Materials Science and Engineering Commons^™

Development And Characterization Of Composite Membranes For Use In Countercurrent Solvent Extraction, Lydia Neves Rodrigues

Dissertations

Porous membranes having a particular wetting characteristic, hydrophobic or hydrophilic, are used for nondispersive membrane solvent extraction (MSX) where two immiscible phases flow on two sides of the membrane. The aqueous-organic phase interface across which solvent extraction/back extraction occurs remains immobilized on one surface of the membrane. This process requires the pressure of the phase not present in membrane pores to be either equal to or higher than that of the phase present in membrane pores; the excess phase pressure should not exceed a breakthrough pressure. In countercurrent MSX with significant flow pressure drop in each phase, this often poses …

Evaluation Of Stretch Film Behavior During Long-Term Storage Under Different Atmospheric Conditions, Kyle Dunno, Maria Symanski

Journal of Applied Packaging Research

This study examined the post-application behavior of two 20.3 micron machine stretch films, one categorized as high-performance and one as general-performance, for thirty days while stored at either 23°C or 38°C. For each film type, the stretch film was applied to a simulated unit load to produce neutral and positive applied total stretch scenarios. The relaxation curves developed from each test indicate the relaxation rate of the films varied based on the storage condition. Observed was an average of 41% containment loss for both high-performance and general-purpose films when the simulated loads were stored at 38°C. For simulated loads stored …

Rapid Annealing Of Perovskite Solar Cell Thin Film Materials Through Intense Pulse Light., Amir Hossein Ghahremani

Electronic Theses and Dissertations

Perovskite solar cells (PSCs) have garnered a great attention due to their rapid efficiency improvement using cheap and solution processable materials that can be adapted for scalable high-speed automated manufacturing. Thin film perovskite photovoltaics (PVs) are typically fabricated in an inert environment, such as nitrogen glovebox, through a set of deposition and annealing steps, each playing a significant role on the power conversion efficiency (PCE), reproducibility, and stability of devices. However, atmospheric processing of PSCs would achieve lucrative commercialization. Therefore, it is necessary to utilize materials and methods that enable successful fabrication of efficient PSCs in the ambient environment. The …

Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed

LSU Master's Theses

Hemp is considered as one of the sustainable agricultural fiber materials. Degumming or surface modification of hemp bast is needed to produce single fibers for ensuing textile and industrial applications. The traditional degumming process necessitates a high amount of alkali, which causes detrimental environmental pollution. This study offers a new method to degum hemp fibers with reduced use of harmful alkali and precious water resources. In this work, hemp bast fibers were degummed by using combined microwave energy and deep eutectic solvent (DES). The properties of hemp fibers manufactured by this method were investigated and compared with the traditional alkali …

Tribological Studies Of Thick Polytetrafluoroethylene Coatings Enhanced By Polydopamine And Nanoparticles, Sujan Kumar Ghosh

Graduate Theses and Dissertations

Polytetrafluoroethylene (PTFE) is a popular low friction solid lubricant with high chemical and thermal stability. Thick PTFE coatings have the potential for many tribological applications, such as replacing Tin-based Babbitt materials in journal bearings. However, the weak bonding strength to the substrate and the high wear rate of PTFE coatings are current limiting factors. The lack of understanding of their tribological properties and wear mechanisms in oil-lubricated conditions and how coating thickness affects the tribological performance further hindered the use of PTFE coatings. In this dissertation, polydopamine (PDA), a bio-inspired adhesive, is used as an underlayer for or as a …

Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration, Michael Rosario Cervellere

Graduate Theses and Dissertations

Porous polymer membrane filters are widely used in separation and filtration process. Micro- and ultra-filtration membranes are commonly used in biopharmaceutical applications such as filtering viruses and separating proteins from a carrier solution. The formation of these membrane filters via phase inversion is a complex and interconnected process where varying casting conditions can have a wide variety of effects on the final membrane morphol- ogy. Tailoring membrane filters for specific performance characteristics is a tedious and time consuming process. The time and length scales of membrane formation make it extremely difficult to experimentally observe membrane formation. Modeling the membrane formation …

Investigation Of Membrane Based Processes For Biomedical Applications, Efecan Pakkaner

