Chemical Engineering Commons^™

Activated Carbon Synthesis From Lignin-Rich Byproduct Streams Of Biorefineries, Chengjun Wu

All Dissertations

Over the past decade, the production of biofuels from lignocellulosic biomass has steadily increased to offset the use of fuels from petroleum. To make biofuels cost-competitive, it is necessary to add value to the “ligno-” components (up to 30% by mass) of the biomass. Instead of just burning it for heat and electricity generation, direct conversion of lignin carbon into a product provides a complementary path to carbon capture, promoting a more environmentally conscious approach. However, the utilization of these lignin-rich byproduct streams, which are separated from the biofuels production, for industrial products can be challenging. The use of specific …

Improving Lignin Recovery From Paper Mill And Biorefinery Waste Streams Via Liquid-Phase Splitting, Carter Fitzgerald

All Dissertations

Lignin is an abundant biopolymer with significant promise due to its aromaticity. It has been targeted as a replacement for a number of petroleum-based products including adhesives, coatings, polyurethane foams, activated carbon, and carbon fibers. However, commercially available bulk lignins are too polydisperse, and contain too many residual metals from the pulping process that are detrimental to the properties of the final product.

The Sequential Liquid-lignin Recovery and Purification (SLRP) process was developed by Michael Lake and John Blackburn, in collaboration with Clemson, with the intention of creating a continuous method for recovering lignin from paper-mill black liquors. Thies and …

Development Of Non-Viral Nano-Carriers For Gene Delivery And Covid-19 Vaccines, Zhongyu Li

Dissertations

Gene therapy is one of the most promising medical fields with the potential to effectively advance the treatment of difficult diseases by producing therapeutic proteins or repairing defective gene sequences. However, gene therapy presents severe challenges in delivery including renal clearance, phagocytosis, enzymatic degradation, protein absorption, and cellular internalization barriers, which have been barriers for translation into the clinic. Naked nucleic acids, with their intrinsic negative charge, electrostatically repulse the anionic cell membrane, preventing cellular uptake. Also, they are considered foreign genetic material when introduced into the body and are rapidly cleared by the reticuloendothelial system or degraded by nucleases, …

The Biological Activity Of Dual-Responsive Glycopolymers For Intracellular Codelivery Of Antigen And Lipophilic Adjuvant, Micaela Shields

Honors Theses

Subunit vaccines present themselves as an attractive alternative to traditional approaches to vaccines, which utilizes whole organisms to trigger an immune response. While these traditional approaches have proven themselves reliable within the history of vaccinations, they generally deliver subpar robust cellular-mediated immunity and pose many safety risks. Composed of proteins and /or peptides, subunit vaccines are safer and more precise alternatives to traditional approaches. However, the pharmacokinetic properties of the macromolecules that make up these vaccines hinder the subunit vaccine’s level of immunogenicity [d1] Examples of this hindrance include but are not limited to aggregation at the injection site and …

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 …

Characterization Of Lignin And Cellulose Biopolymers Structure – Function Relationships, Zachariah Pittman

All Dissertations

Biomass is vital to ongoing efforts to secure a sustainable future. While many of our efforts focus on finding alternative forms of energy, biomass among them, only biomass has the potential to serve as a sustainable materials feedstock. However, biomass is heterogenous, complicating the upgrading processes needed to manufacture commodity and performance products. For example, plant biomass consists largely of cellulose, a crystalline polysaccharide, and lignin, a highly stable polyaromatic. The specific properties of cellulose and lignin depend greatly on the plant, harvesting conditions, and isolation procedures. Thus, accurate and reliable determination of the fundamental properties of biomass is crucial …

Lignin Copolymer Property Prediction Using Machine Learning, Collin Larsen

Chemical Engineering Undergraduate Honors Theses

Lignin, an abundant biopolymer, is a waste byproduct of the paper and pulp industry. Despite its renewable nature and potential applicability in various products, such as plastics and composites, the development of lignin-based materials has been impeded by the cumbersome, Edisonian process of trial and error. This research proposes a novel approach to forecasting the properties of lignin-based copolymers by utilizing a recurrent neural network (RNN) based on the Keras models previously created by Tao et al. Example units of modified lignin were synthesized via esterification and amination functional group modifications. To increase the efficiency and accuracy of the prediction …

