Doctor of Philosophy, University of Akron, 2022, Polymer Engineering

Epoxy resins are versatile thermosetting resins providing properties like strength, durability, compatibility with various substrates, chemical and corrosion resistance to their cured system, making them a preferred choice in applications like aerospace, marines, electronics, and construction. Recently, the demand for lightweight multifunctional materials has increased, especially in the aerospace and electronic sectors. However, it is not easy to develop lightweight multifunctional materials using typical epoxy resin formulations consisting of epoxy resin, curing agents, fillers, and other additives. Developing multifunctional components for epoxy resin formulations is a promising approach to achieving lightweight epoxy composites. In this work, we develop a coordination polymer-based multifunctional filler for epoxy resins using an ionic liquid, 1-ethyl-3-methylimidazolium dicyanamide. The discussion involves understanding the influence of constituent ions like metal salts, ligands, and solvents on the structure and properties of coordination polymer(CP) to develop insight for engineering desired structure of CP. This work shows two approaches for synthesizing the desired CP using mineralizing agents like water and alkali chloride salts. Different starting metal salts and mineralizing alkali salts were used to understand the influence of cations and anions in the reaction system on the yield and structure of the desired CP, which helped provide insight to engineer synthesis approaches for the desired CP. The last part of the work focuses on using synthesized CP as a multifunctional filler in an epoxy system. We discuss the additive and concentration effects of CP loading in an epoxy resin system towards developing an epoxy resin-based conductive adhesive.

Committee: Ruel McKenzie (Advisor) Subjects: Aerospace Materials; Automotive Materials; Engineering; Materials Science; Polymers

Master of Science (MS), Ohio University, 2012, Electrical Engineering (Engineering and Technology)

Curcumin is a versatile chemical. It is used in food, medicine and electrical engineering. Use of curcumin in medical fields has been concentrated on the treatment of cancer, but it is a traditional spice that has been used in food preparation for millennia. Curcumin has seldom been used in physics, and electronics. In fact, curcumin gained its importance for its under representing ligand suitable for holding metal ions suspended in an insulating matrix of organic polymer. It consists of two regions: The ¿¿¿¿--diketone moiety for holding the metal, and the phenol group for attaching to the organic polymer. Its electronics applications have been focused primarily on the conversion of light to electricity. The unmodified structure of curcumin is not stable enough for photoluminescence because of its severe absorption in 340 nm - 535 nm wavelength range. Surprisingly, modified curcumin structures proved to be photo stabile in the visible range of 420 nm - 580 nm. Recently it was reported that 0.6% efficient photovoltaic material can be achieved using curcumin. In addition, curcumin dyes are chemically stable and eco-friendly. The project began with Dr. Butcher's, Department of Chemistry, Ohio University, suggestion that curcumin might serve as a means for making electrically conducting polymers. Initial work conducted by this research led to the investigation of photovoltaic properties of engineered curcuminated epoxy and ITO glass as a transparent electrode. No photovoltaic behavior was observed, but the changes in resistance noted that were sufficiently interesting to warrant detailed investigation. In the project, we used purified curcumin to prepare a novel copper doped curcuminated epoxy polymer and studied electrical properties at ambient temperature. The Design of Experiments method was applied to this study for the purpose of determining the significance of various constituents on the conductivity. Sixteen compositions were prepared and investigated using a Kei (open full item for complete abstract)

Committee: Jadwisienczak Wojciech PhD (Advisor); Savas Kaya Savas (Committee Member); Butcher Jared (Other); Whaley Ralph (Committee Member) Subjects: Engineering

Master of Sciences (Engineering), Case Western Reserve University, 2008, Macromolecular Science

Polymerization induced phase separation (PIPS) is a widely existing process where an initially miscible, single-phase mixture undergoes phase decomposition during the polymerization of one component, and finally transforms to a phase separated blend. In this thesis, a study of PIPS in DGEBA based epoxy/poly(ε-caprolactone) systems is presented in two parts. The first part involves monitoring of the phase separation process and final morphologies, including an investigation on the impact of processing conditions on ultimate morphologies. The second part contains a series of thermomechanical studies of cured epoxy/poly(ε-caprolactone) blends. It has been discovered that at relatively high temperatures (60 °C~200 °C), depending on the morphology, the material can behave as a high-strength glassy polymer, a low-Tg chemically crosslinked semi-interpenetrating network (semi-IPN), or a physically crosslinked “pseudo-elastomer”. Such epoxy/poly(ε-caprolactone) blends have a great potential and versatility for a large range of applications.

