Polymer Science Commons^™

Development Of Glutathione-Responsive Disulfide-Containing Poly(Beta-Amino Esters) With Varied Hydrophilicity And Acrylate Functionality, Anastasiia Aronova

Theses and Dissertations--Chemical and Materials Engineering

Smart biomaterials are becoming promising for therapeutic deliveries due to their ability to respond to changes in the environment. Redox-responsive hydrogels are a promising type of smart polymer that can swell and degrade according to cellular oxidative stress levels. Glutathione, abundant in cells, is crucial in redox-responsive biomaterials, serving as a key reactive molecule. This study explored the degradation kinetics of glutathione-responsive poly(β-amino ester) (PBAE) polymers created through a single-step Michael addition. We examined how disulfide content influences the degradation kinetics of these PBAE networks. Additionally, we investigated how the hydrophilicity and functionality of acrylate affect the degradation of disulfide-containing …

Sustained Release Systems For Endometrial Cancer, Claire E. Rowlands

Theses and Dissertations--Chemical and Materials Engineering

Endometrial cancer (EC) is the sixth most common cancer in women worldwide and is the most common cancer of female reproductive organs. From 2007-2016 there has been a global rise in incidence of EC of 1.3 %. Typically, EC is treated with surgery, but at later stages surgery is less effective requiring chemotherapy and/or radiation therapy. These treatment options are less effective than surgery and there are very few FDA approved chemotherapies for EC. The minuscule number of effective treatment options as well as an increase in incidence shows the need for creating improved treatments for EC. There has been …

Novel Membrane Materials For Nutrient Recovery From Nutrient-Rich Resources, Km Prottoy Shariar Piash

Graduate Theses, Dissertations, and Problem Reports (ETD)

Global demand for fertilizer production is expanding substantially to meet the food demand of an increasing world population. Anaerobic digestate (AD) of various centralized wastewater facilities contains substantial amounts of ammonium (NH₄⁺) (300-800 mg/L), potassium (K⁺) (13-120 mg/L), and phosphorus (P) (30-100 mg/L)- based nutrients. In addition to reducing energy costs and CO₂ emissions compared to conventional fertilizing raw material manufacturing, recovering nutrients from these waste streams could help mitigate problems such as eutrophication, which otherwise incurs billions of dollars losses to US economy annually. Apart from nutrients, wastewater streams also contain organic pollutants …

Polylactic Acid (Pla) Containing Talc Microparticles And Amorphous Polyhydroxyalkanoates (Aphas) For Improved Barrier And Mechanical Properties In Food Packaging, Mohammed Alfaifi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Polylactic acid (PLA) is a biobased and compostable polymer that is increasingly being used as an alternative to petroleum-based, non-biodegradable polymers for single-use food packaging due to its environmental benefits. It is also commercially available in large quantities, and it can be processed like polyethylene. However, it has a higher water-vapor permeability (WVP) as compared to polyolefins and polyethylene terephthalate that are the incumbent materials. This results in a competitive disadvantage in employing PLA for packaging baked goods since the shelf life of the food is likely to be reduced. In the past, barrier properties of PLA were improved by …

Robust Gasification Trial Results For A Variety Of Difficult-To-Recycle Packaging-Related Materials, Bruce A. Welt

Journal of Applied Packaging Research

Currently, recycling requires nearly absolute sorting of materials to accommodate the limited capabilities of existing recycling infrastructure. Whether a material is “recyclable” depends more on the method of recycling than the material itself. Our dependence upon sorting has limited success of recycling and has stifled our ability to achieve circular economy sustainability with plastic packaging materials. Our dependence upon sorting is rooted in our material-specific recycling processes. However, newer robust recycling processes are commercially available that reduce or eliminate the need to sort waste, and can convert mixed waste into primary feedstock chemicals, such as methanol for subsequent manufacture of …

Using Afm-Ir To Study Nanoscopic Phase Behavior Of Polymer Blends And Photovoltaic Bulk Heterojunctions, Nathaniel L. Prine

