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Item Surface Property Modification of Coatings via Self-Stratification(North Dakota State University, 2010) Pieper, Robert JosephBiological fouling occurs everywhere in the marine environment and is a significant problem for marine vessels. Anti-fouling coatings have been used effectively to prevent fouling; however, these coatings harm non-targeted sea-life. Fouling-release coatings (FRC) appear to be an alternative way to combat fouling. FRC do not necessarily prevent the settlement of marine organisms but rather allow their easy removal with application of shear to the coatings surface. These coatings must be non-toxic, non-leaching, have low surface energy, low modulus, and durability to provide easy removal of marine organisms. Here the goal is to develop FRC based on thermosetting siloxane-polyurethane, amphiphilic polyurethane, and zwitterionic/amphiphilic polyurethane systems. A combinatorial high-throughput approach has been taken in order to explore the variables that may affect the performance of the final coatings. Libraries of acrylic polyols were synthesized using combinatorial high-throughput techniques by either batch or semi-batch processes. The design of the experiments for the batch and semi-batch processes were done combinatorially to explore a range of compositions and various reaction process variables that cannot be accomplished or are not suitable for single reaction experiments. Characterization of Rapid-GPC, high-throughput DSC, and gravimetrically calculated percent solids verified the effects of different reaction conditions on the MW, glass transition temperatures, and percent conversion of the different compositions of acrylic polyols. Coatings were characterized for their surface energy, pseudobarnacle pull-off adhesion, and were subjected to bioassays including marine bacteria, algae, and barnacles. From the performance properties results the acrylic polyol containing 20% hydroxyethyl acrylate and 80% butyl acrylate was selected for further siloxane-polyurethane formulations and were subjected to the same physical, mechanical, and performance testing. Amiphiphilic copolymers based on PDMS molecular weight and the addition of PEG based polymer blocks on the properties of acrylic-polyurethane coatings were explored. The key properties screened were surface energy, determined by contact angle measurements using water and methylene iodide, dynamic water contact angle, and pseudobarnacle adhesion properties. The data from all of the biological assays indicates that the novel coatings were able to resist fouling and have low fouling adhesion for the broad variety of fouling organisms tested.Item Surface Optimization of Siloxane-Polyurethane Marine Coatings for Improved Fouling-Release Properties(North Dakota State University, 2016) Galhenage, Teluka PasanBiofouling has been an economically and environmentally costly problem to mankind ever since they set sail. Biofouling causes frictional drag leading to slow vessel speeds, and increased fuel costs. Antifouling (AF) coatings containing biocides have been used for decades, however, since some biocides have shown undesired effects towards the environment, a non-toxic solution to combat fouling is desired. Subsequently, fouling release (FR) coatings quickly gained acceptance as a non-toxic approach to contend with biofouling. Unlike AF coatings, FR coatings not necessarily prevent settlement of organisms, they permit weak adhesion which is easily released by water shear or light grooming. The siloxane-polyurethane (SiPU) coatings based on the concept of self-stratification is a non-toxic and durable approach to prepare FR coatings. In this work, several approaches were considered to optimize surface properties of SiPU coatings. Incorporation of phenyl-methyl silicone oils led to improved FR properties towards several marine organisms in laboratory assays and in ocean field immersion. Enhancement in FR properties may be attributed to slowly exuding silicone oil providing surface lubricity, weakening the adhesion of marine organisms. Addition of diphenyldimethyl siloxane in to SiPU coatings at different ratios resulted in micro-scale surface topographical features which negatively affected microfouling-release while several coatings displayed good FR performance towards macrofouling organisms. In another study, decreasing the acid group content helped to improve FR performance towards barnacles, but FR performance towards diatoms were compromised. Novel amphiphilic siloxane-polyurethane (AmSiPU) coatings from polyisocyanate pre-polymers modified with polydimethyl siloxane and polyethylene glycol displayed excellent FR properties towards several marine organisms during laboratory assays. These AmSiPU coatings show promise as contenders to commercial FR standards. Initial development of SiPU coatings with hydrophilic surfaces showed promise, as the coatings showed rapidly rearranging surfaces with comparable FR performance to commercial standards which claim hydrophilic surface