Reducing Print Time While Minimizing Loss In Mechanical Properties In Consumer Fdm Parts, Long Le, Mitchel A. Rabsatt, Hamid Eisazadeh, Mona Torabizadeh

Mechanical & Aerospace Engineering Faculty Publications

Fused deposition modeling (FDM), one of various additive manufacturing (AM) technologies, offers a useful and accessible tool for prototyping and manufacturing small volume functional parts. Polylactic acid (PLA) is among the commonly used materials for this process. This study explores the mechanical properties and print time of additively manufactured PLA with consideration to various process parameters. The objective of this study is to optimize the process parameters for the fastest print time possible while minimizing the loss in ultimate strength. Design of experiments (DOE) was employed using a split-plot design with five factors. Analysis of variance (ANOVA) was employed to …

Amino-Polymer For Co2 Capture By Vacuum Swing Adsorption, Sean Billy

Williams Honors College, Honors Research Projects

The applications of sorbent compounds in conjunction with amines and other additives is an innovative method at combating CO2 pollution. An ideal solution would use an amine sorbent to trap the high levels of absorbed CO2 with a low binding energy (less than 45 kJ/mol) and subsequently release them into a stored vessel at ambient temperature with a vacuum swing adsorption system. Attempts at finding a best mixture will be conducted through the usage of a vacuum swing system, utilizing a bed syringe containing the sorbent mix and a vacuum syringe to pull on and subsequently release the CO2 into …

Wetting Transition On 3d-Printed Surfaces, Isabelle Moryan

Williams Honors College, Honors Research Projects

Taking the previous research conducted, this project aims to further the study and research of the wettability of surfaces. Surface features and types are important factors to their wettability. The geometric properties of a surface can make it more hydrophobic and hydrophilic. Extreme cases of hydrophobic and hydrophilic surfaces lead to water repulsion or water absorption, even under extreme conditions. The goal of this project is to gain further insight on how fabricated 3D-printed featured surfaces and examine the wetting transition on these surfaces. In particular, cylindrical pillars will be studied with varied pillar spacing, height and diameter. In addition, …

Application Of Sla 3d Printing For Polymers, Taylor Wilson

Williams Honors College, Honors Research Projects

Stereolithography is a type of 3D printing that allows liquid photopolymer resin to be cured into layers that make up a 3D object. Creation of such resins for these purposes can require a significant amount of time to test and develop, and commercial resins also require some amount of testing for printer settings before use. This paper reviews how stereolithography works, the materials used, and experimentation done to compare the resin properties to the determined curing times. Using several commercially available resins, varying base exposure and layer exposure times were used to determine the lowest possible curing time that gave …

Amine-Functionalized Interpenetrating Polymer Networks For Co2 Capture, James Wills

Williams Honors College, Honors Research Projects

The research performed looked to advance the studies of vacuum swing absorption of Carbon Dioxide to help combat global climate change issues. The focus of the project was to create an anime-polymer sorbent that will weakly absorb and desorb CO2. The sorbent must be durable and be able to withstand multiple uses. The creation of a porous polymer matrix aided in the amines' ability to absorb CO2. Created samples underwent several qualitative and quantitative tests to determine their usefulness as an industrial sorbent. Infrared spectroscopy was used to study the effectiveness of the amine sorbents. Studying the changes in the …

Retention And Stability Of Polystyrene Sulfonic Acid And Polyethylene Glycol Anti- Fouling Films With 3-Aminopropyltriethoxysilane Coupling Agent, Brian Cameron

Williams Honors College, Honors Research Projects

Fouling is a process where particles, proteins, or microorganisms will accumulate onto a material [2]. This can lead to biofilms in medical implants, which can trap and create drug resistant bacteria [5]. Due to this, the study and creation of anti-fouling polymeric films that is stable in aqueous environments is essential. The goal of this study is to utilize APTES to retain the already studied PSS-PEG anti-fouling films. The films that are created is a thermally crosslinked network of the polystyrene sulfonic acid (PSS) and polyethylene glycol (PEG) with differing mass fractions (75- 25 and 55-45 PSS-PEG). To retain the …

Recycled Printer Filament, Charlotte Hyland, Troy D. Molinar

Williams Honors College, Honors Research Projects

The purpose of this research is to examine the effects of recycling PLA filament for 3D printing on its material properties. After examining these effects, PLA and carbon fiber additives were mixed with recycled PLA pellets in different ratios to attempt to regain material properties lost in the recycling process. To complete these findings, an experiment was design and executed.