Committee: Patrick Mather (Advisor) Subjects:

Master of Science, Miami University, 2024, Mechanical and Manufacturing Engineering

Selective laser sintering (SLS) technique has emerged as an important method in additive manufacturing, facilitating the manufacturability of complex lattice structures, known for their high stiffness-to-weight ratios. However, these structures face mechanical limitations, such as low compressive strength and energy absorption, restricting their use in demanding industries like aerospace and automotive. This study addresses these challenges by reinforcing SLS-printed Nylon 12 (Polyamide 12, PA12) lattice structures with thermoset resins (Bisphenol A, BPA epoxy), forming layered composites that significantly improve compressive performance. A continuous rotation coating technique was introduced to overcome the uneven reinforcement observed in traditional dip-coating methods, achieving a uniform resin distribution. The optimized coating method resulted in a 13% improvement in compressive yield strength compared to dip-coated samples, contributing to an overall 139% increase relative to unreinforced PA12. Further enhancement was achieved through the incorporation of functionalized graphene nanofillers into the PA12/thermoset matrix, with the optimal configuration (68:32 PA12-to-BPA epoxy ratio with 0.1 wt% graphene) yielding a 201% increase in compressive yield strength and a 154% increase in specific energy absorption. Image analysis confirmed improved adhesion, and improved structural integrity at the samples with optimal configuration. Findings from this study provide a pathway for industrial applications of SLS-printed lattice structures, enabling lightweight, high-strength components for aerospace and automotive industries.

Committee: Muhammad Jahan (Advisor); Kumar Singh (Committee Member); Jinjuan She (Committee Member); Yingbin Hu (Committee Member) Subjects: Aerospace Materials; Automotive Materials; Engineering; Materials Science; Mechanical Engineering

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

The purpose of this research was to synthesize and incorporate two novel spirocyclic, phosphorous containing reactive flame-retardant for inclusion in polymer systems, such as epoxy resins, with variable applications in industry. The novel compounds are P-SBE-1 and P-SBE-2. The target P-SBE-1 has been synthesized and fully characterized utilizing 1H-, 13C- and 31P-NMR spectroscopy. This compound has also been successfully incorporated into an epoxy resin and showed very promising flammability results. The target P-SBE-2 will require further efforts to complete its synthesis and characterization.

Committee: Vladimir Benin Dr. (Advisor); Donald Klosterman Dr. (Committee Member); Shawn Swavey Dr. (Committee Member) Subjects: Chemistry; Materials Science

Master of Science in Engineering, University of Akron, 2022, Civil Engineering

This paper details the research analyzing the effects of monotonic and cyclic loading on beam-end specimens with corrosion. The test consisted of 44 beam-end specimens tested in a vertical setup with a 55-kip actuator. Each step of the experimental process from specimen design, concrete cast and curing, accelerated corrosion procedure, and testing of each specimen are described in this paper. The variables that were the focus of this study were: Concrete cover (ranging from 1in to 3in), diameter size of rebar (#5, #6, and #8), presence of transverse stirrups, corrosion level (0%-20%), and the ratio of concrete cover to the diameter of the rebar. Additionally, Sajedi and Huang's (2015) bond strength model was evaluated for its accuracy in predicting the bond strength. Finally, each variable was analyzed to determine the impact they had on the failure modes (splitting or pull-out) for reinforced concrete.