properties. During freshwater field immersion trials, SiPU coatings displayed excellent mussel FR performance up to 3 years. Surface analysis suggested that solvent content affected self-stratification and morphology of SiPU coatings. The SiPU coating system is a highly tunable, tough, environmentally friendly, and practical FR solution which can evolve along with non-toxic commercial marine coatings.Item Implementation of Bus-Based and NoC-Based MP3 Decoders on FPGA(North Dakota State University, 2011) Kasisomayajula, Subramanyam VenkataThe trend of modern System-on-Chip (SoC) design is increasing in size and number of Processing Elements (PE) for various and general purpose tasks. Emergence of Field Programmable Gate Array (FPGA) into the world of technology has lowered the limitations faced by Application Specific Integrated Circuit (ASIC) design. FPGA has a less timeto- market and is a perfect candidate for prototyping purposes due to the flexibility they create for the design and this is the key feature of the FPGA technology. Technology advancements have introduced reconfiguration concepts which increase the flexibility of FPGA designs more. One method to improve SoC's performance is to adopt a sophi sticated communication medium between PEs to achieve a high throughput. Bus architecture has been improved to meet the requirements of high-performance SoCs, however, its inherently poor scalability limjts their enhancement. The Network-on-Chip (NoC) design paradigm has emerged to overcome the scalability limitations of point-to-point and bus communkation. This thesis presents an investigation towards NoC versus bus based implementation of an SoC. An MP3 decoder has been selected as an application to be implemented on the proposed design. The final design in the thes is demonstrated that the NoC based MP3 decoder achieves a 14% faster clock frequency and real time operation with the NoC based design decode an MP3 frame on average in 10% less time that the bus based MP3 decoder.Item Magnesium Alloy Particulates used as Pigments in Metal-Rich Primer System for AA2024 T3 Corrosion Protection(North Dakota State University, 2011) Xu, HongAs an alternative to the present toxic chromate-based coating system now in use, the Mg-rich primer technology has been designed to protect Al alloys (in particular Al 2024 T3) and developed in analogy to Zn-rich primers for steel substrate. As an expansion of this concept, metal-rich primer systems based on Mg alloy particles as pigments were studied. Five different Mg alloy pigments, AM60, AZ91B, LNR91, AM503 and AZG, were characterized by using the same epoxy-polyamide polymer as binder, a same dispersion additive and the same solvent. Different Mg alloy-rich primers were formulated by varying the Mg alloy particles and their pigment volume concentrations (PVC). The electrochemical performance of each Mg alloy-rich primer after the cyclic exposure in Prohesion chamber was investigated by electrochemical impedance Spectroscopy (EIS). The results indicated that all the Mg alloy-rich primers could provide cathodic protection for AA 2024 T3 substrates. However, the Mg alloys as pigments in metal-rich primers seemed to exhibit the different anti-corrosion protection performances, such as the barrier properties, due to the different properties of these pigments. In these investigations, multiple samples of each system were studied and statistical methods were used in analyzing the EIS data. From these results, the recommendation for improved EIS data analysis was made. CPVC studies were carried out on the Mg alloy-rich primers by using three Mg alloy pigments, AM60, AZ91B and LNR91. A modified model for predicting CPVC is proposed, and the results showed much better agreement between the CPVC values obtained from the experimental and mathematical methods. Using the data from the AM60 alloy pigment system, an estimate of experimental coarseness was done on a coating system, the first time such an estimate has been performed. By combining various surface analysis techniques, such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and confocal Raman microscopy, the oxidation products formed after exposure were identified. It was found that variation of Al content in Mg alloy could significantly affect the pH of the microenvironment in the primer films and result in the formation of various oxidation products.Item Surface Modifying Amphiphilic Additives for the Improvement of Fouling-Release Properties of Siloxane-Polyurethane Coatings(North Dakota State University, 2022) Benda, JacksonSince mankind has navigated the world’s oceans, marine biofouling has been a persistent problem with several negative economic and environmental consequences. In modern times, the buildup of biofouling causes a significant reduction in vessel speed, leading to increased power consumption, higher costs of operation, and an increase in greenhouse gas emissions. Two of the most widely used protection strategies to combat this highly complex and dynamic phenomenon include the application of biocide