Chemistry Commons^™

The Effect Of The Carbon Nanotubes’ Surface Area On The Morphology And Performance Of Cellulose Acetate Nanocomposite Membranes In Nanofiltration Applications, Nouran Elbadawi

Theses and Dissertations

Population increase and climate change have significantly affected the availability of fresh water for consumption. Studies by UNESCO showed that more than 28% of the world population didn’t have access to clean safe drinking water in 2020. This situation is expected to get more serious over the coming 30 years with the limited availability of natural fresh water sources. The need to find solutions from alternative non-freshwater resources for drinking or irrigation is becoming a necessity. Within the context of desalination technologies, thousands of investigations are conducted to find the cheapest most efficient way of water treatment aiming at expanding …

Sunflower Oil-Based Wood Adhesive With High Mechanical Strength And Enhanced Bonding By Introducing Fillers, Arjun Chaudhari

Electronic Theses & Dissertations

Petroleum-based compounds are generally utilized in industries for getting higher mechanical strength for wood application, where the process of synthesis releases toxins into the environment and causes health issues.

Because of this, scientists are trying to make biobased compounds and products. In this research, sunflower polyol was used to make polyurethane (PU) resin. For the formation of polyol, an epoxidation reaction followed by a ring-opening reaction was performed. The presence of hydroxyl groups was confirmed using Fourier transform infrared spectroscopy (FT-IR) and hydroxyl value determination test to confirm the polyol formation. After that, hydroxyl groups of polyol were reacted with …

Effect Of Graphene-Based Fillers On The Properties Of Sunflower-Based Polyurethane, Vishwa Suthar

Electronic Theses & Dissertations

Polyurethane market majorly depends on synthetic materials which are noxious. This stimulated an idea to replace petrochemical resources with renewable resources for polyurethane production. Keeping this in mind, this research focused on the use of sunflower oil for the preparation of polyol and its use in polyurethane composition. The reaction mechanism of epoxidation and ring-opening was approached for the conversion of sunflower oil to polyol. During the conversion of sunflower oil, unsaturated groups of sunflower oil were converted into hydroxyl groups of polyol.

Sunflower oil-based polyol was successfully blended with methylene diphenyl diisocyanate (MDI) to form urethane bonds. Confirmative tests …

Evaluation Of Promising Eco-Friendly Flame Retardants For Bio-Based Rigid Polyurethane Foams Based On Modified Castor Oil, Prasadi Abeysinghe Arachchilage

Electronic Theses & Dissertations

Fossil fuel derivatives in the polyurethane industry are gradually being replaced with environmentally friendly alternative bio-based resources. Vegetable-oil-based polyols are emerging bio-based resources that can decrease cost competitiveness in polyurethane markets, reduce environmental impacts, and meet the urgent need for green and sustainable development strategies. Among this, interest is the use of castor oil to make polyurethane because of its inedibility and the fact that it contains many functionalizable chemical groups. However, the poor thermal stability and low load-bearing capacity of castor-oil-based rigid polyurethane foam limits its application. Two methods were used to address these limitations: (i) more hydroxyl groups …

Optimizing Process Conditions And Characterizing Elastomeric Properties Of Immiscible Polymers For 3d Printing Applications, Matthew Long

Electronic Theses & Dissertations

Within recent years, 3D printing within the plastics and polymer industries has becoming increasingly prevalent. Also known as additive manufacturing, 3D printing enables the creation of rapid prototypes for short production runs without the need for complex tooling. This allows for runs that are shorter and lower in cost than conventional processes. Polylactic acid (PLA) is a thermoplastic that is widely used in 3D printing for its mechanical properties and low cost. The qualities of PLA however are lacking in the areas of flexibility and toughness which is required in many prototyping scenarios. The solution to this is to incorporate …

Enhancing Compatibility And Mechanical Properties Of Natural Rubber Composites, Krisma Yessi Sianturi, Adam Febriyanto Nugraha, Belle Kristaura, Mochamad Chalid

Journal of Materials Exploration and Findings

Pure natural rubber (NR) exhibits low mechanical properties, necessitating the incorporation of additives like vulcanizing agents and fillers. Carbon black and silica, conventional fillers, are relatively expensive and not environmentally friendly. This study explores using Oil Palm Empty Fruit Bunch (OPEFB) fiber as an affordable, abundant, and biodegradable alternative filler for NR. However, compatibility issues arise between the nonpolar NR and the polar OPEFB fiber. A latex-starch hybrid coupling agent (CA (NR-St)) was added to the composite formulation to address this. NR, OPEFB fiber, and the coupling agent were mixed using an open roll mill with a 10 phr OPEFB …

Separation Of Organic Acids Through Direct Catalysis From Sugars, Katelyn Robinson

Chemical Engineering Undergraduate Honors Theses

Society relies on plastic products, whether they are single use or durable. A downside of plastic is that the most common type is a product of oil and oil is not only a limited resource but also a climate-damaging resource. Polylactic acid (PLA) is a bio-based, biodegradable plastic. However, the process of converting biomass to polylactic acid polymer has the largest environmental impact of the PLA production process, so alternative methods of conversion are needed (Moretti et al., 2021). The polylactic acid polymer can be made with lactic acid, which can be converted from glucose.

