecular weight of homopolymers and block co-polymer. Gradient non-iridescent structural colors were attained from films of differential thickness via tunable coffee ring effect. We further examined the absence of green and red c (open full item for complete abstract)

Committee: Alamgir Karim (Advisor); Matthew Shawkey (Advisor); Sadhan Jana (Committee Member); Xiong Gong (Committee Chair); Erol Sancaktar (Committee Member); Tianbo Liu (Committee Member) Subjects: Polymer Chemistry

Doctor of Philosophy, Case Western Reserve University, 2019, Macromolecular Science and Engineering

Polymers can be applied to a myriad of applications, but high flammability remains an issue for their general and engineering uses. Flame retardants (FRs) that are found in commercial products usually contain halogens, phosphorus, and other elements. However, research has shown that halogenated FRs are persistent in the environment, bioaccumulate and are toxic. An example of such FR is pentabromodiphenyl ether, a polybrominated diphenyl ether (PBDE), which was banned in the European Union and the United States in 2004. Ongoing research is being conducted to develop alternative non-halogenated FR systems that are effective and can be used in industry. Poly(1,4-butylene terephthalate) "PBT" is a semi-crystalline, thermoplastic engineering polyester produced in high volume that is used in the electrical, electronics, and automotive industries. These applications require FR PBT systems, but the most commonly used contain bromine and an antimony source. In addition, PBT poses technical challenges as it depolymerizes and dehydrates to butadiene at fire temperatures, giving off flammable gas. Chapter 2 explores a bioavailability study that examined two commercial FR PBT systems. Literature has shown that FRs may bloom out of the polymer matrix. Through thermo-oxidative aging studies, we will explore if the halogenated and phosphorus-based FRs in PBT become bioavailable through a synthetic finger oil solution. Chapter 3 demonstrates the use of additives derived from nature as non-halogenated FR alternatives for PBT. The thermal, flammability and mechanical properties of the bio-based FR system will also be discussed. Chapter 4 explores the flammability effect of aging on lumber samples. The flammabilities of bio-based wood stain coatings are also studied before and after aging. Chapter 5 details techniques to reduce the flammability of polyurethane foam in residential upholstered furniture through testing configuration and barriers fabrics. The studies performed will c (open full item for complete abstract)

Committee: David Schiraldi (Advisor); Hatsuo Ishida (Committee Member); Gary Wnek (Committee Member); James T'ien (Committee Member) Subjects: Engineering; Polymer Chemistry; Polymers