containing anti-fouling (AF), or more environmentally friendly non-toxic fouling-release (FR) coatings. Traditional FR coatings utilize low surface energy components such as polydimethylsiloxane (PDMS), but often suffer mechanical failure and poor adhesion to the substrate. Recently, the development of a self-stratifying siloxane-polyurethane (SiPU) FR coating combined the desirable FR properties of PDMS containing materials, with the mechanically durable and tough attributes of a polyurethane. Several methods to improve on the FR properties of these coating systems involved the incorporation of hydrophilic moieties like polyethylene glycol (PEG), zwitterionic polymers, or carboxylic acid containing groups into the SiPU network, producing a heterogenous, amphiphilic surface. These types of amphiphilic surfaces have great potential to become a major component of the next generation of highly performing FR coatings. In this work, the use of non-reactive surface modifying amphiphilic additives (SMAAs) consisting of PDMS and PEG was explored as a viable method for further improvement of FR properties of SiPU coatings, while also maintaining coating integrity in marine environments. Additives with varying amounts of PDMS and PEG content were incorporated at several concentrations in both hydrophobic, and inherently amphiphilic SiPU FR coating systems. It was shown that these additives significantly alter the surface properties and morphology, producing surfaces that improve AF/FR performance against several model marine fouling organisms. The methodologies used for these types of coatings were also applied to a non-FR, polyurethane coating. This allowed for a more fundamental investigation into how these SMAAs are distributed throughout a coating system, and how FR properties arise. Lastly, commonly used FR coatings, including SiPUs, were applied to oil boom fabrics to observe their effect on FR properties and cleanability.Item Highly Functionalized Thermosets from Renewables for Composites and Coatings Applications(North Dakota State University, 2017) Yu, ArvinRenewable sources have attracted attention due to their affordable cost and wide availability. Vegetable oils are renewable sources that have been extensively studied as potential replacement for petroleum derived chemicals. However, vegetable oils tend to produce soft materials with modest properties due to their chemical structure. Consequently, their modifications have been studied to develop high performance materials with improved properties. One of the modifications involves substituting the glycerol core with sucrose to increase the functionality per molecule. Another approach is converting the less reactive internal carbon-carbon double bonds with the more reactive epoxy groups, which permits access to a variety of crosslinking pathways. Epoxidized sucrose soyate (ESS) is a sucrose ester fatty acid (SEFA), which was epoxidized via the Prilezhaev reaction. ESS has a rigid sucrose core and epoxy functionalized fatty acid side chains. The high functionality of ESS was exploited and it was converted to methacrylated and carbonated resins. The methacrylated resins were applied in producing themosets by free-radical polymerizations while the carbonated resins were studied in step-growth polymerizations. Several studies were done to exploit the high functionality of the methacrylated resins: reduction of the viscosity while increasing crosslinkable moieties, introduction of ductility, structure-property relationships, and investigation of resin versatility in photocurable systems. Meanwhile, the carbonated resins were used to form non-isocyanate polyurethane (NIPU) coatings via cyclic carbonate-amine reactions. Overall, the highly functionalized bio-based thermosets showed very promising properties for composites and coatings applications.Item Investigation of Novel Approaches for Improved Amphiphilic Fouling-Release Coatings(North Dakota State University, 2020) Rahimi, AlirezaMarine biofouling has troubled mankind, both environmentally and economically, since they set sail, resulting in many undesired consequences such as increased drag, reduced maneuverability, increased fuel consumption and greenhouse gas emissions, and heightened maintenance costs. This problem is highly complex as it involves more than 4000 marine organisms with varying modes of adhesion and surface preferences as well as many aquatic environments. The common state-of-the-art approaches to contend with marine biofouling on the submerged surfaces of ships in seawater has antifouling (AF) and fouling-release (FR) surfaces. As AF coating systems utilize biocides which are often toxic to the environment to prevent settlement of biofoulants, the endeavors have been shifted towards non-toxic FR marine system. Many FR systems take advantage of low surface energy and modulus polydimethylsiloxane (PDMS) on their surface, while the recent attempts explored the simultaneous effect of PDMS and hydrophilic moieties (i.e. polyethylene glycol (PEG) or zwitterionic polymers) on an FR