Committee: Qindan Huang (Advisor); David Roke (Committee Member); Ping Yi (Committee Member) Subjects: Civil Engineering

Master of Science (MS), Ohio University, 2020, Industrial and Systems Engineering (Engineering and Technology)

Additive manufacturing (AM) is well known for its freedom of design, but components that are printed or solidified in layers are weak compared to solid castings. This research develops a method of rapid tooling that uses a cost-effective AM process to create dissolvable mold boxes that, when cast out of a filled thermoset material, produce durable tools for injection molding. The method, otherwise referred to as the rapid dissolvable mold box (RDMB) method, describes the steps required to start with a moldable part design and finish with a tool capable of being used in both hobbyist level and industrial-grade injection molding machines. Testing and statistical analyses prove the addition of CNTs has a significant effect on the impact, flexural, and compressive properties of a cast epoxy tool as well as the time required to cool in between molding cycles. These findings, and others, suggest that CNTs are an excellent additive for polymer tooling materials. The method successfully reduced rapid tooling material costs by 75 and 84 percent when it was applied and tested. It is also hypothesized to be an effective solution for creating tools for extrusion, blow molding and end-of-arm tool applications.

Committee: Dale Masel PhD (Advisor); Tao Yuan PhD (Committee Member); Gary Weckman PhD (Committee Member); Chulho Jung (Committee Member) Subjects: Design; Engineering; Mechanical Engineering; Polymer Chemistry; Polymers

Doctor of Philosophy, Case Western Reserve University, 2020, Macromolecular Science and Engineering

Epoxy adhesives constitute a large majority of the structural adhesive market. Most of these adhesives are 2-component systems consisting of a bisphenol A based resin and an amine based hardener. Bisphenol A is an endocrine disruptor and a known carcinogen, as well as derived from petroleum which in itself is a finite resource. Due to these disadvantages, BPA has been banned in multiple countries and replacements for BPA based resins are persistently sought. One of the most common amine curing agents used in epoxy adhesives is petroleum derived isophorone diamine (IPDA) which has been found to be toxic and a skin sensitizer. The need for adhesive systems that can replace bisphenol A based resins and petroleum based IPDA has never been more urgent. A family of biobased epoxies derived from diphenolic acid (DGEDP epoxies) were recently synthesized that have an estrogen binding capacity of an order of magnitude less than BPA but similar thermo mechanical properties to the diglycidyl ether of bisphenol A (DGEBA), the most commonly used epoxy resin derived from BPA. This family of resins, differing amongst each other only in ester chain length in terms of structure exhibited excellent potential as suitable replacements to DGEBA. Their curing kinetics with regards to IPDA were studied to determine which resin would be suitable for adhesive applications. Isoconversional analysis indicated that the resins cured via an autocatalytic mechanism and modeling of the curing behavior using the Kamal Sourour model showed that the methyl ester resin (DGEDP-methyl) exhibited unusually high curing rates. This resin was then chosen for further development as the resin component for a biobased adhesive. However, when lap shear samples on aluminum were prepared, DGEDP-methyl when cured with IPDA exhibited extremely brittle behavior failing at very low stresses. A commercially available highly aliphatic biobased epoxy resin (NC-514) derived from cashew nut shell liquid was hypot (open full item for complete abstract)

Committee: Ica Manas-Zloczower Prof. (Committee Chair); Donald Feke Prof. (Committee Member); Gary Wnek Prof. (Committee Member); Rigoberto Advincula Prof. (Committee Member) Subjects: Materials Science; Polymers; Sustainability