Graduate Theses and Dissertations

As substantial developments were achieved in nanotechnology and polymer engineering, especially in the last few decades, the use of membranes and membrane-based procedures was found to be expanding into more and more research and development areas; including biological engineering, life sciences and biomedical engineering. Not only have they been the main focus of meaningful research, but they have also been the main pieces of the solutions to very thorny problems encountered within a wide range of applications from microfluidics to water treatment, thanks to their versatility, cost-effectiveness and biocompatibility, when compared to conventional separation techniques. To celebrate and embrace these …

Experimental Investigation Of The Performance Of A Hybrid Self-Healing System In Porous Asphalt Under Fatigue Loadings, Shi Xu, Liu Xueyan, Amir Tabakovic, Erik Schlangen

Articles

Self-healing asphalt, which is designed to achieve autonomic damage repair in asphalt pavement, offers a great life-extension prospect and therefore not only reduces pavement maintenance costs but also saves energy and reduces CO2 emissions. The combined asphalt self-healing system, incorporating both encapsulated rejuvenator and induction heating, can heal cracks with melted binder and aged binder rejuvenation, and the synergistic effect of the two technologies shows significant advantages in healing efficiency over the single self-healing method. This study explores the fatigue life extension prospect of the combined healing system in porous asphalt. To this aim, porous asphalt (PA) test specimens with …

Heated Assembly And Transfer Of Van Der Waals Heterostructures With Common Nail Polish, Kristine L. Haley, Jeffrey A. Cloninger, Kayla Cerminara, Randy M. Sterbentz, Takashi Taniguchi, Kenju Watanabe, Joshua O. Island

Physics & Astronomy Faculty Research

Recent advances in the manipulation and control of layered, two-dimensional materials has given way to the construction of heterostructures with new functionality and unprecedented electronic properties. In this study, we present a simple technique to assemble and transfer van der Waals heterostructures using common nail polish. Commercially available nail polish acts as a resilient sticky polymer, allowing for the fabrication of complex multi-material stacks without noticeable fatigue. Directly comparing four commercially available brands of nail polish, we find that one stands out in terms of stability and stacking characteristics. Using this method, we fabricate two top-gated devices and report their …

Analysis Of The Use Of Waste Material In 3d Printing, Alexander Laurence

Materials Engineering

Globally, only 9% of plastic by mass is recycled. Allowing consumers to directly convert polyethylene terephthalate (PET) waste into 3D filament can increase the recycling rate by reducing contamination and costs from traditional large-scale recycling methods. This was tested by heating strips of PET to various temperatures within its glass transition region and pressing a roller with a 1.75 mm indentation against it to observe strip deformation. PET was also placed in a hemispherical well with a 1.75 mm diameter hole at the bottom and heated above its melting temperature to determine the mass of PET required to extrude 3D …

Void And Density Analysis Of Cyanate Ester Composites, Cameron B. Atwood

Materials Engineering

In large scale composite manufacturing, voids and their frequency within prepreg materials play an important role in predicting the mechanical properties of a final composite laminate. The industry standard process for determining voids in composite materials is through resin digestion and resin ignition via ASTM D3171. One limitation to this standard is its ability to frequently produce negative void volume values in quality control testing, due to the calculation sensitivity of input resin and fiber densities. For this reason, Toray Advanced Composites wanted to investigate the process steps of ASTM D3171 to determine if discrepancies in resin density data may …

Uv Polymerization Of A Zwitterionic Antifouling Membrane Coating, Amanda Jia-Hwa Tsai, Vincent Matthew Guarino

Materials Engineering

Membrane filtration is used in a wide array of industries to separate components in a mixture. Filtration membranes suffer from the external deposition of pollutants and microorganisms, a phenomenon known as fouling. Fouling reduces the lifetime of a membrane and therefore increases production costs. The goal of this project was to modify the surface of a hydrophobic commercial membrane with a charged coating to induce antifouling properties. A zwitterionic monomer, sulfobetaine methacrylate (SBMA), was used for its steric hindrance and hydration shell formation mechanisms, which result in superior non-specific antifouling performance. When polymerizing the coating onto the surface of the …

Effects Of Uv Exposure On The Thermo-Mechanical Properties Of Cactus Based Biopolymers, Madison Glozer, Megan Bolling, Addison Wolfson

Materials Engineering

The viability of renewable biopolymers as sustainable alternatives to synthetic plastics is promising, however ultra-violet (UV) radiation can lead to premature degradation and reduction in the material’s performance. Biopolymers comprised of nopal cactus juice, animal protein, natural wax, and glycerin in differing percentages were studied to obtain thermo-mechanical data in relation to UV exposure. To quantify degradation, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy, goniometry and gravimetric measurements were performed. Each formulation experienced mass loss as a result of UV exposure, which could be attributed to water evaporation. The thermogravimetric analysis indicated a reduction in the second …