Dpd Guided Insight On The Formation Process Of Polyethersulfone Membranes By Nonsolvent Induced Phase Separation And The Effects Of Additives, Eric Ledieu

Graduate Theses and Dissertations

Dissipative particle dynamics (DPD), a coarse grain simulation method, was applied to the membrane formation process of non-solvent induced phase separation (NIPS) to gain further insight on the mechanism of certain variables and how they affect the final morphology. NIPS involves two solutions, an organic polymer dissolved in an organic solvent colloquially called the dope and an aqueous coagulation bath, brought into contact with one another. The solvents then mix, causing the polymer to fall out of solution as an asymmetric membrane with a dense surface layer and a more open subsurface layer in response to the decreasing solubility. Polyethersulfone …

The Influence Of Diamine Curing Additives On The Network Architecture Of Phthalonitrile Thermosetting Polymers, Tyler J. Richardson

Dissertations

Phthalonitrile monomers undergo diamine-promoted polymerization by a complex reaction mechanism involving two competitive cure pathways, forming two primary network architectures: linear polyisoindoline chains and branched triazine crosslinks. The influence of the diamine curing additive on the polymerization pathway, and the influence of the resulting network architectures on cured network properties, have not been adequately explored within the phthalonitrile field. Two structurally different diamine curing additives, bis[4-(3-aminophenoxy)phenyl] sulfone (mBAPS) and 1,3-phenylenebis((4-(4-aminophenoxy)phenyl)methanone) (AEK-134), were studied for the polymerization of resorcinol phenylphosphate phthalonitrile (RPPhPN), where the influence of diamine structure and concentration on the polymerization behavior, network architecture, and bulk thermal and thermomechanical …

New Alkyd Resins From Underutilized Indigenous Seed Oils: Synthesis And Characterization, Aliru O. Mustapha, Hakeem B. Ayoku, Halimah A. Amao

Karbala International Journal of Modern Science

The underutilization of sesame (Sesamum indicum L.), sweet almond (Prunus amygdalus), and jatropha (Jatropha curcas) seeds indicates a significant resource waste. Nine different varieties of 25% (short), 40% (medium), and 60% (long) alkyd resins were produced from the cross-section of drying, semi-drying, and non-drying oils. A large amount of conversion occurred, with the extent of the reaction (Pav) decreasing as time progressed and the corresponding increase in alkyds' average degree of polymerization (Dp) showing synthesized alkyds. Surface drying from the set-to-dry and dry-through periods climaxed at 2 hours for all the alkyds. Except for alkali, synthesized alkyd resins demonstrated outstanding …

Science Club, Danielle Gibson, Krista Andersen

Honors Program: Expanded Learning Clubs

Honors After School program for elementary age children to engage with scientific principles. Students performed hands-on experiments to explore various STEM fields. Each weekly lesson consisted of a different concept to be learned or explored by early elementary aged students.

Swelling Studies Of Poly(Ionic Liquids) In Different Solvents And Salt Solutions, Pierson Perdue, Ali Alshaikh, Creighton Baltier, Jason E. Bara, Sourav Chatterjee

Scholars Week

Poly(ionic liquid)s (PILs) represented a special class of polymers, which comprised of a polymeric backbone and ionic liquids (ILs) species in each monomeric repeating units. PILs has properties that combined the properties of ionic liquids (ILs) (i.e., high conductivity, better thermal and chemical stability, and tailor-made functionality) with the intrinsic properties of polymer (i.e., mechanical stability). This synergistic property makes PILs a good candidate for various applications such as stable-ion conductors, membranes for gas separations and sorbents. In the past, it was shown that PILs are capable of swelling when dissolved in different ILs but there are few literature reported …

Synthesis And Characterization Of Semi-Interpenetrating And Double Networks Of Sulfonimide- And Imidazolium-Containing Poly(Ionic Liquids), Jeremiah Coughlon, Seth Taylor, Jason Bara, Kevin Miller, Sourav Chatterjee