Doctor of Philosophy, University of Akron, 2019, Mechanical Engineering

The epoxy resins are well known for its advanced mechanical and chemical properties that they have been of significant industrial and commercial importance since decades ago. Nowadays, more and more fields are utilizing it as structure materials where a great toughness is required, which is, however, not an outstanding property for the virgin kind of epoxy resins. Considering this, toughened epoxy resins are awaited to be developed. In this dissertation, we tried epoxidized poly(styrene-butadiene-styrene) as modifiers to ensure a good distribution among the epoxy matrix. And SBSs of different topologies, various molecular weight are prepared to study the corresponding effect on toughening. For samples containing each type of SBS, different composition and epoxidation degree are tried to have a systematic understanding of influences on the toughening effect from these factors. Mechanical behaviors and the toughening mechanisms are summarized according the results obtained. It is found that epoxidized SBS with higher molecular weight and multi-armed structure will enhance the impact resistance more effectively, while a polydispersity of the SBS will result in samples of higher strain at break. The kinetic precipitation of SBS during the epoxy curing is will automatically form the SBS particles, which is of relatively wide distribution. While a general trend is still obtained that SBS with better compatibility with the matrix would be of smaller but narrower-size-distributed particles, and further addition of SBS cause this distribution and average size to be larger. According to the results obtained, we found that cavitation is not necessarily a precondition for inducing of shear yielding, since there exit small particles with whitening borders and semi-induced shear bands around in our epoxidized S4318 containing samples, without a cavitation, however. This indicates that the shear yielding could be formed ahead of the formation of cavitation, although the dilatio (open full item for complete abstract)

Committee: Shing-Chung Wong (Advisor); Xiaosheng Gao (Committee Member); Kwek Tze Tan (Committee Member); Rajeev Gupta (Committee Member); Dmitry Golovaty (Committee Member) Subjects: Chemistry; Materials Science; Mechanical Engineering; Polymers

Doctor of Philosophy, The Ohio State University, 2019, Materials Science and Engineering

Metal-rich primers have been used for corrosion protection on metals for over 40 years. Recently, researchers started to investigate the use of metal-rich primers on aluminum alloys as an alternative to hexavalent-chromate systems because of their good corrosion-protective properties. The active aluminum-rich primer (AlRP) was invented and developed at NAVAIR (Patuxent River, MD) to protect aluminum alloys and steels. The Al alloy (Al-Zn-In) pigments in AlRP were fabricated from a sacrificial anode alloy, which has a lower open circuit potential (OCP) than common aluminum alloys. However, initial results indicated that the pigment particles in AlRP tended to undergo severe self-corrosion. Therefore, the Al pigments are pretreated in a trivalent chromium passivation (TCP) bath to reduce the self-corrosion rate. The objectives of this study are to understand the corrosion protection properties of AlRP on aluminum alloy 2024-T3 substrate and to evaluate the effect of TCP treatment on the Al pigment particles. The polarization curves of AA2024-T3 and the active aluminum alloy (Al-Zn-In) show that TCP-treated active aluminum alloy has a lower corrosion potential than AA2024-T3 and thus would cathodically protect it. AlRP-coated samples were exposed in accelerated exposure tests, GMW14872 and B117. Exposed samples were then examined using scanning electron microscopy and energy dispersive X-ray spectroscopy to understand the coating degradation process. In addition, samples were immersed in 0.1M NaCl solution for an extended time and were monitored using electrochemical impedance spectroscopy. The AlRP with TCP-treated pigments out performs the coating with untreated pigments. The TCP treatment on the Al-Zn-In pigments was evaluated. The chemistry and morphology of Al pigment particles treated in a TCP bath for three different immersion times were characterized using X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and ener (open full item for complete abstract)

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

Doctor of Philosophy, Case Western Reserve University, 2019, Physics

Recently, bio-based materials are increasingly considered to replace traditional components for opto-electronic applications as part of a massive effort to reduce our carbon footprint. This thesis describes opto-electronic applications developed for two classes of bio-based materials, a bio-based epoxy and bacterial cellulose mats, and it also describes the dielectric investigation of thermoplastic polyurethane composites with improved properties for sensing applications. Specifically, a series of bio-based epoxy resins with similar chemical structure to petroleum derived diglycidyl ether of Bisphenol A (DGEBA), are considered as a replacement for energy capacitive storage applications. Also applications were developed for bacterial cellulose, a bio-based 3D matrix of cellulose fibers produced by a bacterial culture. Ultra-thin (<1 μm thick) bacterial cellulose mats were produced and shown to have antireflective properties for silicon wafers suggesting antireflective applications for silicon based solar cells. Bacterial cellulose has an interesting and complex geometry consisting of entwined, crystalline, cellulose nanofibers. Also, electro-optical switchable window devices were fabricated with bacterial cellulose mats filled with liquid crystals as the electro-optical component. Additionally, the bicontinuous network of nanpores is an interesting environment for studying liquid crystal physics. Dynamic light scattering and broadband dielectric spectroscopy were employed to study the liquid crystal relaxations for the composites give insight into the fundamental liquid crystal physics of the system. Lastly, thermoplastic polyurethane composites using different ratios of carbon nanostructure and graphene nanoplatelet inorganic fillers were investigated for mechanical and dielectric properties. Composites with 0.5 weight percent of filler were considered for temperature sensing applications. Additionally, composites with 2.0 weight percent of filler we shown to have a (open full item for complete abstract)