The Effects Of Glass Fiber Fillers On Epoxy Resin Performance, Ashton Robert Reinhold, Manuel Jose Aguirre Ii

Materials Engineering

Premature failure of filtration members in biochemical processing is a costly issue for manufacturers. This research aims to determine whether or not the premature failure due to thermal fatigue in medical filtration devices can be mitigated by glass fiber addition. The study was conducted to identify the effects of e-glass fiber filler content in an epoxy matrix on the mechanical and thermal properties of the epoxy system. The epoxy was evaluated over a filler content of 0-50wt% in level increments of 12.5wt% and temperatures ranging from ambient to 160°C in increments of 15°C. Cylindrical and tensile bar specimens were prepared …

Solvent Analysis Of Phenolic Resin Glass Fiber Reinforced Prepreg During Out-Time, Sixin Zhai, Crystal Ipong

Materials Engineering

Phenolic resin glass fiber reinforced prepregs are highly suitable for airplane interior components due to their high fire resistance, high temperature performance, and low-density characteristics. Safran Cabin seeks to improve their storage of the phenolic resin prepreg during their manufacturing process. The issues the company faces are the occasional delamination of prepreg laminas or the loss of tackiness rendering the lamina unfit for use. The area of investigation was determining the weight loss of volatiles during out-time. The term “out-time” consists of the time the prepreg experiences in transit, on the shop floor, and in short-term temperature-controlled storage. Simulated storage …

Reducing The Fouling Of Microfiltration Membranes Through Uv-Initiated Surface Modifications Using Poly (Ethylene Glycol) Based Monomers, Christopher Lo, Matthew Truong

Materials Engineering

Meissner Filtration Product Inc. designs and manufactures membranes for food and beverage, microelectronics, ultrapure chemicals, and pharmaceutical industries. Membrane filters utilized in these industries have lifetimes greatly limited due to membrane fouling. Increasing membrane lifetime will reduce downtime, waste, and cost of operation. The proposed project is aimed to develop a methodology for synthesizing a fouling-resistant polymer coating layer on hydrophobic membrane surfaces for reducing membrane fouling and increasing membrane filterability (membrane lifetime) that are critical for effective membrane operations in the pharmaceutical industry. In this study, commercial membranes were coated with a solution containing a monomer, crosslinker, and photoinitiator …

Development Of A Marine Biodegradable Target Balloon, Blake Samuel Robinson, Arash Sam Akhavi, David Leonardo Albarran-Martinez

Materials Engineering

The US Navy utilizes PVC target balloons, known as Killer Tomatoes, that are inflated onboard a naval vessel then deployed into the ocean to calibrate a variety of weaponry. The Navy has requested the investigation of biodegradable polymers to replace the PVC in attempts to reduce ocean waste that is generated from the leftover PVC material. After communicating with American Pacific Plastic Fabricators (APPF), the current manufacturer of the Killer Tomatoes, we gained an understanding of the manufacturing process and the material requirements that would allow a new material to be integrated into their current process. Two proprietary, trial polymers …

Pressure Driven Desalination Membranes: Lyotropic Liquid Crystals Containing Single Walled Carbon, Matteo A. Del Giudice, Samantha Castillo Merigold

Materials Engineering

This project presents a potential alternative desalination technique that utilizes the ion rejection properties of single walled carbon nanotubes dispersed in a lyotropic liquid crystal (LLC) matrix. Previous research has pointed to the polymerizable surfactant methacryloxy ethyl hexadecyl dimethyl ammonium bromide (C16MA) having capabilities of filtering molecular components smaller than a nanometer, when oriented in cylindrical micelles. SWCNTs were dispersed in deionized water by probe sonication and addition of surfactant cetyltrimethylammonium bromide (CTAB) due to SWCNTs’ hydrophobic properties. Membranes were produced containing 55wt% C16MA, 37wt% DI water, 0.1wt% with respect to the monomer (WRM) SWCNTs, 1.9 wt% WRM 2,2-dimethoxy-2-phenylacetophenone (photointiator), …

Composition For Protecting Technological Equipment Against Salt Deposits And Internal Corrosion, Hasan Kadirov, Sadritdin Turabdjanov