Scholars Week

In recent years, there has been increased research interest in creating electrically conductive polymer membranes with materials that are widely available and environmentally safe. Herein, we report how polymeric membranes comprised of unique combinations of ionenes and poly(ionic liquids), including a recently developed sulfonimide- and imidazolium-containing methacryloxy-based monomer, were produced via UV photopolymerization. These membranes were specifically tailored to exhibit both ionic conductivity and an affinity for carbon dioxide, which are both crucial characteristics in such applications as electron transport in lithium-ion batteries and gas sorbency in separation techniques. Monomers, such as the aforementioned methacryloxy-based ionic liquid (IL) and C4VIm, …

Synthesis And Properties Of Bio-Based 3d Printable Resins, Cameron Woods, Seth Taylor, Jeremiah Coughlon, Turner Perdue, Sourav Chatterjee, Jason E. Bara

Scholars Week

A photopolymer resin is a monomer that, when introduced to light of a certain wavelength, starts to polymerize into a solid. This has become a growing part of the 3D printing industry. There have been many advancements in the field of 3D printing, however, a lot of these resins are not environmentally friendly and even harmful if not handled in the correct manner. Plant based resins are becoming more and more popular because of their biodegradability and for the possibility of using renewable resources. Glycerol is a plant-based compound that is produced in excess in industry. Glycerol obtained from bioethanol …

Physiochemical Properties Of Urethane-Containing Ionic Liquids And Ionenes From A Non-Isocyanate Synthetic Approach, George Timmermann

Scholars Week

Ionic polymers that are designed to contain ionic liquids (ILs) in their backbones have been shown to exhibit a high degree of variability through changing the type of ionic character and the location of the ionic region within the molecule. This large amount of variability in both the structure and characteristics of ILs allows researchers to design task-specific ionic polymers and ILs for a variety of applications including gas separation membranes and solid polymer electrolytes. The synthesis of a specific class of ILs and ionenes through the incorporation of urethane groups with imidazolium rings by reacting carbonyl diimidazole with various …

Microscale Chemical Manipulation And Imaging Using Photoactive Molecules And Light, Uroob Haris

Chemistry Theses and Dissertations

Chemical manipulation with light has been an active and growing area of research with important implications in materials science, biotechnology, and environmental science. From early investigations of light sensitive materials for photography in the 19^th century, to printing billions of transistors on a semiconductor chip in present day, scientists have gained a deep understanding of photochemistry and the processes that allow us to harness light for everyday applications. In this work, we explore microscale fabrication and molecular imaging using light and photoactive molecules as foundational tools. We develop a visible-light mediated technique for high resolution microscale chemical lithography comprising …

Hydrothermal Liquefaction Of Saccharina Latissima For The Production Of Biofuel, Mayokun A. Oke

Mechanical Engineering Theses

We performed hydrothermal liquefaction of brown macroalga (Saccharina latissima) in the presence of homogenous and heterogenous catalysts such as KOH, Na₂CO₃, Pd/C, HZSM-5, Ce/HZSM-5, and Ni/SiO₂-Al₂O₃ in hot compressed water, to investigate their effects on product yield and composition in the biocrude. To investigate hydrocarbon production, we used methanol as co-solvent (methanol-to-water 1/4 vol.%) and as the only liquefaction solvent. We carried out the experiments in a batch reactor at 330^oC and 120-130 bar, and varying temperature, algae-to-water ratio, residence time, and pretreatment method. The biocrude yields …

Pyrrolopyrrole-Based Materials For High-Contrast Electrochromics, Allison Marie Hawks

Master of Science in Chemical Sciences Theses

Understanding structure-property relationships of underutilized p-conjugated chromophores is an important task for the continued discovery of materials that will find utility in organic electronic applications. Dihydropyrrolo[3,2-b]pyrroles (DHPPs) are synthetically simple and highly tailorable chromophores that can be decorated with diverse functionalities that readily manipulate optoelectronic properties useful for a variety of applications. However, a thorough understanding of how these functionalities influence properties of DHPPs that will be useful in applications such as electrochromism is unknown. Motivated to exploit the synthetic simplicity and tailorability of DHPPs, a family of DHPP chromophores was synthesized to probe how functionality and connectivity …

Design And Fabrication Of Single-Chain Nanoparticles, Vitrimers, Bottlebrush And Comb Polymers, Logan Dugas