Committee: Kenneth Singer (Advisor); Ica Manas-Zloczower (Committee Member); Rolfe Petschek (Committee Member); Charles Rosenblatt (Committee Member) Subjects: Physics

Master of Science (M.S.), University of Dayton, 2018, Chemical Engineering

A series of eight novel phosphoryl hydrazine compounds were evaluated for their effectiveness as co-curing flame retardants (FR) in an epoxy resin system. First, the FR compounds were systematically evaluated with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) for their behavior in pure form and when co-cured with epoxy. The phosphorous content was kept constant at 2.5 wt% for each formulation. Results showed that three of the FR compounds were able to cure with the epoxy, while the others were not. Incorporation into the network increased the onset temperature of the flame retardant action according to DSC results. Cured samples were also characterized with microscale combustion calorimetry (MCC). Three of the formulations showed excellent flame retardation, as indicated by a 30% reduction in total heat release and three times increase in char yield compared to the control sample (no flame retardant). It proved difficult to scale up the formulations to making resin plaques for further testing due to the release of gas bubbles not observed in prior work with smaller samples. Limited success was achieved with one compound, with which 4 inch x 4 inch cured resin plaques were produced for cone calorimeter testing. Cone calorimeter results indicated good char formation behavior, but only a minor reduction in peak heat release rate (HRR) compared to the control sample. Also, it exhibited a highly erratic char formation and gas/fire plume formation, which led to poor reproducibility in heat release measurements. The level of gas/fire plume formation was undesirably high, but the smoke release rate was much lower than the control. Despite an only minor reduction in peak HRR, the flame-retardant effects that were characterized for this compound showed promise in regards to the mechanism of flame retardancy and lowering of total heat release and total smoke release.

Committee: Donald Klosterman (Advisor); Alexander Morgan (Committee Member); Vladimir Benin (Committee Member) Subjects: Chemical Engineering; Materials Science

Master of Science (MS), Wright State University, 2018, Chemistry

The emerging world of nanotechnology has been of great interest within the last few decades. In this regard, nanomaterials have since been implemented in a number of commercial applications including: aerospace technology, coatings, sensors, and biomedical technology. This work aimed to elucidate upon the applications of transition metal nanomaterials in two separate experimental studies. The first of these studies involved the investigation of two-dimensional molybdenum disulfide (MoS2) nanoparticles, and their role in the toughening mechanism of epoxy composites. Two separate exfoliation techniques were implanted to target the influence surface chemistry of the nanomaterial and solvent quality had on the bulk thermal, mechanical and chemical properties of the nanocomposite system. A suite of characterization tools including UV-Vis spectrophotometry, differential scanning calorimetry, thermal gravimetric analysis, dynamic mechanical analysis, FT-IR spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were executed to provide detailed information regarding property changes. In addition, a method was developed to monitor the nanoscale fracture mechanics of MoS2-epoxy nanocomposites using micro-tensile testing and SEM upon altered films. Results concluded that surface functionality of MoS2 within the studied models played a significant role in the toughening mechanism of epoxy composites. In addition, it was found that solvent quality greatly contributes to the curing behavior, as well as the chemical network formation of the material system. The second study involved a systematic investigation of the toxicity mechanism behind positively charged cetyltrimethyl ammonium bromide (CTAB)-capped silver nanoparticles (AgNPs) in Sprague-Dawley rats. To fully assess the toxic effects within the studied specimens, CTAB-capped AgNPs, as well as Ag+ and CTAB solutions were orally administered to experiment (open full item for complete abstract)