CHEMISTRY AND CHEMICAL ENGINEERING

Aimed studies on the synthesis of metal complexonates have carried out. The reaction of obtaining zincate zincate oxyethylene diphosphonic acid OEDP has studied. On the basis of synthesized zincate-OEDP, compositions of corrosion inhibitors and deposits of mineral salts with the addition of a vacuum residue of monoethanolamine (RMEA) and polyaminocrotanol (PKI-3), which are able to effectively suppress corrosion processes in environments with different initial corrosive activity, have been compiled. It is proved that the high efficiency of the composition OEDP : zincate-OEDP : PKI-3 (maximum protective effect - 97.9%) is much more effective than the composition OEDP : zincate-OEDP : …

Rational Disposal Of Pet Containing Waste And Prospects For The Synthesis Of New Polymers, Asror Juraev, Muzaffar Alimukhamedov, Ravshan Adilov, Farhod Magrupov

CHEMISTRY AND CHEMICAL ENGINEERING

As a result of the research on the utilization of polyethylene terephthalate-containing household waste, a promising direction was identified in the production of a new type of secondary polyethylene terephthalate (SPET) - unsaturated polyesters.It was revealed that the final product, which formed when the alcoholization process is complete in any proportion of of glycol and secondary polyethylene terephthalate, is the bisalkylent terephthalate of terephthalic acid; the content of the alcoholysis product consists of bisalkylent terephthalate, different molecule mass, functionally hydroxyl-containing complex polyester polyol and free diols.

The laws of alcoholization of secondary …

Rehology And Electrical Conductivity Of Particulate Composites In Additive Manufacturing, Bin Xia

Mechanical Engineering Research Theses and Dissertations

Extrusion-based multi-functional additive manufacturing (AM) has been a rapidly developing area in AM recently. Particulate composites are widely used in this area to provide different functionalities with different types of particulate additives. However, there is no systematic understanding of the behavior of particulate composites during extrusion (especially in small nozzles) or of their properties once deposited in the build. This work investigates the properties of the type of particulate composites usually used in additive manufacturing, composed of a polymer matrix material and particulate additives within the micrometer scale. The focus is on the material rheology in the nozzle/capillary (for the …

Atomic Oxygen Resistant Low Earth Orbit Stable Polymer Matrix Composites Employing Phenylphosphine Oxide Epoxy-Amines, Witold Fuchs

Dissertations

Atomic oxygen (AO) attacks polymer matrix composites (PMC’s) on the surfaces of spacecraft in low earth orbit (LEO) and threatens safe spacecraft operation and service life. Incorporating phenylphosphine oxide (PPO) groups into polymer chains offers a self-regenerating method of protection from AO but remains poorly understood. Herein, epoxies containing PPO groups were synthesized with increasing concentrations of phosphorus [P] from 0 to 8 wt % to investigate their AO resistance. Measurements confirmed the exposure of these materials to AO produces a passivation phosphate (POx) layer on the surface of the sample and the efficacy of the resultant layer was directly …

Biopolymeric Materials For Tissue Regeneration, Cell Manufacturing, And Drug Delivery, David Alfonso Castilla-Casadiego

Graduate Theses and Dissertations

The development of materials for tissue regeneration, cell manufacturing, and drug delivery is possible by the manipulation of polymer properties and the use of three different techniques including layer-by-layer, electrospinning, and molding technique.

By applying the layer-by-layer technique over biomaterials, it is possible to develop polymeric multilayers that promote a more favorable environment for cellular functionality, increasing the possibility of improving their acceptance in the area of implantation. IRVASE demonstrated being a powerful technique that allows for a reliable characterization of the physical-chemical and thermal properties of the fabricated surfaces. This opens the possibility to monitor the design of surfaces …

Characterization Of Gesn Semiconductors For Optoelectronic Devices, Hryhorii Stanchu

Graduate Theses and Dissertations

Germanium-tin alloys with Sn compositions higher than 8 at. % to 10 at. % have recently attracted significant interest as a group IV semiconductor that is ideal for active photonics on a Si substrate. The interest is due to the fact that while at a few percent of Sn, GeSn is an indirect bandgap semiconductor, at about 8 to 10 at. % Sn, GeSn transitions to a direct bandgap semiconductor. This is at first surprising since the solid solubility of Sn in Ge under equilibrium growth conditions is limited to only about 1 at. %. However, under non-equilibrium growth conditions, …

Utilizing The Oxygen-Barrier Properties Of Poly(Isobutylene) To Enhance Photon Upconversion In Thermoplastic Elastomers, Haley Carroll