Dissertations

The introduction of novel dynamic exchange chemistries into polymer chains and networks has shown great potential of giving next generation polymeric materials. Within the scope of this thesis, dynamic chemistry is employed to realize single-chain nanoparticles, vitrimer networks, bottlebrush and comb polymers. CHAPTER I provides a broad introduction to the topics at hand, focusing upon the techniques utilized to achieve such materials with relevant literature and understanding of the techniques and architectures explored. CHAPTER II focuses upon the synthesis of single-chain nanoparticles via a copolymerization of polyisobutylene macromonomers with norbornene monomers equipped with pendant anthracene moieties. Through this work, the …

The Synthesis, Characterization, And Utilization Of Functionally Diverse Romp-Based Bottlebrushes, Cheyenne Liu

Dissertations

Bottlebrush polymers have garnered interest in many disciplines for their unique structure-property characteristics and potential applications. These polymers typically exhibit extended rodlike conformations as a result of sterically crowded side-chains. Further, extensive work has focused on expanding the synthetic toolbox for these systems, resulting in excellent molecular weight control, diverse functional group utility and corresponding stimuli-responsive behaviors. This dissertation examines both synthetic and stimuli-responsive tools in the context of bottlebrush systems.

A broad overview of bottlebrush characteristics, synthesis, and applications is discussed in CHAPTER I. CHAPTER II focuses on the use of a chain-transfer agent in the ring-opening metathesis polymerization …

Engineered Plga Nanofibers For Drug Delivery, Andrew Mancuso

Dissertations, Theses, and Capstone Projects

Poly-lactic-co-glycolic acid (PLGA) polymers are rapidly gaining momentum as a platform for next-generation drug delivery systems due to their ease and low cost of synthesis, favorable biocompatibility and biodegradability, and lack of toxicity. In particular, the application of drug-loaded PLGA nanofibers directly to a target tissue may represent a promising alternative to traditional routes of drug administration (e.g., oral, injectable) as they offer the potential to greatly improve bioavailability, increase efficacy, and reduce off-target toxicity. Furthermore, the use of such a system may potentially allow for greater flexibility in clinical drug development, by enabling the use of compounds which have …

Carbon Dioxide Capture Potential Of Chitosan-Nanocrystalline Cellulose Aerogel Composite Materials: Synthesis, Functionalization, And Characterization, Victor Oghenekohwo

Theses and Dissertations

The carbon dioxide capture technology has been established as an invaluable player in the current global efforts to allay the warming of the planet and climate change. In this connection, the study centers on the valorization of waste organic materials for the application described herein. The sorbents, sourced from a combination of by-products of food processing and agricultural residue waste products, viz. seafood waste and sugarcane bagasse, showed prospects for selective carbon dioxide capture, adsorbing up to 5.78 mg/g of the gas at 273 K and 2.82 mg/g at 298 K, as observed on the Micromeritic ASAP 2020 surface area …

Polyethersulfone Thin-Film Nanocomposite Membrane Embedded With Amine-Functionalized Graphene Oxide For Desalination Applications, Ahmed Bahaeldin

Theses and Dissertations

Thin-film nanocomposite (TFN) desalination membranes were prepared based on a polyethersulfone (PES) support, where the polyamide (PA) layer was embedded with amine-functionalized graphene oxide (GO). The effect of adding various concentrations of functionalized and un-functionalized GO on the desalination performance, hydrophilicity, and morphology of the membranes was additionally assessed throughout this work. Scanning electron microscopy (SEM) measurements were used to assess the morphology of the membranes in combination with Brunauer-Emmett-Teller (BET) analysis. Contact angle measurements were used to gauge the hydrophilicity of the synthesized membranes. The membrane with the best desalination performance contained 1x10^-3 wt/vol% of functionalized GO in …

Magnetic Interactions In Open-Shell Conjugated Polymers, Michael Steelman

Dissertations

Most materials are closed shell in which every electron participates in a bond, resulting in unremarkable magnetometry signatures and functionalities. While rare, modern technologies rely on magnetic materials in which unpaired electrons are localized to inorganic atomic centers. In recent decades, a collection of organic open-shell π-conjugated molecules have shown magnetic ordering, albeit at exceedingly low temperatures; a result of weak noncovalent intermolecular interactions limiting long range electronic exchange. Thus, practically applicable sp orbital magnetism that persists at or above room temperature remains a grand challenge for chemistry and physics. Despite the wide variety of chemical structures afforded by organic …

Potential Of Biduri Fiber (Calotropis Gigantea) As Material For Oil Spill Absorbent, Anne Sukmawati, Wulan Septiani