The research found that tensile strength during multiple iterations of recycling remained mostly unaffected, however, the strain degraded exponentially. In the PLA additive study, high ratios of PLA additive were able to increase the strength and strain properties of the …

Retaining Thermoresponsive Poly(Vinyl Methyl Ether) To Cellulose Via (3-Aminopropyl)Triethoxylsilane Network, Grace Tolhurst

Williams Honors College, Honors Research Projects

Stimuli-responsive supports and devices that are fabricated from inexpensive materials are attractive candidates for a variety of applications, such as environmental protection, and regenerative medicine. Poly(vinyl methyl ether) (PVME), a thermoresponsive polymer (TRP), has recently been used as thermoresponsive cell culture supports for cell growth/proliferation followed with cell/cell sheet harvesting by simply switching temperature. Cellulose is an attractive candidate to replace glass/silicone supports as it is inexpensive and environmentally friendly. This project focuses on retaining PVME to the cellulose membrane via 3-aminopropyltriethoxysilane (APTES) network to generate TR membranes and flexible liners that can be incorporated into bioreactors for producing cells …

Mimicking The Namib Desert Beetle With Hydrophilic And Hydrophobic Surfaces, Tyler Bracewell

Williams Honors College, Honors Research Projects

The Namib Desert beetle, Stenocara gracilipes, condenses fog that rolls in off the west coast of Namibia to provide itself with the water it needs for the day. By lifting its abdomen into the air to collect the water vapor, it condenses on hydrophilic bumps that are about 500μm in diameter and are spaced apart about 500-1500μm. Once the water reaches a critical size, the droplet rolls off the hydrophilic bump and onto the flat hydrophobic surface of the elytra. Since the beetle is angled with its abdomen in the air, the water rolls down to its mouth. A …

Design Project: 3d Printer/Injection Molder Hybrid, Lee Paolucci, Luke Everhart, Brandon Leap, Karson Lorey

Williams Honors College, Honors Research Projects

In the realm of rapid, small-scale prototyping, there are a few main factors that drive decisions to invest resources in technology to make that prototyping possible. Cost and ease of use are two of the most influential when looking at most SMEs (Small to Medium-sized Enterprises). The U.S. Small Business Administration defines an SME as smaller than 1,250 employees. According to An Assessment of Implementation of Entry-Level 3D Printers from the Perspective of Small Businesses, 59% of small manufacturers had implemented 3D printers as of 2014. However, no matter what technology is used in rapid prototyping, there are common …

Development Of Co2 Capture Method Via Polyurethane-Amine Sorbent In Vsa, Samantha Starkey, David S. Rinehart

Williams Honors College, Honors Research Projects

With increases in extreme weather and global temperatures, research is delving into CO₂ capture to help reverse climate change. This project explored utilizing vacuum swing adsorption (VSA) for CO₂ capture and release. VSA uses a sorbent, in this case amine sorbents, to capture CO­­₂ from air and subsequently removes it via vacuum. Polyurethane (PU) foam was investigated as a potential matrix for amine sorbents to increase exposure of CO₂ capturing amines to air by utilizing its porous structure. PU mixing studies were conducted to determine the feasibility of mixing PU foam with amines and coating foams …

Development Of Soluble Bioactive Poly(Beta Amino Esters) (Pβaes) For Post-Synthesis Processing, Kelley Wiegman

