Thermally Rearranging Polyimide Networks For High-Temperature Applications,
2023
The University of Southern Mississippi
Thermally Rearranging Polyimide Networks For High-Temperature Applications, William Guzman
Dissertations
High-performance polymers can retain functional properties when exposed to long-term or short-term durations of harsh conditions, such as mechanical action, at elevated temperatures (>177 °C). A mixture of intramolecular and intermolecular forces of and between polymer chains provide excellent property retention at elevated temperatures. Specifically, the highly aromatic nature of high-performance polymer backbones provides outstanding thermal stability, which is typically attributed to π-π stacking. However, the interrelationship between thermal stability and high aromaticity creates a challenging structure-processing relationship paradigm, which causes poor polymer processability in most high-performance polymers. Herein, it was demonstrated that rationally designing a crosslinking phenylethynyl imide …
Fabrication Of Alumina Membranes From Uv Resin– Alumina Particle Slurries,
2023
California Polytechnic State University, San Luis Obispo
Fabrication Of Alumina Membranes From Uv Resin– Alumina Particle Slurries, Dominique Henry Porcincula
Master's Theses
Ceramics membranes are made in a wide variety of different techniques using a wide variety of different materials. However, many of the common techniques utilize a slurry of ceramic particles, additives, and either organic solvent or water that is shaped into a membrane, left to dry, and then sintered together. Drying is a time consuming process, often requiring several hours for the liquid medium to evaporate. Defect formation caused by development of partial pressures across the drying membrane, including cracks and warpage, also typically occurs during the drying process. To address this, slurries of ceramic particles made with a low …
A Comprehensive Review On Metal Oxide-Nanocellulose Composites In Sustainable Active And Intelligent Food Packaging,
2023
Technological University Dublin
A Comprehensive Review On Metal Oxide-Nanocellulose Composites In Sustainable Active And Intelligent Food Packaging, Kalpani Y. Perera, Amit Jaiswal, Swarma Jaiswal, Dileswar Pradhan
Articles
The aim of this article is to provide an overview of the potential advantages and drawbacks of nanocellulose and metal oxide-based composites in food packaging. These materials offer improved mechanical and barrier properties, as well as antioxidant and antimicrobial benefits that extend the shelf life of food products. Nanocomposite structures protect food from various physiological factors and immobilize enzymes, while metal oxide nanoparticles provide antibacterial effects against Gram-positive and Gram-negative bacteria. However, there are concerns regarding the safety of nanoparticles and their potential migration into packaged food during processing and storage. This article explores these issues and highlights the need …
Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory,
2023
Clemson University
Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams
All Dissertations
While Carbon Fiber Reinforced Polymers (CFRPs) have exceptional mechanical properties concerning their overall weight, their failure profile in demanding high-stress environments raises reliability concerns in structural applications. Two crucial limiting factors in CFRP reliability are low-strain material degradation and low fracture toughness. Due to CFRP’s low strain degradation characteristics, a wide variety of interlaminar damage can be sustained without any appreciable change to the physical structure itself. This damage suffered by the energy transfer from high- stress levels appears in the form of microporosity, crazes, microcracks, and delamination in the matrix material before any severe laminate damage is observed. This …
Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts,
2023
Florida Institute of Technology
Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav
Theses and Dissertations