Interactions And Phenomena Between Disodium Cromoglycate And Polyelectrolytes, Brandon Tipton

Chemical Engineering Undergraduate Honors Theses

The interactions between polyelectrolytes and oppositely charged macroions have been widely studied, but few reports have been made on the interaction between chromonic mesogens and polyelectrolytes. Here, we report on the formation of liquid crystalline coacervates achieved by the liquid-liquid phase separation of an aqueous solution of negatively charged liquid crystal and polycations. As well as the occurrence of tactoids that form in the absence of these interactions. The liquid crystal that is experimented with is disodium cromoglycate, better known as DSCG. This acts as a negative charge that is paired with a variety of positively charged polyelectrolytes. The first …

Chloramine Devulcanization Of Waste Rubber., Patrick Kroeger

Electronic Theses and Dissertations

The disposal of waste rubber, particularly tire rubber, continues to pose a challenge in the 21st century. As a result, most end-of-life tires (ELTs) are either dumped in landfills or burned as tire-derived fuel. Chloramine devulcanization may offer a viable solution to this problem. Chloramine devulcanization is a low-temperature, low-pressure, process that selectively breaks sulfur crosslinks while preserving the polymer backbone. Chloramine devulcanization enables the recovery of chloramine recovered carbon black (CrCB) and devulcanized rubber (CdR) as separate products. Initial analysis of CdR revealed that it was formable and malleable, suggesting that crosslinking was absent. Spectroscopy showed that CdR contained …

Elucidating The Mechanical And Transport Properties Of Lignin-Based Hydrogel Composites, Nicholas Gregorich

All Dissertations

The use of lignin in the fabrication of soft composites has become an emerging area of research in polymer science and polymer chemistry. These lignin-based materials present numerous benefits, notably, a reduction in the use of petroleum-based precursor, improved structural benefits to otherwise soft host polymers, as well as the inherent antimicrobial and antioxidant properties of lignin, making it suitable for biomaterials. Herein, we present two chemical reaction pathways of incorporating lignin that was fractionated and cleaned using the Aqueous Lignin Purification with Hot Agents (ALPHA) process into poly(vinyl alcohol) (PVA) hydrogel composites for aqueous-based separations. By leveraging the ALPHA …

Bridging The Gap Between Phase Behavior And Processing For Renewable And Refinable Carbonaceous Precursors, Graham Tindall

All Dissertations

As a category of materials, engineered carbons, specifically carbon fibers, are first-in-class for properties such as modulus, specific strength, and thermal resilience; however, the inability to directly process atomic carbon necessitates the development and optimization of carbonaceous precursors. Because the structure and properties of carbon are highly dependent on the precursors and requisite processing, numerous materials have been investigated as feedstocks for large-scale production. Although cellulose and rayon were among the first investigated, polyacrylonitrile (PAN) is the current hegemon of carbon fiber precursors. PAN feeds 90% of this market, but it is neither inexpensive nor renewable. Because a significant fraction …

Removal Of Hexavalent Chromium From Water By Chitosan-Enhanced Ultrafiltration, Putu A. Y. Indiasih, Anindita D. Syaifudin, Nurul Faiqotul Himma, Bambang Ismuyanto

Makara Journal of Technology

Polymer-enhanced ultrafiltration has gained increasing attention as a selective separation process to remove small solutes, such as metal ions, from water or wastewater. Hexavalent chromium Cr(VI) is one of the metal ions in wastewater that has received considerable attention because of its toxicity. Chitosan was used in this study as the polymer to bind Cr(VI) to enhance its removal by ultrafiltration. The effects of chitosan-to-Cr(VI) ratio on Cr(VI) rejection and permeate flux were investigated. In addition, the fouling tendency was evaluated. Results showed that the addition of chitosan with a mass ratio of 12.5 increased the Cr (VI) rejection from …

Poly(Ether Imide)S: Synthesis And Properties, Rachel Price

Honors College Theses

The synthesis of strong polymers is crucial to the creation of heat-resistant, durable, and mechanically useful plastics that we use every day. Poly(ether imide)s are used in applications such as food service, aerospace, automotive, and many more. This thesis will discuss the synthesis and properties of these plastics to help express a larger understanding of these polymers.