Dissertations

Conjugated polymers (CPs) and polymer blends harbor the potential for high-performance organic solar cells (OSCs) due to their short energy payback time, low cost, solution processability, lightweight attributes, and flexibility. However, OSCs suffer from poor thermal stability compared to their inorganic equivalents. This study explores the thermal instability of OSCs, focusing on phase separation of the photoactive layer under heat, resulting in morphology changes and degradation of power conversion efficiency (PCE). Utilizing atomic-force microscopy coupled with infrared spectroscopy (AFM-IR) and differential scanning calorimetry (DSC), we delve into thermal stability-morphology relationships to devise strategies to improve OSC blend durability under thermal …

Amine-Functionalized Lignin-Based Ionomer Nanocomposites For Redox Flow Batteries, Joshua Wilder

All Theses

As the development of energy storage technologies for renewable energy sources continues to garner attention, vanadium redox flow batteries (VRFBs) have emerged as promising source for grid-scale energy storage. A major component of the VRFB is the ion exchange membrane (IEM), as it serves to physically separate the two liquid electrolytes and also directly impacts the battery’s capacity, efficiency, and cost. The current industry standard IEM, Nafion™, not only accounts for a large portion of the cost of the VRFB but also suffers from poor proton selectivity. Herein, we have synthesized sulfonated poly(ether ether ketone) (SPEEK) composite membranes containing amine …

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 …

Development Of Lignin-Based Copolymers And Polymer Blends, David Chem

Graduate Theses and Dissertations

Increasing industrial interest in reducing fossil fuels in virgin polymer production and incorporating bio-based polymeric materials has led researchers to explore the potential of utilizing plant-based polymers such as lignin. Chapter 1 of this thesis presents a comprehensive overview of copolymerization and blending techniques for lignin and synthetic polymers, emphasizing different types of modifications and copolymerization techniques as well as key parameters such as temperature, reaction time, pH level, and solution compositions. These valorization methods are directed towards the development of high-value lignin-based materials with properties well-suited for various commercial applications. Chapter 2 offers a fundamental exploration into the amination …

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. …

Influence Of Metal-Coordinating Comonomers On The Coordination Structure And Binding In Magnetic Poly(Ionic Liquid)S, Kayla Foley, Lucas Condes, Keisha B. Walters

Chemical Engineering Faculty Publications and Presentations

A poly(ionic liquid) (PIL), poly(acrylamide-co-diallyl dimethylammonium chloride), was systematically complexed with Co²⁺, Fe³⁺, and Co²⁺/Fe³⁺ (mixed) at different molar equivalencies to form a series of magnetic PILs (MPILs). These novel MPILs were utilized to examine molecular structure and binding between the polymer and metal species using comprehensive spectroscopic studies in both dry and liquid states. FTIR, X-ray photoelectron, UV-vis, and Raman spectroscopies showed evidence of metal coordination of both the iron and cobalt chloride species with the acrylamide comonomer. Using AC susceptibility measurements, the MPILs were found to have magnetic properties …

Engineering Of Functionalized Carbon Nano-Onions Embedded Bsa Nanocomposite Fibers For Stimuli-Responsive Drug Release, Ramiro Manuel Velasco Delgadillo, Narsimha Mamidi

Research Symposium

Background: Advanced drug delivery systems (DDSs) have received enormous attention in biomedical applications due to their pharmacodynamic and pharmacokinetic drug properties. For the present study, poly 4-hydroxyphenyl methacrylate (PHPMA)/CNOs (f-CNOs) inserted bovine serum albumin (BSA) nanofibers were prepared for stimuli-responsive release of Doxorubicin (DOX). Temperature and pH would be altered to study the release of DOX in acidic microenvironments.