Recent advances in additive manufacturing technologies have already led to wide-scale adoption of 3D-printed parts in various industries. The expansion in choice of materials that can be processed, particularly using Fused Deposition Modeling (FDM), and the steady advancements in dimensional accuracy control have extended the range of applications far beyond rapid prototyping. However, additive manufacturing still has considerable limitations compared to traditional and subtractive manufacturing processes. This work addresses limitations associated with the as-deposited surface roughness of 3D-printed parts. The effects of roughness-induced stress concentrations were studied on ultimate tensile strength and fatigue life. The samples were manufactured using a …
Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla),
2023
University of Nebraska-Lincoln
Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …
Cellulose Materials For Drug Delivery Applications,
2023
University of Texas at Tyler
Cellulose Materials For Drug Delivery Applications, Reham Mohamed
Mechanical Engineering Theses
Non-healing wounds are a growing global public health concern due to inadequate or ineffective therapeutic products available. Cellulose-based biopolymers are attractive wound dressing materials due to their biocompatibility, biodegradability, non-toxicity, and cost-effectiveness. This study aims to design and fabricate solid dosage formulations using carboxymethyl cellulose (CMC) and ethyl cellulose (EC) to facilitate multi-stage releases of phenytoin (PHT) and tetracycline hydrochloride (TCH) from plain carriers, fibers/films composites, and layer-by-layer fiber composites. Results from in vitro drug release assays demonstrated a time-dependent release up to 8 hours from PHT-loaded EC fibers, while TCH-loaded CMC films exhibited a rapid release within 5 minutes. …
Interfacial Thermomechanical Behavior Of Hybrid Carbon Fibers,
2023
Embry-Riddle Aeronautical University
Interfacial Thermomechanical Behavior Of Hybrid Carbon Fibers, Sriraj Srihari
Doctoral Dissertations and Master's Theses
The carbon fiber/epoxy interface is of great importance in composite design due to its load transfer mechanisms from the weak epoxy to the stronger fiber. Improving the strength of the interface reduces the risk of failure at the interface and improves the load transfer to the fiber. In this study, two types of nano-species ZnO nanowires and nickel-based metal organic frameworks were grown on carbon fibers to improve the interfaces. The interfacial mechanics of the enhanced fibers are evaluated using nanoindentation studies. Composite samples with Aeropoxy matrix and vertically aligned fibers are fabricated for this purpose. A Bruker TI-980 TriboIndenter …
Synergistic Effect Of Nanoclay And Barium Sulfate Fillers On The Corrosion Resistance Of Polyester Powder Coatings,
2023
Western University
Synergistic Effect Of Nanoclay And Barium Sulfate Fillers On The Corrosion Resistance Of Polyester Powder Coatings, Jinbao Huang, Marshall Shuai Yang, Chengqian Xian, James Joseph Noel, Yolanda S. Hedberg, Jian Chen, Ubong Eduok, Ivan Barker, Jeffrey Daniel Henderson, Haiping Zhang, Liqin Wang, Hui Zhang, Jesse Zhu
Chemistry Publications
No abstract provided.
Investigating The Rheological Behavior Of A Simple Yield Stress Fluid Under Shear Flows,
2023
New Jersey Institute of Technology
Investigating The Rheological Behavior Of A Simple Yield Stress Fluid Under Shear Flows, Francesco Accetta
Theses
Many soft materials display unique and complex rheological behavior characterized by a transition from a solid-like to a fluid-like state upon the application of a force that exceeds the threshold to flow, known as the yield stress. Yield stress fluids are found in a wide range of commonly encountered materials including microgels, emulsions, and foams, and have been widely studied by rheologists over the last several decades. Carbopol is a popular polymeric microgel system as it displays simple, non-thixotropic rheological behavior and is typically seen as an ideal yield stress fluid. Previous research has demonstrated the reproducible behavior of shear …
Glass Bubbles Grafted With Polymer Brushes For Liquid Hydrocarbon Fire Extinguishment,
2023
Clemson University
Glass Bubbles Grafted With Polymer Brushes For Liquid Hydrocarbon Fire Extinguishment, Randall Snipes
All Dissertations
The current most efficient solution to fighting liquid pool fires involves the use of firefighting foams containing fluorinated surfactants. The physiochemical properties of these foams are considerably different to all other currently available firefighting foams. Fluorinated surfactants lower the surface tension to a point where the foam solution draining from the foam structure forms a continuous aqueous film on the surface of a volatile hydrocarbon fuel, adding an additional barrier to fuel vapor diffusion to the burning fire. For this reason, these foams qualify as aqueous film forming foams (AFFFs). However, fluorinated compounds are extremely harmful for the environment due …