Honors Theses

Upconversion (UC) is the conversion of low energy light to higher energy light. It is utilized for a broad range of applications such as solar energy harvesting, microscopy of cellular biology, and cancer therapy. Specifically, triplet-triplet annihilation UC (TTA-UC) involves two dye species, a sensitizer and an annihilator, which are capable of upconverting noncoherent light such as sunlight. Traditionally, TTA-UC is achieved in solution, rubbers, or glasses, however, this work probes the capabilities of a thermoplastic elastomer (TPE) matrix to examine the effect of phase-separated morphology on the energy transfers necessary for TTA-UC. The system herein consists of poly(styrene-isobutylene-styrene) (SIBstar) …

Development Of Biomaterials For Drug Delivery, Raquel De Castro

Graduate Theses and Dissertations

Drug delivery systems (DDS) have highly evolved in the last decades with the development of hydrogels and nanoparticles. However, high systemic uptake, side effects, low bioavailability, and encapsulation efficiency continue to be a major hurdle faced by such DDSs.

Nanoparticles and hydrogels can be specifically designed for targeted DDSs to mitigate some of the problems. This dissertation aimed to design two DDSs for ocular drug delivery and one for cancer treatment. The first project sought to develop chitosan nanoparticles (Cs-NP) using PEGDA as a copolymer to encapsulate gentamicin (GtS) for ocular drug delivery. Cs-NPs contain positive charges that can interact …

Peptoid-Based Microsphere Coatings For Biomaterial Applications, Jesse Leland Roberts

Graduate Theses and Dissertations

Peptoids are peptidomimetic oligomers that predominantly harness similarities to peptides for biomimetic functionality. The incorporation of chiral, aromatic side chains in the peptoid sequence allows for the formation of distinct secondary structures and self-assembly into supramolecular assemblies, including microspheres. Peptoid microspheres can be coated onto substrates for potential use in biosensor technologies, tissue engineering platforms, and drug-delivery systems. They have the potential for use in biomedical applications due to their resistance to proteolytic degradation and low immunogenicity. This dissertation focuses on the physical characteristics and robustness of the peptoid microsphere coatings in various physiological conditions, along with their ability to …

Oxone® Mediated Tempo-Oxidized Cellulose Nanomaterials: Material Characterization, Ultrafiltration Membrane Separations, And Thin Film Composite Gas Transport Analysis, John Phillips Moore

Graduate Theses and Dissertations

Cellulose nanomaterials (CNMs) are derived from plant matter and are comprised of nanoscopic cellulose crystals and fibers. They have a diverse set of applications, from cosmetics to oil recovery. This study focuses on the properties of Oxone® mediated TEMPO-oxidized cellulose nanomaterials (OTO-CNMs) and their use in controlling the transport properties of polymeric substrates. Synthesis and characterization of cellulosic nanoparticles have resulted in the creation of OTO-CNMs with properties that increase hydrophilicity. With added hydrophilicity, OTO-CNMs possess lower fouling propensity, making them ideal membrane additive for transport limited separations such as hemodialysis.

To utilize the material and unique properties thereof, this …

Effects Of Static Mixer Geometry On Polyurethane Properties, Christian R. Dixon

Honors Theses

The field of additive manufacturing has gained significant academic interest in the past few decades with a recently developed type of three-dimensional (3D) printing. Reactive extrusion additive manufacturing combines precursor materials within a static mixer (SM) head, where polymerization begins before deposition. Variable static mixer geometries currently exist, but the relationship between mixer geometry and post-polymerization mechanical properties is undefined. To elucidate this relationship, a series of experiments with identical chemistry was performed using a high shear SM, a low shear SM, and a comparative batch reaction. While higher shear mixing trends with faster polymerization for step-growth polymerizations, consistent precursor …

Synthesis Of Superabsorbing Hydrogels Based On Starch Copolymers, Baxodir Kholnazarov, Khayit Turaev, Abdulakhat Jalilov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to synthesize highly swellable superabsorbent hydrogels based on starch copolymers. To achieve this goal, mineral-containing superabsorbent hydrogels based on starch, acrylamide, binder and initiator were synthesized. The optimal synthesis conditions were determined and studies were carried out on the influence of the molar ratios of the starting substances on the composition and physicochemical properties of the synthesized superabsorbent hydrogel. In the course of research, the optimum copolymerization temperature was 60 ° C, and the reaction time was 3 hours.

As a result of the study, a superabsorbent hydrogel based on starch, acrylamide and bentonite …