surface, known as amphiphilic surfaces. Thus, the work in this dissertation focused on attaining amphiphilic surfaces with desirable FR performance. The studies in this dissertation were investigated to deliver two goals: 1) Enhancing the (FR) fouling-release performance of previously developed coating systems; 2) Introducing novel fouling-release marine coatings with set criteria. To address the former, a series of amphiphilic additives containing PDMS and hydrophilic polymers (zwitterionic-based or PEG) were prepared in chapters two-five. These additives were incorporated in several previously developed FR coating systems in order to modify their surfaces and enhance their FR performance. To address the latter, two amphiphilic marine coating systems were explored for accessing durable, non-toxic, and effective FR surfaces using epoxy-amine crosslinking chemistry. Overall, the studies in this dissertation not only demonstrated viable FR surfaces with desirable performance against several representative marine organisms such as N. incerta, U. linza, C. lytica, barnacles, and mussels but also contributed a deeper understanding about the effect of amphiphilicity concentration/balance on surface and FR properties.Item Modification of Diglycidyl Ether of Bisphenol-A Epoxy Primer for Multi-Substrate Application(North Dakota State University, 2022) Chea, GwendorleneTraditional vehicles and aircraft have consisted primarily of steel and aluminum alloys which due to their density, has resulted in various logistic problems including transportation, maneuverability, fuel efficiency. These hindrances have led to a major increase in the incorporation of composites material into this equipment. As the use of these composite increases, multi-substrate coating systems that can provide adequate corrosion protection to metal components, as well as superior adhesion and flexibility to the composites, are needed. The goal of this work is the modification of diglycidyl ether of bisphenol-A epoxy coating systems for improved flexibility and adhesion for the development of multi-substrate primer. For this purpose, commercial additives of various chemistry (liquid rubber, polysulfide, novolac phenolic resins, silane coupling agents, and polyethers) were incorporated into a model epoxy-polyamine coating and their effect on flexibility and adhesion was investigated. Based on their performance, the top-performing additives were incorporated into a fully pigmented modified primer. Overall, the studies in this dissertation not only demonstrated improved flexibility and adhesion to metal and composites but also improved overall corrosion protection compared to an unmodified primer.Item Phytic Acid Enriched Biobased Membranes for Lead Ion Removal From Water(North Dakota State University, 2021) Ukey, Mayur IndalPollution by heavy metals, such as lead (Pb), in bodies of water is a serious problem today that poses great risk to human health and the environment. In this study, cellulose-acetate (CA) based membranes were synthesized by immersion precipitation process, and commercially available CA membranes were modified by a layering method. Phytic acid (PA), a phosphorus rich compound known for its chelating properties, was doped into the membrane films to improve their efficiency in removing Pb (II) ions from water. As formulation additives, cellulose nanocrystals (CNCs), amine-functionalized cellulose nanofibers (CNFs) and chitosan were used. Mechanical properties, and filtration efficiency of the resulting membranes as a function of PA content, PA incorporation method, and additive types were assessed. Synthesized membrane films containing CNC, and chitosan/ PA coated membrane films showed up to 60% and 90% removal of Pb (II) ions respectively from water.Item Corrosion Investigation of Structural Transition Joints Through Scanning Electrochemical Microscopy and the Characterization of High-Temperature Coatings at Different Temperatures(North Dakota State University, 2021) Wiering, Luke PeterScanning electrochemical microscopy is a method that incorporates an ultramicroelectrode capable of facilitating electrochemical reactions paired with an XYZ positioning system capable of micron-level movements. This study investigates the corrosion behavior of structural transition joint clad material that contains steel, pure aluminum, and an aluminum alloy blast welded into a single joint. This study will characterize the corrosion response of the structural transition joint and identify the galvanic activity measured between its layers. High-temperature coatings in this study are designed to be used effectively up to 1400°F. In this study, we characterized several commercial high-temperature coatings exposed to different levels of heat. General trends of decreasing barrier performance were observed with the exception when these coatings are exposed to their rated temperature limit of 1400°F, at which the barrier increased slightly, indicated by their low-frequency impedance modulus. The cause is a combination of sintering and oxide formation.