Life Cycle Energy Assesment Of Advanced Fiber Reinforced Composite Design And Manufacturing Methodologies,
2023
Clemson University
Life Cycle Energy Assesment Of Advanced Fiber Reinforced Composite Design And Manufacturing Methodologies, Urjit Lad
All Theses
Automotive industry at large is focused on vehicle light-weighting since a 6%-8% increase in fuel efficiency can be achieved with a 10% reduction in vehicle weight [1]. With the growing demand for cost-effective and sustainable light weighting of automobile structures, interest has increased in the application of fiber reinforced plastic (FRP) composites for use in the Body-in-White (BiW), which can account for up to 40% of the total vehicle weight. Traditional FRP composite manufacturing processes like vacuum assisted resin transfer molding, autoclave consolidation or use of automated fiber placement have been successfully used for marine and aerospace applications. However, these …
Double Cantilever Beam Mode-I Testing Validation In Large-Scale Additive Manufacturing Carbon Composite,
2023
University of Texas at El Paso
Double Cantilever Beam Mode-I Testing Validation In Large-Scale Additive Manufacturing Carbon Composite, Luis Alfonso Camacho
Open Access Theses & Dissertations
Testing for mechanical properties for additive manufacturing has been based on already existing standards for traditional manufacturing methods. For composites in large scale additive manufacturing there is a research gap in bond strength and fracture toughness for a single layer interface. By using Double cantilever beam Mode I, this thesis manuscript validates testing parameters and protocols to describe the intricacies of ABS matrix 20 wt.% carbon filled composite, specifically on the layer-to-layer interface. Studies suggest that fracture toughness is sensitive to process parameters, like deflection speed and sharpened crack tip at the layer interface of BAAM 3D printed part and …
Characterization Of Mechanically Recycled Polylactic Acid (Pla) Filament For 3d-Printing By Evaluating Mechanical, Thermal, And Chemical Properties And Process Performance,
2023
Clemson University
Characterization Of Mechanically Recycled Polylactic Acid (Pla) Filament For 3d-Printing By Evaluating Mechanical, Thermal, And Chemical Properties And Process Performance, Mahsa Shabani Samghabady
All Theses
Polylactic acid (PLA) is a biopolymer made from renewable resources such as sugar and corn. PLA filament is a popular material used in Fused Deposition Modeling (FDM) 3D-printing. While this material has many advantages, all the failed parts, support structures, rafts, nozzle tests, and the many prototype iterations during the 3D-printing process contribute to the plastic pollution and release of greenhouse gases. Although PLA is biodegradable, it can take years to degrade in landfills. Instead of throwing away PLA waste and buying new filaments, PLA can be recycled. Amongst the different recycling technologies, mechanical recycling is the most environmentally friendly. …
Carbon Fibers From Athabasca Oil-Sand Asphaltenes,
2023
Clemson University
Carbon Fibers From Athabasca Oil-Sand Asphaltenes, Blake Reardon
All Theses
Carbon fibers possess ultra-high specific strength and modulus. Therefore, the material is popular in aerospace, automotive, and sports industries. Approximately 95% of all carbon fibers are spun from a high-cost precursor, polyacrylonitrile (PAN). There is a need for a cheaper grade of carbon fiber for low-cost applications because about half of carbon fiber cost is associated with precursor cost. A promising alternative to the high-cost PAN precursor is petroleum-based asphaltene. Asphaltenes are highly aromatic and have a high carbon content but lack the purity of the PAN precursor. Processes like the molten- sodium desulfurization upgrading have been used to harvest …
Molybdenum Disulfide (Mos₂) As A Nanocellulose Substrate,
2023
University of Northern Iowa
Molybdenum Disulfide (Mos₂) As A Nanocellulose Substrate, Mariana Torres, Dylan Seiffert, Elise Hong-Miller, T. E. Kidd
Summer Undergraduate Research Program (SURP) Symposium