Methods: PHPMA were coupled with COOH-CNOs via ester coupling via the sonochemical method to produce PHPMA-CNOs (f-CNOs). Then, f-CNOs/DOX embedded BSA nanofibers were prepared at room temperature using Forcespinning. UV spectra of DOX-loaded nanofibers were studied to investigate the …

Solution And Film Self-Assembly Behavior Of A Block Copolymer Composed Of A Poly(Ionic Liquid) And A Stimuli-Responsive Weak Polyelectrolyte, Kayla Foley, Keisha B. Walters

Chemical Engineering Faculty Publications and Presentations

Cu(0)-mediated atom transfer radical polymerization was used to synthesize a poly(ionic liquid), poly[4-vinylbenzyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide] (PVBBImTf₂N), a stimuli-responsive polyelectrolyte, poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA), and a novel block copolymer formed from these two polymers. The synthesis of the block copolymer, poly[2-(dimethylamino) ethyl methacrylate]-block-[poly(4-vinylbenzyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide] (PDMAEMA-b-PVBBImTf₂N), was examined to evaluate the control of “livingness” polymerization, as indicated by molecular weight, characterizations of degree of polymerization, and ¹HNMR spectroscopy. 2D DOSY NMR measurements revealed the successful formation of block copolymer and the connection between the two polymer blocks. PDMAEMA-b-PVBBImTf₂N was further characterized …

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 …

Retracted: Fabrication And Characterization Of Wood Fiber Reinforced Polymer Composites, Firoz Ahmed, Omar Faroque, Saif Hasan, Khan Rajib Hossain, Rezaul Karim Sheikh

Al-Bahir

Wood-polymer composites (WPCs) combine the properties of wood and polymers. Creating composites involves adding plant or wood fibers as fillers to a polymer matrix. This study used mahogany and mango wood sawdust as reinforcement materials, while high-density polyethylene (HDPE) and polyvinyl chloride (PVC) were used as matrices. The investigated data in this study comprises four different (10, 20, 30, and 40) weight percentages (wt%) of mahogany and mango sawdust paired with corresponding wt% (90, 80, 70, and60) of HDPE and PVC matrices. The extrusion method produced composites with different amounts of sawdust and polymer matrices. Wood polymer composites were characterized …

Elucidating Self-Assembly Of Semiconducting Polymers In The Presence Of A Low Molecular Weight Gelator, Madhubhashini Lakdusinghe

Theses and Dissertations

Semiconducting polymers with a conjugated backbone are important for energy storage, conversion, and biomedical field applications. The self-assembly process of these polymers in solutions depends on the polymer concentration and quality of the solvent. The electrical properties of thin films obtained from the solution phase depend on the self-assembled process. Thin films of conjugated polymer gels with percolating networks of self-assembled structures display improved electrical conductivities. In this dissertation, we studied the impact of the secondary gel matrix formed by a low molecular weight gelator, on the self-assembly of conjugated polymers, the preservation of assembled structures in dried gel films …

The Cosolvent And Association Effect On Polymer Behaviors, Xiangyu Zhang

Theses and Dissertations

The blending or mixing is extensively utilized in diverse processes of polymers to bring about advantageous properties, but the behavior becomes intriguing when associations are involved and multi-solvents are used. Explanations based on chemistry-specific arguments are less than satisfactory in abstracting essential features, and lack the general applicability across various systems. So, this work focuses on capturing the physical force governing the phenomenon of interest by using a generic model. Highly non-trivial behaviors of polymers are often observed in multi-solvent solutions. It is known that polymers swell and dissolve in good solvents, while they tend to collapse and aggregate in …

Designing Bioinspired Materials With Tunable Structures And Properties From Natural And Synthetic Polymers, Anandavalli Varadarajan

Theses and Dissertations

Biological systems are composed of complex materials which are responsible for performing various functions, such as providing structural support, mobility, functional adaptation to the environment, damage repair, and self-healing. These complex materials display excellent mechanical properties and can rapidly adapt to external stimuli. Thus, nature inspires in terms of source materials, functions, and designs to develop new-generation structural and functional materials. Polymers (natural or synthetic) are excellent sources of developing materials to mimic the functions of soft segments in biological systems. This dissertation focuses on synthesizing and characterizing two different materials with tunable structures and properties: complexes from natural polysaccharides …

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, 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 …