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 …

Comparing Weathering Effects Of Ultraviolet And Xenon Arc Accelerated Aging On Polyvinyl Chloride, Collin Mcinnes

Williams Honors College, Honors Research Projects

As the ubiquitousness of polymers increases and begins seeing use in outdoor settings, the need to fully understand how these materials degrade is also necessary. This study aims to compare two known accelerated aging methods, namely an ultraviolet light chamber and a xenon arc light chamber, to understand what differences, if any, manifest in the mechanical, chemical, and cosmetic deterioration of polyvinyl chloride (PVC) after long-term exposure. The study utilizes Fourier-transform infrared spectroscopy, dynamic mechanical analysis, thermogravimetric analysis, and colorimetry analysis to determine the extent of degradation and potential discrepancies between the aging methods.

An Experimental Study On The Mechanical Properties And Chemical Composition Of Lcd 3d Printed Specimens, Sebastian Gomez

College of Graduate Studies: Theses & Dissertations

Additive manufacturing technologies have been enhanced throughout the years yet have surprised the manufacturing industry due to their high-end surface finish and dimensional accuracy. Different experiments have been done to identify a specific phenomenon known in the vat-polymerization field. Distortion and dimensional inaccuracy tend to affect the overall properties of the process, either physical or chemical. This approach allows the understanding of how the physical properties have been affected and how to study the chemical properties to avoid this type of phenomenon. The chemical reaction between polymer and UV light has been studied and experimented with to the point that …

Running Shoe Pedometer, Benjamin Kasper

Williams Honors College, Honors Research Projects

Running shoe pedometer aims to solve the issue of worn out running shoes. It can be difficult to know just how many miles you have run in your shoes and when a new pair is needed. Running in old shoes and worn out shoes is heavily linked to injury. My proposed project is a device that is powered by the compressive forces on the shoes soles that counts the number of steps the wearer takes using a microcontroller. Then, when the shoe reaches milestone that indicate it has been used 75% 90% and 100% of its expected life, it will …

Mechanisms Of Emulsion Destabilization: An Investigation Of Surfactant, Stabilizer, And Detergent Based Formulations Using Diffusing Wave Spectroscopy, Jordan N. Nowaczyk

Theses and Dissertations

Conventional approaches for studying emulsions, such as microscopy and macroscopic phase tracking, present challenges when it comes to establishing detailed mechanistic descriptions of the impact of emulsifier and stabilizer additives. Additionally, while a combination of sizing methods and macroscopic phase tracking can provide insights into droplet size changes and concentration, the use of multiple measurements can be cumbersome and error-prone. It is the focus of this work, to present a new method for studying water in oil (W/O) emulsions that involves using diffusing wave spectroscopy (DWS) to examine the impact of three different surface stabilizing additives at varying concentrations. By …

Development Of A Solution Synthesis Of Poly(Sebacic Anhydride) With The Activating Agent 4-Toluenesulfonyl Chloride: Understanding The Effect Of Different Bases On The Reaction Products, Patricia Poley

Honors Theses

The overall goal of this honors thesis was to develop a solution synthesis of Poly(Sebacic Anhydride) with the activating agent 4-toluenesulfonyl chloride and understand the effects of varying temperature, bases, and the addition order of reagents on the reaction.