Committee: Ioana Pavel Ph.D. (Advisor); Steven Higgins Ph.D. (Committee Member); Dhriti Nepal Ph.D. (Committee Member) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 2018, Industrial and Systems Engineering

Light weighting is a cornerstone of the automotive industry's push to achieve greater fuel economy, thereby conserving fossil fuel resources and decreasing CO2 emissions. Composites are the focus of much of the research in the light weighting space. Carbon fiber laminates in particular, are one of the leading material choices because they have a high strength to weight ratio, and exceptional energy absorption characteristics, coupled with being almost completely impervious to the effects of environmental factors. These highly desirable properties are contrasted by characteristics that have limited the use of carbon fiber composites in many situations. In the cost driven automotive industry, high material cost is one of the main limiting factors for the introduction of new technology. Additional hidden costs arise from the highly anisotropic material behavior. This leads to joining difficulties requiring exceptional increases in the time spent on design and simulation of composite material systems. The combination of these costs limits their use in many situations. Progress is constantly being made to improve carbon fiber material and production costs as well as the design and simulation systems for composite materials in general. One area that still has opportunities for substantial improvement is in the joining methods for composite structures. This was the basis of the authors' previously researched hybrid joining method. The focus of this research is to understand the strengthening mechanisms of multi-axial loads on the epoxy adhesive system used in composite joints. This is integral to the strength improvement of the previously investigated hybrid structural composite joining method. This was accomplished by investigating two main areas, the bulk epoxies under test using basic tests, and a simplified version of the hybrid joint under different compression values and inclusion/epoxy/thickness combinations. Bulk epoxies were tested using ASTM D638 co (open full item for complete abstract)

Committee: Jose Castro (Advisor); Rebecca Dupaix (Committee Member); Soheil Soghrati (Committee Member) Subjects: Industrial Engineering; Materials Science; Mechanical Engineering

Master of Science, The Ohio State University, 2017, Welding Engineering

Bi-metal structures made of aluminum and steel are increasingly used for light-weighting applications. Replacing steel parts with aluminum in the body in white can reduce the weight of a vehicle up to 30%. The coefficient of thermal expansion (CTE) of aluminum is almost twice that of steel. Due to such large CTE mismatch, thermal buckling can become a concern when the bi-metal structure is exposed to elevated temperature. When adhesive is added between the aluminum and steel, its curing process can be affected due to buckling of the dissimilar metals. Moreover, stress in the structure developed at high temperature can be permanently locked in when the adhesive fully cures. This can lead to a higher residual gap between the aluminum and the steel than in structures without adhesive. The objective of this research is to quantitatively understand the stress and strain evolution in a bi-metallic Al / adhesive / steel structure exposed to a thermal cycle representative of that used in automotive paint bake process, including delamination of adhesive between the substrates. To achieve this objective, it is essential to first capture the behavior of the bi-metallic structure without adhesive and validating such models. Once validated, addition of cured adhesive and its delamination behavior is then incorporated. Delamination behavior relies on the fracture energy release rate of the adhesive material, which is determined through fracture toughness testing. Specially, the research consists of the following two main tasks. First, preliminary finite element models have been developed to capture the behavior of thermal induced buckling, including its deflection profile and stress close to the fasteners. These studies revealed that for a maximum paint bake temperature of 180°C residual stress is only found within the fastening region. This indicates that paint bake process itself does not produce enough heat to exceed elastic strain limits of the bulk structure. Several ge (open full item for complete abstract)

Committee: Wei Zhang (Advisor); Avraham Benatar (Committee Member) Subjects: Engineering; Materials Science; Mechanics

Doctor of Philosophy, The Ohio State University, 1987, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1966, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

MS, University of Cincinnati, 2016, Engineering and Applied Science: Materials Science