Cellulose is a substance abundant in nature, found in fruits and vegetables, plant cell walls (National Center for Biotechnology Information, 2023), and wood (Sjostrom, 1993). The abundance of cellulose is attributable to its linear chemical structure, as it is composed of long strands of glucose molecules linked together by hydrogen atoms, which enable the substance to withstand significant pressure without breaking (Rongpipi et al., 2019). This property—known as high tensile strength—is joined by its non-toxicity and sustainability, given cellulose may be degraded and renewed naturally (Kaur, 2021). These various properties indicate versatility, and its resultant current and desired uses—such as …
Flow Through Processing Of Nanocellulose For Space Exploration Applications,
2023
University of Northern Iowa
Flow Through Processing Of Nanocellulose For Space Exploration Applications, Dylan Seiffert, T. E. Kidd
Summer Undergraduate Research Program (SURP) Symposium
Nanocellulose is synthesized from cellulose, which is the most abundant organic molecule found in nature. Nanocellulose solids are biodegradable and have a strength-to-weight ratio eight times that of steel1. The production of nanocellulose solids is challenging due to the large volume loss that occurs during the curing process as well as the time and cost associated with ultrasonic processing. The loss of volume during curing often results in cracking and deformation of the cured solid. The issues caused by the large volume loss can be mitigated using additives that do not compromise the strength, shape, or machineability of …
Impacts And Applications Of Vegetable Glycerin On Nanocellulose,
2023
University of Northern Iowa
Impacts And Applications Of Vegetable Glycerin On Nanocellulose, Elise Hong-Miller, Dylan Seiffert, T. E. Kidd
Summer Undergraduate Research Program (SURP) Symposium
Nanocellulose is created by breaking down cellulose, the most common organic molecule found in nature. Nanocellulose has attractive properties, such as a very high strength-to-weight ratio, for many different applications. A major challenge is that nanocellulose has a very high shrinkage % (~90%) when it is dried, as well as a strong probability to crack. Different additives can be added in varying amounts to either mitigate or intensify these aspects, as well as affect its drying conditions. This investigation is helping the National Aeronautics and Space Administration (NASA) and the U.S. Army to find a use for this highly renewable …
Measurement Of Thermal Conductivity Of Epoxy Resin Reinforced With Different Weight Ratios Of Glass And Carbon Powders,
2023
Dpt. of physics, College of Science, University of Mosul, Mosul, Iraq.
Measurement Of Thermal Conductivity Of Epoxy Resin Reinforced With Different Weight Ratios Of Glass And Carbon Powders, Edrees Edaan Ghadeer
Al-Bahir
The effect of thermal conductivity was studied on the composites prepared before and after reinforcement with different weight fractions (10, 20, 30, 40, 50, 60 wt %), using a Disc Lee's device, and the dispersion of the filler was studied by morphological analysis of the complexes using scanning electron microscopy (SEM). The (SEM) of glass composite powders, showed a smooth surface with a chance of forming very few voids, clusters and blisters on the surface of the sample, which increased with the increase of the weight fractions of the filled powder. While the composites filled with carbon powders show smooth …
Biopolymer-Based Sustainable Food Packaging Materials: Challenges, Solutions, And Applications,
2023
Technological University Dublin
Biopolymer-Based Sustainable Food Packaging Materials: Challenges, Solutions, And Applications, Kalpani Y. Perera, Amit Jaiswal, Swarna Jaiswal
Articles
Biopolymer-based packaging materials have become of greater interest to the world due to their biodegradability, renewability, and biocompatibility. In recent years, numerous biopolymers—such as starch, chitosan, carrageenan, polylactic acid, etc.—have been investigated for their potential application in food packaging. Reinforcement agents such as nanofillers and active agents improve the properties of the biopolymers, making them suitable for active and intelligent packaging. Some of the packaging materials, e.g., cellulose, starch, polylactic acid, and polybutylene adipate terephthalate, are currently used in the packaging industry. The trend of using biopolymers in the packaging industry has increased immensely; therefore, many legislations have been approved …