Journal of Materials Exploration and Findings

Biduri fiber (Calotropis gigantea) is a natural hollow fiber with hydrophobic and oleophilic properties potentially used as oil spilled sorbent from seawater. This study aims to determine the absorption capacity and efficiency of the Biduri fiber and membrane to fuel oil. Measurement of oil absorption to seawater was carried out at various fiber weights (0.5-1.5 g), fiber composition (50-95%), contact time (10-90 minutes), temperature (30 and 50°C), and compared with commercial products. The results showed that the fiber weight variation of 0.5-1.5 g has an average absorption efficiency of 96.67%, and the highest absorption was obtained in a weight of …

Dual Ionic Liquid-Functionalized Cellulosic Materials: Thermal, Mechanical And Conductive Properties, Elizabeth Mcgrew, Kevin M. Miller Phd

Posters-at-the-Capitol

Cellulose, an inexpensive and renewable biomacromolecule, represents an intriguing synthetic foundation for new materials with task-specific properties. Here, we wish to report a synthetic route for functionalizing cellulose with a side chain containing two ionic liquid functional groups using azide-alkyne ‘click’ cyclization strategy, followed by quaternization of the two resulting heterocycles (1,2,3-triazole and imidazole). Through this functionalization strategy, the resulting cellulosic materials exhibited significant softening, with several glass transition (T_g) values observed below room temperature, indicating the amorphous nature of the materials, with the T_g dependent on both the length of the side chain and the …

Paek- And Pes-Like Perarylated Phosphonium Ionenes: Synthesis, Thermal Properties, And Conductivity, Samantha Sims

Murray State Theses and Dissertations

Ionic liquids (ILs) are useful for many applications due to the tunability of their characteristic properties making these salts ideal for many applications. To further increase possible areas of application for these materials, some ILs can be incorporated into polymer structures to form poly ionic liquids (PILs) or ionenes. The specific ions used within the material will determine the thermal, mechanical, and chemical stability properties exhibited by the polymer. Adjustments can be made to the ion structures during the synthetic process to influence these observed properties.

Fuel cells, batteries, solar cells, and capacitors, all require materials that can withstand high …

Testing Different Approaches For The Stabilization Of Mdi: Design Of Low-Valent Molybdenum Complexes In Redox-Active Environments And Capture-Release Reactions Using N-Heterocyclic Carbenes, Asanka Indrajith Dissanayake

Wayne State University Dissertations

Methylene diphenyl diisocyanate (4,4’-MDI) is an aromatic diisocyanate, which is widely used as a monomer in the polyurethane industry. One of the main challenges with using 4,4’-MDI is its dimerization into uretdione. The polyurethane industry seeks solutions that could suppress dimerization of 4,4’-MDI and extend its shelf-life. The focus of this dissertation is on the design of chemical solutions to this problem including: (1) reversible coordination of MDI (heteroallene) to low-valent mono- or dimolybdenum complexes in redox-active ligand environment, and (2) reversible coordination of MDI with two equivalents of an appropriate N-heterocyclic carbene.

MDI (isocyanate) is a heteroallene, and heteroallenes …

Scaffolds From Natural Polymers And Soy Protein For Cultured Meat Production, Utumporn Butkatanyoo

Chulalongkorn University Theses and Dissertations (Chula ETD)

To overcome the problems of livestock farming, cultured meat technologies have been developed. Cultured meat is an alternative way to produce meat by culturing cells in vitro using tissue engineering technology. The construction of cultured meat requires a scaffold to support cell proliferation and differentiation. Herein this research, polysaccharides namely high acyl gellan gum (HG) and konjac (KJ) together with a plant-based protein, soy protein isolate (SP) were used to develop scaffolds for cultured meat production. The composite scaffolds were prepared by freeze-drying and followed by ionic crosslinking. The composition of HG, KJ, and SP had a strong influence on …

Use Of Porphyrin Derivatives As Ionophore In Polymeric Membrane Electrode For Ferric Ion Detection, Tanakorn Khongluang

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, a polymeric membrane electrode was prepared for ferric ion detection (Fe3+) in water by using a porphyrin derivative, tetrakis (4-dodecyloxyphenyl)porphyrin (L1) and tetrakis(4-methoxyphenyl) porphyrin (L2), as ionophore. Different ratios of membrane composition were studied to prepare membranes containing a total mass of 220 mg. The membrane prepared using polyvinyl chloride (PVC) 33% wt, bis(2-ethylhexyl)sebacate (DOS) 66% wt, ionophore L1 0.18 %wt (0.3 µmol) and potassium tetrakis(4-chlorophenyl)borate (KTClPB) 2.71 × 10-3 %wt (40 mol% relative to ionophore) as membrane additive showed the best response to Fe3+, judging from the selectivity coefficients of the polymeric membrane electrode against other …