Theses and Dissertations--Chemical and Materials Engineering

Polymers have proven to be a viable platform to facilitate the controlled and targeted release for a variety of therapeutic agents. Polymeric prodrugs are a growing area of drug delivery in which active pharmaceutical ingredients are covalently linked to a polymeric form in an effort to enhance stability, delivery, and pharmacology. One naturally occurring class of active ingredients, known as polyphenols, can potentially offer a vast array of beneficial therapeutic properties. However, the therapeutic efficacy of these compounds is severely limited due to poor solubility and bioavailability as well as an oxidative and thermal instability. To improve the efficacy of …

Nano-, Encapsulated Manganese Oxide (Nemo) Particles For Mri Enhancement In Microfluidic Tumor Models, Kasey Alexis Freshwater

Graduate Theses, Dissertations, and Problem Reports (ETD)

Breast cancer is among the deadliest cancers in women, with approximately 2.3 million new cases and 685,000 deaths reported globally in 2020 alone. Magnetic Resonance Imaging (MRI) is commonly used to diagnose, stage, and develop treatment plans for patients predisposed to breast cancer. However, current MRI-based screening of breast cancer has high false-positive rates up to 25%, leading to unnecessary invasive follow-up screening and testing. The gold-standard intravenous gadolinium (Gd)-based contrast agents (GBCAs) account for false-positive rates because they are always “ON”, providing a constant MRI signal that highlights both benign and malignant tumors. The work detailed in this thesis …

The Study Of Oxygenated Compounds For Oil Fingerprinting Application, Khairunisa Betariani

Chulalongkorn University Theses and Dissertations (Chula ETD)

Oil spills have a large impact on the marine and coastal environments. The characterization of petroleum or its products spilled in the environment to its source rocks is an important tool to assist in the resolution of issues of environmental impact and legal responsibility. The composition and physical properties of spilled oils have changed during the weathering process. Petroleum biomarkers is a tool for defining the origin of each oil, which is unique for each type of oil. In general, petroleum biomarkers (i.e., hopane group) are widely used for oil fingerprinting by following the NORDTEST methodology. Besides the hopane group, …

Therapeutic Injectable Iron-Chelating Hydrogels, Debbie Campbell-Rance

Theses and Dissertations

ABSTRACT

Therapeutic Injectable Iron-Chelating Hydrogels for Improved Central Nervous System Regeneration

By

Debbie S. Campbell-Rance

A dissertation submitted in partial fulfillment of the requirements of the degree of Doctor of Philosophy at Virginia Commonwealth University 2021.

Director: Xuejun Wen, M.D., Ph.D., AIMBE Fellow, Alice T. and William H. Goodwin Jr. Endowed Chair Professor in Regenerative Medicine, Institute for Engineering and Medicine, Department of Chemical and Life Science Engineering

Severe traumatic brain and spinal cord injuries are major global public health and socioeconomic problems in terms of mortality and morbidity. Currently there are two main lines of treatment under development for …

Molecular Modeling Of High-Performance Thermoset Polymer Matrix Composites For Aerospace Applications, Prathamesh P. Deshpande

Dissertations, Master's Theses and Master's Reports

The global efforts from major space agencies to transport humans to Mars will require a novel lightweight and ultra-high strength material for the spacecraft structure. Three decades of research with the carbon nanotubes (CNTs) have proved that the material can be an ideal candidate for the composite reinforcement if certain shortcomings are overcome. Also, the rapid development of the polymer resin industry has introduced a wide range of high-performance resins that show high compatibility with the graphitic surface of the CNTs. This research explores the computational design of these materials and evaluates their efficacy as the next generation of aerospace …

Recovering And Upgrading Kraft Lignin For Application In Flexible Polyurethane Foam, Peng Quan

Dissertations, Master's Theses and Master's Reports

Lignin is the second abundant natural polymer and has been highlighted as a potential substitute for fossil-based raw materials. However, the inherent molecular heterogeneity and the complex recovery processes result in the challenge of controlling the molecular properties and value-added applications of lignin in large scale. To address those issues, a novel acid-liquefaction process was developed in this study to recover Kraft lignin with improved molecular homogeneity directly from black liquor.

In the first study, the liquefaction parameters were screened based on yield and molecular weight properties of the recovered lignin. Then, the recovered lignin samples were used to replace …