Polyanhydrides are a class of hydrophobic, degradable polymers used in controlled drug delivery for 30 years. They are synthesized through three general methods: melt polycondensation, solution polycondensation, and ring-opening polymerization. Of these three methods, solution polycondensation typically results in products with lower molecular weight. Previous work in the Vogel lab identified two new ways to synthesize anhydrides using solution polycondensation reactions …

Solid-State Shear Pulverization: A Comprehensive Study On Polymer Processing Technology From A Systematic Innovation Perspective, Tyler A. Will

Master’s Theses

Solid-state shear pulverization (SSSP) is a continuous and scalable processing technique that imposes mechanochemical changes in polymer-based materials. It has been shown to impart beneficial properties onto homopolymers or create copolymers and composites through continuous fragmentation and fusion. The unique technology employs cold temperature to keep the polymer in the solid state. This thesis investigates industrial polymer processing in the context of real-world applications. This thesis analyzes SSSP using an organized methodology called systematic innovation (SI). SI facilitates problem solving by assisting engineers in conducting root cause analysis around a material and studying the physical setup of the equipment.

This …

Beeswax Wraps As An Alternative To Single-Use Plastics, Sarah Skiver

Williams Honors College, Honors Research Projects

The project goal was to compare the food storage efficacy of sustainable beeswax wraps verses the single-use plastic methods of resealable plastic sandwich bags and plastic cling wrap. The goal was also to test the reusability of the beeswax wraps, as it is a key advantage of beeswax wraps that is advertised. The project purpose was to explore sustainable and eco-friendly alternatives to single use plastics, which are harmful to the environment in both their production and their disposal. Food spoilage was compared in beeswax wrap, plastic sandwich bags, and plastic cling wrap, and spoilage was also observed in a …

Structural Design And Application Of Polymeric Silicon Elastomers, Jacob Wyant

Williams Honors College, Honors Research Projects

The purpose of this project was to determine how the polymeric structure and mechanical properties of this elastomer are affected by the ratio between the polydimethylsiloxane macromolecular chains and the crosslinkers. These were determined via tensile and compression testing. Then, spiropyran was added to observe how this fluorescence and crosslinking agent affected the elastomer. Also, the elastomer’s fluorescent and icephobic nature were tested. The elastomers with a higher ratio of crosslinker to macromolecular chain could withstand higher tensile and compressive strains but failed at lower stresses than their counterparts with lower concentrations of crosslinkers. The elastomers were also found to …

Defining The Proper Operating Time For The Septa Extractor, Abigail Jones

Williams Honors College, Honors Research Projects

Anionic polymerizations are a common type of reaction used to produce synthetic rubber. During these reactions, it is necessary to charge initiators, modifiers, and other substances, through pressurized containers that are sealed with rubber septa. These septa prevent oxygen and moisture from entering the pressurized container, and the reactor, though they need to be cleaned before use to remove other impurities. Currently a glass Soxhlet Extractor is used to remove such impurities, and though effective, it has a limited capacity, so it has to run frequently. This limitation led to the commissioning of the Septa Extractor, which is an automated …

Anti-Freeze Double Network Hydrogels, William Gross

Williams Honors College, Honors Research Projects

Three polyethylene glycol (PEG) based crosslinkers with repeat unit nominal weights of 62.1, 200, and 400 g/mol in agar/PAM double network (DN) hydrogels were used to study the effect of different crosslinkers on thermal and mechanical properties. Using the one-pot synthesis method, hydrogels with the PEG crosslinkers or methylene-bis-acrylamide (MBAA) were made via sol-gel transition for formation of agar network, and photopolymerization of the PAM network using Irgacure 2959 as photo initiator. Tensile and compression tests were performed on as prepared, swollen, and swollen & cooled specimens of each hydrogel. Freezing time and thermal imaging were performed in -20 °C …

Utilizing Computer-Aided Molecular Design With Azido-Ester Plasticizers, Justin Ebert

Williams Honors College, Honors Research Projects

The goal of this project was to utilize Computer-Aided Molecular Design (CAMD) using the Signature molecular descriptor to inversely design optimized azido-ester plasticizers. Azido-ester plasticizers are used to modify the mechanical properties of propellant and explosive formulations. With the assistance of quantitative structure-property relationships, QSPRs, and two types of constraint equations, these new, novel plasticizers have the potential to possess optimal physical and chemical properties. Properties investigated in this work were decomposition temperature, heat of formation, glass transition temperature, and molecular weight. These properties were chosen for their importance when formulating propellants or explosives. After the filters were applied to …