Toxicity of commercially available curing agents for epoxy resins pose a severe environmental threat. There is therefore a need for alternative non-toxic curing agents for epoxy resins. In this research, Chitosan, a biomaterial, was employed as an environmentally friendly curing agent for crosslinking Diglycidyl Ether of Bisphenol A (DGEBA) resins. Properties such as cross-linking behavior, viscoelastic behavior, and thermal stability were investigated. Curing behavior of diglycidyl ether of bisphenol A resin using chitosan was studied by Fourier Transform Infrared (FTIR) Spectroscopy. Degree of crosslinking, correlated with the epoxy fractional conversion (α), was determined by following the change in area of oxirane ring peak at 914 cm-1. Four molar ratios (Epoxy:Chitosan) 1:1, 1:2, 1:3, and 1:4 cured at three isothermal curing temperatures 160°C, 180°C, and 200°C for 5 hours, were used to determine the effect of temperature and concentration of chitosan on the epoxy fractional conversion (α). It was found that the value of `α' increased over curing time, curing temperature, and chitosan concentration. The maximum epoxy fractional conversion of 70% was obtained for molar ratio of 1:4 at 200°C. A four parameter kinetic model with two rate constants was employed to simulate the experimental data obtained from FTIR analysis. Total order of the reaction was found to be about 2.8 and the activation energy was in the range of 27-48 KJmol-1. Result obtained shows that cure reaction is autocatalytic in nature, and does not follow simple nth order cure kinetics. Avrami analysis was performed on the curing reaction and parameters such as Avrami exponent (n), rate constant (k) and activation energy (Ea) were determined. At 200°C, the value of n, k and Ea were 0.87, 8.88 and 24.21 KJmol-1 respectively for molar ratio of 1:4 (Epoxy:Chitosan). Dynamic Mechanical Analysis (DMA) was used to study the viscoelastic properties of the chitosan cured epoxy resin films. Glass transi (open full item for complete abstract)

Committee: Jude Iroh Ph.D. (Committee Chair); Relva Buchanan Sc.D. (Committee Member); Raj Manglik Ph.D. (Committee Member) Subjects: Materials Science

MS, University of Cincinnati, 2016, Engineering and Applied Science: Materials Science

Epoxy is a thermosetting polymer known for its excellent adhesion, thermal stability, chemical resistance and mechanical properties. However, one of the major drawbacks of epoxies is its inherent brittleness. In order to overcome this drawback, incorporation of a thermoplastic as a second phase has proven to improve the impact strength without affecting the mechanical properties of epoxy. Researchers in the past have studied polyamide/epoxy blends in terms of blend compatibility, thermo-mechanical properties and morphology via solution blending.

Committee: Jude Iroh Ph.D. (Committee Chair); Relva Buchanan Sc.D. (Committee Member); Raj Manglik Ph.D. (Committee Member) Subjects: Materials Science

Master of Science, University of Akron, 2016, Polymer Engineering

ABSTRACT Using organic coating is one of the most effective methods to prevent material from the corrosion which acts as barriers to air, ions and water. The organic/inorganic hybrid material not only combines the inorganic and organic characteristic, but also may own some unique properties. Generally speaking, the organic/inorganic hybrid coating can own the specific property from inorganic part such as: thermal stability, hardness and scratch resistance, and the specific property form organic phase such as: flexibility, toughness, impact resistance and adhesion. Also, the inorganic phase can improve the anticorrosive property of organic coating. In this dissertation, six kinds of the titanium alkoxide/epoxy hybrid coating have been prepared and characterized. The standard liquid BPA epoxy resin was modified by the 3-isocyanatopropyltrietoxysilane (IPTES). The structures were confirmed by Fourier transform infrared spectroscopy (FTIR) liquid state 29Si NMR and mass spectrometry (MS).The viscoelastic properties of coating films were tested by DMTA and DSC. General coating properties including pencil hardness, cross-hatch adhesion, pull-off adhesion, reverse impact resistance and MEK resistance were tested in aluminum panel according ASTM standards. Most importantly, the anticorrosion performance was evaluated by electrical impedence spectroscopy (EIS), 240h salt spray test in steel panel and acid undercutting test.

Committee: Mark D Soucek (Advisor) Subjects: Polymers