The Effect Of Different Fracturing Fluids On The Productivity Of Multi-Staged Fractured Marcellus Shale Horizontal Wells, Vida Gyaubea Matey-Korley

Graduate Theses, Dissertations, and Problem Reports (ETD)

While hydraulic fracturing has undeniably improved the production from oil and gas reservoirs, this technology is not without limitations. The primary hurdles lie in the areas of proppant transport, fluid rheology, and stress management. Despite the extensive research conducted in this domain, there remains a considerable amount of work to be done for comprehensive solutions that account for the complex interactions among fracturing fluid, proppant distribution, and geomechanical conditions. Achieving this will then make room for a holistic and efficient hydraulic fracturing strategy.

This study addresses the above-mentioned problem by examining the impact of fluid type on proppant transport and …

Development Of Polymeric Sorbents As Reusable Filtration Systems For Remediation Of Pfas Contaminated Water, E. Molly Frazar

Theses and Dissertations--Chemical and Materials Engineering

Decades of use of per- and polyfluoroalkyl substances (PFAS) in a multitude of consumer and industry-based products have led to a devastating amount of soil and water contamination. Although these chemicals and compounds possess advantageous qualities – such as that of PFAS in the role of fire-fighting foams that have no doubt saved countless lives and homes, we must take responsibility for the anthropogenic hazards that threaten our global health. This entails being able to cost-effectively remediate problems created in the past from overuse of toxic substances that could negatively impact our future, and in this case, the future of …

Mechanical And Adhesive Properties Of Supramolecular, Mussel-Inspired Hydrogels, Daniel Darby

Theses and Dissertations--Chemical and Materials Engineering

The exceptional mechanical and adhesive properties of mussel byssal threads come from supramolecular interactions of ligands found in the proteins comprising them. Ligands can form hydrophobic interactions, π-π stacking interactions, and hydrogen bonds, but the strongest supramolecular interaction they demonstrate is metal-ligand coordination. Specifically, Histidine (His-) and nitrodopamine (nDOPA) ligands coordinate to metals in a bidentate fashion and take on tris-, bis-, and mono- modalities (3, 2, or 1 ligand per ion, respectively). The distribution of these modalities is controlled by equilibrium thermodynamics. These same ligands can be used as crosslinks in supramolecular hydrogel networks. Supramolecular hydrogel networks are dissipative, …

Chemical Decomposition Of Flexible Polyurethane Foam To Generate A Media For Microbial Upcycling, Kaushik Baruah

Dissertations, Master's Theses and Master's Reports

Polyurethane waste is becoming a global concern as a large amount is being disposed of in landfills every year, and only a fraction is being recycled. Several polyurethane recycling techniques exist, of which ammonolysis and base-catalyzed hydrolysis is the least explored. Flexible polyurethane foam (FPUF) decomposition can generate amines that can act as a carbon source for the growth of microbial consortia. This study aims to generate a novel media capable of microbial upcycling via ammonolysis and base-catalyzed hydrolysis of flexible polyurethane foams (FPUFs) using ammonium hydroxide and subsequently determine the reaction conditions for maximum solubilization of polyurethane foam in …

Investigation Of Additives And Ingredients Of Bio-Resin For Visible Wavelength Laser-Induced Polymerization, Patrick Riggs

College of Graduate Studies: Theses & Dissertations

Optical 3D printing is a branch of Additive manufacturing (AM) that utilizes low-waste production leading to efficient and rapid prototyping. Currently, this method of AM is associated with mainly petroleum-based resins. Bio-resin polymerization is an emerging research area for finding replacements for petroleum-based resins, but curing the resin with laser energy is not normally a practical use case. Current optical 3D printing uses lasers to cure liquid resins to form solid 3D objects in a layer-by-layer process which is time consuming, defect prone, and a leading limiting factor for high volume production; so, finding a way to incorporate bio-resin into …